Open Collections

UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Geochemistry and mineralogy of sediments from southeast Explorer Rift (50 N, 130 W), northeast Pacific… Hansen, Kenneth Frederick 1983

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1984_A6_7 H35.pdf [ 19.72MB ]
Metadata
JSON: 831-1.0052436.json
JSON-LD: 831-1.0052436-ld.json
RDF/XML (Pretty): 831-1.0052436-rdf.xml
RDF/JSON: 831-1.0052436-rdf.json
Turtle: 831-1.0052436-turtle.txt
N-Triples: 831-1.0052436-rdf-ntriples.txt
Original Record: 831-1.0052436-source.json
Full Text
831-1.0052436-fulltext.txt
Citation
831-1.0052436.ris

Full Text

GEOCHEMISTRY AND MINERALOGY OF SEDIMENTS FROM SOUTHEAST EXPLORER RIFT (50°N; 130°W), NORTHEAST PACIFIC: IN SEARCH OF EVIDENCE OF HYDROTHERMAL ACTIVITY by KENNETH FREDERICK HANSEN B . S c , The University of Alberta, 1978 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE In THE FACULTY OF GRADUATE STUDIES (Department of Geological Sciences) We accept th is thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA April 1984 (c) Kenneth Frederick Hansen, 1983 In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t of the requirements f o r an advanced degree at the U n i v e r s i t y o f B r i t i s h Columbia, I agree t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and study. I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e copying of t h i s t h e s i s f o r s c h o l a r l y purposes may be granted by the head o f my department o r by h i s or her r e p r e s e n t a t i v e s . I t i s understood t h a t copying or p u b l i c a t i o n of t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be a llowed without my w r i t t e n p e r m i s s i o n . Department of (~n*o /ocf'c^l ^C/g/\ces The U n i v e r s i t y of B r i t i s h Columbia 2075 Wesbrook P l a c e Vancouver, Canada V6T 1W5 Date D F - f i ( 2 / 7 ° ^ ABSTRACT The composition of sediments In a portion of Explorer Spreading Centre, Explorer Deep, Is examined. Clay mineral, bulk mineral and chemical compositions (Al , Ba, Ca, CI, Co, Cu, Fe, K, Mg, Mn, Nl , P, S i , Na, T l , Zn) of hemlpelaglc sediments on the floor of Explorer Deep are compared to those on adjacent f lanks, and to Explorer Deep metalliferous sediment, to determine the extent of hydrothermal mineral formation. Explorer Deep hemlpelaglc sediments are composed of quartz, opal , feldspar, amphlbole, carbonate, phyl losl I Icates, Iron and manganese hydroxides, Ilmenlte, ru t l l e and hematite. Individual phyllost IIcates have dist inct s lze -dfst r lbut lons ; f ine clay (<0.2 urn) Is composed almost entirely of smectite. In contrast, II l i te and ch lor i te are most abundant In coarser clay and s i l t . Three types of smectite are present: very f ine grained smectite, l ikely detr l ta l montmor11 IonIte; smectite In mixed-layer c lays ; and authigenlc nontronlte. Smectite Is more abundant In sediments from the floor of Explorer Deep than In flank sediments. The chemical composition of Explorer Deep hemlpelaglc sediments Is between that of "average shale" and average "Pac i f i c pelagic c lay" . Sediments from the f loor are A l - and P-poor but have higher Ba, N l , Zn, and non-terrigenous Fe and S! contents than sediments from the f lanks. Detr l tal a I urnInos11icates are the principal source of A l , suggesting an abundance of detr l tal minerals In sediments from the f lanks. The d i s t -ribution of Ca ref lects dissolution of carbonate with Increased water depth. Ba, Fe, Nl , SI and Zn are associated with smectite In an AI - , Ca- and P-poor phase that Is present In sediments from the f loor . 1 I The tectonic setting In Explorer Deep Is suitable for c i rcu lat ion of hydrothermal solutions, and recovery of a metall iferous crust Indicates that formation of mounds of hydrothermal minerals has occurred loca l l y . Differences In mineral and chemical composition of sediments from the floor of Explorer Deep and those away from the Influence of hydrothermal ac t i v i t y , on the f lanks, can be explained by the presence of hydrothermal minerals In sediments on the f loor . Slow percolation of hydrothermal solutions through sediments on the f loor results In In s i tu formation of authlgenlc Iron oxides and nontronlte similar to those In the metalliferous crust . The presence of a hydrothermal component In sediments from the f loor of Explorer Deep Is obscured by dlagenetlc processes which modify element and mineral d ist r ibut ions, and by di lut ion due to high rates of hemlpelaglc sedimentation. I I TABLE Q£_CQNT£JiIi. Page ABSTRACT 11 LIST OF TABLES vi LIST OF FIGURES v i II ACKNOWLEDGEMENTS x v i i CHAPTER ONE. INTRODUCTION 1 1.1 General background 1 1.2 Purpose of the study 2 CHAPTER TWO. TECTONICS AND REGIONAL SETTING 6 2.1 Meta l logenes i s and the hydrothermal model 6 2.2 Physiography 11 2.3 Hydrology 14 2.4 Tec ton i c se t t i ng 15 2.5 S t ruc ture of Exp lorer Deep 20 CHAPTER THREE. MINERALOGY 25 3.1 Introduct ion 25 3.2 Mineral i d e n t i f i c a t i o n 33 3.3 Crys ta l I i n i t y 36 3.4 Mineral d i s t r i b u t i o n 40 CHAPTER FOUR. CHEMISTRY 53 4.1 Introduct ion 53 4.2 Chemical composit ion of sediments from the Explorer Deep area 60 4.2.1 Major element chemistry 60 D i s t r i b u t i o n of aluminium 60 D i s t r i b u t i o n of s i l i c o n 64 D i s t r i b u t i o n of ca lc ium 71 D i s t r i b u t i o n of phosphorus 78 D i s t r i b u t i o n of t i t an ium 84 D i s t r i b u t i o n of potassium 87 D i s t r i b u t i o n of sodium 90 D i s t r i b u t i o n of magnesium 93 D i s t r i b u t i o n of i ron 97 D i s t r i b u t i o n of manganese 103 4.2.2 Minor element chemistry 109 D i s t r i b u t i o n of barium 109 D i s t r i b u t i o n of z inc and the t r a n s i t i o n metals c o b a l t , copper and n icke l 120 4.3 Chemical composit ion of Explorer Deep vo l can i c rocks 140 CHAPTER FIVE. THE HYDROTHERMAL COMPONENT IN EXPLORER DEEP SEDIMENTS 143 I v Pgge CHAPTER SIX. SUMMARY AND CONCLUSIONS 170 Recommendations for further study 176 REFERENCES 178 APPENDIX A. SAMPLE COLLECTION METHODS AND DESCRIPTION OF SAMPLES 199 A.1 Sample col lection 200 A.2 Core description 202 A. 3 Explorer Deep metalliferous sediment description 202 APPENDIX B. ANALYTICAL METHODS 217 B. 1 Mineralogy: X-ray d i f f ract ion 218 B.2 Chemical analysis: X-ray fluorescence spectrometry 222 Major elements 222 Minor elements 229 APPENDIX C. MINERALOGICAL AND CHEMICAL DATA 235 APPENDIX D. CONTINUOUS SEISMIC PROFILE DATA, WITH INTERPRETATIONS 270 v L I S T OF TABLES Page 1.1 Locat ion and depth of samples c o l l e c t e d during s c i e n t i f i c c r u i s e PGC-79-06. 3.1 Clay mineral r a t i o s and crysta11 InIty data, o r ien ted sample mounts. 37 3.2 Unorlented powder mounts, r a t i o s of areas of X-ray d i f f rac togram peaks. 50 3.3 Average d i f f rac togram peak area r a t i o s In t o t a l (untreated) samples of sediment In cores from the Explorer Deep area . Data are from Tab le 3.2. 52 4.1 Inter-element c o r r e l a t i o n c o e f f i c i e n t s (r) for sediments from the Exp lorer Deep a rea . A t o t a l of e i g h t y - s i x samples (n=86) were used (except Ba with n=85), Including a l l sur face samples p lus v e r t i c a l samples from f i v e cores (Appendix C ) . C o e f f i c i e n t s were c a l c u l a t e d using a TI—55—11 c a l c u l a t o r . A l l data are on a s a l t - f r e e ba s i s . 55 4.2 Inter-element c o r r e l a t i o n c o e f f i c i e n t s (r) for sediments from the Exp lorer Deep area . Element concentrat ions are normalized t o aluminium. A t o t a l of e l g h t y - s l x samples (n=86) were used (except Ba/AI with n=85) Including a l l sur face samples p lus v e r t i c a l samples from f i v e cores (Appendix C ) . C o e f f i c i e n t s were c a l c u l a t e d using a TI-55-II c a l c u l a t o r . A l l data are on a s a l t - f r e e bas i s . 56 4.3 C o r r e l a t i o n c o e f f i c i e n t s between element/aluminium concentrat ion r a t i o s and c l a y mineral X-ray d i f f r a c t i o n peak area r a t i o s fo r sediments from the Exp lorer Deep area. A t o t a l of fourteen sample pa i r s (n=14) were used In the c a l c u l a t i o n . C o r r e l a t i o n c o e f f i c i e n t s were c a l c u l a t e d using a T I - 5 5 - l l c a l c u l a t o r . 58 4.4 Chemical composit ion of sediments from the northeast P a c i f i c , near the Exp lorer Deep study area. 59 4.5 P a r t i t i o n i n g of s i l i c a between ter r i genous and non-ter r i genous components In sur face sediments from the Exp lorer Deep a rea . A l l data are on a s a l t f ree ba s i s . 68 4.6 P a r t i t i o n i n g of ca lc ium between ter r i genous and b iogenic components in sur face sediments from the Explorer Deep area . A l l data are on a s a l t f r e e ba s i s . 75 4.7 P a r t i t i o n e d non-terr igenous Iron and t o t a l phosphorus In su r face sediments from the Exp lorer Deep area. A l l data are on a s a l t - f r e e ba s i s , expressed as weight percent oxide equ iva len t . 81 v i Page 4.8 Elemental composit ion of vo l can i c g l a s s from the Explorer Deep p i l l ow basa l t s recovered by dredging at s t a t i on PGC-79-06-32, p lus data fo r the south Juan de Fuca Ridge and average ba sa l t . Major element concent ra t i ons are In weight percent ox ide equ iva lent ; minor element concentrat ions are in parts-per-mfI I Ion (ppm). 141 5.1 Chemical composit ion of se lec ted hydrothermal depos i ts p lus m e t a l l i f e r o u s and non-meta l l i fe rous sediments from the the northeast P a c i f i c Ocean. 144 5.2 Major element composit ion of the non-terr igenous f r a c t i o n In sediments from the Explorer Deep and Juan de Fuca Ridge areas. The terr igenous component was ca I cu la ted-us lng oxlde/alumlna r a t i o s fo r average " P a c i f i c pe lag i c c l a y " and subt rac ted, a l l CaO and NaoO was assumed to represent carbonate and i n t e r s t i t i a l - s a l t s and was subtracted. The remainder was reca l cu l a ted t o equal 100/6. 150 A. 1 Legend of symbols for s t r i p logs. 204 B. I Standards used fo r c a l I b r a t l o n In major element ana lyses , and recommended va lues . 226 B.2 Analyses of c h l o r i n e contents In Exp lo re r Deep sediments. 227 B.3 Ana l y t i c a l operat ing cond i t i ons used f o r XRF ana l y s i s of major and minor elements. 232 B. 4 ( a f te r Pedersen, 1979) X-ray f l uo rescence a n a l y t i c a l p r e c i s i o n for major and minor elements In Panama Bas in sediments. 233 C. 1 Minera log ica l data. 236 C.2 Major element compos i t ion. 240 C.3 Minor element composit ion. 260 v i i LIST OF FIGURES ENCLOSURE ONE Explorer Deep bathymetrlc map (uncorrected V g = 1500 m/s) 1:100 000. ENCLOSURE TWO Explorer Deep sediment I sot I me map (two-way traveltlme) 1:100 000. 1.1 Location map for cruise PGC-79-06, showing C.S.P. l ines, core stations and dredge stations used In th is study. Location of dredge station 69-11, which recovered metal-l iferous sediment (EDMS) (Gr i l l et a l . r 1981). Isobaths are In metres. Bathymetry compiled from 1979 data, see Enclosure 1 for detailed bathymetry map (1:100 000). 2.1 Major physiographic and tectonic features of the sea f loor off northern Vancouver Island, modified after Keen and Hyndman (1979) and Davis and Rlddlhough (1982). Sol id and double lines mark plate boundaries and spreading centres. Dashed lines follow major turbldl te sea channels. Bathymetry from Chase et a l . (1975), after Mammerlckx and Taylor (1971). Contours are In metres. 2.2 (after Currle et a I.f 1982) Magnetic anomaly map offshore Br i t ish Columbia. Explorer Deep study area enclosed within dashed l ines. IGRF removed. Contour Interval Is 100 nT. Hatched area corresponds to Paul Revere Ridge. 2.3 Explorer Deep basement structure map, with sea-f loor bathy-metry for reference. The heavy fault traces Indicate faults with large vertical displacements. The PGC-79-06 CSP data were used as control for Interpretation (Appendix D). Isobaths are In metres (see Figure 1.1). 3.1 X-ray dlffractograms of unorlented powder mounts of 10/120-124 samples: (a) total (untreated) sample; (b) 5 to 20 urn f ract ion. 3.2 DIffractograms of unorlented powder mounts of Explorer Deep metalliferous sediment (EDMS): (a) EDMS-b (oxide-rich) total sample; (b) EDMS (clay-r ich) total sample; (c) EDMS >20 urn f ract ion; (d) EDMS 5 to 20 urn fraction (see Appendix A for sample descript ion) . 3.3 DIffractograms of oriented sample mounts: A. 10/120-124, <2 urn; (a) clean glass s l i de ; (b) untreated at 20°C; (c) HCI treated at 100°C. B. 10/120-124, <0.2 urn: (a) K-sat at 20°C; (b) K-sat at 300°C; (c) K-sat at 550°C; (d) Mg-sat at 20°C; (e) Mg-sat, Gly-sol at 20°C. v I I I Page 3.4 D!ffractograms of or iented mounts: A. 10/120-124, 0.2-2 urn; B. 10/120-124, 2-5 urn. (a) K-sat at 20°C; (b) K-sat at 300°C; (c) K-sat at 550°C; (d) Mg-sat at 20°C; (e) Mg-sat, G l y - so l at 20°C. 29 3.5 DIffractograms of or iented mount EDMS, <0.2 urn: (a) K-sat at 20°C; (b) K-sat at 300°C; (c) K-sat at 550°C; (d) Mg-sat at 20°C; (e) Mg-sat, g l y - s o l at 20°C. 30 3.6 Dl f f ractograms of or iented mounts: A. EDMS, 0.2-2 urn; B. EDMS, 2-5 urn. (a) K-sat at 20°C; (b) K-sat at 300°C; (c) K-sat at 550°C; (d) Mg-sat at 20°C; (e) Mg-sat, G l y - so l v at 20°C. 31 3.7 P r o f i l e s of r a t i o s of areas of x - r a y d i f f r a c t i o n peaks f o r II l i t e t o quartz In K-saturated (20 bC) and Mg-saturated g l y c e r o l - s o l v a t e d (20°C) o r i en ted mount samples from cores 79-06-06, 79-06-08, 79-06-10, 79-06-22 and 79-06-31: (a) 0.2 t o 2 urn s i z e - f r a c t i o n ; (b) 2 t o 5 urn s i z e - f r a c t i o n . Note s ca le s vary between Indiv idual p r o f i l e s . Data are from Tab le 3.1. 43 3.8 P r o f i l e s of r a t i o s of areas of X-ray d i f f r a c t i o n peaks f o r c h l o r i t e t o quartz In K-saturated (20°C) and Mg-saturated g l y c e r o l - s o l v a t e d (20°C) o r ien ted mount samples from cores 79-06-06, 79-06-08, 79-06-10, 79-06-22 and 79-06-31: (a) 0.2 t o 2 urn s i z e - f r a c t i o n ; (b) 2 t o 5 urn s i z e - f r a c t i o n . Note s ca le s vary between Indiv idual p r o f i l e s . Data are from ; Tab le 3.1. 45 3.9 P r o f i l e s of r a t i o s of areas of X-ray d l f f rac togram peaks In Mg-saturated g l y c e r o l - s o l v a t e d o r i en ted mount samples of 0.2 t o 2 urn and 2 t o 5 urn f r a c t i o n s from cores 79-06-06, 79-06-08, 79-06-10, 79-06-22 and 79-06-31: (a) v a r i a t i o n of smect i te / I I l i t e r a t i o s ; (b) v a r i a t i o n of smect I te /ch lor I te r a t i o s ; (c) v a r i a t i o n of smect i te/quartz r a t i o s . Note s ca le s vary between Indiv idual p r o f i l e s . Data are from Tab le 3.1. 47 4.1 Histogram fo r aluminium concentra t ion In sediments from the Explorer Deep a rea . A l l data are on a s a l t - f r e e b a s i s . 61 4.2 Aluminium p r o f i l e s for cores_from Exp lorer Deep. The data are on a s a l t - f r e e bas i s . AI Is weighted average concent ra t ion aluminium. 62 4.3 Histogram for s i l i c o n concentrat ion In sediments from the Exp lorer Deep a rea . A l l data are on a s a l t - f r e e b a s i s . 65 ix Page 4.4 SIIicon/alumlnlum prof i les for cores from the Explorer Deep area. Al l data are on a s a l t - f r e e basis. SI/AI Is weighted average value for SI/AI. 66 4.5 Prof i les showing down-core distr ibut ion of the partitioned non-terrigenous s i l i c a component In cored sediments from the Explorer Deep area. A rat io of SIC>2/Al203=3.31 for average "Pac i f ic pelagic clay" (after Landergren, 1964) was used In the part i t ioning calculat ions. Al l data are on a sa l t - f ree basis. SIO2 Is weighted average value for SIC^. 69 4.6 Histogram for calcium concentration In sediments from the Explorer Deep area. A l l data are on a sa l t - f ree basis . 72 4.7 Calcium/aluminium prof i les for cores from the Explorer Deep area. Al l data are on a s a l t - f r e e basis . Ca/AI Is weighted average value for Ca/AI. Note dif ferent scale for 79-06-06. 73 4.8 Correlation between water depth and calcium to aluminium rat io In surface sediments from the Explorer Deep area. A l l data are on a sa l t - f ree basis. B e s t - f i t l ine determined by linear regression. 76 4.9 Histogram for phosphorus concentration In sediments from the Explorer Deep area. A l l data are on a sa l t - f ree basis . 79 4.10 Phosphorus/aluminium prof i les for cores from the Explorer Deep area. Al l data are on a s a l t - f r e e basis. P/AI Is weighted average value P/AI. 80 4.11 Correlation between phosphorus and non-terrigenous Iron In surface sediments from the Explorer Deep area. Non-terrigenous Iron was calculated using FeoC^/AI 0 0 3 = 0 . 4 6 4 for the terrigenous component (see Table 4.7) . AIT data are on a s a l t - f r e e basis . B e s t - f i t l ine determined by linear regression. 82 4.12 Histogram for titanium concentration In sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis . 85 4.13 Titanium/aluminium prof i les for cores from the Explorer Deep area. Al l data are on a s a l t - f r e e basis . Tt/AI Is weighted average value for the core. 86 4.14 Histogram for potassium concentration In sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis . 88 4.15 Potassium/aluminium prof i les for cores from the Explorer Deep area. Al l data are on a s a l t - f r e e basis . K/AI Is weighted average for core. Note scale change for core 79-06-31. 89 x I Page 4.16 Histogram for sodium concentration In sediments from the Explorer Deep study area. Al l data are on a s a l t - f r e e basis. 91 4.17 Sodium/aluminium prof i les for cores from the Explorer Deep area. A l l data are on a s a l t - f r e e basis . Na/AI is weighted average value for each core. 92 4.18 Histogram for magnesium concentration In sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis . 94 4.19 Magnesium/aluminium prof i les for cores from the Explorer Deep area. Al l data are on a s a l t - f r e e basis . Mg/AI=welghted average for each core. 95 4.20 Correlation between magnesium and aluminium for sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis. B e s t - f i t l ine determined by linear regression. 96 4.21 Histogram for Iron concentration In sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis . 98 4.22 Iron/aluminium prof i les for cores from the Explorer Deep area. Al l data are on a s a l t - f r e e basis . Fe/AI Is weighted average value. 99 4.23 Correlation between titanium and iron for sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis . B e s t - f i t l ine determined by linear regression. 100 4.24 Correlation between magnesium and Iron for sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis . B e s t - f i t l ine determined by linear regression. 100 4.25 Correlation between Iron and aluminium for sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis . 102 4.26 Histogram the manganese concentration In sediments from the Explorer Deep area. Al l data are on a s a l t - f r e e basis . 104 4.27 Manganese/aluminium prof i les for cores from the Explorer Deep area. Note different scales for core 79-06-08 and core 79-06-22. Al l data are on a s a l t - free basis. Mn/AI= weighted average. 105 4.28 Histogram for barium concentration in sediments from the Explorer Deep area. Al l data are on a s a l t - f r e e basis. 111 xi Page 4.29 P r o b a b i l i t y graphs of minor element concentrat ions In sediments from the Explorer Deep a rea . A l l data are on a s a l t - f r e e b a s i s . Symbols Indicate data po ints from which the smooth curves were cons t ruc ted . *87 samples analyzed f o r barium, a l l other elements had 88 samples (Appendix C ) . 112 4.30 P r o b a b i l i t y graph of barium concentra t ion fo r 87 samples of sediments from the Explorer Deep a rea , showing I n f l ec t i on po in t s (arrowheads) and ,three p a r t i t i o n e d populat ions A, B and C. O r i g i na l data po int s used t o generate the smooth curve are p l o t t e d In F igure 4.29; open c i r c l e s are c a l c u l a t e d po in t s used t o est imate p a r t i t i o n e d popu la t ion ; open t r i a n g l e s are check po ints obtained by combined p a r t i t i o n e d populat ions In the proport ion A:B:C=50:15:35. A l l data are on a s a l t - f r e e bas t s . 113 4.31 BarJum/alumlnfurn p r o f i l e s f o r cores from the Exp lorer Deep a rea . A l l data are on a s a l t - f r e e b a s i s . Ba/AI Is weighted average va lue f o r each c o r e . 114 4.32 C o r r e l a t i o n between ca lc ium and barium In sediments from the Exp lorer Deep a rea . A l l data are on a s a l t - f r e e ba s i s . Note tha t sample 22/10-11 (with Ca=12.66* and Ba=0.0636£) was omi t ted. B e s t - f i t l i n e determined by l i nea r reg re s s i on . 116 4.33 C o r r e l a t i o n between s i I Icon/a Iumlnlum and barium/aluminium In sediments from the Explorer Deep a rea . A l l data are on a s a l t -f r e e ba s i s . B e s t - f i t l i n e determined by l i near r eg re s s i on . 118 4.34 C o r r e l a t i o n between manganese and barium In sediments from the Explorer Deep area. A l l data are on a s a l t - f r e e ba s i s . L ine of maximum s lope f o r data Is Indicated. 119 4.35 Histogram for coba l t concentra t ion In sediments from the Exp lorer Deep a rea . A l l data are on a s a l t - f r e e b a s i s . 121 4.36 Coba l t /a Iumlnlum p r o f i l e s fo r cores from the Exp lorer Deep a rea . A l l data are on a s a l t - f r e e ba s i s . Co/AI Is weighted average va lue f o r each c o r e . 122 4.37 Histogram for copper concentrat ion In sediments from the Exp lorer Deep a rea . A l l data are on a s a l t - f r e e b a s i s . 124 4.38 Copper/a Iumlnlum p r o f i l e s f o r cores from the Exp lorer Deep a rea . A l l data are on a s a l t - f r e e ba s i s . Note the d i f f e r e n t sca les f o r cores 79-06-22 and 79-06-31. Cu/AI Is weighted average value fo r each c o r e . 125 4.39 Histogram fo r n i cke l concentra t ion In sediments from the Exp lorer Deep a rea . A l l data are on a s a l t - f r e e ba s i s . 126 x i i Page 4.40 P r o b a b i l i t y graph of n i cke l concentrat ion for 88 samples of sediments from the Explorer Deep area, showing I n f l e c t i o n po int (arrowhead) and two p a r t i t i o n e d populat ions A and B. Or i g ina l data po int s used t o generate the smooth curve are p l o t ted In F i gure 4.29; open c i r c l e s are c a l c u l a t e d po int s used t o est imate the p a r t i t i o n e d log-normal popu la t ion ; open t r i a n g l e s are check po ints obtained by combined p a r t i t i o n e d populat ions In the proport ion A:B=50:50. A l l data are on a s a l t - f r e e b a s i s . 127 4.41 Nickel/alumlnfurn p r o f i l e s fo r cores from the Explorer Deep a rea . A l l data are on a s a l t - f r e e ba s i s . Nl/AI Is weighted average value fo r each c o r e . 129 4.42 Histogram for z i n c concentrat ion In sediments from the Explorer Deep a rea . A l l data are on s a l t - f r e e b a s i s . 130 4.43 P r o b a b i l i t y graph of z i nc concentrat ion fo r 88 samples of sediments from the Explorer Deep area , showing I n f l e c t i o n po int (arrowhead) and two p a r t i t i o n e d populat ions A and B. Or i g i na l data po in t s used t o generate the smooth curve are p lo t ted In F i gure 4.29; open c i r c l e s are c a l c u l a t e d po int s used t o est imate p a r t i t i o n e d log-normal popu la t ion; open t r i a n g l e s are check po int s obtained by combined p a r t i t i o n e d populat ions In the proport ion A:B=50:50. A l l data are on a s a l t - f r e e b a s i s . 131 4.44 ZInc/alumlnlum p r o f i l e s f o r cores from the Explorer Deep a rea . Note the d i f f e r e n t s ca le s fo r cores 79-06-10 and 79-06-22. A l l data are on a s a l t - f r e e ba s i s . Zn/AI Is weighted average value for each co re . 132 4.45 C o r r e l a t i o n between z inc and n i cke l In sediments from the Explorer Deep a rea . A l l data are on a s a l t - f r e e b a s i s . B e s t - f i t l i n e determined by l i nea r reg res s ion . 135 4.46 C o r r e l a t i o n between n icke l and barium In sediments from the Explorer Deep a rea . A l l data are on a sa l t— f ree ba s i s . B e s t - f i t l i n e determined by l i nea r reg res s ion . 136 4.47 C o r r e l a t i o n between z inc and barium In sediments from the Exp lorer Deep a rea . A l l data are on a s a l t - f r e e ba s i s . B e s t - f i t l i n e determined by l i nea r reg res s ion . 136 4.48 C o r r e l a t i o n between st I Icon/alumlnlum and nlckel /a lumlnlum aluminium In sediments from the Explorer Deep a rea . A l l data are on a s a l t - f r e e ba s i s . B e s t - f i t l i n e determined by l i nea r reg re s s i on . 139 4.49 C o r r e l a t i o n between s i IIcon/alumlnlum and zlnc/alumlnlum In sediments from the Explorer Deep area. A l l data are on a s a l t -f r e e b a s i s . B e s t - f i t l i n e determined by l inear r e g re s s i on . 139 x i i i Page 5.1 (after Dymond et a I., 1973) Al-Fe-Mn ternary diagram relat ing Explorer Deep non-metal 11ferous surface sediments (ED) to Pac i f i c pelagic sediments, the Domes area sediments, Nazca Plate nodules, East Pac i f i c Rise metalliferous sediments, Dellwood Seamount deep-sea Iron deposit (DSM), Bauer Deep metalliferous sediments, and Explorer Deep metall iferous sediments (1=sample #5; 2=sample #4; 3=average samples #7,8,9; 4=average samples #2,6). New data from Table 4.8 and Appendix C. 145 5.2 (after Bostrom et a l . r 1972) Fe/AI versus AI/AI+Fe+Mn, demonstrating mixing relationships of non-metaI 11ferous surface sediments from the Explorer Deep area (ED), average Pac i f i c pelagic clay (PPC), the Domes area sediments, East Pac i f i c Rise average heat-flow area and high heat-flow area (metalliferous) sediments (EPR), Bauer Deep (BD), Explorer Deep metall iferous deposit (EDMS), Explorer Deep volcanic glass (Bg and Bv), and average shale (AS). Data from Table 5.1 and Appendix C. 146 5.3 (modified after Bischoff & Rosenbauer, 1977) Fe/Mn versus Cu+NI showing compositional relationship between Explorer Deep non-metal 11ferous sediments, average Pac i f ic pelagic sediment and c lay , average shale, Explorer Deep volcanic glass (Bg, Bv), average basalt , Explorer Deep metall iferous deposit (EDMS), other metall iferous sediments from East Pac i f ic Rise (EPR), Bauer Deep (BD), basal DSDP, Domes 18B, and N.E. Pac i f i c basal core #13, plus Pac i f i c ferromanganese nodules. Note new data are from (Tables 4.8 and 5 .1 ; Appendix C). 148 5.4 Fe/Mn versus Ba+Ni+Zn showing compositional relationship between: Explorer Deep non-metal IIferous sediments (weighted average values for f ive cores and average for twelve core surface samples); average shale; average 'deep-sea c l a y ' ; average ' P a c i f i c pelagic c l a y ' ; average basalt ; Bauer Deep metall iferous sediments (BDMS); Galapagos Ri f t hydrothermal mounds (GR); Explorer Deep metall iferous deposit (EDMS); Dellwood Seamount Iron deposit. Data are from Tables 4.8 and 5 .1 , and Appendix C. 155 A.I Core 79-06-01; s t r ip - log and descript ion. 205 A.2 Core 79-06-02; s t r ip - log and descr ipt ion. 206 A.3 Core 79-06-04; s t r ip - log and descript ion. 207 A.4 Core 79-06-06; s t r ip - log and descript ion. 208 A.5 Core 79-06-07; s t r ip - log and descript ion. 209 xiv Page A.6 Core 79-06-08; s t r ip - log and descr ipt ion. 210 A.7 Core 79-06-10; s t r ip - log and descript ion. 211 A.8 Core 79-06-21; s t r ip - log and descr ipt ion. 212 A.9 Core 79-06-22; s t r ip - log and descr ipt ion. 213 A.10 Core 79-06-29; s t r ip - log and descript ion. 214 A.11 Core 79-06-30; s t r ip - log and descript ion. 215 A.12 Core 79-06-31; s t r ip - log and descript ion. 216 B.I Graph showing weight-loss during heating of sediments from Explorer Deep, in muffle furnace. Each point represents 20 minutes continuous heating at the indicated stabi l ized temperature. 224 D.01 CSP line PGC 79-06-03 paral le l to the str ike of Paul Revere Ridge, Just north-east of the crest of Paul Revere Ridge. 271 D.02 CSP l ine PGC 79-06-04 across northern end Explorer Deep. Core 79-06-21 location Is projected. The poor quality of the l ine due in part to close proximity to Paul Revere Ridge. 272 D.03 CSP line PGC 79-06-05 across northern end Explorer Deep. Cores 79-06-02, 79-06-05, and 79-06-06 are located on the l ine. Note that core 79-06-05 contained no sample. 273 D.04 CSP l ine PGC 79-06-07 across north-central Explorer Deep. Locations of cores 79-06-07 and 79-06-10 are indicated. 274 D.05 CSP l ine PGC 79-06-08 across central Explorer Deep. Locations of cores 79-06-04 and 79-06-09 are Indicated. Note core 79-06-09 contained only a few rock fragments In core catcher. 275 D.06 CSP lines PGC 79-06-09 and PGC 79-06-10 across south-central Explorer Deep. Locations of cores 79-06-08, 79-06-11, 79-06-12 (projected), 79-06-31 and dredge 79-06-32 (projected) are Indicated. Note core 79-06-11 contained a core catcher sample only, and core 79-06-12 was empty. Note data are missing in a section of l ine PGC 79-06-09 due to air-gun f a i l u r e . 276 D.07 CSP lines PGC 79-06-11 and PGC 79-06-13 across south end Explorer Deep. Locations of cores 79-06-29 and 79-06-30 are Indicated. Note data are missing In a section of l ine PGC 79-06-13. 277 xv Page D.08 CSP lines PGC 79-06-15 and PGC 79-06-16 paral lel to st r ike of Explorer Deep long axis . Locations of core 79-06-29 and 79-06-30 are Indicated; dredge PZ-69-11d (source of Explorer Deep metalliferous sediment; G r i l l et a I., 1981) Is also Indicated. 278 D.09 CSP lines PGC 79-06-22 to -25 along escarpment forming the Paul Revere Ridge. Locations of cores 79-06-21 and 79-06-22 are Indicated. 279 D.10 CSP lines PGC 79-06-26 and PGC 79-06-33 sub-paral lel to st r ike of Explorer Deep long axis. Position of core station 79-06-23 indicated, although core 79-06-23 contained no sample. Note the different scales for the two l ines. 280 D.11 CSP line PGC 79-06-42 across the south end Explorer Deep, and line PGC 79-06-43 paral le l to s t r ike of Explorer Deep long axis . Note the location of core 79-06-10 Is projected. 281 xvi ACKNOWLEDGMENTS I am Indebted to a large number of Indiv iduals without whose as s i s tance and support t h i s study would not have been po s s i b l e . In p a r t i c u l a r , I would l i k e t o thank the fo l l ow ing : Captain Bowles, o f f i c e r s and crew of the CFAV ENDEAVOUR for t h e i r support during c r u i s e PGC-79-06; the s c i e n t i f i c crew for c r u i s e PGC-79-06, R.L. Chase and D.L. T i f f i n (co-senior s c i e n t i s t s ) , B. Bornhold, R. C u r r l e , E. Davis, D. F ranc i s , I. Frydecky, E.V. G r i l l , R. Macdonald, M. Malott , D. Seemann and E. Wi l l iams; the members of my advisory committee R.L. Chase, E. V. G r i l l , J.W. Murray and T . Pedersen; S. Horsky, L. Lavku l l ch and T . Pedersen, whose techn ica l a s s i s tance was Invaluable during the data c o l l e c t i o n ; R. Cook, M. P r i c e and T . Pedersen, for the many conversat ions which helped t o formulate some of the Ideas Incorporated In t h i s study; R.L. Chase, D. Johnson and T . Pedersen for c r i t i c a l l y reading t h i s t h e s i s ; f i n a l l y my wi fe Debra, who s teadfas t l y encouraged me to persevere and complete t h i s study. Funding for t h i s study was provided by grants t o R.L. Chase, E.V. G r i l l and J.W. Murray from: the B r i t i s h Columbia M in i s t ry of Energy, Mines and Petroleum Resources; Comlnco L t d . ; Energy, Mines and Resources Canada; the Natural Science and Engineering Research Council of Canada; and P lacer Development L t d . xv i i 1. INTRODUCTION 1.1 GENERAL BACKGROUND The Departments of Geological Sciences and Oceanography, at the Un iver s i t y of B r i t i s h Columbia, have been Involved in studies of the Juan de Fuca and Explorer systems o f f the Canadian West Coast s ince the l a te 1960's. I n i t i a l l y e f f o r t s centred on the vo lcan ic basement rocks, and on the s t ruc tu re and t e c t o n i c s , for example: Murray and T i f f i n (1969); Barr (1972), (1974); Bertrand (1972); Barr and Chase (1974); Chase et a l . (1975). The recogn i t ion that metaI Iogenesis may be assoc ia ted with submarine volcanism, together with the discovery of an i r o n - r i c h deposit in the Dellwood Seamounts area (Bertrand, 1972; P iper et a I.P 1974) s h i f t e d the focus t o sediments of the Ridge systems o f f the West Coast. Consequently, s tud ies of Juan de Fuca Ridge sediments were undertaken by Cook (1981) and P r i c e (1981), and of the Explorer Ridge by Beland ( in p rep . ) . Research into a l l aspects of the geology of the West Coast o f f shore i s cont inu ing at the P a c i f i c Geoscience Centre (Geological Survey of Canada) and the Un i ve r s i t y of B r i t i s h Columbia. In 1969, a Un iver s i t y of B r i t i s h Columbia research group recovered a va r i co loured crus t over ly ing hemipelagic muds, while dredging for basement rocks on the northeast end of Explorer Ridge. The nature of the c ru s t was not recognized at the time of recovery, and the sample was simply placed into p l a s t i c bags and s to red . Fol lowing the i n i t i t a t i o n of s tud ies by Beland ( in p rep . ) , Cook (1981) and P r i ce (1981), the 1969 Explorer Ridge dredge sample was rediscovered and examined as a pos s ib le m e t a l l i f e r o u s depos i t . A program was i n i t i a t e d to examine the extent of. - 1 -hydrothermal act iv i ty and mineral formation within the segment of Explorer Ridge from which the deposit had been recovered. Subsequently G r i l l et a l . (1981) confirmed that the crust was Indeed a hydrothermal deposit from southeast Explorer R i f t . Basement rocks from Explorer Ridge have been studied by Cousens (1982). i This thesis wi l l examine the mineralogy and chemistry of sediments collected from southeast Explorer R i f t , herein cal led Explorer Deep. 1.2 PURPOSE OF THE STUDY With the recognition that a metalliferous sediment had been recovered by dredge haul 69-11, from Explorer Deep, a study was Initiated to determine the extent of hydrothermal act iv i ty and associated metal enrichment. The ultimate goal was to determine whether the deposit discovered was a local phenomenon, or If widespread hydro-thermal c i rculat ion was occurring In Explorer Deep. A portion of the joint sc ien t i f i c cruise PGC-79-06, by the Paci f ic Geosclence Centre and the University of Br i t i sh Columbia, was dedicated to this end. Detailed bathymetric control was established by a grid of continuous seismic prof i le and high resolution prof i le l ines. Using these data, gravity cores were positioned down the axis of the trough, on each of the flanks, and along the base of a fault-bounded valley separating Paul Revere Ridge from Explorer Deep (Figure 1.1). In addition several dredging operations were attempted. Table 1.1 l i s ts the sample stations, their location, the water depth and recoveries. Navigation for cruise PGC-79-06 was by Loran-C. 50°20 ' 1 1 W "JR^ "—i r 135* 125* BRITISH ^ . C O L U M B I A - 5 0 * • ' / / STUDY AREA K W A S H . I I I i KN: l 50°00 ' 4 9 ° 4 5 F i g . 1.1 Location map for c r u i s e PGC-79-06, showing C.S.P. l ines ( ), core s t a t i ons ( • ) and dredge s ta t ions ( — ) used In t h i s study. Locat ion of dredge s ta t ion 69-11 (*v%*), which recovered meta l l i f e rou s sediment (EDMS) ( G r i l l et a I . f 1981), Isobaths are In metres. Bathymetry compiled from 1979 data, see Enclosure 1 for de ta i l ed bathymetry map (1:100 000). - 3 -TABLE 1.1 Location and depth of samples collected during sc ient i f i c cruise PGC-79-06. SAMPLE LATITUDE LONGITUDE DEPTH1 SAMPLING GEAR RECOVERY (NORTH) (WEST) (m) 79 -06 -01* 50°04.8' 129°46. 8' 3150 gravity corer? 125 cm 79--06 -02* 50°06.59' 129°45. 27' 3160 gravity corer 122 cm 79-06 -03 50°06.10' 129°44. 67' 3276 hydrocast 10 bottles 79 -06 -04* 50°01.88' 129°54. 33" 2540 gravity corer 134 cm 79 -06 -05 50°06.28' 129°44. 45' 3275 modified grav. corer empty 79--06 -06* 50°06.73' 129°45. 50' 3245 gravity corer 132 cm 79 -06 -07* 50°03.28' 129°48. 46' 3300 modified grav. corer • 85 cm 79--06 -08* 49°57.52' 129°56. 00' 2545 gravity corer 158 cm 79--06 -09 50°00.97' 129°51. 87' 2660 gravity corer few rock frag. 79 • -06 -10* 49°59.83' 129°44. 75' 2350 gravity corer 133 cm 79--06 -11 49°59.00' 129°53. 75' 2460 gravity corer empty 79 • -06 -12 49°58.02' 129°54. 52' 2380 gravity corer catcher sample 79--06 -14 50°00.38' 129°45. 90' 3210 (start) chainbag empty 50°04.08' 129°45. 30' 2520 (end) dredge 79--06 -15 49°58.12' 130°01. 62' 2390 (start) chainbag empty 49°57.13' 130°02. 129°56. 129°50. 53' 2570 (end) dredge 79--06 -16 49°54.80' 47' 2600 hydrocast 10 bottles 79--06 -20 50°13.67' 67' 1800 hydrocast 1 bottle 79--06 -21* 50°12.63' 129°51. 83' 2850 boomerang corer plus 91 cm & sample 129°57. hydrocast bottom water 79--06' -22* 50°14.92' 02' 2400 boomerang corer 69 cm 79--06 -23 50°10.58' 129°49. 129°46. 37' 3000 boomerang corer empty 79--06 -24 50°05.58' 03' 3088 (start) chainbag empty 50°06.25' 129°48. 85' 3210 (end) dredge 79--06- -25 49°59.73' 129°54. 33' 2400 (start) chainbag empty 49°59.87' 129°52. 30' 2500 (end) dredge 79--06- -26 50°06.0' 129°45. 3' 3270 pore water corer approx. 50 cm 79--06' -27 49°57.05' 130°01. 10' 2390 hydrocast bottom water spl 79--06^ -28 49°57.57' 130°01. 10' 2375 boomerang corer not recovered 79--06' -29* 49°58.33' 130°00. 53' 2395 boomerang corer 102 cm 79--06 -30* 49°58.45' 130°00. 43' 2380 boomerang corer 98.5 cm 79--06 -31* 50°03.10' 130°01. 68' 1960 gravity corer 164 cm 79--06^ -32* 49°59.47' 129°53. 17' 2465 (start) chainbag ful1-basalt 49°59.22' 129°53. 28' 2375 (end) dredge water depths uncorrected for the speed of sound in water ( le . 1500 m/s = V g ) . * sampled for th is thesis . - 4 -Disappointingly, no v is ib ly anomalous sediments were recovered during the 1979 program (see core descriptions in Appendix A). This study was then redesigned to determine if the apparently typical hemi-pelagic sediments collected contained any subtle indications of wide-spread hydrothermal act iv i ty in the area. To accomplish t h i s , a detailed mineralogical examination, together with extensive chemical analyses of the sediment was undertaken. This thesis contains a compilation of the data obtained, and an interpretation of the resul ts . -5-2. 2.1 REGIONAL AND TECTONIC SETTING  METALLOGENESIS AND THE HYDROTHERMAL MODEL Metalliferous deposits have been recovered from the sea floor by many researchers, and were f i r s t reported by Murray and Renard (1891). The widespread occurrence of these deposits, their chemistry, mineralogy and morphology has been the subject of an extensive l i terature. The diverse morphology of these deposits (as encrustations on volcanic base-ment, as hydrothermal mounds and r idges, as metal-rich muds, as mineral-ization within the oceanic crust , as nodules and pavements, and as rubble-pl les of euhedral crystals) together with variations In the chemistry and mineralogy, suggest that several processes are l ikely reponslble for their o r ig in . Bonattl ejL_aI. (1972b) and BonattI (1975) proposed the following c lass i f i ca t ion for submarine metalliferous deposits: 1) Dlagenetlc deposits: formed by the remoblIIzatlon of elements during the dlagenesls of marine sediments. Reducing conditions are established in the sediment column, below the sea water-sediment Interface, causing the dissolution of certain compounds. The mobilized elements migrate upward and are redeposlted at the oxidized zone. 2) Halmyrolltlc deposits: develop from low temperature reactions (halmyrolysls) of solids (predominately volcanic glass) with sea • water. The reactions release elements Into the water column, which are subsequently precipitated on the sea f loor . This process Is part icularly Important In areas of abundant exposed volcanic talus and pyroclast lcs. 5) Hydrogenous deposits: formed by slow precipitation of metals from normal sea water. The primary source for the metals Is continental weathering. These deposits are widespread In areas with low rates of terrigenous sedimentation. 4) Hydrothermal deposits: associated with Igneous act iv i ty and the c i rculat ion of geothermally heated waters. The water percolates through the hydrothermal system, Is heated and enriched In various elements. Magmatlc water, enriched In elements, may be Introduced - 6 -to the hydrothermal convection system, and mix with the c i rculat ing f lu ids . Precipitat ion of the elements occurs when hot reducing hydrothermal f lu ids debouche Into the cooler oxygenated surroundings. An individual metalliferous deposit wil l typical ly have contributions from more than one of these processes. Comprehensive reviews of the various aspects of submarine metaIlogenesls were presented by BonattI et a l . (1972), Dymond et a l . (1973), BonattI (1975), Rona (1978) and Price (1981). This study Is primarily concerned with the poss ib i l i ty that hydro-thermal convection Is active In Explorer Deep, and as a resul t , metal-l iferous deposits may be forming. An understanding of the hydrothermal convectlve model ts therefore necessary. The hydrothermal model Involves a heat source, a permeable substrate, and "groundwater", In a thermally driven c i rcu lat ion system. "Groundwater" Is Introduced to the system at recharge areas, c i rculates through the permeable medium, and Is geothermally heated. The hot f lu id leaches elements from the medium through which It passes, and becomes Increasingly reduced. Fraction-ation of the magmatlc heat source may produce a vo la t i le phase, which Is enriched In various elements. The vo lat i le component may mix with the c i rculat ing "groundwater" and be Incorporated Into the hydrothermal solution. At discharge s i t e s , where the hot reducing f lu ids mix with cooler oxygenated surface waters, the enriched elements may be precipitated as hydrothermal minerals. The hydrothermal deposit wl11 be affected by dlagenetlc processes, and become diluted by hydrogenous and halmyrolltlc precipi tates, as well as by terrigenous and biogenic sediments. Relative contributions of each component to the deposit wil l depend upon the speci f ic sedlmentolog leal regime dominant In the area. - 7 -While convectlve systems are thought to be active at oceanic ridge spreading centres, direct measurement has proven to be d i f f i c u l t . The study of heat flux at these si tes has shed some light on the nature of the convectlve process. Heat flux measurements at oceanic spreading centres have repeatedly determined values that are anomalously low, assuming purely conductive heat flow. To account for the difference between expected and measured values, convectlve c i rculat ion of hydro-thermal f lu ids within the oceanic crust and overlying sediments has been proposed (L ister , 1970, 1972; Davis and L is ter , 1977a; Cor I Iss £ t _ _ a l . , 1978; Fehn and Cathles, 1979; Anderson et a I.f 1979). Patterns of osci l latory heat flux are common at the crest of spreading centres, Indicating the presence of hydrothermal convectlve c e l l s . In general, such systems are characterized by fa i r l y broad areas of Intake with low heat flow, and localized narrow discharge areas with high heat flow (Lister , 1972; Anderson and Hobart, 1976; Sclater je_t_al., 1976; Davis and L i s te r , 1977a; Weiss et a I.f 1977; Crane and Normark, 1977; Hyndman et a l . . 1978; Anderson et a l . P 1979; Fehn and Cathles, 1979; Williams et a I.P 1979). The discharge areas are commonly located along faults or fractures which provide conduits for the r is ing hydrothermal f l u ids . A close association between hydrothermal deposits and discharge vents has been observed In detailed studies of several hydrothermal f ie lds (Rona, 1976; Weiss et a I.f 1977; Cor l iss and Normark, 1977; Lonsdale, 1977; Corl Iss £+__al . , 1978; Hoffert £ L _ a ± . , 1978; Heklnlan et a I.. 1978; Turner and Gustafson, 1978; WJ11 lams £ ± _ a l . , 1979; Temp le .e j_al . , 1979; Lonsdale, 1979; Edmond et a I., 1979a; Crane and Bal lard , 1980). The actual hydrothermal convectlve system Is quite complex In - 8 -d e t a i l , part icularly the discharge areas. Sealing of permeable vents by the deposition of hydrothermal minerals results In abandonment and relocation of discharge to more permeable areas (Temple et a I., 1979). Repeated movement along faults often reopens abandoned vents, resulting In multiple generations of hydrothermal mineral deposition. Crane and Normark (1977) suggest that pulses of Increased hydrothermal f lu id emanation occur, controlled by sporadic periods of tectonic act iv i ty at the ridge crest . Recent work by Edmond et a l . (1979) Indicates that extensive subsurface mixing occurs between reducing hydrothermal f lu ids and cool oxygenated surface waters, and that differences In hydrothermal deposit character may be a manifestation of the degree of mixing that has occurred. The rate of discharge of hydrothermal solutions probably controls the degree of subsurface mixing, and explains the presence of different types of hydrothermal deposits within the same general area. Heat flux measurements made In the Explorer Deep area (Lister , 1972) showed low heat flow In the trough (1.3 and 1.9 ucal cm~2s~^)* and higher values on the flanks (8.4 and 6.6 ucal cm s ). The measure-ments obtained from Explorer Deep are consistent with the low heat flux typ ical ly found at spreading centre ridge crests . Higher heat flux measured on the flanks of Explorer Deep may ref lect local discharge associated with fau l ts . The recovery of fresh-lookIng basalts from Explorer Deep (dredge PGC-79-06-32) provides evidence for recent volcanic act iv i ty , and Indicates the presence of a geothermal heat source. The highly faulted and fractured nature of the oceanic crust *(1.0 ucal cm' 2s~ 1=41.9 mW m"2) - 9 -and overlying sediment (see section 2.4 and Appendix D) suggests that permeable substrate Is l ikely present in Explorer Deep. The pre-requisites for hydrothermal convection, a heat source, a permeable substrate and a suitable "groundwater" (sea water), are a l l present within Explorer Deep; therefore hydrothermal c irculat ion is possible. Indeed, recovery of a hydrothermal mineral deposit from Explorer Deep (Gri l l et a I.f 1981) indicates that hydrothermal mineral deposition ha occurred at least local ly . The extent of hydrothermal mineral deposition in Explorer Deep may perhaps be determined by a detailed study of sediments from the area, which is the intent of this study. - 1 0 -2.2 PHYSIOGRAPHY Bathymetry of the western Canadian continental margin off northern Vancouver Island, together with names of major physiographic and tectonic features Is shown In Figure 2.1. This Is a physlograph-Ically and tectonlcal ly complex region. The area of concern In th is study Is a portion of the Explorer spreading centre, Southeast Explorer R i f t (Gri l l et a I.f 1981), herein cal led Explorer Deep. The Explorer spreading centre has a poorly defined central r idge, with a series of pronounced troughs, ranging In depth from 2800 m In the northeast to greater than 3300 m to the southwest. The northern end of the Explorer spreading centre Is marked by two subparallel troughs which abut Paul Revere Ridge. Explorer Deep Is the southern trough, and Is separated from the northern trough by a prominent ridge. To the northeast of Explorer Deep Is Winona Basin, located between Paul Revere Ridge and the continental slope. Davis and Rlddlhough (1982) reported that Winona Basin contains up to 7.2 km of sediment, predominantly turb ld l tes . Approximately 20 km north of Explorer Deep are Del I wood Knolls and Del I wood Basin, which are separated from the older Dellwood Seamount Range by Dellwood fracture zone (Bertrand, 1972). S t i l l further north are Tuzo Wilson Knolls and the escarpment of Queen Charlotte fracture zone. The continental shelf between Queen Charlotte Islands and Vancouver Island Is cut by channels of Queen Charlotte Sound. Several major turbldlte sea channels have been Identified off I Fig. 2.1 Major physiographic and tectonic features of the sea f loor off northern Vancouver Island, modified after Keen and Hyndman (1979) and Davis and Riddihough (1982). Southeast Explorer Rift study area is outl ined. Solid and double l ines mark plate boundaries and spreading centres. Dashed l ines follow major turbidite sea channels. Bathymetry from Chase et a l . (1975), after Mammerickx and Taylor (1971). Contours are in metres. -12-northern Vancouver Island (Chase et a I.f 1975; Davis and RIddthough, 1982). To the north are the Moresby and Scott channels Which transport sediments to the abyssal depths west of the study area; to the east and south are Halda channel and several unnamed channels which transport sediments Into Winona Basin and south to the Juan de Fuca abyssal plain and Cascadla Basin. At present there Is no channel feeding Into the Explorer Deep area; however, prior to the up l i f t of Paul Revere Ridge one may have existed (see Section 2.4) . - 1 3 -2.3 HYDROLOGY Plckard (1975) described the c i rculat ion and water masses of the Paci f ic ocean; elements affecting the Explorer Deep area are reviewed In th is section. The major feature of large scale surface circulat ion off the Br i t ish Columbia coast Is separation of the eastward flowing North Paci f ic Current Into northward and southward components. As the North American continent Is approached part turns south as the Cal i fornia Current, the remainder turns north to form the Alaska Gyre In the Gulf of Alaska. The divergence occurs at 45°N In the winter, shift ing north to 50°N In summer. Over the continental shelf and upper slope off Oregon and as far north as Vancouver Island the flow at Intermediate depths beneath the Cal i fornia Current Is frequently northward, forming the Cal i fornia Undercurrent (Reld and Halpern, 1976; Halpern et a I., 1978; Karl In, 1980). Surface countercurrents and eddy I Ike features often observed over the continental slope off Vancouver Island may be produced by Interaction between the southward flowing Cal i fornia Current and northward flowing Cal i fornia Undercurrent (Halpern et a I., 1978). The North Pac i f i c Central Water mass extends from the Equatorial Water mass to about 40°N. North of the North Paci f ic Centra1! Water mass Is the Paci f ic Subarctic Water mass which extends across a large part of the Ocean, and forms part of the eastward flowing North Paci f ic Current. Below the North Paci f ic Central Water to a depth of 2500 m Is the North Paci f ic Intermediate Water, then the Paci f ic Deep and Bottom Water. Below 2000 m water characterist ics are very uniform, pr incipal ly because at present no Bottom Water Is created In the Pac i f ic Ocean. -1 4 -2.4 TECTONIC SETTING Considerable effort has been directed toward understanding the tectonic history of the northeast Pac i f ic offshore region. Indeed, the development of modern plate tectonic theories was In part a result of pioneering studies off the west coast of North America by Raff and Mason (1961), Vine and Wilson (1965), Wilson (1965), Vine (1966), Tobln and Sykes (1968), Atwater (1970) and others. Numerous geophysical methods have been employed In the study of the tectonics of the West Coast Including seismic ref lect ion p ro f i l i ng , seismic refract ion, gravity, magnetics, heat-flow and selsmlclty . Comprehensive reviews of research efforts In the northeast Paci f ic are presented by Chase et a l . (1975), RIddlhough and Hyndman (1976), Riddlhough (1977), Keen and Hyndman (1979), and Davis and RIddlhough (1982). The West Coast offshore region Is tectonlcal ly complex, resulting from Interactions between three major l lthospherlc plates: the America, P a c i f i c , and once larger Farallon plates. The Farallon plate, subjected to stresses associated with convergence and oblique subductlon, has broken Into smaller subplates, which move almost Independent of one another (Si lver , 1971; Chase e±_a_L., 1975; RIddlhough, 1977; Hyndman et a I.. 1978; Keen and Hyndman, 1979; Davis and RIddlhough, 1982). The Explorer and Juan de Fuca subplates are remnants of the Farallon plate, and are separated by the Nootka fracture zone. Transform motion along the Nootka fault Is I ef t - la tera l at about 2 cm a~* (Hyndman et a I.. 1978; Keen and Hyndman, 1979). Present location of the t r i p l e Junction Is In the Dellwood KnolIs-Tuzo WIIson Knolls area, shown In Figure 2.1 -1 5 -(Chase fi±_ai., 1975; RIddlhough, 1977; RIddlhough et a l . . 1980; Davis and RIddlhough, 1982). North of the t r i p l e junction. Queen Charlotte fracture zone forms a transform boundary with r ight - latera l motion at about 5.5 cm a~^ between the Pac i f ic and America plates (Keen and Hyndman, 1979). Tuzo Wilson Knol ls , Dellwood Knol ls , an unnamed (poorly defined) fracture zone between them, Del I wood-Revere fracture zone, Explorer spreading centre, Sovanco fracture zone, and Juan de Fuca spreading centre form the segmented boundary between the Paci f ic plate and Explorer-Juan de Fuca subplates. Present rates of motion across th is boundary range between 4 to 6 cm a~^, fu l l spreading rate (Keen and Hyndman, 1979). The base of the continental slope essential ly marks the edge of the America plate south of Dellwood Knol ls . The America p late -Explorer and Juan de Fuca subplates boundary Is a zone of convergence and subductlon with underthrustIng rates of 1 to 3 cm a~^ (RIddlhough and Hyndman, 1976; Keen and Hyndman, 1979). The study of magnetic anomalies has proven to be very useful In unraveling the northeast Pac i f ic tectonics (RIddlhough, 1977). In addi -t ion to the regional map of Raff and Mason (1961), several researchers have produced local detailed magnetic maps. Figure 2.2 Is a portion of the map by Currle et a l . (1982); the most str iking feature Is the sharp contrast between the quiet magnetic character of Winona Basin and the high amplitude linear magnetic anomalies south and west of Paul Revere Ridge. The sharp termination of linear anomalies marks the Dellwood-Revere transform faul t . Davis and RIddlhough (1982) suggested that Winona Basin Is floored by oceanic crust , and that the low magnetization Is the result of a variety of factors associated with high rates of -1 6 -F i g . 2.2 (a f ter C u r r i e et a I.f 1982) Magnetic anomaly map o f f shore B r i t i s h Columbia. Explorer Deep study area enclosed within dashed l i n e s . IGRF removed. Contour Interval Interval Is 100 nT. Hatched area corresponds to Paul Revere Ridge. -17-sedimentation and rapid burial of the young oceanic basalts. A similar mechanism, interlayering of basalt and sediments, was proposed by Riddihough (1980) to account for weak magnetic anomalies of the crust at DelIwood KnolIs. Several models have been developed for the tectonic evolution of the northeast Paci f ic region (Chase et a I.f 1975; Riddihough, 1977; Riddihough et a I.. 1980; Davis and Riddihough, 1982). The most recent model (Davis and Riddihough, 1982) includes a chronological reconstruc-tion that spans the past 5 Ma and describes the evolution of Explorer Deep. According to their model, Paul Revere Ridge originated as a le f t -lateral transform on the Explorer spreading centre. Subduction of the Explorer plate and spreading centre resulted In the northeastward migration of the transform faul t . At approximately 80 km from the continental slope, stresses associated with fore-arc bending in the sub-ducting plate caused vert ical fracturing along the weak crustal zone at or near to the transform faul t . T i l t ing of the now par t ia l l y detached Winona' block occurred In response to continued underthrustIng, and resulted in asymmetrical subsidence of Winona Basin and up l i f t of Paul Revere Ridge. Spreading on the section of ridge off northern Vancouver Island then ceased and the t r i p l e junction jumped to a position near Dellwood Knol ls . The now ful ly detached young crust of the Winona block resisted subsidence, result ing in a reduced rate of subduction. In the last 1 Ma, spreading on the Explorer Ridge migrated northwestward, f i r s t by asymmetric spreading and then by jumping of the spreading centre from Explorer Deep to northwest Explorer R i f t . High sedimentation rates have caused deposition to keep up with subsidence in Winona Basin, and - 1 8 -deformation of the sediments has occurred due to the convergence and subduct ion. Recent studies of mlcroseismicity indicate that the bulk of earth-quake epicentres are concentrated along the Del I wood-Revere fracture zone near the northern trough, supporting the Explorer spreading centre jump aspect of the model (Hyndman et a I . f 1978; Milne et a I., 1978; Keen and Hyndman, 1979; RIddihough et a I.f 1980). While active spreading has jumped to northwest Explorer Rif t (Figure 2.1) , very fresh-looking pillow basalts recovered from Explorer Deep (dredge haul PGC-79-06-32) indicate that some volcanic extrusion is s t i l l occurring at Explorer Deep. -19-2.5 STRUCTURE OF EXPLORER DEEP An extensive grid of prof i le lines over the Explorer Deep area was acquired during cruise PGC-79-06 (Figure 1.1). Approximately 515 km of combined 12 kHz, 3.5 kHz and continuous single channel seismic prof i le (CSP) data were obtained for study of the detailed morphology of the Explorer Deep area. A magnetometer was towed concurrently with the prof i ler array; the magnetic data were Incorporated In the map by Currle et a l . (1982), part of which Is presented In Figure 2.2. The high resolution prof i le data were used to construct a bathymetrlc map (Enclosure one). The CSP data, together with Interpreted line drawings (Appendix D) were used to construct a sediment thickness Isopach map (Enclosure two) and a basement structure map (Figure 2.3) . The map Isobaths (Enclosure one) define a northeast trending trough 40 km In length, with a maximum seafloor depth of greater than 3200 m. Paul Revere Ridge forms the abrupt northeast l imit of the trough, r is ing sharply to a depth of less than 1700 m. A northeast trending ridge, subparallel to the trough, forms the southeastern margin of the study area. The unnamed ridge trends at right angles to Paul Revere Ridge, then plunges toward the southwest. Less Imposing topographic highs form the southern and western margins of the study area, with seafloor depths of up to 2000 m. A steep-walled val ley, between the western flank of Explorer Deep and Paul Revere Ridge, deepens and widens toward the southeast Into the deep. The northern half of Explorer Deep Is a well defined r i f t , up to - 2 0 -S0°20' 2.3 Explorer Deep basement structure map, with sea-f loor bathymetry for reference. The heavy fault traces indicate faults with large vertical displacements. The PGC-79-06 CSP lines were used as control for interpretation (Appendix D). Isobaths are in metres (see Figure 1.1). - 2 1 -15 km In width. This r i f t structure Is part icularly well displayed by CSP lines PGC-79-06-04, - 0 5 , -07 , and -08 (Figures D.02, D.03, D.04 and D.05 respectively) . The southern half of the trough is characterized by a series of grabens and horsts with a poorly defined central r i f t (Figures D.06, D.07 and D.11). The dominant structural style is normal extenslonal fault ing and associated t i l t i n g of fault blocks. Intensity of the faulting decreases toward the southwest. The basement structure map (Figure 2.3) reveals an orthogonal system of faults ; one set paral -lel to the trend of the trough, the other paral lel to Paul Revere Ridge. With the exception of Dell wood-Revere fracture zone, vert ical displace-ments across northeast trending faults are larger than those across northwest trending fau l ts . Del I wood-Revere fracture zone contains a major escarpment which terminates the Explorer Deep trough. To the northwest the steep-walled val ley, mentioned above, Is fault-bounded and forms part of the fracture zone. Displacements across some of the northwest trending faults may well have a minor s t r i ke - s l i p component, Indicated by apparent lateral offset of several faults (Figure 2.3) . A sediment thickness tsotlme map of the Explorer Deep area (Enclosure two) was generated using the prof i le data (Figure 1.1). If an average velocity of sound of 2000 metres/second Is applied to the sediments, the magnitude of measured two-way travel-t ime In milliseconds is equivalent to the thickness of the sediment in metres (the suggested velocity is the same as that applied to surface sediments In Winona Basin by Clowes et a l . (1981)). Sediment overlying the acoustic basement varies In thickness from 0 to greater than 300 m (0 to greater than 300 ms). A mantle of sediment thickens toward the northwest, both on the - 2 2 -crest of Paul Revere Ridge and on the adjacent flank of Explorer Deep. More than 200 m (200 ms) of sediment l ies In parts of the deeper north-ern half of Explorer Deep, but sediment thins to zero In the southern half of the trough. Fresh basalt was recovered In dredge haul 79-06-32, located within the bald spot In the southern half of the trough (see Figure 1.1 for dredge location). The southern and southeastern margins of the study area appear to have thin or negligible sediment. A well defined layering typ i f ies the sediments (see Appendix D). In general, Individual layers show considerable lateral continuity. Hersey (1965) suggested that such layering commonly observed In acoustic prof i les of ponded marine sediments results from contrasts In acoustic Impedance between coarse grained and fine grained layers. The prof i les commonly show basement faults displacing and deforming overlying sediment (Appendix D). This Indicates that deposition of the sediment occurred, at least In part , prior to the termination of tectonic act iv i ty and associated fault ing In Explorer Deep. Two generations of turbldltes were recognized In both the Juan de Fuca Ridge area (McManus et a I., 1972) and Winona Basin (Davis and RIddlhough, 1982); a deformed and faulted lower sequence and a less deformed upper turbldl te sequence, which In turn Is overlain by a thin veneer of pelagic and hemlpelaglc sediment. DSDP s i te 177, near the crest of Paul Revere Ridge, Intersected 460 m of Pliocene turbldltes with a single basalt lens, overlain by 60 m of Pleistocene hemlpelaglc sediments (Kulm e ± _ a ± . , 1973). Init ial up l i f t of Paul Revere Ridge Is dated by the lower turbldl te sequence at Pliocene (1.5 to 2 Ma). The - 2 3 -upper turbldite sequence represents post -upl i f t In f i l l ing of the newly formed Winona Basin (Davis and RIddlhough, 1982), hence Is not present on Paul Revere Ridge. At present, no turbldite channels feed Into Explorer Deep (Section 2.2) ; however, a channel may have existed In the past, as the acoustic character of sediments In Explorer Deep suggests that they are turb ld l tes , overlain by hemlpelaglc sediments. Inter-pretation of magnetic anomalies (Vine, 1966; RIddlhough et a I.P 1980) Indicates that Explorer Deep Is Brunhes ( le . <600 000 years o ld) , therefore the sediments In Explorer Deep are Quaternary In age. Several Interesting 'mound-like' features appeared on CSP line 79-06-15 (Figure D.08), from the southwest flank of Explorer Deep, an area of thin sediment cover. Core stations 79-06-29 and 79-06-30 were selected to sample these anomalies. It was hoped that these features might be similar to mounds of hydrothermal or igin observed In the Galapagos Ri f t (Lonsdale, 1977; Cor 11 ss £ j i _ a ± . , 1978; Wi l l i ams £t__a_L., 1979) and Cal i fornia offshore (Lonsdale, 1979), or to ridges of hydrothermal deposits reported from the Famous area of the Mld-Atlantlc Ridge (Hoffert et a I.P 1978). The cores however, recovered no v is ib ly anomalous sediments (Figures A.10 and A.11). It would appear either that the features were not of hydrothermal or igin or that a mantle of younger sediment more than a metre thick was deposited after; cessation of hydrothermal act iv i ty and has burled the mounds. Alternatively the cores may have sampled Inter-mound areas, with latera l ly equivalent ' t yp i ca l ' hemlpelaglc sediments which may contain l i t t l e or no hydro-thermal minerals (Lonsdale 1977, 1979; Cor 11ss £ i _ a ± . , 1978; Heklnlan et a I .. f 1978; Hoffert et al . . 1978; WIN lams s i_a j . . , 1979). - 2 4 -3. MINERALOGY 3.1 INTRODUCTION If Explorer Deep Is a s i te of extensive hydrothermal act iv i ty , the distr ibution of minerals within the study area should show areal and/or vert ical var iat ions. To examine the d ist r ibut ion, mlneraloglcal (and chemical) analyses were performed on the samples from f ive widely spaced sediment cores: 79-06-06, 79-06-08, 79-06-10, 79-06-22 and 79-06-31 (see Figure 1.1). Samples of the Explorer Deep metalliferous deposit (from dredge haul 69-11; G r i l l et a I.f 1981) were also analyzed. The samples are. described In Appendix A. The samples were separated Into several size f ract ions, and both the bulk sediment and Individual size fractions were examined by X-ray di f f ract ion (XRD); Figures 3.1 to 3.6 are representative examples of the dlffractograms. The par t l c le -s l ze sub-samples were pre-treated for removal of carbonate, soluble sa l t s , free Iron-oxides and organic matter, as described In Appendix B. Removal of Iron-oxides Is necessary for three reasons: 1) the oxides tend to coat grains, cementing d i f -ferent minerals together; 2) the large mass absorption coef f ic ient of Iron-oxfdes reduces sensit iv i ty (Carrol l , 1969); and 3) the strong fluorescence of Iron results In high background noise. Figure 3 .2 -a Is an example of very high background fluorescence In an untreated sample (EDMS-b Is a black ferromanganese oxide-rich sample of the Explorer Deep metalliferous deposit) . Following sample pre-treatment, three oriented mounts were made for each of <0.2 urn, 0.2 to 2 urn, and 2 to 5 urn s i ze -fractions: 1) with potassium as saturating cat ion; 2) with magnesium as - 2 5 -D (71 I CD J_ 3 30 a OB oo M >o M b o o cr W *• >o o cr M to 7^ + O o O 01 0) w OD J L 55 45 35 DEGREES 2 6 25 15 Fig. 3.1 X-ray diffractograms of unoriented powder mounts of 10/120-124 samples: (a) total (untreated) sample; (b) 5 to 20 urn fract ion. Q=quartz; Im=ilmenite; R=rutile; Cb=carbonate; H=halite; F=feldspar; A=amphibole; He=hematite; K+C=chlorite; I - i l l i t e ; P=total phy l los i l icates . ro o 3© CO CO 4=. ro 3© o -p. -P> • O ro to cn 01 3© 3d 3© 30 3© u ^ ^ ^ ^ ^ W r V ^ ro 3*> 1 ro 1 ^ ^ ^ ^ ^ 63 59 55 51 47 43 r39 35 31 DEGREES 2 9 27 23 19 15 11 Fig. 3.2 Diffractograms of unoriented powder mounts of Explorer Deep metalliferous sediment (EDMS): (a) EDMS-b (oxide-rich) total sample; (b) EDMS (clay-r ich) total sample; (c) EDMS >20 um f ract ion ; (d) EDMS 5 to 20 um fraction (see Appendix A for sample description). Fig. 3.3 Diffractograms of oriented sample mounts: A. 10/120-124, <2 urn; (a) clean glass s l i d e ; (b) untreated at 20°C; (c) HC1 treated at 100°C. B. 10/120-124, <0.2 urn: (a) K-sat at 20°C; (b) K-sat at 300°C; (c) K-sat at 550°C; (d) Mg-sat at 20OC; (e) Mg-sat, Gly-sol at 20OC. -28-Fig. 3.4 Diffractograms of oriented mounts: A. 10/120-124, 0.2-2 urn; B. 10/120-124, 2-5 urn. (a) K-sat at 20°C; (b) K-sat at 300°C; (c) K-sat at 550°C; (d) Mg-sat at 20°C; (e) Mg-sat Gly-solv at 20°C. -29 -0 0 C D 3 * EDMS ( <0.2 um) ^ ^ ^ ^ ^ ^ ^ 19 15 DEGREES 2 0 Fig . 3.5 Diffractograms of oriented mount EDMS, <0.2 um: (a) K-sat at 20OC; (b) K-sat at 300°C; (c) K-sat at 550°C; (d) Mg-sat at 20°C; (e) Mg-sat, Gly-sol at 20°C. -30 -Fig. 3.6 Diffractograms of oriented mounts: A. EDMS, 0.2-2 um; B. EDMS, 2-5 um. (a) K-sat at 20°C; (b) K-sat at 300°C; (c) K-sat at 550°C; (d) Mg-sat at 20°C; (e) Mg-sat Gly-sol v at 20°C. -31 -the saturating cat ion; and 3) magnesium-saturated and glycerol -solvated. Oriented mounts were prepared on glass s l ides ; the general shape of the dlffractograms represents the XRD response to 'amorphous' glass (Figure 3.3a) . Areas of XRD peaks In oriented mounts of K-saturated (20°C) , and Mg-saturated glycerol-solvated (20°C) preparations of <0.2 urn, 0.2 to 2 urn and 2 to 5 urn s ize - f ract ions are l isted In Appendix C. Unorlented powder mounts were prepared for 5 to 20 urn, >20 urn s ize - f ract ions and for total (bulk) samples; areas of selected XRD peaks In unorlented samples are l isted In Appendix C. The XRD equipment and operating conditions together with sample preparation technique are described In Appendix B. - 3 2 -3.2 MINERAL IDENTIFICATION The following minerals are present In sediments from Explorer Deep: Amphlbole: Characterized by a typical ly sharp peak at 8 .4-8.5 ft. Amphlbole Is present In both unorlented powder mounts, and oriented mounts (Figures 3 . 1 , and 3.3 to 3.4 respectively) . Carbonate; Present In non-treated unorlented powder mounts of total sediment. The ca lc l te response Is a major peak at 3.04 ft with less Intense peaks at 2.29 and 2.10 ft. Dolomite Is Identified by a major peak at 2.88 ft, with lesser peaks at 2.19 and 1.80 ft. The 3.0 ft peak Is complex (Figure 3.1-a) Indicating the presence of several types of carbonate. No attempt was made to Identify Individual minerals. Feldspar: A major peak at 3.2 ft with a less Intense ref lect ion at about 4.04 ft, are character ist ic of feldspar. The 4.04 ft peak Indicates plagloclase content, while the strong 3.2 ft peak Is In response to both K-feldspar and plagloclase (GIbbs, 1967). The 3.2 ft peak Is generally complex (Figure 3 .1) , Indicating the presence of several types of feldspar. No attempt was made to Identify Individual types. Feldspar Is present In the majority of unorlented and oriented samples. HalIte: A sharp peak at 2.84 ft Is characterist ic for ha l i te . It Is present In trace amounts, only In unwashed samples (Figure 3 . 1 - a ) , Indicating the occurrence of sea-sa l t from sample drying. Hematite: Identified by a major peak at 2.69 ft with lesser peaks at 2.59 and 1.69 ft. Hematite may be present In trace amounts (Figure 3 .1 ) . 11 menIte: A major ref lect ion at 2.74 ft with lesser peaks at 1.72 and 2.54 ft are diagnostic for llmentte. Trace amounts may be present In sediments from the Explorer Deep area (Figure 3.1) . Quartz; A strong ref lect ion at 3.34 ft with a weaker ref lect ion at 4.26 ft and minor peaks at 1.82 and 1.53 ft are character ist ic of quartz. Samples must contain >]0% quartz before a 4.26 ft peak Is v i s ib le (Jackson, 1956). Quartz Is present In both unorlented and oriented mounts (Figures 3 . 1 , and 3.3 and 3.4 respectively) , and In trace amounts In Explorer Deep metalliferous deposit samples (Figure 3 .2) . Rutl le; Identified by peaks at 3.26, 1.69 and 2.49 ft. The 3.26 ft peak Is masked by the feldspar 3.2 ft and quartz 3.34 ft peaks; peaks at 2.49 and 1.69 ft (Figure 3 .1 ) , Indicate trace amounts of r u t l l e . Clay Minerals Total phyI lost I Icates; Total phy11os11Icate content tn unorlented powder mounts Is expressed by the Intensity of the 4.52 ft peak. The peak at 1.50-1.53 ft represents the (060) re f lec t ion ; dloctahedral phyI-loslIIcates tend to produce a peak at about 1.50 ft, while trloctahedral phylIos11Icates exhibit a peak at 1 .525-1 .534 ft (Jackson, 1956). Chlorlte; Recognized by ref lect ions at 14.3 and 7.2 ft, with lesser peaks at 4.8, 3.6 and 2.87 ft, which are not affected by glycerol solvation. Chlorite Is distinguished from vermlcullte by non-collapse of the 14 ft peak (to 10 ft) upon K-saturatlon and heating to 300°C. Boil ing for 20 minutes In .0% HCI eliminated the 3.6 ft peak and reduced the Intensity of other ch lor i te peaks (Figure 3.3A-c) ; kaol lnl te Is unaffected by th is treatment (Carro l l , 1969). Heating to 550°C eliminated the 7 ft peak as well as the minor peaks and Intensified the chlor i te (001) 14.3 ft ref lect ion (Figures 3.3B-C and 3 . 4 - c ) ; as the crystal IInlty of kaol ln l te Is lost upon heating to 550°C (Jackson, 1956; Car ro l l , 1969), the Intensified 14 ft peak Indicates that the mineral Is ch lo r i te . There Is no evidence of kaol ln l te In Explorer Deep sediments, the K+C (7 ft) peak therefore represents only ch lor i te content. 11 IIte: Diagnostic ref lect ions for TI IIte occur at 10 and 5 ft with a less Intense peak at 3.32 ft (commonly masked by the large 3.34 ft quartz peak; Figure 3 .4 ) , and are not affected by glycerol solvation. Smectite: A broad peak at 12-14 ft which collapses to 10 ft upon heating to 300°C Is character ist ic of smectite In K-saturated samples (Figures 3 .5 -e and 3 .6 ) . The smectite response to Mg-saturatlon Is a peak at 12-14 ft which expands to 17-18 ft upon glycerol solvation, and a fa i r l y Intense second order peak at 8.9-9.1 ft (Jackson, 1956). Explorer Deep metall iferous deposit samples y ie ld ref lect ions at 12, 4.53, 2.60 and 1.52 ft (Figures 3.2 and 3 .6 ) ; these Identify the mineral as nontronlte an Iron-rich smectite mineral (MacEwan, 1961; Car ro l l , 1969; G r i l l et a I.f 1981). Three types of smectite are present In Explorer Deep: (1) det r l ta l smectite dominating the very f ine clay f ract ion, l ikely montmoriI IonIte; (2) smectite In mixed-layer clays (discussed below); and (3) nontronlte. Mixed-layer c lays: The presence of 11 IIte-smectIte mixed-layer clays Is suggested by high background levels between 10 ft and 14 ft peaks In K-saturated samples, which are reduced after heating (Figure 3 .4) . Larger 10 ft peaks In K-saturated compared Mg-saturated samples (Table C.I) , are Indicative of degraded 11 IItes (InterstratIf led layers of hydrated non-hydrated I l l l t e s ) . With g lycero l -so lvat lon, penetration of organic molecules Into hydrated layers can occur, causing expansion of the basal spacing (cf . smectite). Direct Identif ication of randomly InterstratIf led mixed-layer clays Is d i f f i c u l t because sh i f ts in f i r s t order XRD re f lec t ions , character ist ic of ordered mixed-layer c lays, donot occur (Car ro l l , 1969; Hower, 1981). - 3 5 -3.3 CRYSTALLINITY A measure of the crystal 11nlty of the clay minerals was determined using X-ray dlffractogram peak heights as described by BIscaye (1965). An "Index of crystal I InIty" (IC) was calculated as follows: IC = peak width (at 1/2 peaK height?, peak height Lower IC values Imply better crystal I InIty. The IC for II l i t e was determined using the 1002 (10 ft) peak, and for ch lor i te using the K+C (7 ft) peak. IC for smectite was not calculated due to sensi t iv i ty of the technique to variations In concentration of the mineral (BIscaye, 1965). IC data for Explorer Deep sediments are l isted In Table 3 . 1 . The crystal I InIty of 11 l i te Improves as grain size Increases (Table 3 .1 ) ; some fluctuation Is evident between the 0.2 to 2 um and 2 to 5 um fractions but, II l i t e crystal IInlty In the 0.2 to 2 um fraction Is much higher than In the <0.2 um f ract ion . I 11Ite crystal I InIty shows no consistent variation across the study area, nor over the thickness of sediment column sampled. I I l i t e IC values are typ ical ly lower In K-saturated preparations compared to Mg-saturated samples. Indicating an improvement In crystal I InIty following uptake of potassium (Grlffen and Goldberg, 1963; Carrol 1, 1969; E lder f le ld , 1976). The difference Is interpreted to Indicate the presence of degraded I l l l t e s (randomly InterstratIf led hydrated and non-hydrated layers, possibly I l l l t e -smectlte mixed-layer clays) In Explorer Deep sediments. Chlor i te crystal IInlty also Improves In the coarser part le le -sJze - 3 6 -Table 3.1 Clay mineral ratios and crystal 1inity data, oriented sample mounts. SAMPLE SIZE RATIOS OF AREAS OF X-RAY DIFFRACTOGRAM PEAKS INDEX OF CRYSTALLINITY* FRACTION K-6aturated Mg-saturated, qLvceroL solvatad K-sat Ma-sat. alv-aolv (urn) 1002(108] K+CI7S] 1002(108] K+C{78] 1002(108] S00K188) S001(188) S001[188) 1002(108] 1002(108) K+C(78] 0(3.348] 0.(3.348) 0(3.348) 0(3.348] K+C(78) 1002(108] K+CI78] Q[3.34A>J EDMS <0.2 0 0 0 0 0 I (ntr) K+C (ntr) 0 (ntr] ntr ntr ntr 0.2-2 0 Q (ntr) 0 1.22 0 I (ntr) 11.71 14.24 ntr ntr 0.22 2-5 0.61 1.61 0.50 0.60 0.83 3.38 2.82 1.70 1.6 0.45 0.26 674-8 <D.2 Q (ntr) 0 (ntr) 0 Q [ntr] 0 I (ntr) 6.22 Q (ntr) 0.71 ntr 0.45 0.2-2 1.09 1.40 0.77 1.75 0.44 3.78 1.67 2.91 0.10 0.19 0.06 2-6 1.07 1.27 0.58 1.33 0.43 1.13 0.49 0.66 0.11 0.20 0.09 6/20-24 <0.2 n.a. n.a. 0 (ntr) Q (ntr] I (tr) I (tr) 7.34 Q (ntr) n .a . t r 0.19 0.2-2 n.a. n.a. 1.24 2.32 0.53 1.63 0.86 2.00 n.a. 0.18 0.08 2-5 1.06 1.70 0.27 0.67 0.41 0 0 0 0.11 0.22 0.09 6/60-64 <D.2 n.a. n.a. Q [ntr] Q (ntr) 0.33 50.3 16.3 Q (ntr) n .a. 1.7 0.55 0.2-2 n.a. n.a. 1.00 1.92 0.37 5.44 2.00 3.84 n .a . 0.24 0.14 2-5 1.00 1.38 0.54 1.19 0.45 1.29 0.58 0.69 0.11 0.10 0.06 6/120-124 <0.2 0 Q (ntr) 0 Q (ntr) 0 I (ntr) 14.2 Q (ntr) ntr ntr 0.78 0.2-2 0.98 1.92 0.84 2.46 0.44 3.96 1.74 4.29 0.11 0.18 0.06 2-5 0.78 1.02 0.68 1.23 0.55 1.16 0.64 0.79 0.12 0.09 0.07 8/4-8 <D.2 0 Q (ntr) 0 Q (ntr] 0 I (ntr) 22.9 Q (ntr) ntr ntr 0.27 0.2-2 1.42 1.59 0.60 1.03 0.58 3.06 1.78 1.85 0.16 0.26 0.14 2-5 n.a. n.a. 0.65 1.47 0.44 0.85 0.37 0.55 n .a . 0.15 0.08 8/60-64 <0.2 0 Q (ntr) Q (ntr) Q (ntr] 0.42 59.7 26.1 Q (ntr) ntr 0.47 0.33 0.2-2 1.00 1.65 1.00 3.07 0.46 4.13 1.93 5.93 0.09 0.18 0.08 2-5 n.a. n.a. 0.71 1.62 0.44 1.04 0.44 0.71 n .a . 0.21 0.08 10/4-8 <D.2 0 Q (ntr) 0 Q (ntr) 0 I (ntr) 13.6 Q (ntr) ntr ntr 0.48 0.2-2 1.08 1.42 0.63 1.B3 0.34 5.65 1.95 3.58 0.14 0.20 0.10 2-5 0.90 1.08 0.56 1.44 0.39 1.13 0.44 0.63 0.11 0.18 0.07 Table 3.1 Clay mineral ratios and crystal 1inity data, oriented sample mounts, (continued) SAMPLE S I Z E RATIOS OF AREAS OF X-RAY DIFFRACTOGRAM PEAKS INDEX OF CRYSTALLINITY* FRACTION K-saturated Mg-saturated. glycerol solvatad K - sa t Mg-sat. qly-solv (um) I002[1o8] K+C[7&) I002[1o8] K+C(78) 1002[10%) S001[1B8) S001[1B8) S001[1B8) I002[1O8) I002[1O8) K+C[78) CO 0.(3.348) Q[3.348] 0.(3.348] 0(3.348] K+CI78) I002[108] K+C[78] 013.348) 10/20-24 <0.2 n.a n.a. 0 Q [ntr] 0 I (ntr) 15.6 0 [ntr) n .a . ntr 0.28 0.2-2 1.48 1.67 0.72 2.31 0.31 3.41 1.08 2.49 0.17 0.16 0.06 2-5 0.66 1.34 0.80 1.72 0.47 0.49 0.23 3.96 0.15 0.12 0.06 10/60-64 <0.2 n.a. n.a. Q [ntr] Q [ntr] 0.26 32.3 8.42 Q (ntr) n .a. 0.63 0.34 0.2-2 n.a. n.a. 1.13 3.83 0.29 1.31 0.38 1.47 n .a . 0.16 0.07 2-5 1.75 1.56 0.64 2.69 0.25 0.51 0.12 0.32 0.12 0.10 0.04 10/120-124 <0.2 0 Q Intr) 0 Q [ntr] 0 I [ntr) 6.82 Q (ntr) ntr ntr 0.42 0.2-2 1.33 1.82 1.58 3.54 0.45 1.45 0.65 2.29 0.14 0.13 0.06 2-5 1.35 1.29 0.65 1.77 0.39 0.28 0.11 0.19 0.09 0.10 0.03 22/0-4 <0.2 0.60 2.42 Q [ntr] Q [ntr] 0.21 97.4 20.5 Q (ntr) 1.0 1.4 0.29 0.2-2 1.82 2.12 0.58 1.58 0.37 5.70 2.16 3.40 0.14 0.24 0.09 2-5 n.a. n.a. 0.48 1.21 0.39 1.48 0.59 0.71 n .a . 0.19 0.12 22/60-64 <0.2 Q (ntr) Q [ntr] Q (ntr) Q (ntr) 0.11 63.5 6.98 Q (ntr) 0.34 0.79 0.24 0.2-2 2.10 1.45 1.15 3.76 0.31 0.78 0.24 0.90 0.10 0.12 0.05 2-5 n.a. n.a. 0.45 1.53 0.29 0.23 0.07 0.10 n .a . 0.13 0.05 31/4-8 <0.2 n.a. n.a. 0 6.81 0.20 40.0 7.93 Q (ntr) n .a . 0.43 0.16 0.2-2 1.98 1.88 0.73 2.14 0.34 3.90 1.32 2.83 0.16 0.16 0.10 2-5 n .a . n .a . 0.84 1.74 0.48 1.41 0.68 1.17 n .a . 0.22 0.10 31/66-70 <D.2 n.a. n.a. 2.04 9.77 0.21 57.4 12.0 117.0 n .a . 0.27 0.13 0.2-2 1.34 1.87 1.32 3.28 0.49 2.19 0.88 2.89 0.11 0.12 0.06 2-5 n.a. n.a. 0.88 1.73 0.51 0.35 0.18 0.31 n.a. 0.07 0.05 31/120-124 <0.2 Q (ntr) Q (ntr) n .a. n .a . n .a . n .a . n .a . n .a . 0.40 n .a . n .a . 0.2-2 2.15 1.07 1.74 7.57 0.23 0 0 0 0.08 0.19 0.06 2-5 n.a. n.a. 0.31 1.40 0.23 0 0 0 n.a. 0.28 0.07 1=11 L i te ; K+C=kaol1n1 te+chloritej Q=quartz; S=smect1ta; tr=trace; ntr=no trace; n.a.=not analyzed; •INDEX OF CRYSTALUNITY= ratio of half peak width/peak height, after BIscaye [1965. fractions (Table 3 .1 ) . The crystal 11nlty of chlor i te In the 0.2 to 2 um sub-samples was much Improved compared to the <0.2 um fractions but, no signif icant difference was observed between the 0.2 to 2 um and 2 to 5 um s i ze - f rac t ions . Arcaro (1978) showed that In sediments from Cascadla Basin and Juan de Fuca abyssal plain the crystal I InIty of IIIIte and ch lor i te Is poorest In the <0.49 um fraction and Improves markedly In the 0.49 to 0.98 um sub-samples. The crystal IInlty continued to Improve In the coarser grain sizes up to 2.0 to 3.3 um, then decreased s l i gh t l y . The Holocene 0.49 to 2 um size fraction IC values ranged between 0.04 to 0.10 for ch lor i te and between 0.06 to 0.015 for II l i t e . The ch lor i te IC values are comparable to those of sediments from the Explorer Deep area. Since Arcaro (1978) did not saturate the samples with potassium, his IIIIte IC data should be comparable to the Mg-saturated sub-samples In this study. The crystal I InIty of Explorer Deep sediments (Table 3.1) appears poorer; however, the discrepancy l ikely ref lects a difference In the par t l c le - s l ze fractions used. In th is study, the clay fraction examined contains part ic les from 0.2 to 2.0 um In s i z e , whereas Arcaro (1978) used a coarser fraction 0.49 to 2.0 um. Arcaro (1978) calculated IC values for montmor11lonlte (a smectite mineral) and found a sl ight Improvement In crystaI I InIty In f ine grained fract ions. These results should be viewed cautiously, as smectite Is concentrated In f iner s ize - f ract ions (dominating <0.2 um portion), and the apparent Improvement In crystal IInlty may actually Just re f lect an abundance of smectite In the fine grained samples (BIscaye, 1965). 3.4 MINERAL DISTRIBUTION This section describes the mineral distr ibution within sediments of the Explorer Deep area. Samples were selected from sur f l c la l sediments and at various depths from f ive cores (chosen to be representative of sediments In the entire study area). The samples were divided Into f ive size f ract ions; the clay and f ine s i l t fractions (less than 5 um) were treated prior to XRD analysis as described In Appendix B.1. Areal and vert ical variations In mineral distr ibution were assessed using peak area ra t ios , calculated for both oriented and unorlented mounts (see below). No attempt was made to quantify concentrations of minerals Identified In the sediments sampled. Numerous factors cause serious d i f f i c u l t i e s when X-RD analysis Is used for seml-quantItatIve determinations Including variations due to sample-mounting techniques, d i f f i cu l t y In obtaining satisfactory standards, variations In machine operating conditions during XRD analysis , the varying d i f f ract ing power of different clay minerals, variations In mass absorption coeff ic ients for Individual minerals, and differences In mineral crystal I Inlt les (Jackson, 1956; BIscaye, 1965; Glbbs, 1967, 1968; Carrol , 1969; Stokke and Carson, 1973; Towe, 1974; Hume, 1978; Pearson, 1978; Heath and PIsIas, 1979; Pedersen, 1979). The principal mechanism responsible for clay mineral segregation In the marine environment Is physical sorting of sediment by par t ic le s i ze . Glbbs (1977) showed that In sediments from the Amazon Rlver -At lant lc Ocean area the following grain size predominance existed for c lay - s i ze minerals: - 4 0 -chlor i te - no mean quoted, range = 0.5 um to sand size kaolin ite - mean grain s ize = 1 to 2 um, range = 0.4 to 10 um mica - mean grain size = 2 to 4 um, range = 0.4 to sand size montmori11 on ite - mean grain s ize = 0.4 um, range = <0.1 to 0.9 um quartz - no mean quoted, range = 0.8 um to sand s i ze . Arcaro (1978) and Carson and Arcaro (1983) also concluded that grain size was the primary control l ing factor In the distr ibution of c lay -size minerals in sediments from Jaun de Fuca Abyssal plains and Cascadla Bas in . In th is study, the distr ibution of minerals within sediments from the Explorer Deep area is examined as re lat ive variations in content, using rat ios of areas of XRD peaks for clay minerals, rather than attempting to quantify absolute concentrations of Individual minerals. The distr ibution of minerals Is examined separately In the total (bulk) sediment and In each of the f ive par t i c le - s i ze sub-samples. Fine clay (less than 0.2 um) The <0.2 um part Ic le -s ize fraction Is composed almost entirely of smectite with traces of i l l I t e , ch lor i te and rare quartz (Appendix C). Ratios of areas of XRD peaks for 11 11te/chI orIte (1002(10 ft)/K+C(7 ft); Table 3 .1 ) , where present, are usually smaller than rat ios In coarser partIcIe-slze sub-samples. This may ref lect a higher concentration of ch lor i te than II IIte In the f ine clay f ract ion; however, proximity of the 10 ft II l i t e peak to the second order 9 ft smectite peak made measurement and even detection of a possible IIIIte peak d i f f i c u l t (Figure 3.3B-e) . Clay (0.2 to 2 um) Coarse clay has a more complex mineral composition than fine clay (Figures 3.4A and 3.3B respectively) , consisting of 111Ite, ch lo r i te , smectite, quartz, feldspar and amphlbole. The data show no evidence of kaol ln l te In the samples; the K+C (7 A) peak Is therefore considered to ref lect only ch lor i te content. The absence of kaol ln l te In West Coast sediments has also been reported by Rateev et a I. (1969), Karl In (1980), Cook (1981) and Price (1981), supporting the conclusion In th is study. Ratios of areas of XRD peaks for II l i te to quartz (1002(10 ft)/ Q(3.34 ft)) are consistently higher In K-saturated samples than In Mg-saturated glycerol -solvated samples (Table 3 .1 ) . The apparent Increase of II l i t e In K-saturated samples Is due to uptake of potassium by degraded 111Ites, which causes collapse of hydrated 11 IIte layers and Improved crystal I InIty, hence stronger and sharper 10 ft peaks (Grlffen and Goldberg, 1963; C a r r o l l , 1969; E lder f le ld , 1976). Degraded 11 IItes are l ikely randomly Interlayered hydrated and non-hydrated l l l l t e s . In Mg-saturated samples 11 IIte/quartz rat ios Increase at depth In a l l cores (Figure 3 .7 ) ; In contrast, In K-saturated samples 111Ite/quartz rat ios remain fa i r l y constant within Individual cores. The difference In 11 IIte/quartz ratios between K-saturated and Mg-saturated samples Is part icular ly pronounced In su r f l c la l sediments and diminishes at depth, suggesting a decrease In the abundance of degraded l l l l t e s at depth. In the study area, sur f l c la l sediments are potassium-poor (Chapter Four). The Increase In both potassium below sur f l c la l minima may ref lect scavenging of potassium Ions from sea water and pore waters by degraded l l l l t e s , s imilar to the uptake of potassium that occurred following - 4 2 -1002(10 ft) Q(3.34 ft) K-saturated 0.2 to 2 um 2 to 5 um i 2 q i 7 i 1 1 1 1 i r 1 1 1 Ca) (b) 1002(10 ft) Q(3.34 ft) Mg-saturated Glycerol-solvated 0.2 to 2 um 2 to 5 um Fig. 3.7 Prof i les of ratios of areas of X-ray d i f f ract ion peaks for i l l i t e to quartz in K-saturated (20°C) and Mg-saturated glycerol -solvated (20dC) oriented mount samples from cores 79-06-06 ( O — O ) , 79-06-08 ( • — a ) , 79-06-10 ( B — B ) , 79-06-22 (A—A) and 79-06-31 (•—•): (a) 0.2 to 2 um s i ze - f rac t ion ; (b) 2 to 5 um s i z e - f r a c t i o n . Note scales vary between individual p rof i les . Data are from Table 3 .1 . - 4 3 -K-saturatlon during sample preparation. In K-saturated samples, 111Ite/quartz rat ios are s igni f icant ly higher In sediments from the northwest flank of Explorer Deep (cores 79-06-22 and 79-06-31) than In sediments from the f loor (cores 79-06-06 and 79-06-08), while those from the southeast flank are Intermediate. Since degraded I l l l t e s are products of continental weathering, sediments from the flanks of Explorer Deep appear to have higher detrltaI mineral content than sediments from the f loor . No consistent areal or vert ical variations In 11 IIte/chlorlte ratios (1002(10 ft)/K+C(7 ft)) are evident In Mg-saturated g lycero l -solvated samples (Table 3 .1) . Chlorite/quartz rat ios are generally higher In Mg-saturated glycerol-soIvated samples than In K-saturated samples (Figure 3 .8 ) , suggesting uptake of Mg^+ Ions by degraded chlor l tes and Improved crystal IInlty. The Increase of ch lor i te re lat ive to quartz after Mg-saturatlon, Is part icular ly dramatic In core 79-06-31 at 120-124 cm. (Figure 3 .8) . Sur f lc la l sediments from the Explorer Deep area are generally magnesium-poor (Chapter Four); the Increase In magnesium at depth may ref lect scavenging of magnesium Ions from sea water and pore waters by degraded ch lo r l tes , similar to potassium scavenging by degraded II l i t e . Ratios of areas of XRD peaks for smectite to II l i t e (S00K18 ft)/ 1002(10 ft)), smectite to ch lor i te (S00K18 ft)/K+C(7 ft)) and smectite to quartz (S00K18 ft)/Q(3.34 ft)) are s imilar In su r f l c la l samples from a l l f ive cores (Figure 3.9) however, at depth variations In smectite content are evident. In sediments from the flanks (cores 79-06-10, 79-06-22, - 4 4 -0 20 , 40 E o 60 X 1- 80 0. Ul o 100 120 140 *-K+C(7 ft) Q(3.34 8) K-saturated - 0.2 to 2 um I 2 T i 1 r 6 10 T 0 (b) 20 40 o m -o 60 H X 80 n 3 100 120 140 UJ o O r 20 40 60 80 100 120 140 0 r K+C(7 ft) QC3.34 ft) Mg-saturated Glycerol-solvated 0.2 to 2 um 2 4 6 8 I 1 T o m to 0 20 40 60 x 80 _ 100 3, 120 140 Fig. 3 .8 .Prof i les of ratios of areas of X-ray d i f f ract ion peaks for chlor i te to quartz in K-saturated (20°C) and Mg-saturated glycerol -solvated (20°C) oriented mount samples from cores 79-06-06 ( O — O ) , 79-06-08 (•—•), 79-06-10 (•—•), 79-06-22 (A-—A) and 79-06-31 (•—•): . (a) 0.2 to 2 um s i ze - f rac t ion ; (b) 2 to 5 um s i ze - f rac t ion . Note scales vary between individual p ro f i les . Data are from Table 3 .1 . - 4 5 -79-06-31) smectite contents decrease dramatically at depth; In contrast, In f loor sediments (cores 79-06-06 and 79-06-08) smectite ratios remain constant or Increase s l ight ly at depth. During glycerol solvation, penetration of organic molecules Into hydrated layers of the degraded 111Ites and chlor l tes may occur, causing swell ing. Smectites are Identified by such expansion of basal spaclngs; therefore, degraded clays appear to be analogous to randomly InterstratI f led I I 11te-smectIte and chlor Ite-smectIte mixed-layer clays (Carro l l , 1969; Hower, 1981). High smectite rat ios for su r f l c la l sediments may re f lect high concentra-t ions of degraded II IItes and ch lor l tes ; however, as the degraded 11 IIte content decreases at depth, the abundance of smectite at depth In sediments from the f loor Is not due to degraded IIIItes. ChlorIte/quartz rat ios are similar for a l l cores (Figure 3 .8 ) , suggesting that degraded chlor l tes (chI or Ite-smectIte mixed-layer clays) are not the source of smectite In sediments from the f loor . The sample at 20-24 cm from core 79-06-06 has much less smectite than other samples from the core, and may ref lect an absence both of degraded clays and smectite. These data suggest a real Increase In the smectite content of sediments from the floor re lat ive to those from the f lanks. The distr ibut ion of smectite In Explorer Deep sediments Is examined In detai l In Chapter F ive. Very fIne s111 (2 to 5 um) Very f ine s i l t Is composed of the same minerals as clay (Figure 3 .4 ) . Ratios of 111Ite/quartz In Mg-saturated samples of very f ine s i l t are s ign i f icant ly lower than those In clay (Table 3 .1 ) ; however, rat ios In K-saturated samples are quite s imi lar . The differences In IIIIte/ quartz rat ios between K- and Mg-saturated samples In very f ine s i l t are Mg-saturated Glycerol-solvated samples of 0.2 to 2 um Fraction o r 0 20 e 4 0 u - 60 S001(18 ft) 1002(10 ft) 2 T 80 -100 -120 140 4 T 6 1 O r S001(18 ft) K+C(7 ft) 2 T L 31 (a) 3 1 S001(18 ft) Q(3.34 ft) Mg-saturated Glycerol-solvated samples of 2 to 5 um Fraction S001(18 ft) 1002(10 8) S001(18 ft) K+C(7 ft) S001(18 ft) Q(3.34 ft) o r o r o r 31 10 (a) _ 31 10 (c) F ig . 3.9 Profi les of ratios of areas of X-ray diffractogram peaks in Mg-saturated glycerol -solvated oriented mount samples of 0.2 to 2 um and 2 to 5 um fractions from cores 79-06-06 ( O — O ) , 79-06-08 (•—•), 79-06-10 ( » — • ) , 79-06-22 ( A — A ) and 79-06-31 (9—©); (a) variation of smectite/i l1ite ra t ios ; (b) variation of smectite/ chlor i te ra t ios ; (c) variation of smectite/quartz rat ios . Note scales vary between individual p rof i les . Data are from Table 3.1. -47 -larger than In c lay , Indicating that degraded l l l l t e s are more abundant In the coarser f ract ion . No consistent areal or vert ical variations are evident In f11Ite/quartz rat ios In Mg-saturated samples (Figure 3 .7 ) . In s i tu uptake of potassium from the water column and pore waters by fine si I t -s ize degraded l l l l t e s Is apparently not suf f ic ient to cause collapse of a majority of hydrated layers, as was the case tn clay (see previous sect ion) . Ratios of areas of XRD peaks for II l i t e to ch lor i te (1002(10 ft)/ K+C(7 ft)) show no consistent areal or vert ical variations (Table 3 .1 ) . I 11Ite/chlorIte rat ios are the same magnitude In both very fine s i l t and c lay . Ratios of ch lor i te to quartz (K+C(7 ft)/Q(3.34 ft)) In core 79-06-10 are consistently higher In Mg-saturated samples compared to K-saturated samples, while In core 79-06-06 the discrepancy Is var iable. If f ine si I t -s ize degraded chlor l tes are present In the sediments, the uptake of magnesium Ions does not appear to be suf f ic ient to cause complete col lapse of the hydrated layers to any great extent. Very f ine s i l t contains much less smectite than c lay , Indicated by smaller rat ios of smectite to 111Ite, to ch lo r i te , and to quartz (Table 3 .1) . The smectite distr ibut ion tn very f ine s i l t Is s imilar to that tn clay (Figure 3 .9 ) , decreasing at depth In sediments from the f lanks, but remaining high In sediments from the f loor . High rat ios of smectite In sur f l c la l sediments may ref lect swelling of hydrated layers In degraded l l l l t e s ; however, the higher rat ios at depth In sediments from the; f loor , re lat ive to the f lanks, represent an Increase In abundance of smectite, not degraded l l l l t e s , tn sediments from the f loor . The distr ibution of smectite In Explorer Deep sediments Is examined In detail In Chapter F ive. - 4 8 -Fine s i l t (5 to 20 um) and coarser O20 um) Fine s i l t and coarser sub-samples, and total (bulk) samples were prepared as unoriented powder mounts and analyzed by XRD (as described in Appendix B) . Ratios of areas of XRD peaks are l isted in Table 3 .2 . a The quartz to total phyIlosiI icates rat io (0(4.26 ft)/clays (4.5 ft)) showed considerable flutuations within both size fract ions, but no consistent pattern was evident in areal or vert ical distr ibutions within the individual s ize - f ract ions (Table 3 .2) . Comparison of the quartz/ total phyIlosiI icate ratios between 5 to 20 um and >20 um fractions indicates less phyI IosiIicate in the coarser f ract ion. In the EDMS sample however, phyIlosiI icate dominated even in the coarser fractions (Figure 3 .2 ) . Areal and vert ical variations in the quartz/feldspar rat io (0(3.34 ft)/F(3.20 ft)) show no consistent pattern within individual size sub-samples. The rat io for >20 um fraction Is typ ica l ly smaller than that for 5 to 20 um fract ion, suggesting that f ine s i l t Is richer In quartz than the coarser f ract ion. The presence of more than one type of feldspar is suggested by the complex 3.2 ft peak. A rat io of the Interference-free 4.04 ft plagloclase peak to the complex 3.2 ft total feldspar peak should indicate changes in the feldspar content (Glbbs, 1967); the rat ios within individual par t ic le s ize - f ract ions show no consistent var iat ion. Ratios in the 5 to 20 um fraction are s l ight ly higher than In the >20 um fract ion, suggesting a small decrease In plagioclase content In the coarser s i l t . - 4 9 -Table 3.2 Unorlented powder mounts, rat ios of areas of X-ray dlffractogram peaks. SAMPLE SIZE-FRACTION 0(4.26 ft) 0(3.34 ft) F(4.04 ft) isml ; clays (4.5 ft? F(3 .20 ft? F(3 .20 ft? EDMS 5 to 20 0.29 0.87 0.40 >20 0.15 1.54 0.35 tota 1 0.10 1.62 0.17 6/4-8 5 to 20 3.53 1.54 0.28 >20 clays (tr) 1.51 0.22 total 0.63 1.26 0.28 6/20-24 5 to 20 3.21 1.85 0.26 total 0.52 1.37 0.30 6/60-64 5 to 20 13.4 0.86 0.28 total 1.18 1.14 0.31 6/120-124 tota 1 0.85 1.60 0.37 8/4-8 5 to 20 3.47 1.58 0.30 >20 7.61 1.19 0.22 total 0.89 1.40 0.34 8/20-24 total 1.67 1.18 0.26 8/60-64 5 to 20 2.54 1.59 0.27 >20 4.62 1.10 0.25 total 0.87 1.49 0.35 10/4-8 5 to 20 5.84 1.96 0.28 total 0.85 1.35 0.36 10/20-24 5 to 20 5.44 1.26 0.25 total 1.33 1.07 0.22 10/60-64 5 to 20 4.29 1.14 0.29 total 1.14 0.94 0.23 10/120-124 5 to 20 5.78 1.43 0.30 >20 4.95 1.69 0.21 total 1.26 1.12 0.23 22/0-4 5 to 20 5.16 1.26 0.27 >20 clays (tr) 0.98 0.13 22/10-12 total 4.86 0.92 0.13 22/60-64 5 to 20 4.23 0.99 0.25 tota 1 5.50 0.92 0.16 31/0-4 5 to 20 4.46 1.27 0.24 >20 12.4 0.78 0.12 total 2.17 0.79 0.19 31/20-24 total 1.93 0.86 0.21 31/66-70 5 to 20 2.86 1.23 0.21 >20 6.67 0.99 0.15 total 1.70 1.52 0.26 31/103-105 total 1.62 2.26 0.18 31/120-124 5 to 20 5.00 0.79 0.21 total 2.22 0.72 0.25 Q=quartz; F=feldspar; tr=trace. - 5 0 -Tota l (untreated) sediment Samples of sediment were analyzed without any pre-treatment or par t i c le - s i ze separation, to try and examine Inter-re IatlonshIps between minerals In the sediment as a whole. Within the sediment the following minerals were Identified (Section 3.2) : quartz, feldspar (more than one type present), carbonate (more than one type l ikely present), ha l i te (In unwashed samples), hematite, llmenlte, r u t l l e , amphlbole, ch lor i te and 11 l i t e . Smectite Is not revealed In the unorlented mounts, even though It was shown to be a s igni f icant part of the f ine grained sediment. The metalliferous sediment (EDMS) Is mlneralogleally quite different than hemlpelaglc sediment (Figures 3.2 and 3.1 respectively) , being almost entirely composed of smectite with only minor amounts of quartz and feldspar. Quartz/total phyIloslIIcate rat ios (0(4.26 ft)/clays (4.5 ft)) for total sediment are lower than the rat ios for 5 to 20 um and >20 um sub-samples, Indicating that the bulk of the phyIloslIIcate minerals are contained within the <5 um f ract ion . A comparison of the mean rat io of quartz to total phyIloslIIcate In f ive cores (Table 3.3) Indicates that sediments from the northwest flank of Explorer Deep (79-06-22 and 79-06-31) have higher quartz content than those from the f loor (79-06-06 and 79-06-08) and from the southeast flank (79-06-10). Core 79-06-22 has considerably higher quartz content than the other cores, l ikely due to the abundance of coarse quartz-r ich mater ial . A subtle difference In the quartz to feldspar rat io (Q(3.34 ft)/ F(3.2 ft); Table 3.3) between sediments of the flanks and the f loor of - 5 1 -Table 3.3 Average dlffractogram peak area ratios In total (untreated) samples of sediment In cores from the Explorer Deep area. Data are from Table 3 . 2 . SAMPLE RATIOS OF X-RAY DIFFRACTOGRAM PEAKS 0(4.20 ft) 0(3.34 ft) F(4.04 ft) clays (4.5 ft) F(3.20 ft) F(3.20 ft) EDMS 0.10 1.62 0.17 79-06-06 0.80 1.34 0.32 79-06-08 1.14 1.36 0.32 79-06-10 1.14 1.12 0.26 79-06-22 4.22 0.92 0.14 79-06-31 1.93 1.23 0.22 Q = quartz; F = feldspar; clays = total phyl losl1Icate. Explorer Deep, suggests a possible s l ight feldspar enrichment on the f lanks. Ratios for samples at 103-105 cm and 66-70 cm In core 79-06-31 are higher than the other three determinations. These two zones were sampled due to their anomalous appearance (Figure A.12). No consistent variation of the quartz/feldspar rat io to sediment thickness Is evident. The rat io of plagloclase to total feldspar (F(4.04 ft)/F(3.2 ft)) Is quite constant for a l l the samples analyzed, except EDMS. Considerable variation Is evident between unorlented powder mounts of 5 to 20 um, >20 um and total (untreated) sub-samples of EDMS (Table 3 .2 ) , l ikely ref lect ing errors In measurement of peaks areas due to small peak s i ze . Mean rat io values show a s l ight plagloclase enrichment In cores from the floor compared to the flanks (Table 3 .3 ) . The highest values of plagloclase/total feldspar are In metall iferous sediment (EDMS) sub-samples 5 to 20 um and >20 um. The variat ion In feldspar composition Is very subtle, and more data are required before the presence of a real variation In feldspar distr ibution can be confirmed. - 5 2 -4. CHEMISTRY 4.1 INTRODUCTION The distr ibution of elements within marine sediments Is dictated by the relat ive contributions of terrigenous, biogenic, hydrogenous and hydrothermal components. Once deposited the sediment is subjected to modification by diagenetic processes. In th is chapter chemical analyses of sediments and volcanic rocks from the Explorer Deep area are used to examine relat ive contributions of the four components to the total sediment. The prime objectives are to Indicate whether a hydrothermal component Is present In sediments from Explorer Deep, and If so to estimate the extent of the contribution. In th is study two samples of volcanic glass plus eighty-six samples of sediment from twelve cores were chemically analyzed for both major and minor elements (see Table 1.1 for a l i s t of sample locations). The samples were analyzed for sixteen elements plus loss-on-lgnltton (data are In Appendix C). In addition surface samples from the cores were scanned for molybdenum; however the concentrations were below the detection l imit of the Instrument ( le . below 10 ppm Mo, at the Instrument setting used). Al l chemical analyses were by X-ray fluorescence as described In Appendix B. Chave and Mackenzie (1961) suggest a model where. In a group of chemical analyses of pelagic sediments, the highest correlation coeff ic ients between element concentrations would be between those elements which occur In the same mineral. Using the chemical analyses for sediments from the Explorer Deep area, a set of Inter-element correlation coeff ic ients were calculated (Table 4.1) . Interpretation of correlation coeff ic ients In closed number systems (such as percentages or ppm data) Is subject to l imitations (Chave and Mackenzie, 1961; Krumbeln and Grayb l l l , 1965; Cronan, 1969a), since as one component Increases the others must naturally decrease. It Is l ikely that the Inter-element correlation coeff ic ients calculated In th is study (Table 4.1) suffer from these l imitat ions. In an attempt to l imit variance due to variations In the amount of terrigenous material , the data were normalized to aluminium (assuming that aluminium Is contained exclusively In the terrigenous component) and a second set of cor -relation coeff ic ients calculated (Table 4.2) . Elemental concentrations In sediments from the Explorer Deep area are displayed In histogram form; the data Include surface samples from twelve cores plus down-core analyses for f ive of the cores. Vertical elemental distr ibutions In the f ive cores are also considered using element/aluminium rat io versus depth plots. Aluminium Is considered to be contained almost exclusively within terrigenous minerals In marine sediments (Bostrom, 1970, 1973; Piper, 1973; Chester and Aston, 1976; Pedersen, 1979). Normalization of element concentrations to aluminium tends to minimize the ef fects of di lution by biogenic debris, permitting the Investigation of element distributions In the non-blogenlc phases without calculating concentrations on a carbonate-free basis (Piper, 1973; BonattI, 1975; Pedersen, 1979). Investigation of re lat ive contributions of terrigenous and non-terrigenous components Is accomplished by part i t ioning whole sediment analyses using measured Table 4.1 Inter-element correlation coeff icients (r) for sediments from the Explorer Deep area. A total of eighty-six samples (n=86) were used (except Ba with n=85), Including a l l surface samples plus vert ical samples from five cores (Appendix C). Coefficients were calculated using a TI—55—11 calculator . Al l data are on a sa l t - f ree basis. Al 1 Ba -0.77 1 Ca 0.17 -0.87 1 Co 0.17 -0.10 -0.03 1 Cu -0.14 0.18 -0.04 0.26 1 Fe 0.48 -0.20 -0.12 0.47 0.37 1 Mg 0.62 -0.44 0.15 0.54 0.36 0.80 1 Mn -0.14 0.06 -0.06 0.19 0.07 0.14 -0.06 1 Nl -0.69 0.87 -0.59 0.13 0.20 -0.09 -0.31 0.06 1 P 0.68 -0.70 0.38 0.12 0.02 0.08 0.58 0.24 -0.73 1 K 0.51 -0.22 -0.14 0.25 0.00 0.37 0.41 -0.22 -0.06 0.18 1 Na -0.17 0.22 -0.34 -0.02 0.14 0.05 0.00 0.02 0.10 -0.09 -0.45 1 SI 0.13 0.19 -0.60 -0.32 -0.37 -0.23 -0.41 0.01 0.07 -0.18 -0.10 0.05 1 Tl 0.72 -0.35 -0.14 0.28 0.13 0.66 0.77 -0.14 -0.31 0.56 0.65 -0.12 -0.06 Zn -0.62 0.89 -0.61 0.14 0.41 0.07 -0.12 0.00 0.88 -0.60 -0.01 0.13 -0.05 Al Ba Ca Co Cu •Fe Mg Mn Ni P K Na Si level of significance (n=86): 95% confidence level r=0.18; 99% confidence level r=0.25. Table 4.2 Inter-element correlation coeff ic ients (r) for sediments from the Explorer Deep area. Element concentrations are normalized to aluminium. A total of eighty-six samples (n=86) were used, (except Ba/AI with n=85) Including a l l surface samples plus vert ical samples from f ive cores (Appendix C). Coefficients were calculated using a TI—55—1 I calculator . Al l data are on a sa l t - f ree basis. Ba/AI 1 Ca/AI -0.45 1 Co/AI 0.31 -0.16 Cu/AI 0.51 -0.43 Fe/AI 0.80 -0.14 Mg/AI 0.19 0.09 Mn/AI 0.19 -0.02 NI/AI 0.90 -0.39 P/AI -0 .59 0.30 K/AI 0.37 -0.26 Na/AI 0.57 -0.24 SI/AI 0.83 -0.28 TI/AI 0.60 -0.36 Zn/AI 0.93 -0.36 Ba/AI Ca/AI 1 0.40 1 0.54 0.65 1 0.57 0.57 0.68 0.31 0.18 0.35 0.48 0.50 0.63 -0.17 -0.15 -0.08 0.23 0.16 0.24 0.22 0.39 0.43 0.15 0.30 0.36 0.34 0.44 0.62 0.46 0.66 0.72 Co/AI Cu/AI Fe/AI 1 0.08 1 0.27 0.16 1 0.14 0.29 -0.66 0.16 -0.12 0.45 0.20 0.13 0.46 -0.14 0.22 0.73 0.59 0.08 0.56 0.41 0.11 0.91 Mg/AI Mn/AI NI/AI 1 -0.34 1 -0.26 -0.13 1 -0.57 0.14 0.62 -0.11 0.50 0.26 -0.56 0.45 0.50 P/AI K/AI Na/AI 1 0.29 1 0.67 0.66 1 SI/AI TI/AI Zn/AI level of significance (n=86): 95% confidence level r=0.18; 99% confidence level r=0.25. oxide/alumina ratios and subtracting the values for average "Pac i f i c pelagic clay" suggested by Landergren (1964). Relative contributions by Individual clay-minerals to the elemental composition of the whole sediment are determined by correlating ratios of areas of XRD peaks for clay minerals and element/aluminium ratios (Table 4.3) . Al l chemical data used In this study are calculated on a sa l t - f ree basis using the measured chlorine content and average composition of normal sea water (as described in Appendix B) . In th is chapter elemental compositions of sediments from the Explorer Deep area are compared to other chemical analyses of sediments from the northeast Paci f ic region (Table 4.4) . Several attempts have been made to recognize geochemlcally dist inct sedimentary units within the upper few metres .of the sedimentary column (Bornhold et a I.r 1981; Pr ice , 1981). Local occurrences of metalliferous sediments, l ikely of hydrothermal o r ig in , have been reported from the northeast Paci f ic (Piper £ t _ a ± . , 1975; Bornhold £ ± _ a i . , 1981; Gr i l l et a l . r 1981; Pr ice , 1981; Delaney et a I . f 1982). Elemental compositions of "average shale", average "deep-sea clay" and average "Pac i f ic pelagic clay" have been suggested (Goldberg and Arrhenlus, 1958; El Wakeel, and Ri ley, 1961; Tureklan and Wedepohl, 1961; Landergren, 1964; Bostrom and Petersen, 1969; Cronan, 1969b). Chemical analytical data are available for volcanic rocks recovered from the northeast Paci f ic spreading centres (Engel and Engel, 1963; Kay et a I.. 1970; Bertrand, 1972; Mel son et a I.. 1976; Cousens, 1982), and for typical oceanic basalts (Tureklan and Wedepohl, 1961). - 5 7 -Table 4.3 Correlation coeff ic ients between element/aluminium concentration rat ios and clay mineral X-ray d i f f ract ion peak area ratios for sediments from the Explorer Deep area. A total of fourteen sample pairs (n=14) were used In the calculat ion. Correlation coeff ic ients were calculated using a T I - 5 5 - l l ca lculator . ELEMENT RATIOS1 CLAY MINERAL XRD PEAK AREA RATIOS2 1002(10 ft) K+C(7 ft) S00K18 ft) 1002(10 ft) S00K18 ft) K+C(7 ft) Al -0.37 -0.55** -0.64** Ba/AI 0.53** 0.50* 0.69** Ca/AI -0.37 -0.47* -0.58** Co/AI 0.21 0.24 0.27 Cu/AI -0 .19 -0.37 -0.31 Fe/AI 0.34 0.44 0.50*' K/AI 0.58** 0.14 0.25 Mg/AI 0.17 -0.14 -0 .09 Mn/AI -0.21 0.34 0.29 Ni/AI 0.52* 0.62** 0.75** P/AI -0.41 -0.47* -0.56** SI/AI 0.30 0.58** 0.67** TI/AI 0.47* 0.03 0.12 Zn/AI 0.58** 0.43 0.60** * signif icant at 95% confidence level ; ** signif icant at 99% confidence level ; 1) a l l data are on a sa l t - f ree basis (see Appendix C for compIete chemical analyses); 2) I = II l i t e , K+C = kaolInite+chlorIte, S = smectite for (0.2 to 2 um) Mg-saturated glycerol-solvated oriented sample preparation (see Table 3 .2) . -58-Table 4.4 Chemical composition of sediments from the northeast Pac i f i c , near the Explorer Deep study area. SAMPLE SI ELEMENTAL CONCENTRATIONS (weight percent) AL Mn T1 Na Ca Ba (parta-per-ml LLIon) Co Cu Mo Nl Zn 1 Bf Explorer Deep [avg. sfc. samples) Explorer Deep (avg. a l l samples)^ Juan de Fuca Ridge (unit #1)2 Juan de Fuca Ridge [unit #2) Juan de Fuca Ridge [unit #3) 77-07/0 ca 3 77-08/0 cm 77-09/0 cm 77-10/0 cm 4 average s h a l e ^ deep-sea c l ay 8 f Pacific pelagic c lay c f 5 Pacific pelagic c lay c f 26.47 7.55 5.06 1.72 0.16 0.48 2.89 2.04 1.54 0.05 2150 19 37 <10 92 124 25.9 8.05 5.13 1.87 0.09 0.51 2.82 3.1 1.70 0.05 1370 21 38 nd 75 112 21.72 6.68 5.08 nd 0.22 0.40 nd 4.51 nd nd nd 22 105 nd 123 128 24.56 7.96 4.66 nd 0.11 0.50 nd 3.70 nd nd nd 17 48 nd 51 111 21.12 7.34 4.40 nd 0.15 0.40 nd 6.55 nd nd nd 24 69 nd 69 230 nd nd 5.00 nd 0.07 nd nd 3.40 nd nd nd 16 38 13 37 100 nd nd 5.40 nd 0.10 nd nd 3.00 nd nd nd 18 48 11 43 112 nd nd 4.95 nd 0.14 nd nd 1.60 nd nd nd 14 58 12 68 148 nd nd 5.40 nd 0.10 nd nd 1.70 nd nd nd 17 74 8 98 192 27.30* 8.00 4.72 1.50 0.08 1.38 0.95 2.21 2.66 0.07 580 19 45 3 68 95 25.99 8.73 6.76 1.96 0.70 0.48 2.83 2.86 2.46 0.16 2390 77 260 28 234 172 23 9.2 6.5 2.1 1.2 0.73 4.0 2.9 2.5 nd 3900 160 740 nd 320 nd 25.7 8.8 5.4 2.05 1.29 0.42 0.96 0.51 2.24 nd 1200 150 560 nd 210 85 sf = salt-free; cf = carbonate-free; nd = not determined; * assumed value [1e. presented value 73 000 ppm SI is Likely a misprint); 1] average composition of surface samples and a l l samples in cores from the Explorer Deep area (this study); 2) Juan de Fuca Ridge sediments, average composition of "geochemical units" (#1 is uppermost unit; Price, 1981); 3] composition of surface samples In cores 77-07 and 77-08 from northwest flank of Explorer Deep, and cores 77-09 and 77-10 from southeast flank of Explorer Deep [Bo mho Id et a l . . 1981); 4) after Tureklan and Nadepohl (1961), data corrected for interetltleL-selt using reported chlorine content and the technique described in Appendix B; 5] after Goldberg and Arrhenius (1958); 6] after Landersren (1964); and Landersren and Manheim (1963) cited In Sayles and Bischoff (1973). 4.2 CHEMICAL COMPOSITION OF SEDIMENTS FROM THE EXPLORER DEEP AREA 4.2.1 MAJOR ELEMENT CHEMISTRY Distribution of Aluminium Aluminium In deep-sea sediments Is primarily associated with the terrigenous fraction (Bostrom, 1970, 1973, 1976; Piper, 1973; Chester and Aston, 1976; Pedersen, 1979), pr incipal ly in phyIlos11icates, feldspars, amphiboles, pyroxenes and pyroclastlc materials. Hydrogenous minerals such as zeol i tes and smectites may also contribute aluminium to the whole sediment, although typical ly the hydrogenous component has only a minor Influence on aluminium distr ibution in marine sediments. Sediments from the Explorer Deep area have a mean aluminium concen-tration of 8.05$ (Figure 4.1) which Is comparable to the aluminium content of "average shale" (8.0$ A l ; Turekian and Wedepohl, 1961) and average "Pac i f ic pelagic clay" (8.8$ A l ; Landergren, 1964). The mean aluminium content In Explorer Deep sediments ref lects a dominance of terrigenous material consistent with the high rates of hemlpelaglc sedimentation character ist ic of the study area; however In detail the aluminium distr ibution Is complex with at least two compositional modes present (Figure 4.1) . Surface samples, plus cores from the floor of Explorer Deep (79-06-06 and 79-06-08) have relat ively low aluminium concentrations, while cores from the flanks (79-06-10, 79-06-22 and 79-06-31) have higher aluminium contents. In core 79-06-10 ,the low aluminium content of su r f l c la l sediments extends to 20 cm; the remainder of the core has a considerably higher aluminium content. The low aluminium sample In core 79-06-22 (10-11 cm; Figure 4.2) corresponds to -60-20 cu o S-cu CL >•> o c: cu cr CD i-10 -n=86 x=8.05 S=0.61 CI=0.20 7 8 9 aluminium (weight percent) ' 10 Fig. 4.1 Histogram for aluminium concentration in sediments from the Explorer Deep area. All data are on a sa l t - f ree basis. — =surface sediments; V//A =core 79-06-06; ^ =core 79-06-08; • =core 79-06-10; 1323 =core 79-06-22; lljrjJJ =core 79-06-31. a carbonate-rich sample (12.66$ Ca). Cores 79-06-06, 79-06-10 and 79-06-31 have surface alumtnium-mlnima, and the aluminium content in a l l f ive core remains constant or Increases s l ight ly with depth. Weighted average aluminium concentrations in cores from the floor of Explorer Deep (7.63-7.83$ A l ; Figure 4.2) are s igni f icant ly lower than those for cores from the flanks (8.15-8.70$ A l ) . If the assumption that aluminium Is exclusively associated with the terrigenous fraction is correct, then sediments from the floor of Explorer Deep have lower terrigenous mineral content than those from the f lanks. The clay mineralogy data (see Chapter Three) show variations in the smectite content, which may help explain the aluminium distr ibut ion. -61 -ALUMINIUM (weight percent) 7 8 6 7 8 7 8 9 6 7 8 9 8 9 (AW.68) 79-06-31 (AT=8.70) Fig. 4.2 Aluminium profi les for cores from Explorer Deep. The data are on a sa l t - f ree basis. AT is weighted average concentration aluminium. Surface samples from al l f ive cores analyzed have similar smectite contents; however, with depth smectite content decreases markedly in cores from the flanks of Explorer Deep, while in cores from the floor smectite content remains constant or Increases s l ight ly with depth. Strong negative correlations between aluminium content and the smectite ratios (Table 4.3) indicate that some of the smectite is aluminium-poor compared to average terrigenous minerals. Variations In the smectite content in Explorer Deep sediments appears to be in part responsible for observed distr ibution of aluminium. -63-Distribution of SI I Icon Si l icon is the dominant element on the Explorer Deep sediments; the si I lea content commonly exceeds f i f t y weight percent (Appendix C). Si l icon is contributed to marine sediments in four phases: biogenic, terrigenous or IIthogenous, hydrogenous and hydrothermal. The principal si l icon-bearing mineral Is detr ltal quartz; a IumlnoslIIcates also form an Important group of s i l icon-bearing minerals which Includes feldspars, phyIlosiIIcates, amphlboles, pyroxenes and pyroclastic materials (Chester and Aston, 1976). Opaline s i l i c a In marine sediments is primarily the result of biological ac t i v i t y . Authlgenic processes including "reverse weathering" (reactions Involving dissolved s i l i con and degraded alumlnoslIIcates), formation of authlgenic s i l i c a t e s , and formation of secondary authlgenic minerals (eg. zeol i tes and smectites) also may contribute s i l i con to the sediment (Calvert, 1974; Chester and Aston, 1976). Although the primary source of s i l i con for authlgenic processes is dissolution of biogenic opaline s i l i c a , hydrothermal sources are locally Important (Krauskopf, 1959; L is l t syn , 1967; Calvert, 1974; Chester and Aston, 1976; Pr ice , 1976; Edmond et a I.f 1979). Si l icon In sediments from the Explorer Deep area is normally d i s t -ributed (Figure 4.3) with a mean of 25.9% SI, a value similar to that of average "Pac i f ic pelagic clay" (25.1% S i ; Landergren, 1964) and of average "deep-sea clay" (25.99$ S i ; Tureklan and Wedepohl, 1961). Prof i les of the vert ical distr ibution of the si IIcon/alumlnlum rat io for cores 79-06-06 and 79-06-08 show maximum values at or near the surface, and a general decrease with depth (Figure 4.4) ; the anomalously high -64-20 22 24 26 28 30 s i l i con (weight percent) Fig. 4.3 Histogram for s i l i con concentration in sediments from the Explorer Deep area. All data are on a sa l t - f ree basis. •=surface sediments; E22=core 79-06-06"> ^ = c o r e 79-06-08; . CZ]=core 79-06-10; E3=core 79-06-22; (LTD =core 79-06-31. value at 20 cm In core 79-06-08 coincides with a low-alumlnlum content (Appendix C). Cores from the flanks (79-06-10, 79-06-22 and 79-06-31) a l l show pronounced surface maxima. The variable si I Icon/alumlnlum ratios and high quartz/total phyIlosiIIcates ratios (Table 3.3) In cores 79-06-22 and 79-06-31 l ikely ref lect high quartz content of the coarser sediment (evident in Figures A.09 and A.12). In core 79-06-10, s i l i con/ aluminium ratios are relat ively constant below the surface maximum ( le . below 20-22 cm). Weighted average si IIcon/alumlnlum values for cores from the floor of Explorer Deep (SI/AI=3.3-3.4, for cores 79-06-06 - 6 5 -Si/Al u in I— Q -L U Q 79-06-08 Fig. 4.4 (WAT=3.'33) Silicon/aluminium profi les for cores from the Explorer Deep area, free basis. Si/Al is weighted average value for S i/Al . 79-06-31 0 20 40 60 80 100 -I 120 - 140 J 160 m -o —I n (Si/Al=2.97) Al l data are on a salt -and 79-06-08) are higher than those of cores from the flanks (SI/AI= 3 . 0 - 3 . 2 , for cores 79-06-10, 79-06-22 and 79-06-31). The high s i l icon/ aluminium, low quartz/clays ratios for cores from the floor of Explorer Deep suggest that a mineral with a low aluminium content Is present In larger quantities In the deep than on the flanks; l ikely candidates are smectite (see Chapter Three) and biogenic opal . Rledel (1959) and Ltsltsyn (1967) show that In the Explorer Deep area, opal commonly forms between one and ten percent of the total sediment. S i l i c a In surface samples from the Explorer Deep area may be partitioned Into terrigenous and non-terrigenous components assuming that the si IIca/alumlna rat io for average "Pac i f ic pelagic clay" (Sl02/Al20j=3.31; Table 4.5) Is due solely to a terrigenous component, and that the Explorer Deep sediments have a similar component. Non-terrigenous s i l i c a contents calculated by th is method range between six and thirteen weight percent (Table 4.5) , consistent with the values of Rledel and L l s l t syn . Since the non-terrigenous s i l i c a content was calculated by subtracting a constant, prof i les of non-terrigenous s i l i c a for the f ive cores (Figure 4.5) mimic the si I Icon/a Iumlnlum prof i les (Figure 4.4) . A general decrease In non-terrigenous s i l i c a with depth Is evident In a l l cores, suggesting that regionally, rates of production of biogenic skeletal s i l i c a have Increased, and/or rates of hemlpelaglc sedimentation have decreased. While dissolution of opal does occur with bur ia l , the thickness of section considered here Is l ikely Insufficient for dissolution to account for the large decrease Indicated. The strong negative correlation coeff ic ient between s i l i con and - 6 7 -Table 4.5 Part it ioning of s i l i c a between terrigenous and non-terrigenous components In surface sediments from the Explorer Deep area. All data are on a salt free basis. SAMPLE s i o 2 WEIGHT PERCENT SI02* A l 2 0 3 NON-TERRIGENOUS** TERRIGENOUS T0TAI 1/0-2 4.03 9.7 44.3 54.0 2/0-2 3.79 7.1 49.2 56.3 4/0-2 3.99 9.4 45.9 55.3 6/0-2 3.96 9.0 45.9 54.9 7/0-2 3.71 " 5.9 48.8 54.7 8/0-2 4.11 11.1 46.0 57.1 10/0-2 4.01 10.0 47.1 57.1 21/0-2 4.02 10.2 47.5 57.7 22/0-1 4.12 12.2 49.8 62.0 29/0-5 4.09 10.7 45.2 55.9 30/0-2 4.13 11.3 45.3 56.6 31/0-2 3.74 6.6 51.1 57.7 *the value Si02/Al203=3.31 was used here for the terrigenous component, as determined for average "Paci f ic pelagic clay" (after Landergren, 1964); th is value compares we I I with that for deep-sea clay (SIO2/A12^3=^«37; Tureklan and Wedepohl, 1961), but Is less than that compiled by El Wakeel and Riley (1961) of S 1 0 2 / A I 2 ° 3 = 5 « 4 8 f ° r "average pelagic sediment" (which Included s f l i c lous deposits) and Is greater than that complied by Goldberg and Arrhenius (1958) of SI02/Al203=2.83 for average "Pac i f i c pelagic c lay" . **the non-terrigenous fraction wi l l Include biogenic and hydrogenous s i l i c a present In the sediment. Hydrogenous s i l i c a enrichment may be s ignif icant In volcanlcally active areas such as Explorer Deep, where hydrothermal emanations, enriched In s i l i c a (Edmond et a I.. 1979b), may be local sources of s i l i c a . - 6 8 -NON-TERRIGENOUS SiOo (weight percent) 0 5 10 15 0 5 10 15 20 0 5 10 15 0 5 10 15 0 5 10 | 1 1 1 | 1 1 1 1 I 1 1 1 | 1 1 1 I 1 1 Fig. 4.5 Profi les showing down-core distribution of the partitioned non-terrigenous s i l i c a component in cored sediments from the Explorer Deep area. A ratio of S i 0 2 / A l 2 ° 3 = 3 • 3 1 f ° r average "Paci f ic pelagic clay" (after Landergren, 1964) was used in the partit ioning calculat ions. Al l data are on a sal t - f ree basis. S i0 9 is weighted average value for S i 0 ? . calcium In sediments from the Explorer Deep area (r=-0.60; Table 4.1) suggests an Inverse relationship for the distr ibution of the two elements. The correlation between si IIcon/alumlnlum and calcium/ aluminium (r=-0.28; Table 4 .2) Is s t i l l negative; however, the strength Is considerably less than for the non-normalized data. Posit ive correlations between si IIcon/alumlnturn and the smectite rat ios (Table 4 .3) Indicate an association. Ratios of si I Icon/a Iumlnlum are higher In sur f lc la l sediments from a l l twelve cores, and at depth In sediments from the floor of Explorer Deep, than at depth In sediments from the flanks (Figure 4.4), which may be due In part to the corresponding abundance of alumlnlum-poor smectite In sediments from the f loor . - 7 0 -Distribution of Calcium Calcium Is present in marine sediments pr incipal ly as biogenic calcium carbonate. The terrigenous fraction may contain calcium in a number of minerals including phyIloslIIcates, feldspars, amphiboles, pyroxenes, detr ltal carbonates and pyroclastlc materials (Chester and Aston, 1976). Authigenic and hydrogenous minerals such as zeol ites and smectites may also contain calcium. The histogram of calcium concentrations In sediments from the Explorer Deep area (Figure 4.6) shows a complex elemental d ist r ibut ion, strongly posit ively skewed, with at least two populations. Cores from the floor of Explorer Deep (79-06-06 and 79-06-08) plus the surface samples from al l cores form a low calcium population, while cores from the flanks (79-06-10, 79-06-22 and 79-06-31) form a higher calcium content grouping. Concentrations range between 1.63 to 12.66$ Ca, with a mean of 3.1$. The content of average "deep-sea clay" (2.86$ Ca; Tureklan and Wedepohl, 1961) compares favourably with that of the Explorer Deep sediments. The calcium/aluminium prof i le for core 79-06-06 Is very uniform over the entire length (Figure 4.7) , with a weighted average value of Ca/AI=0.23. The prof i le for core 79-06-08 shows maxima at 20 cm and at the base, with a higher weighted average (Ca/AI=0.36). A s l ight overall Increase In Ca/AI with depth of burial Is evident In core 79-06-10 and a maximum occurs between 40 to 60 cm. The prof i le for core 79-06-22 Indicates a general Increase In Ca/AI with depth of bur ia l ; a pronounced -71 -3 0 - , c cu o s_ cu a. o c cu CT CU s-<4-n=86 x=3.1 S=1.43 CI=0.50 I ' I ' I • I I I I I I I I 6 7 8 9 10 11 12 calcium (weight percent) 13 Fig. 4.6 Histogram for calcium concentration in sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis. =surface samples; ff7Z\ =core 79-06-06; =core 79-06-08; • =core 79-06-10; E£3 =core 79-06-22; QjrrjJ =core 79-06-31. maximum between 10 and 20 cm corresponds to a foramlnIfera-rich zone observed In the core (Figure A.9) . The abundant foramlnlferal debris l ikely originated at or near the crest of Paul Revere Ridge, and was transported to the valley f loor (at station 79-06-22) by gravity-Induced slumping or as a density current, rather than representing a period of locally Intense biological productivity. The Ca/AI p ro f i le for core 79-06-31 has a local minimum at 103 cm, and maxima at 60 cm and at the base. It Is Interesting that the basal samples from cores 79-06-08 and 79-06-31 (at 150 and 160 cm respectively) are both calc lum-r lch. - 7 2 -Ca/AI 0.2 0.3 0.3 0.5 0.7 0.3 0.5 0.7 0.3 0.5 0.7 0.3 0.5 (Ca7AT=0.36) 79-06-31 (Ca7AT=0.42) Fig. 4.7 Calcium/aluminium profi les for cores from the Explorer Deep area. All data are on a s a l t -free basis. Ca/AI is weighted average value for Ca/AI. Note dif ferent scale for 79-06-06. Chemical analyses for three long cores from the Explorer Deep area obtained by the Geological Survey of Canada (Bornhold et a I., 1981) show calcium maxima at 174 cm In core #7 and at 150 cm In core #10; the only analyses available for core #8 are at 146 cm and 190 cm, and no calcium maximum Is evident. The vert ical and horizontal extent of these calclum-rlch sediments remains unclear, but may represent a period of increased carbonate deposition ref lect ing an Increase In organic productivity or an extensive turbidity current deposit. More data are required before a correlation can be properly made. Most of the calcium In sediments from the northeast Pac i f ic occurs as biogenic calcium carbonate (Bornhold et a I., 1981; Pr ice , 1981). Partit ioning of surface samples from the twelve cores Into biogenic and non-blogenlc fractions was accomplished assuming for the terrigenous fraction the ratio CaO/A1203=0.043 (for average "Pac i f ic pelagic c lay" ; Table 4.6) , and subtracting to separate the biogenic component. The data Indicate that In surface sediments from the Explorer Deep area, between 70 and 85$ of the total calcium content Is biogenic. The terrigenous calcium contribution remains quite constant over the study area at approximately 0.6 wt.$ CaO. Variations In the calcium concentration are therefore considered to ref lect differences In the carbonate content In the sediment ( le . with a terrigenous background contribution of 0.6 wt.$ CaO). A strong negative correlat ion exists between the rat io of calcium/ aluminium In surface samples from the Explorer Deep area and Increased water depth (Figure 4.8) . Riley and Chester (1971) placed the lysocllne - 7 4 -Table 4.6 Part it ioning of calcium between terrigenous and biogenic components in surface sediments from the Explorer Deep area. All data are on a sa l t - f ree basis. SAMPLE CaO WEIGHT PERCENT CaO* A l 2 0 3 BIOGENIC TERRIGENOUS TOTAL 1/0-2 0.169 1.69 0.58 2.27 2/0-2 0.121 1.72 0.63 2.35 4/0-2 0.217 2.41 0.60 3.01 6/0-2 0.167 1.73 0.59 2.32 7/0-2 0.186 2.11 0.63 2.74 8/0-2 0.198 2.15 0.60 2.75 10/0-2 0.202 2.27 0.61 2.88 21/0-2 0.174 1.88 0.62 2.50 22/0-1 0.255 3.19 0.65 3.84 29/0-5 0.215 2.35 0.59 2.94 30/0-2 0.190 2.01 0.59 2.60 31/0-2 0.267 3.47 0.66 4.13 *the value CaO/AI203=0.043 was used here for the terrigenous component, as determined by Landergren (1964) for 'carbonate-free' average "Paci f ic pelagic c lay" ; th is value Is considerably less than that determined by Goldberg and Arrhenlus (1958) of CaO/AI203=0.23 for 'carbonate-free' average "Pac i f ic pelagic c lay" . -75 -Fig . 4.8 Correlation between water depth and calcium to aluminium rat io for surface sediments from the Explorer Deep area. All data are on a sa l t - f ree basis. Bes t - f i t l ine determined by linear regression. at approximately -2500 m water depth In the Explorer Deep area, and the carbonate compensation depth (CCD) at about -3000 m, as did Berger and Winterer (1974). Data In th is study tend to support this depth for the lysocllne and suggest that variations in the calcium contents In sediments over the study area are primarily due to dissolution of calcium carbonate with increasing water depths. Using the Explorer Deep data, the CCD occurs at -4280 m (calculated by extrapolation to the value for average "Pac i f ic pelagic clay" of Ca/AI=0.06; Landergren, - 7 6 -t 1964), which Is considerably deeper than that suggested by Riley and Chester (1971) and Berger and Winterer (1974). Part of the discrepancy may be due to method used In this study to calculate the CCD; the simple linear relationship between carbonate dissolution and water depth used Is undoubtedly an oversimplif ication of the process. In addition, the rapid transport of biogenic carbonate to the sea floor by density currents or within fecal pel lets protected by organic membranes (Honjo and Roman, 1978) results in low exposure-time during transit through the water column, and potentially Increased preservation. The highly pel let l ferous nature of most of the sediment recovered in cores from the study area (see Appendix A), and the relat ively uncorroded nature of coccollths observed in scanning electron-micrographs of several of the pel lets (personal communication from J .P . Syv l tsk l , University of Calgary) suggests that the latter Is certainly a factor In the Explorer Deep area. 7 7 -Distribution of Phosphorus Phosphorus occurs In marine sediments In a number of forms; In detr l tal minerals (principally apat i te) , adsorbed on or occluded In skeletal material . In organic matter, disorganized ferriphosphates and associated with oxide coatings on minerals (Bender, 1973; E lder f ie ld , 1976; Chester and Aston, 1976; Froellch et al . . 1977; Pedersen, 1979). Concentrations of phosphorus in sediments from the Explorer Deep area have a s l ight ly skewed distr ibution (Figure 4.9) , with a mean of 0.054$ P. The phosphorus content of sediments from the Explorer Deep area is lower than that of average "deep-sea clay" (0.15$ P; Turekian and Wedepohl, 1961), but Is similar to "average shale" (0.07$ P; Turekian and Wedepohl, 1961). Phosphorus levels In cores from the floor of Exp I orer Deep (79—06—06 and 79—06—08) group at the low phosphorus end of the dist r ibut ion, while sediments from the flanks (cores 79-06-10, 79-06-22 and 79-06-31) form the higher phosphorus end. Phosphorus concentrations In surface samples range over the entire distr ibution of values and are not s igni f icant ly different from the down-core determinations. The vertical distr ibution of phosphorus was examined In f ive cores from the study area using phosphorus/aluminium ratios (Figure 4.10). The prof i les show a high degree of var iab i l i t y In a l l cores; however the range In values Is small (P/AIO.003 to 0.010). Weighted average phosphorus/aluminium values In sediments from the floor of Explorer Deep (P/AI=0.005 to 0.006) are s l ight ly smaller than those, from the flanks (P/AI=0.007 to 0.009), consistent with the bulk sediment phosphorus concentration distribution (Figure 4.9) . 30 - , n=86 x=0.054 S=0.017 CI=0.005 phosphorus (weight percent) F ig . 4.9 Histogram for phosphorus concentration in sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis, H =surface samples; X/7A =core 79-06-06; £Sg =core 79-06-08; | [ =core 79-06-10; EH) =core 79-06-22; [{TJJJ =core 79-06-31. Phosphorus correlates poorly with Iron (r=0.08; Table 4 .1) , s imilar ly a poor correlation Is evident between phosphorus/aluminium and Iron/alumlnlum (r=-0.08; Table 4.2) , Indicating that the association between phosphorus and Iron oxide seen In some other marine sediments (Berner, 1973; Froellch et a I.r 1977) may be relat ively unimportant In the Explorer Deep area. A good correlation Is evident between non-terrigenous Iron (calculated using Fe203/Al203=0.464 as terrigenous contribution; Table 4.7) and total phosphorus In sur f lc la l sediments (Figure 4.11), and Indicates that an association does ex ist . The large y-Intercept (0.08$ P2O5? Implies that most of the phosphorus does not - 7 9 -0.4 0.6 i—i—i—r—) P/AI (X10~2) 0.4 0.6 0.8 0.4 0.6 0.8 0.4 0.6 0.8 1.0 0.6 0.8 1.0 1—I I—I—I—I—I 1—I I—I 1—I—I—I i CO o 79-06-10 (P7AT=0.007) 79-06-08 (P/AI =0.007) -|0 20 40 60 o m 8 0 ^ H100 H120 140 -1160 Fig. (P/AI=0.006) 4.10 Phosphorus/aluminium profi les for cores from the Explorer Deep area, sal t - f ree basis. P/AI is weighted average value P/AI. 79-06-31 (P/AI=0.009) All data are on a Table 4.7 Partitioned non-terrigenous Iron and total phosphorus In surface sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis, expressed as weight percent oxide equivalent. SAMPLE* F e ^ / A l o O y NON-TERRIGENOUS Fe 2 0 3 ** TOTAL P 2 0 5 1/0-2 0.558 1 .26 0.16 2/0-2 0.464 0 0.08 4/0-2 0.513 0.68 0.13 6/0-2 0.542 1.08 0.12 7/0-2 0.516 0.77 0.11 8/0-2 0.566 1.42 0.15 10/0-2 0.496 0.46 0.11 21/0-2 0.522 0.83 0.13 22/0-1 0.421 0 0.09 29/0-5 0.519 0.75 0.09 30/0-2 0.536 0.99 0.10 31/0-2 0.462 0 0.11 * for complete chemical analyses see Appendix C. ** non-terrigenous Iron calculated by subtracting the Iron/alumlna rat io for average "Pac i f i c pelagic clay" (Fe 2 0 3 /Al 2 0 3 =0.464; after Landergren, 1964); th is rat io Is lower than values proposed by Goldberg and Arrhenlus (1958) of Fe203/AI nth =0•535 for average "Paci f ic pelagic clay" and by Turekian and Wedepohl (1961) of Fe 20 3/Al 20 3=0.774 for average "deep-sea c lay" . -81 -0.20-1 0 0.5 1.0 1.5 2.0 non-terrigenous Fe?0o (weight percent) F ig . 4.11 Correlation between phosphorus and non-terrigenous Iron In sur f l c la l sediments from the Explorer Deep area. Non-terrigenous Iron was calculated using F6203/^1203=0.464 (after Landergren, 1964) for the terrigenous component (see Table 4.7) . Al l data are on a sa l t - f ree basis. Bes t - f i t l ine determined by linear regression. not occur as ferr I phosphate In sediments from Explorer Deep. Good correlation between phosphorus and Iron In sur f l c la l sediments, but poor correlation In the entire data set, suggests that ferr I phosphate Is not present In sediments at depth. DIagenetIc recycling of Iron by dissolution of hydroxides In the reducing environment of the sediment column, and subsequent repreclpltatlon of hydroxides In the oxidizing - 8 2 -layer at or near the sediment-water Interface, may be responsible for the lack of ferr I phosphate at depth. Good correlations between phosphorus and aluminium (r=0.68; Table 4 .1) , phosphorus and magnesium (r=0.58) and phosphorus-and titanium (r=0.56) Indicate that phosphorus associated with the terrigenous component may account for a s igni f icant portion of the total concentration. Strong negative correlations are evident between a l l the clay-mineral rat ios and phosphorus/aluminium (Table 4.3) , casting doubt on the Importance of phosphorus adsorbed on detr l tal grains In the Explorer Deep sediments. Detr ltal apatite In small quantities could account for the bulk of the phosphorus content and would be compatible with these data. There Is no evidence of apatite In samples examined by X-ray di f f ract ion (Chapter Three); however, the low phosphorus content suggests that quantities may be too small to be detected by the technique used. A weak correlat ion between phosphorus/aluminium and calcium/aluminium (r=0.30; Table 4.2) Is consistent with the weak correlation between phosphorus and calcium (r=0.38; Table 4.1) and suggests a possible association with the biogenic component. Weak posit ive correlations between phosphorus and manganese (r=0.24) and between phosphorus/aluminium and manganese/aluminium (r=0.29; Table 4.2) may ref lect the association between phosphorus and Iron oxides and hydroxides, which tend to coexist with manganese oxides. - 8 3 -Distribution of Titanium Titanium In marine sediments occurs pr incipal ly In IIthogenous minerals Including r u t l l e , llmenlte, phyIlosiIIcates (with titanium substituting for aluminium), anatase, feldspars, amphlboles, pyroxenes and pyroclastic materials (Chester and Aston, 1976; Pedersen, 1979). Authlgenic smectites, zeol ites and possibly anatase may also contribute titanium to the sediment (Arrhenlus, 1963; Chester and Aston, 1976; Pedersen, 1979). Titanium concentrations In sediments from the Explorer Deep area are normally distributed with a mean of 0.51$ TI (Figure 4.12), comparable to average "Pac i f ic pelagic clay" (between 0.42 and 0.73$ Tl Landergren (1964) and Goldberg and Arrhenlus (1958) respectively) . Samples from cores 79-06-10 and 79-06-31 have the highest titanium contents. The titanium/aluminium prof i le for core 79-06-06 (Figure 4.13) shows l i t t l e fluctuation over the entire core length. Cores 79-06-22 and 79-06-31 have pronounced surface minima which are not evident In the other cores. A general decrease In the var iabi l i ty and magnitude of titanium/aluminium rat io with depth Is evident In cores 79-06-08, 79-06-10 and 79-06-31. Weighted average titanium/aluminium values are fa i r l y constant (Tl/AI=0.058 to 0.065) for a l l cores. Sediments from the Explorer Deep area contain both ru t l l e and Ilmenlte (Chapter Three); these detr l ta l oxides are l ikely major hosts of titanium In sediments from the study area. The strong correlation between titanium and aluminium (r=0.72; Table 4.1) Implies that, l ike 40 — , a cu a s_ a> CL >> u c cu CT cu 30 20 -10 -n=86 x=0.51 Sx=0.038 CI=0.02 PL T 0.6 (weight percent) 1 1 1 I 0.7 Fig. 4.12 Histogram for titanium concentration in sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis. H I s u r f a c e samples; =core 79-06-06; ^ =core 79-06-08; | 1 =core 79-06-10; Wm =core 79-06-22; QTJJJ] =core 79-06-31. aluminium, titanium Is predominately of terrigenous or ig in . Posit ive correlation between titanlum/alumlnlum and 111Ite/chlorlte (r=0.47; Table 4.3) Indicates an associat ion. Titanium may substitute for magnesium In b lot l te (Berry and Mason, 1959); the association suggests that continental weathering of b lot l tes Is a source of l l l l t e s . The contribution of titanium by feldspar Is unknown at present. Titanium In Explorer Deep sediments Is associated with the terrigenous component, ref lect ing proximity to a detr l ta l source, the North American landmass. - 8 5 -Ti/Al (X10~2) 6.2 6.6 7.0 6.2 6.6 7.0 6.1 6.5 5.0 5.4 5.8 6.2 5.9 6.3 6.7 (Ti/Al=0.065) 79-06-31 (Ti7AT=0.062) Fig. 4.13 Titanium/aluminium profi les for cores from the Explorer Deep area. Al l data are on a sal t - f ree basis. Ti/Al is weighted average value for core. Distribution of Potassium Potassium occurs In marine sediments primarily In phyIlosiIIcates, feldspars, amphlboles, pyroxenes and pyroclastic materials (Chester and Aston, 1976). Authlgenic minerals, pr incipal ly smectites and zeol i tes , may also contribute potassium to the sediment. Potassium contents of sediments from the Explorer Deep area are normally distr ibuted, with a mean of 1.70$ K (Figure 4.14). The sediments are potassium-poor compared to average "Pac i f ic pelagic clay" (2.24 and 2.5$ K; Landergren (1964) and Goldberg and Arrhenlus (1958) respectively) , and to "average shale" (2.66$ K; Tureklan and Wedepohl, 1961). ' Surf lc la l sediments have part icular ly low potassium contents (1.54$ K; Table 4.4) , and vert ical prof i les for f ive of the cores a l l have surface minima (Figure 4.15). Considerable variation In potassium/ aluminium ratios with depth Is evident In a l l cores, apparently with no consistent pattern. Weighted average potassium/aluminium values are similar for a l l f ive cores (K/AI=0.19 to 0.22). Good correlations between potassium and titanium (r=0.65; Table 4.1) and between potassium and aluminium (r=0.51) Indicate elemental associations. Since both aluminium and titanium are hosted primarily In the terrigenous fraction (see previous discussions), the Inference Is that potassium Is also pr inc ipal ly of detr l tal o r ig in . The good correlation between potassium/aluminium and 111Ite/kaolIntte+chlorIte (r=0.58; Table 4.3) suggests that II l i t e Is the principal host mineral for potassium sediments (Table 4.3) ; scavenging of potassium from the - 8 7 -30 c cu o s-cu Q . +-> cn cu 2 o c cu cr cu s_. 20 n=86 x=1.70 S=0.19 CI=0.10 10 -1.0 I | l " l I I | 1.5 2.0 2 .5 . 3.0 potassium (weight percent) Fig. 4.14 Histogram for potassium concentration in sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis. •I ^surface samples; g%%[ =core 79-06-06; ESSI =core 79-06-08; | [ =core 79-06-10; fJ23 = c o r e 79-06-22; [JJJTJ] =core 79-06-31. water column and pore waters by degraded l l l l t e s (Chapter Three) may account for part of the Increase In potassium at depth (Figure 4.15). Normal sea water (of sal in i ty 35 °/oo) has 0.39 g/kg K (PIckard, 1975); an Increase of 2 g/kg K, requires complete removal of potassium In 5 kg sea water/1 kg sediment. While some of the Increase of potassium may be due to scavenging, the cycling of large volumes of sea water through the sediments Is unl ikely; other mlneraloglcal differences must also exist . Amphlboles, pyroclastlc materials and feldspars (predominantly plaglo-c lase , not K-feldspar; Chapter Three) may also contribute some potas-sium. Poor correlations between potassium/aluminium and smectite ratios (Table 4.3) suggest that this association Is relat ively unimportant. - 8 8 -K/Al (X10~2) 19 21 23 21 23 19 21 23 17 19 21 18 22 26 30 (K7AT=0.22) /y-Ub-Ji (K7AT=0.20) Fig. 4.15 Potassium/aluminium profi les for cores from the Explorer Deep area. Al l data are on a sa l t -free basis. K/AT is weighted average for core. Note scale change for core 79-06-31. Distribution of Sodium Sodium in marine sediments occurs in number of minerals: hal i te (formed by precipitation from sea water during sample drying), phyl lo-si I icates, feldspars, amphiboles, pyroxenes and pyroclastic materials (Chester and Aston, 1976). Sodium may also be incorporated In authigenlc minerals such as smectites and zeol i tes . During drying, water in the sediment migrates toward external surfaces, thus more NaCl precipitates on these surfaces (personal communication with T .F . Pedersen). Unless the selection of sub-samples is very consistent, the salt content can vary considerably between individual sub-samples. As a measure of the salt content, chlorine concentration was determined for each sample. Using the chlorine data and the average composition of sea water, a correction was applied to the analyses, as described in Appendix B. In th is study a l l element concentrations are considered on a sa l t - f ree basis. The correction for sal t contribution In several samples was quite large (up to 40$ of the total uncorrected sodium content). Clearly the sa l t - f ree calculation has a major Influence on the distr ibution of sodium (salt - f ree) In the sediment. Large salt corrections for sodium may Introduce variations In the distr ibution that mask real minora Iogleal changes; therefore In th is study the detailed distr ibution of sodium was not considered. Sodium concentrations (salt - f ree) In sediments from the Explorer Deep area are normally distributed (Figure 4.16), with a mean of 2.82$ Na; which compares well with average "deep-sea clay" (2.86$ Na (sa l t --90 -30 +-> cu o s_ cu Q . o sr cu cr cu 4-20 10 -n=86 x=2.82 S=0.39 CI=0.20 1.0 2.0 sodium (weight percent) Fig. 4.16 Histogram for sodium concentration in sediments from the Explorer Deep study area. Al l data are on a sa l t - f ree basis, gg| =surface samples; =core 79-06-06; =core 79-06-08; | — | =core 79-06-10; =core 79-06-22; njTjj =core 79-06-31. free; Turekian and WedepohI, 1961); however, sodium contents reported for average "Paci f ic pelagic clay" show considerable variation ( le . 0.96$ to 4.0$ Na; Landergren (1964) and Goldberg and Arrhenlus (1958) respectively) . The reason for the observed discrepancy Is unclear at present, but may ref lect the method of correction for In te rs t i t ia l - sa l t used. There Is considerable fluctuation In the sodlum/alumlnlum ratios In a l l cores (Figure 4.17), but a general decrease with depth Is evident. Weighted average sodlum/alumlnlum values for a l l f ive cores are fa i r l y consistent, between 0.31 and 0.41, with highest values in cores from the floor of Explorer Deep (79-06-06 and 79-06-08). -91 -Na/Al (X10~2) 30 40 50 30 40 50 20 30 40 50 30 40 20 30 40 (Na/Al=0.36) 79-06-31 (Na7AT=0.33) Fig. 4.17 Sodium/aluminium profi les for cores from the Explorer Deep area. Al l data are on a sa l t -free basis. Na/Al is weighted average value for each core. Distribution of Magnesium Magnesium occurs In marine sediments In biogenic carbonates, detr l tal minerals Including phyllosiI Icates, feldspars, amphlboles, pyroxenes, carbonates and apatite, pyroclastic materials and hydrogenous smectites and zeol i tes (Chester and Aston, 1976). Magnesium concentrations In sediments from the Explorer Deep form an approximately normal distr ibution (Figure 4.18), with a mean of 1.87$ Mg, less than average "Pac i f i c pelagic clay" (2.05$ Mg; Landergren, 1964) or average "deep-sea clay" (1.96$ Mg; Tureklan and Wedepohl, 1961). Prof i les of magnesium/aluminium ratios versus depth of burial for cores 79-06-06, 79-06-08 and 79-06-10 show l i t t l e change In value over the entire length of the cores (Figure 4.19). Considerable fluctuation In the rat ios with depth Is evident In cores 79-06-22 and 79-06-31. Surface minima are evident In cores 79-06-08, 79-06-10, 79-06-22 and 79-06-31. Weighted average magnesium/aluminium values are quite similar for a l l f ive cores, ranging between 0.21 and 0.25. Poor correlations between calcium and magnesium (r=0.15; Table 4.1) and between calclum/alumlnlum and magnesium/aluminium (r=0.09; Table 4.2) suggest that carbonates are not major hosts of magnesium In the study area. Good correlations between magnesium and aluminium (r=0.62; Figure 4.20) and between magnesium and titanium (r=0.77) Imply a strong magnesium a f f i l i a t i o n with detr l tal minerals (aluminium and titanium are almost exclusively associated with the terrigenous component). The lack of correlation between magnesium and any single clay mineral ra t io - 9 3 -30 cu o s-cu Q . o c: CT CD S-20 — n=86 x=1.87 S=0.19 CI=0.10 10 — 1.0 1.5 2.0 magnesium (weight percent) Fig. 4.18 Histogram for magnesium concentration in sediments from the Explorer Deep area. All data are on a sa l t - f ree basis. HB1 =surface sediments; ppz\ =core 79-06-06; =core 79-06-08; | 1 =core 79-06-10; =core 79-06-22; [njrjj =core 79-06-31. (Table 4.3) Indicates either that 11 l i t e , ch lor i te and smectite a l l contain magnesium, or conversely that none of the minerals contain magnesium (which Is not possible) . An Increase In magnesium Is evident below sur f l c la l minima In most of the cores (Figure 4.19) and may ref lect scavenging of magnesium Ions from the water column by degraded chlor l tes In chlor Ite-smectIte mixed-layer clays (Chapter Three). The fa i r l y large y- lntercept for magnesium versus aluminium (0.34$ Mg; Figure 4.20) Indicates the presence of a magnesium-bearing alumlnlum-poor component, l ikely smectite; al ternat ively , a biogenic magnesium-Mg/Al (X10~2) cn i 20 40 60 o £ 80 UJ Q 100 120 140 L 160 L 22 26 J I I 79-06-06 (Mg/Al=0.24) 22 26 i — r ~ i — i — i 79-06-08 (Mg/Al=0.24) 79-06-10 (Mg/Al=0.25) 16 20 24 T—I—I—I—I 79-06-22 (Mg/Al=0.21) Fig . 4.19 Magnesium/aluminium profi les for cores from the Explorer Deep area, free basis. Mg/Al=weighted average value for each core. 20 24 i L i i i - o -120 40 60 o m -o 80 ~ 3 100 120 140 -I 160 79-06-31 (Mg/Al=0.23) Al l data are on a salt -3.0 - , 2.5 -+-> CD o J-C1J Q . 3 CD cn E 2.0 1.5 -1 .0 -Fig. 4.20 n=86 x=8.05 Sx=0.61 y=1.87 Sy=0.19 r=0.62 "T 1 — 6 7 aluminium 1 1 — 8 9 (weight percent) 1 10 Correlation between magnesium and aluminium for sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis. Bes t - f i t l ine determined by l inear regression. bearing phase may be present however, the poor correlations between magnesium and calcium, and magnesium/aluminium and caIclum/alumlnlum (previously discussed) argue against a biogenic association. Amphlboles, feldspars and pyroclastlc materials may also contribute . magnesium to the sediments In the Explorer Deep area. - 9 6 -Distribution of Iron Iron occurs In marine sediments In a number of minerals Including: detr ltal phyIloslIIcates, hematite, goethlte, Ilmenlte, feldspars, amphiboles, pyroxenes, pyroclastlc materials and Iron oxides (as coatings on minerals or as discrete grains); hydrogenous ferromanganese nodules, goethlte, zeol i te and smectite; and in cosmic spherules (Chester and Aston, 1976). Concentrations of Iron in sediments from the Explorer Deep area are normally distributed (Figure 4.21); values range from 4.01 to 5.83$ Fe with a mean of 5.13$. These data compare well with previous Iron deter-minations for sediments from the region (3 to 7$ Fe by Skornyakova (1964); average 5.3$ Fe by Bornhold et a l . (1981); 5.4$ Fe for average "Paci f ic pelagic clay" by Landergren (1964)). In general sediments from the northeast Pac i f ic appear to be Iron-poor compared to typical "deep-sea clays" (6.76$ Fe; Tureklan and Wedepohl, 1961). Iron/aluminium prof i les for cores from the floor of Explorer Deep (79-06-06 and 79-06-08; Figure 4.22) show pronounced surface maxima (not evident In cores from the flanks) then fa i r l y constant values to total depth. The prof i le for core 79-06-10 shows a local Iron/a Iumlnlum minimum at 25 cm, with l i t t l e other variation at depth. Core 79-06-22 has a maximum between 15 and 25 cm, with large fluctuations In Iron/a Iumlnlum over the entire core length. The Iron/a Iumlnlum ratios In core 79-06-31 remain fa i r l y constant down to 60 cm, then drop sharply, and fluctuate abruptly from 85 cm to total depth. Weighted average Iron/aIumlnIum Is sl ightly larger In sediments from the floor of Explorer Deep (Fe/AI=0.66 to 0.67; - 9 7 -+-> c cu o s-cu C L >> o c cu CT CU s-4-20 -10 -f i l l 3.0 4.0 n=86 x=5.13 S=0.36 CI=0.10 m i m I I I I I 5.0 6.0 iron (weight percent) 7.0 F ig . 4.21 Histogram for iron concentration in sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis. ^surface samples; V7Z\ = core 7 9 - 0 6 - 0 6 ; f£sg =core 7 9 - 0 6 - 0 8 ; =core 7 9 - 0 6 - 1 0 ; =core 7 9 - 0 6 - 2 2 ; OJTJJJ =Core 7 9 - 0 6 - 3 1 . cores 79-06-06 and 79-06-08) than In sediments from the f lanks (Fe/AI=0.59 to 0.64; cores 79-06-10, 79-06-22 and 79-06-31). P o s i t i v e c o r r e l a t i o n s between Iron and aluminium (r=0.48; Table 4 .1 ) , Iron and t i tan ium (r=0.66; F igure 4.23) and Iron and magnesium (r=0.80; F igure 4.24), supported by p o s i t i v e c o r r e l a t i o n s between Iron/a Iumlnlum and t i t a n Ium/aIumlnlum (r=0.62; Table 4.2) and Iron/ aluminium and magnesium/aluminium (r=0.68), suggest a s i g n i f i c a n t a s soc ia t i on between Iron and the terr i genous component In Exp lorer Deep sediments. The large y - In tercept 0.16$ TI (mean of 0.51$ TI) for iron versus t i tan ium (Figure 4.23) Indicates a t i tan ium excess r e l a t i v e t o - 9 8 -Fe/Al (X10"2) 65 70 65 70 75 55 60 65 55 60 65 70 50 55 60 65 Fe/Al=0.61 Fig. 4.22 Iron/aluminium profi les for cores from the Explorer Deep area. Al l data are on a sa l t - f ree basis. Fe/Al is weighted average value. 2 - i cu • i - CU C C L +-> +J 4> +-> 1 _ <- JZ  l +-> cn cu 3 n=86 x=5.13 Sx=0.36 y=0.51 Sy=0.038 r=0.66 0.0682X+0.16 1 1 1 1 3 4 5 6 7 iron (weight percent) 4.23 Correlation between titanium and iron for sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis Bes t - f i t l ine determined by l inear regression. T 4 T 6 iron (weight percent) 4.24 Correlation between magnesium and iron for sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis Bes t - f i t l ine determined by l inear regression. -100-Iron, Implying an Iron-poor, tItanium-bear I rig component In the sediment (such as anatase, or r u t l l e ) . The x-Intercept at 0.56$ Fe (mean of 5.13$ Fe) for Iron versus magnesium (Figure 4.24) Indicates a s l ight Iron excess, suggesting the presence of a magnesium-poor, Iron-bearing component In the sediment (possibly Ilmenlte, hematite, or goethlte). A large amount of scatter evident for Iron versus aluminium concentrations In sediments from the Explorer Deep area (Figure 4.25), and the b e s t - f i t l ine ( l ine "a") yields an Intercept at 0.7$ A l . The point corresponding to the composition of average "Pac i f i c pelagic clay" (Landergren, 1964) l ies very near line " a " , suggesting that th is line may approximate a regional Iron-aluminium relationship characterist ic for the detr l tal component. When only data for cores from the floor of Explorer Deep (79-06-06 and 79-06-08) are used, the correlation between Iron and aluminium Is dramatically Improved (r=0.76), and the bes t - f i t l ine ("b") has a large Intercept at 4.2$ A l . Surface samples form a grouping above both lines " a " and "b" . The distr ibution may be explained by the mixing of four components in sediments from the study area: 1) Iron oxides and oxyhydroxldes, part icularly abundant In surface sediments from the f loor of Explorer Deep; 2) smectite, present pr inc ipal ly , but not exclusively, In the deep; 3) Iron-bearing detr l tal alumlnoslIIcates; and 4) Iron-poor minerals. The origin of Iron oxides and oxyhydroxldes and of smectite In sediments from the Explorer Deep area wi l l be discussed In Chapter Five. - 1 0 1 -6 -cu o S-cu CL 4-> CT) OJ c o s-5 -4 -8 a b n=86 n'=31 x=8.05 x'=7.64 Sx=0.61 Sx'=0.33 y=5.13 y'=5.10 Sy=0.36 Sy'=0.27 r=0.48 r'=0.76 1 1 9 10 aluminium (weight percent) F ig . 4.25 Correlation between Iron and aluminium for sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis. X =surface samples; O =core 79-06-06; • =core 79-06-08; • =core 79-06-10; • =core 79-06-22; • =core 79-06-31; © =average "Pac i f i c pelagic clay" (Landergren, 1964). Line ' a ' determined by linear regression using a l l data. Line 'b ' determined by linear regression using only cores from the floor of Explorer Deep (79-06-06 and 79-06-08). -102-Distribution of Manganese Manganese In marine sediments occurs In several detr l tal minerals Including feldspars, phyIlosiIIcates, amphtboles, pyroxenes, pyroclastic materials and as manganese oxyhydroxlde coatings on detr l tal minerals. Hydrogenous manganese occurs In ferromanganese nodules, manganese oxides, zeol i tes and smectites (Chester and Aston, 1976). The d is t r ibu -tion of manganese In marine sediments Is strongly modified by diagenetJc processes, pr incipal ly controlled by sediment oxidation potentials (Skornyakova, 1964; Lynn and Bonattl , 1965; Strakhov, 1966; Bonattl et a I . f 1971; Bostrom, 1973; Pr ice , 1976; Hartmann, 1979; Pedersen, 1979). Manganese oxide dissolution takes place In buried sediments, which are reducing at depth, and sustains an upward diffusion of Mn* Ions. Upon encountering higher redox potentials, prevalent at or near the sediment-water Interface, repreclpltatlon of Mn^+ as oxide occurs. A portion of the mobilized Mn* Ions may be lost by diffusion Into the overlying sea water column, prior to precipi tat ion; the remainder accumulates In the oxidizing surface layer. The manganese data for sediments from the Explorer Deep area have a strongly posit ively skewed distr ibution (Figure 4.26); concentrations measured range between 0.038 and 0.423$ Mn, with a mean of 0.087$ Mn. Sediments from the study area are manganese-poor compared to average "Paci f ic pelagic clay" (1.29$ Mn; Landergren, 1964), but have manganese contents similar to "average shale" (0.085$ Mn; Tureklan and Wedepohl," 1961). In surface sediments from the Explorer Deep area manganese concentrations range between 0.056 and 0.423$ Mn (Appendix C) . The - 1 0 3 -40 -30 -cu a s_ cu a c cu CT CU 5-20 10 -mi w. • i i i | T T n 0 0.1 0.2 n=86 x=0.087 S=0.057 CI=0.020 0.3 0.4 0.5 manganese (weight percent) F ig . 4.26 Histogram for manganese concentrations in sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis. =surface samples; yzffi =core 79-06-06; ^ =core 79-06-08; | 1 =core 79-06-10; W7\ =core 79-06-22; QTJJJ =core 79-06-31. manganese concentration decreases rapidly within the top few centimetres of cores 79-06-06, 79-06-08 and 79-06-22 (Figure 4.27); this steep gradient suggests that any loss of su r f l c la l sediments during coring may produce questionable analyses for "surface sediments" In recovered cores. For this reason the areal ( sur f lc la l ) manganese distr ibution wi l l not be discussed here. -104-Mn/Al (X10~2) Mn/Al=0.011 Mn/Al=0.009 Fig. 4.27 Manganese/aluminium profi les for core from the Explorer Deep area. Note different scales for core 79-06-08 and core 79-06-22. Al l data are on a sa l t - f ree basis. Mn/Al= weighted average. Manganese/aluminium prof i les for cores 79-06-06, 79-06-08 and 79-06-22 show pronounced surface maxima (Figure 4.27), then relat ively constant values to total depth. The prof i le for core 79-06-10 shows no surface maximum, but does Indicate a broad zone of high manganese/ aluminium values between 20 and 90 cm. Except for two minima at 65 and 103 cm, the prof i le for core 79-06-31 shows l i t t l e variation In the manganese/aluminium rat io over the length of the core. Weighted average values for a l l f ive cores are very s imi lar , ranging from 0.009 to 0.011. A thin oxidizing surface layer, Indicated by brown-coloured sediment (Price, 1976; Hartmann, 1979), was evident In most of the Explorer Deep area cores (Appendix A). The contact between the upper oxidizing layer and underlying olIve-grey reduced sediment was d is t inc t , being either sharp or gradatlonal over a very short Interval. In the hemlpelaglc sediments, reducing conditions generally prevail at depth, due to oxidation of organic matter. As a resul t , manganese present as Mn^+ oxides and hydroxides In the sediment Is reduced to Mn 2 + Ions upon bur ia l . The manganese Ions migrate upward and either repreclpltate as hydroxides at/or near the sediment-water Interface or dif fuse Into the overlying water column. The upper oxidized sediment layer In Explorer Deep cores Is missing or thinner than Is normally encountered In oceanic sediments, which Is generally several centimetres to a metre or more thick (Price, 1976). Several processes may be responsible for the observed lack of su r f l c la l oxidized sediment. The uppermost sediment Is commonly lost during the coring operation (Berger, 1976; Stow and Aksu, 1978). Several of the Explorer Deep area cores lack surface oxidized sediment (79-06-02, 79-06-21, 79-06-29 and 79-06-31; Appendix A), It Is -1 0 6 -therefore quite l ikely that sediment loss did occur during coring. Areas with high rates of hemlpelaglc sedimentation, such as the northeast Pac i f i c , generally have thin surface oxidized layers (Price, 1976). The low manganese content of non-metalliferous sediments from Explorer Deep may be the result of a combination of these processes. The surface manganese enrichment corresponds well with sediment colour; cores 79-06-01, 79-06-04, 79-06-08 and 79-06-22 a l l have manganese concentrations greater than the mean plus twice the standard deviation, and a l l have brown surface sediments. Two zones of brownish sediment were sampled In core 79-06-31 (at 65 and 103 cm) but both correspond to manganese minima rather than being manganese-rich (Figure 4.27). The two zones are feldspar-poor and c lay - r ich (Chapter Three) and in addition to manganese correspond to sodium and magnesium minima (Figures 4.17 and 4.19 respectively) and to titanium and potassium maxima (Figures 4.13 and 4.15 respectively) . The brown colouration in these subsurface sediments is apparently not caused by Mn oxides; th is finding is at odds with that of Hartmann (1979), where brown colouration of Pacif ic pelagic sediments studied was attributed exclusively to Mn oxides. The source for the colouration of the subsurface sediments in core 79-06-31 Is at present unknown. Total manganese concentration in sediments from the Explorer Deep area does not correlate well with any of the other elements analyzed In th is study (Table 4.1) . When normalized to aluminium weak correlations were evident between manganese and cobalt (r=0.31; Table 4.2) , Iron (r=0.35) and phosphorus (r=0.29) suggesting the presence of ferro --1 0 7 -manganese oxides which have a sight a f f in i ty for cobalt and phosphorus. Manganese does not correlate well with any single clay mineral (Table 4 . 3 ) , although weak posit ive correlations with the smectite ratios Indicate a possible poorly defined association. Manganese occurs as oxides In the enriched surface sediments and may be present as exchangabIe cations adsorbed by smectites (Grim, 1968; Mil lot , 1970; Weaver and Pol lard, 1973). -1 0 8 -4.2.2 MINOR ELEMENT CHEMISTRY Distribution of Barium Barium occurs In marine sediments In crysta l l ine bartte, adsorbed on to other minerals, In certain detr l tal s i l i c a t e s , zeol i te and smectite. Euhedral crystals of barIte, a few micrometres In s ize , are common In marine sediments (Strakhov, 1966; Church and Wolgemuth, 1972; Chester and Aston, 1976; Murray and Brewer, 1977). High concentrations of often somewhat larger (up to 500 um) barIte crystals have been reported from a number of hydrothermal deposits (BonattI et a I.r 1972a; Bostrom eji_al., 1973; Bertlne and Keene, 1975; E lder f le ld , 1976; Heath and Dymond, 1977; Lonsdale, 1979). In many hydrothermal deposits manganese oxides and to a lesser extent, iron oxides and smectites contain high concentrations of adsorbed barium (BonattI et a I., 1972a; Sayles and BIschoff, 1973; BonattI, 1975; Lonsdale, 1977; Murray and Brewer, 1977; Hoffert et a I . f 1978; Chan et .a I.r 1979; G r i l l et a I.r 1981)./ Detrltal s i l i c a t e s such as feldspars and phyIloslIIcates tolerate direct substitution of barium for potassium owing to s imi lar i ty of the Ionic radius of B a + 2 (r=1.35 ft) to that of K + (r=1.33 ft) (Fyfe, 1964; Pedersen, 1979). Harmotome, the Ba-bearlng zeo l i te . Is not common In marine sediments (Bostrom et a I.P 1973). Several processes are Involved In the transportation of barium to the sea f loor . Weathering and erosion of the continental landmass provides a detr l tal source of barium (Bostrom et a I.f 1973). The marine blogeochemlcal cycle appears to control barium distr ibution In the water column, and a number of organisms are reported to concentrate barium -109-(Church and Wolgemuth, 1972; Li et a I.f 1973; Arrhenlus, 1973; Martin and Knauer, 1977; Murray and Brewer, 1977; Chan et a l . 1977), suggesting that there may be biogenic transport of barium to the sea f loor . In areas of high hydrothermal ac t i v i t y , barium-enriched f luids have been recovered from discharge areas, indicating a hydrothermal source for barium (Cor Iiss et a I 1 9 7 8 ; Edmond e ± _ a ± . , 1979b). Barium concentrations in sediments from the Explorer Deep area are bi-modally distributed (Figure 4.28). The low barium population is defined by cores from the flanks of Explorer Deep (79-06-10, 79-06-22 and 79-06-31), while the higher barium population is composed of cores from the floor (79-06-06 and 79-06-08), core surface samples and the top 20 cm of core 79-06-10. Measured barium concentrations were plotted as cumulative percentage on a probabil ity graph (Figure 4.29) after a technique described by S inc la i r (1976). The shape of the probability graph of barium indicates the presence of more than one population; sub-sequent partit ioning of the data suggest that indeed three populations are present (Figure 4.30). The partitioned populations plot as three sub-parallel straight lines implying log-normal distr ibutions: population "A" with a mean of 2050 ppm Ba, represented by 50$ of the samples (n=44); population "C" with a mean of 580 ppm Ba, represented by 35$ of the samples (n=30); the remaining 15$ of the samples (n=13) form population "B" with a mean of 830 ppm. A good f i t was determined between the smooth curve (obtained from the measured data; Figure 4.29) and the check points, plotted as open triangles (obtained by combining partitioned populations), suggesting that the partitioned populations are a reasonable separation of the multimodal curve. The va l id i ty of -110-20 -cu o i. cu Q . n=87 x=1370 S=744 CI=200 >> o c cu cr cu 5-4 -10 1000 barium 2000 (ppm) Fig. 4.28 Histogram for barium concentration of sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis. WM =surface samples; E 3 =core 79-06-06; ^ =core 79-06-08; O =core 79-06-10; m =core 79-06-22; HD =core 79-06-31. population "B" Is suspect given the size of the total data set (n=87) (personal communication from A . J . S inc la i r , University of Br i t ish Columbia); however, trlmodal part it ioning f i t the data better than did a similar blmodal determination. Regardless, following discussions wi l l concentrate primarily upon populations "A" and "C" and treat population "B" In only a cursory manner. The vert ical distr ibution of barium, normalized to aluminium (Figure 4.31) shows a general decrease In Ba/AI with depth of burial In cores from the floor of Explorer Deep (79-06-06 and 79-06-08). A similar Ba/AI decrease with depth of burial was reported In cores from - 1 1 1 -10 I 1 1 1 1 1 1 1 1 1 1 2 10 30 50 70 90 98 probabil ity (cumulative percent) Fig- 4.29 Probability graphs of minor element concentrations in sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis. Symbols indicate data points from which the smooth curves were constructed. *87 samples analyzed for barium, a l l other elements had 88 samples (Appendix C). -112-5000 Q . <0 S-4 J E CU o c o u 5-X3 1000 200 Fig. 4.30 1 1 1 1 — A(50%) n=87 - x=2050 x+SL=2450 -B(15%) x=830 x+SL=950 x-SL=1720 - '—' _xzSL=725 --C(35%) C x=580 x+SL=655 - x-SL=535 -1 1 1 i 10 30 50 70 90 probabil ity (cumulative percent) 98 Probability graph of barium concentration for 87 samples of sediments from the Explorer Deep area, showing inf lect ion points (arrowheads) and three partitioned populations A, B and C. Original data points used to generate the smooth curve are plotted in Figure 4.29; open c i rc les are calculated points used to estimate partitioned population; open triangles are check points obtained by combined partitioned populations in the proportion A:B:C=50:15:35. Al l data are on a sa l t - f ree basis. the Panama Basin by Pedersen (1979); the process whereby th is depletion In barium occurs Is not known. Bar Ium/aluminIum prof i les for cores from the flanks of Explorer Deep (79-06-10, 79-06-22 and 79-06-31) a l l show pronounced surface maxima with re lat ively constant Ba/AI values at depth. Weighted average Ba/AI values for cores from the f loor of Explorer Deep are more than two times greater than values for cores from the flanks, Indicating a substantial barium enrichment in the deep. Ba/AI (X10~3) i i—* i—' 4=> 10 20 -1—I—I Ba/Al=0.0247 Ba/Al=0.0085 Ba/Al=0.0120 79-06-31 - i 0 20 40 60 80 g 100 120 140 •J 160 Fig. 4.31 Barium/aluminium profi les for cores from the Explorer Deep area, basis. Ba/AI is weighted average value for each core. Ba/Al=0.0071 Al l data are on a sa l t - f ree Insight Into the distr ibution of barium In the sediments may be gleaned by examination of correlations between barium and the other major and minor element concentrations (Table 4.1) . Barium does not correlate posit ively with any of the major elements; however a strong negative correlation between barium and aluminium (r=-0.77), and weaker (but s ignif icant) negative correlations between barium and magnesium (r=-0.44), and barium and titanium (r=-0.35) are evident. Problems associated with closed number systems (previously discussed), dictate that Inverse relationships be considered cautiously. As aluminium, magnesium and titanium are dominantly of terrigenous or ig in , these data suggest that detr l ta l minerals do not contribute to the barium content of the sediments; a l t e r n a t e l y a small barium-rich fraction may be present, but Is diluted by a large barium-poor detr l tal Input. The latter appears to satisfy partitioned barium data (Figure 4.30) where population "C" represents a detr l ta l barium-poor background level and population "A" Is the enriched f ract ion. Interestingly the mean for population "C" was 580 ppm Ba, the same value suggested for "average shale" (Tureklan and Wedepohl, 1961), supporting the Inference. 11 l i te contains some barium, as evidenced by the correlation between IIIIte/ chlor i te and barlum/alumlnlum (r=0.53. Table 4.3) . I 11Ite/chlorlte also correlates well with potassium/aluminium (r=0.58) and titanlum/alumlnlum (r=0.47); after normalization to aluminium good correlations also exist between barium and potassium (r=0.37; Table 4 .2) , and barium and titanium (r=0.60). The strong negative correlations between barium and calcium (r=-0.87; Figure 4.32), and barlum/alumlnlum and ca Iclum/alumlnlum 6 n=84 x=0.138 1 1 1 1 1 1 1 0 0.05 0.10 0.15 0.20 0.25 0.30 barium (weight percent) Fig. 4.32 Correlation between calcium and barium in sediments from the Explorer Deep area. All data are on a sa l t - f ree basis. Note that sample 22/10-11 (with Ca=12.66% and Ba=0.0636%) was omitted. Best - f i t l ine determined by 1inear regression. (r=-0.45; Table 4.2) suggest that since calcium Is largely present as carbonate In sediments from the Explorer Deep area, variations In barium content are not due to deposition of skeletal materials. The negative correlation may be In part a ref lect ion of Increased carbonate dissolution with depth, which Is opposite to the barium enrichment In Explorer Deep. Phosphorus, which may be contributed by both biogenic and detr l tal sources (previously discussed), also correlates negatively with - 1 1 6 -barium (r=-0.70) and for barlum/alumlnlum and phosphorus/aluminium (r=-0.59; Table 4.2) . These data suggest that barium in detr ltal minerals and biogenic carbonates cannot account for the dist r ibut ion. Strong s imi lar i ty between Si/Al prof i les (Figure 4.4) and Ba/AI prof i les (Figure 4.30), supported by a good correlation between Ba/AI and Si/Al (r=0.83; Figure 4.33) indicates a non-terrigenous s i l i c o n -barium association. Non-terrigenous s i l i con may be of biogenic o r ig in , and radiolarians from the Oregon coast are reported to be enriched in barium (Martin and Knauer (1973) reported up to 323 ppm Ba in micro-plankton samples). If the 10$ of non-terrigenous s i l i c a present In the surface samples (Table 4.5) were composed entirely of radiolarlan tests , the barium contribution would only be about 35 ppm, clearly not suff ic ient to account for the observed variations in barium content. Organic matter, upon disintegration, wil l release barium into the sedimentary column (Bostrom et a I.P 1973), but the quantity Is thought to be small . Therefore another source of non-terrigenous s i l i con and barium Is required to explain the measured variat ions. Poor correlations between barium and manganese (r=0.06; Table 4.1) , and between barium/aluminium and manganese/aluminium (r=0.19; Table 4.2) Imply that barium is not associated, to any large extent, with manganese oxides tn Explorer Deep area sediments. The barium versus manganese graph (Figure 4.34) shows considerable scatter, but an Inverse re la t ion -ship may exist for the low-manganese data. A maximum slope line through the data (m=1.85) is s t i l l less than the rat io of manganese/barium for "deep-sea clay" (Mn/Ba=2.93; Turekian and WedepohI, 1961). The potential - 1 17-4 - i < •r— 2 -0.01 — I — 0.02 Ba/AI n=85 x=0.018 Sx=0.010 y=3.23 Sy=0.27 r=0.83 0.03 0.04 Fig. 4.33 Correlation between silicon/aluminium and barium/aluminium in sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis. Best - f i t l ine determined by l inear regression. contribution of barium by manganese oxides can be calculated (after Pedersen, 1979) If a l l the manganese Is assumed to be occur as todorokite. The rat io Ba/Mn=0.0066 was determined for todoroklte In the hydrothermal deposit from Explorer Deep (sample #5; G r i l l et a I., 1981), which Is comparable to a maximum rat io of Ba/Mn=0.0063 for todoroklte crusts from the Galapagos R i f t (analyzed by Cor l iss et a l 1 9 7 8 ) . Using the rat io Ba/Mn=0.0066 and the measured manganese content In sediments from the study area (Appendix C) , the barium contribution by manganese oxide was calculated; a maximum of less than 30 ppm Ba may ascribed to association with manganese oxides. -118-0.5 - , n=85 x=0.137 Sx=0..074 y=0.086 Sy=0.057 barium (weight percent) Fig. 4 . 3 4 Correlation between manganese and barium in sediments from the Explorer Deep area. All data are on a s a l t -free basis. Line of maximum slope for data is indicated. Good correlations between bar Ium/aIumlnlum and smectite/11 IIte (r=0.50. Table 4.3) and barlum/alumlnlum and smectJte/chorIte (r=0.69) Indicate that barium Is associated with some of the smectite present In the Explorer Deep area. Adsorption by smectite could account for the "excess" barium In sediments from the Explorer Deep area. The origin of smectite and the source of "excess" barium are discussed In Chapter F ive . -1 19-Distribution of Zinc and the transit ion metals Co r Cu and Nl In marine sediments cobalt , copper, nickel and zinc occur In biogenic detritus and organic matter. In terrigenous materials, In iron and manganese oxides and In cosmic spherules (Chester and Aston, 1976; Murray and Brewer, 1977). Diagenetic processes may strongly modify the distributions of some of these elements (Hartmann, 1979; Pedersen, 1979). In this study cobalt , copper, nickel and zinc d i s t -ributions were examined for the data set of whole sediment analyses. In f ive selected cores the distr ibution of elements with depth of burial was investigated (using element/aluminium rat ios ) . Concentrations of cobalt , copper, nickel and zinc measured in sediments from the Explorer Deep area (Appendix C) are a l l less than those suggested for typical "deep-sea clay" (Table 4.4; Turekian and WedepohI, 1961). The concentrations measured in this study are however within the range of values reported for cores from the northeast Paci f ic by Bornhold et a l . (1981), and for sediments from the Juan de Fuca Ridge by Price (1981). Cobalt In sediments from the Explorer Deep area has a normal distr ibut ion (Figure 4.35) with a mean of 21 ppm. The probability graph for cobalt concentration (plotted as cumulative percentage) has a linear form, which curves downward s l ight ly toward the low-cobalt (right-hand) end of the graph (Figure 4.29). The shape of the cobalt probabil ity curve is typical for a normally distributed population plotted on a log-normal graph (Sinclai r , 1976). Compared to typical "deep-sea clay" - 1 2 0 -30 - i cu a s_ cu Q . u c cu cr cu S -4 -20 -10 -T 12 I 14 16 18 20 22 24 cobalt (ppm) Fig. 4.35 Histogram for cobalt concentration in sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis. MMB =surface sediments; Y///A =core 79-06-06; K ^ F l =core 79-06-08; I I =core 79-06-10; 1^31 =core 79-06-22; mffllll =core 79-06-31. (74 ppm Co; Turekian and WedepohI, 1961) sediments from the Explorer Deep area are coba l t -poor however; t h e i r coba l t content i s s im i l a r t o that suggested for "average sha le " (19 ppm Co; Turekian and WedepohI, 1961). The cobalt/a luminium p r o f i l e s for cores 79-06-06, 79-06-08 and 79-06-10 are a l l qu i te s i m i l a r , with surface minima fol lowed by gradual increas ing values to t o t a l depth (Figure 4.36). P r o f i l e s fo r cores 79-06-22 and 79-06-31 show some f l u c tua t i on In Co/AI but r e l a t i v e l y constant values over major i ty of the core lengths. Weighted average Co/AI values are qu i te s i m i l a r for a l l f i v e cores with cores 79-06-06, Co/Al (X10 _ t +) 2.4 3.2 4.0 2.4 3.2 4.0 2.4 3.2 1.4 2.2 3.0 1.6 2.4 3.2 Co/Al=0.00024 Fig. 4.36 Cobalt/aluminium profi les for cores from the Explorer Deep area. Al l data are on a sa l t - f ree basis. Co/Al is weighted average value for each core. 79-06-08 and 79-06-10 having s l ight ly higher values (Co/AI=0.00028 to 0.00029) than cores 79-06-22 and 79-06-31 (Co/AI=0.00023 to 0.00024). Copper in sediments from the Explorer Deep area has a near normal distr ibution with a mean of 38 ppm (Figure 4.37). The shape of the copper probability graph (Figure 4.29) indicates a single population with a normal d istr ibut ion. Sediments from the Explorer Deep area are copper-poor compared to typical "deep-sea clay" (260 ppm Cu; Turekian and Wedepohl, 1961) and compared to average "Pac i f ic pelagic clay" (720 ppm Cu; Bischoff and Rosenbauer, 1977), but are similar in copper content to "average shale" (45 ppm Cu; Tureklan and Wedepohl, 1961). In core 79-06-06, copper/aluminium is a maximum in sur f lc ia l sediments, and decreases steadily with depth to an abrupt basal maximum at 120 cm (Figure 4.38). Ratios of copper/aluminium in core 79-06-08 fluctuate somewhat In the Interval from 0 to 120 cm, then Increase steadily from 120 to 150 cm. Interestingly the same interval (120 to 150 cm) in core 79-06-08 has a corresponding increase in calcium content (Figure 4.7) . Ratios of copper/aluminium In core 79-06-10 are fa i r l y uniform with local maxima at 15-17 and 50-52 cm. In core 79-06-22, a sharp maximum occurs at 10 cm, otherwise l i t t l e variation Is evident over the entire core length. The copper-rich Interval In core 79-06-22 (at 10 cm) Is also calclum-rlch (12.66$ Ca). Copper/a IumlnIum ratios in core 79-06-31 are constant from 0 to 90 cm, but fluctuate considerably between 90 to 120 cm with a prominent maximum at 120 cm, then remain constant to total depth. The copper-rich determination (71 ppm Cu) at 120 cm In core 79-06-31 appears spurious because i t is twice that of the other samples and does not correspond to any other anomalous element contents - 1 2 3 -30 cu o s-cu Q . >•> o c: cu cr cu i. 4-20 -10 -n=88 x=38 S=5.7 CI=2 1 1 1 1 1 1 1 1 1 1 1 50 60 70 copper (ppm) Fig. 4.37 Histogram for copper concentration in sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis, m =surface samples; g^gj =core 79-06-06; =core 79-06-08; =core 79-06-10; =core 79-06-22; njrrjj =core 79-06-31. however, this concentration Is within the range of copper contents (14 to 1400 ppm Cu) reported by Bornhold et a I. (1981) for sediments from the northeast Paci f ic region. Weighted average Cu/AI values for cores from the floor of Explorer Deep (Cu/AI=0.00052; 79-06-06 and 79-06-08) are higher than those for cores from the flanks (Cu/AI=0.00039 to 0.00046; 79-06-10, 79-06-22 and 79-06-31) indicating a small re lat ive enrichment of copper In sediments from the f loor . The nickel concentration In sediments from the.Explorer Deep area has a definite bl-modal distr ibution (Figure 4.39) with cores from the - 1 24 -ro cn 0 r 20 40 60 e o D-O S 80 100 120 140 160 6 4 n r 79-06-06 U Cu/Al=0.00052 6 4 1 r 79-06-08 Cu/Al (X10"4) 5 6 2 4 •8 2 r 79-06-22 Cu/Al=0.00039 Cu/Al 79-06-10 0.00046 Cu/Al=0.00052 79-06-31 8 20 40 60 80 100 120 140 J 160 o m -o o 3 Fig. 4.38 Copper/aluminium profi les for cores from the Explorer Deep area. cores 79-06-22 and 79-06-31. All data are on a sa l t - f ree basis. Cu/Al=0.00043 Note the different scales for Cu/Al is weighted average. 20 - , c cu a s-O ) C L >, 10 cu 3 nn I i 50 n=88 x=75 S=29 CI=10 1 1 100 1 150 nickel (ppm) Fig . 4.39 Histogram for nickel concentration in sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis. MM =surface sediments; =core 79-06-06; =core 79-06-08; • =core 79-06-10; =core 79-06-22; LTJTJ =core 79-06-31. the floor of Explorer Deep (79-06-06 and 79-06-08) plus sur f ic ia l samples of most cores (Including the large surface maximum in 79-06-10) forming the high-nickel grouping; cores from the flanks (79-06-22 and 79-06-31) form the low-nickel grouping with core 79-06-10 in an intermediate posit ion. The probabil ity curve for nickel also indicates a bi-modal distr ibution (Figure 4.29). Partit ioning of the nickel data (after S i n c l a i r , 1976) reveals two populations with log-normal distr ibutions (Indicated by straight lines) and an Inflection point at 50$ (Figure 4.40). Population "A" with a mean of 96 ppm NI is represented by 50$ of the samples (n=44); population " B " with a mean of 49 ppm Ni is represented by the remaining 50$ of the samples (n=44). - 1 2 6 -Fig. 4.40 Probability graph of nickel concentration for 88 samples of sediments from the Explorer Deep area, and showing inf lect ion point (arrowhead) and two partitioned populations A and B. Original data points used to generate the smooth curve are plotted in Figure 4.29; open c i rc les are calculated points used to estimate partitioned, log-normal population; open triangles are check points obtained by combined partitioned populations in the proportion A:B=50:50. A l l data are on a sa l t - f ree basis. A good f i t between the smooth curve (obtained from measured data; Figure 4.29) and check points, plotted as open tr iangles (obtained by combining the partitioned populations) suggests that the partitioned populations are a reasonable separation of the multi-modal nickel d ist r ibut ion. Typical "deep-sea clay" (225 ppm Ni; Turekian and Wedepohl, 1961) is considerably richer In nickel than are sediments -127-from the Explorer Deep area. The nickel content of "average shale" (68 ppm Ni ; Turekian and Wedepohl, 1961) Is between the two populations of nickel present in the Explorer Deep area sediments. The nickel/aluminium prof i le for core 79-06-06 shows a surface minimum and considerable fluctuation over the entire length of the core (Figure 4.41). Nickel/aluminium in core 79-06-08 is re lat ive ly constant down to 110 cm, with a local maximum at at 15-17 cm, then decreases at depth to total depth. The lower portion of core 79-06-08 Is also a zone of Increasing calcium content (Figure 4.7). A pronounced surface maximum extending to 20 cm is evident in core 79-06-10 below which, except for a local maximum at 100 cm, Ni/AI ratios remain quite constant. In core 79-06-22 NI/AI Is maximum at the surface then decreases at depth, Interrupted by a local minimum at 25-27 cm (which corresponds to an a I urn!nturn-poor Interval). In core 79-06-31 NI/AI Is maximum in sur f ic ia l sediments followed by a pronounced minimum and smaller maximum, then decreases consistently with depth to a basal maximum. Weighted average Ni/AI values are higher for cores from the floor of Explorer Deep (NI/AI=0.0013 to 0.0014; 79-06-06 and 79-06-08) than cores from the flanks (NI/AI=0.0005 to 0.0008; 79-06-10, 79-06-22 and 79-06-31), Indicating nickel enrichment In sediments from the f loor . Zinc has a bt-modal distr ibut ion (Figure 4.42); cores from the floor (79-06-06 and 79-06-08) plus sur f ic ia l samples form the high-zinc grouping, while cores from the flanks (79-06-22 and 79-06-31) form the low-zinc grouping, with core 79-06-10 occupying an Intermediate post i t lon. The bi-modal probabil ity curve (Figure 4.29) Is partitioned - 1 2 8 -Ni/Al (X10'") 10 14 18 6 10 14 18 6 10 14 2 6 10 2 6 10 Ni/Al=0.0013 Ni/Al=0.00048 Fig. 4.41 Nickel/aluminium profi les for cores from the Explorer Deep area, basis. Ni/Al is weighted average value for each core. Al l data are on a sa l t - f ree 20 CU O cu a. 10 -CJ ai OJ s-I 1 — i — i— r 50 zinc i n=88 x=112 S=27 CI=10 i i i i i i I i 100 150 200 (ppm) Fig. 4.42 Histogram for zinc concentration in sediments from the Explorer Deep area. All data are on a sa l t - f ree basis, • I =surface samples; =core 79-06-06; =core 79-06-08; • =core 79-06-10; E 3 =core 79-06-22; (ED =core 79-06-31. revealing two populations with log-normal distr ibutions and an inflection point at 50$ (Figure 4.43). Population "A" with a mean of 139 ppm Zn is represented by 50$ of the samples (n=44); population "B" with a mean of 88 ppm Zn Is represented by the remaining 50$ of the samples (n=44). A good f i t between the distr ibution of data (smooth curve) and the check points (open triangles) suggests that the partitioned populations are a reasonable separation of the data. Population "A" Is somewhat zinc-poor compared to typical "deep-sea clay" (165 ppm Zn; Turekian and Wedepohl, 1961), while population "B" compares well with the zinc content of "average shale" (95 ppm Zn; Turekian and Wedepohl, 1961). -130-1 —I I i s A(50%) n=88 C L x=139 o A x+SL=148 x-SL=130 • l — ' 4J ra s- 100 if — +-> -OJ u — B(50%) B £= o x=88 o X+SL=101 o c x-SL=77 •1— Nl 30 i i i i 2 10 30 50 70 90 98 probability (cumulative percent) Fig. 4.43 Probability graph of zinc concentration for 88 samples of sediments from the Explorer Deep area, showing inf lect ion point (arrowhead) and two partitioned populations A and B. Original data points used to generate the smooth curve are plotted in Figure 4.29; open c i rc les are calculated points used to estimate partitioned log-normal population; open triangles are check points obtained by combined partitioned populations in the proportion A:B=50:50. Al l data are on a sa l t - f ree basis. The zlnc/alumlnlum prof i le for core 79-06-06 (Figure 4.44) has a surface minimum followed by fa i r l y constant values to a basal maximum. In core 79-06-08 Zn/AI generally decreases with depth, with some fluctuations near the surface and a pronounced minium at the base. Core 79-06-10 has a surface maximum of Zn/AI that extends to 25 cm, below which the rat io remains fa i r l y constant to total depth. In core 79-06-22, Zn/AI decreases with depth, punctuated by a pronounced maximum at 10 cm, which corresponds to a calcium-rich Interval (12.66$ Ca). The Zn/AI rat io In core 79-06-31 Is constant down to 70 cm, with some fluctuations In the Interval from 70 to 110 cm, then Is more constant - 1 3 1 -Zn/Al (XIO-*) u> ro i u I — a . u i o 0 r-20 40 60 80 100 120 140 160 L Fig. 4.44 12 18 8 10 12 1—I—I—I I—I—I—I—I—I 79_-06-22 Zn/Al=0.00095 Zn/Al 79^06-06 0.00188 79^06-10 Zn/Al=0.00126 79-06-08 20 40 60 o m -o 80 ^ o 3 100 120 140 160 Zn/Al=0.00180 79-06-31 Zn/Al=0.00101 Zinc/aluminiurn profi les for cores from the .Explorer Deep area. Note the different scales for cores 79-06-10 and 79-06-22. All data are on a sa l t - f ree basis. Zn/Al is weighted average value for each core. from 110 cm to the base of the core. Weighted average values for cores from the floor of Explorer Deep are higher (Zn/AI=0.00180 to 0.00188); 79-06-06 and 79-06-08) than cores from the flanks (Zn/Al=0.00095 to 0.00126; 79-06-10, 79-06-22 and 79-06-31), Indicating a re lat ive zinc enrichment In the deep. Comparing probability graphs of the minor elements (Figure 4.29) It Is readily apparent that the distr ibution of cobalt and copper In sediments from the Explorer Deep area Is quite different than the distr ibution of barium, nickel and z inc. A poor correlation Is evident between cobalt and copper (r=0.26; Table 4.1) , which Is markedly Improved by normalization to aluminium (r=0.40, Table 4.2) . Both elements correlate posit ively with magnesium (Co-Mg, r=0.54; Cu-Mg, r=0.36) and with Iron (Co-Fe, r=0.47; Cu-Fe, r=0.37). S imi lar ly , cobalt normalized to aluminium correlates well with magnesium/aluminium (r=0.57; Table 4.2) and Iron/alumlnlum (r=0.54) as does copper/ aluminium (Cu/AI-Mg/AI, r=0.57; Cu/AI-Fe/AI, r=0.65). Weak negative correlations between cobalt and s i l i con (r=-0.32) and copper and s i l i con (r=-0.37), are not preserved In the normalized to aluminium data (Co/A I -SI/AI, r=0.15; Cu/AI-SI/AI, r=0.30), suggesting that the negative correlations may be ar t i facts ref lect ing randpm variations and not real associations. The poor correlation between cobalt and manganese (r=0.19) Is Improved somewhat by normalization to aluminium (r=0.31), while the correlation between copper and manganese (r=0.19) remains poor even after normalization (r=0.18). A cobalt-manganese association Is possible but, lack of surface maxima In cobalt and copper distr ibutions (Figures 4.36 and 4.38 respectively) and re lat ive ly poor manganese correlations - 1 3 3 -together suggest that manganese oxides are not a major host for cobalt or copper In Explorer Deep area sediments. The lack of correlation between cobalt and calcium (r=-0.03), plus cobalt/alumlnlum and calcium/aluminium (r=-0.16), and between copper and calcium (r=-0.04) plus copper/aluminium and calclum/alumlnlum (r=-0.43) suggest that skeletal remains are not a major source for either transit ion element In the study area. The lack of correlation between phosphorus and either cobalt or copper tends to support th is conclusion A correspondence between Increased calcium and copper contents was, however, evident In cores 79-06-08 and 79-06-22 Implying that there may be a biogenic copper component. The association between copper and blogenous act iv i ty has been reported by several researchers (Martin and Knauer, 1973; Bostrom et a I.P 1975; Murray and Brewer, 1977; and references therein) . Organic matter present In the sediment may, upon breakdown, supply minor elements to the sedimentary column (Bostrom et a I . . 1974; Pedersen, 1979), and given the low concentrations of cobalt and copper present, th is source may be s igni f icant . No attempt was made to quantify the biogenic contribution of copper. A close association between nickel and zinc In sediments from the Explorer Deep area Is Indicated by the s imi lar i ty In distr ibution of the two elements (Figure 4.29), and supported by strong correlations between nickel and zinc (r=0.88; Figure 4.45) and between nIckel/alumlnlum and zinc/alumlnlum (r=0.91; Table 4.2) . Strong correlations between nickel and barium (r=0.87; Figure 4.46), and zinc and barium (r=0.89; Figure 4.47) are supported by good correlations for the normalized to aluminium - 1 3 4 -200 — | Q . 100 — nickel (ppm) Fig. 4.45 Correlation between zinc and nickel in sediments from the Explorer Deep area. Al l data are on sa l t - f ree basis. Bes t - f i t l ine determined by l inear regression. data (Table 4 .2) . Like barium both nickel and zinc correlate negatively with aluminium (r=-0.69 and r=-0.62 respectively; Table 4 .1 ) , with phosphorus (r=-0.73 and r=-0.60) and with calcium (r=-0.59 and r=-0.61). The negative correlations persist for the normalized to aluminium data (Table 4 .2) , suggesting that they ref lect real relat ionships. Mass balance calculations suggest that biogenic material Is not an Important contrlbuter of nickel to the sediments. Sclater et a l . (1976) -135-200 100 n=87 x=1370 Sx=744 y=75 Sy=29 r=0.87 • •• y=0.0338x'+28.2 1000 2000 3000 barium (ppm) 4.46 Correlation between nickel and barium in sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis. B e s t - f i t l ine determined by l inear regression. 200 100 -n=87 x=1370 Sx=744 y=112 Sy=27 r=0.89 y=0.0324x+67.9 I 1000 2000 3000 barium (ppm) 4.47 Correlation between zinc and barium in sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis. Bes t - f i t l ine determined by l inear regression. -136-determined molar rat ios for the various blogenous components. Si l iceous skeletal remains have Nl/SI values up to 6.7x10"^, which when combined with the 10$ non-terrigenous s i l i c a (5$ SI) present In surface sediments from the Explorer Deep area (Table 4.5) , results In a contribution of 3 ppm Nl ; calcareous remains have Nl/Ca values up to 2.7x10"^, and combined with 5$ calcium (most samples have calcium contents below 5$ Ca, see Appendix C), results In a contribution of 2 ppm Ni ; organic t issue had NI/P values up to 9.2x10"^, which combined with a maximum phosphorus content of 0.08$ P (Appendix C), results In a contribution of 7 ppm NI. The total maximum contribution of nickel Is 12 ppm, c lear ly not suf f ic ient to explain the difference In nickel content between the two nickel populations present In sediments from the Explorer Deep area (47 ppm Nl ; Figure 4.40). It Is possible that dissolution of biogenic debris and sequestering of released metals has occurred and would y ie ld a higher nickel contribution than calculated (personal communication from E.V. G r i l l and T . F . Pedersen, University of Br i t ish Columbia); however, why the concentration of biogenic debris would be higher In sediments from the floor than those from the flanks Is unclear. While a comparable treatment of zinc was not attempted, the s imi lar i ty between nickel and zinc distr ibutions Implies that the biogenic contribution of zinc Is also small In the study area. Poor correlations for nickel to manganese (r=0.06; Table 4.1) and zinc to manganese (r=0.00) and for the normalized to aluminium data (NI/AI-Mn/AI r=0.16, and Zn/Al-Mn/Al r=0.11; Table 4.2) Indicate that association with manganese oxides Is not responsible for the variation In nickel and zinc contents In sedtments from the Explorer Deep area. - 1 3 7 -A comparison of nickel and zinc concentrations (normalized to aluminium) with clay mineral rattos (Table 4.3) shows positive correlations between NI/AI and 111Ite/chlorlte (r=0.52) and Zn/Al and 111Ite/chlorlte (r=0.58) suggesting an association with IIIIte. Since both titanium and potassium also correlate posit ively with II l ite. (Table 4.3) , posit ive correlations between both nickel and zinc with titanium (Ni/AI-Ti/AI, r=0.56; and Zn/AI-TI/AI, r=0.66), and with potassium (Nl/AI-K/AI, r=0.45; Zn/AI-K/AI, r=0.45) support the association. 111Ite appears to be an Important detr l ta l mineral host for nickel and zinc In sediments from the Explorer Deep area. Like barium, nickel and zinc are associated with smectite. Good correlations for NI/AI to smectIte/chlorlte (r=0.75) and for NI/AI to smectIte/11 11te (r=0.62) attest to the nickel association. The zinc association Is demonstrated by correlations between Zn/Al and smectite/ ch lor i te (r=0.60) and Zn/Al and smectlte/l11Ite (r=0.43). Strong correlations are evident between si IIcon/alumlnlum and barlum/alumlnlum (r=0.83; Figure 4.33), si I Icon/a Iumlnlum and nlckel/alumlnlum (r=0.73; Figure 4.48), and si I Icon/alumlnturn and zlnc/alumlnlum (r=0.67; Figure 4.49). Iron normalized to aluminium also correlates posit ively with barlum/alumlnlum (r=0.80), nlckel/alumlnlum (r=0.63), and with zlnc/alumlnlum (r=0.72). Since both Iron and s i l i con also correlate posit ively with the smectite rat ios (Table 4.3) a barlum-lron-nIckel-slI Icon-zinc association with smectite Is Indicated. Origin of smectite and Interelemental relationships are examined In detail in Chapter F ive. - 1 3 8 -00 4.0 - i 3.0 2.0 n=86 x=0.00095 Sx=0.00041 y=3.23 Sy=0.27 r=0.73 —I— 0.001 Ni/Al I 0.002 Fig. 4.48 Correlation between silicon/aluminium and nickel/aluminium in sediments from the Explorer Deep area. All data are on a sa l t - f ree basis. Bes t - f i t l ine determined by l inear regression. 4.0 - i 0 0.001 0.002 Zn/AI Fig . 4.49 Correlation between silicon/aluminium and zinc/aluminium in sediments from the Explorer Deep area. Al l data are on a sa l t - f ree basis. Bes t - f i t l ine determined by l inear regression -139-4.3 CHEMICAL COMPOSITION OF EXPLORER DEEP VOLCANIC ROCKS A complete Investigation of the chemistry of Explorer Deep volcanic rocks Is beyond the scope of th is study, but has been undertaken by Cousens (1982). In th is study two samples of volcanic glass were analyzed for comparison with sediments from the Explorer Deep area. The samples were obtained from the ch i l led margins of apparently fresh (unaltered shiny outer surface, without oxide encrustation) pillow basalts recovered by dredging at station PGC-79-06-32 (Figure 1.1) from Explorer Deep. Sample Bg is a 'dense' volcanic glass while Bv Is a sample of scorlaceous glass. The analytical data are presented In fable 4.8, together with analyses of samples of glass from the same Explorer Deep dredge haul by W.G. Melson (of the Smithsonian Institute, 1980), and by Cousens (1982). For comparison, the compositions of Juan de Fuca Ridge volcanic glass (Melson et a I.. 1976) and of average basalt (Tureklan and Wedepohl, 1961) are also Included In Table 4.8. The analyses of samples Bg and 4999 Indicate very similar compositions for most elements; however, the magnesium content was higher for Bg than for 4999, while sodium concentration was higher in 4999. There is however, considerable variation In composition between the 'scorlaceous' samples Bv and 5185; Bv has lower s i l i c a , aluminium and calcium contents than 5185, while magnesium, potassium and sodium concentrations were lower in 5185. The high degree of chemical var iab i l i t y between Bv and the other samples may be due In part to Its highly scorlaceous nature, possibly ref lect ing a more complex elemental distr ibution in the more vo lat l le - r Ich fraction of the melt. The -1 4 0 -Table 4.8 Elemental composition of volcanic glass from the Explorer Deep pillow basalts recovered by dredging at station PGC-79-06-32, plus data for the south Juan de Fuca Ridge and average basalt . Major element concentrations are In weight percent oxide equivalent; minor element concentrations are In parts-per-ml11 Ion (ppm). SAMPLE S i0 2 A l 2 0 3 FeO* MnO MgO CaO Na20 K20 T i 0 2 P 2°5 CI Ba Co Cu Ni Zn (welaht Dercent) (ppm) Bg' 50.01 15.43 10.14 0.21 8.02 11.14 1 .95 0.34 .1 .73 0.16 <200 nd 48 67 121 83 49992 50.54 15.20 10.18 nd 7.11 11.46 2.42 0.38 1 .64 0.21 nd nd nd nd nd nd Bv1 47.83 14.92 8.50 0.17 12.19 10.72 2.49 0.18 1.18 0.08 <200 nd 55 71 424 7*8 51852 50.02 15.81 8.60 nd 9.66 12.23 2.17 0.02 1.14 0.11 nd nd nd nd nd nd 7 9-06-3 2-3 <£> 49.11 13.44 11.05 0.20 8.95 11.29 2.23 0.43 1 .75 0.20 nd 102 42 nd 136 nd average basa l t^ 49.21 14.74 11.13 0.19 7.63 10.63 2.43 1.00 0.77 0.25 60 330 48 87 130 105 Juan de (mln)^ Fuca Ridge (max) 47.83 51.11 12.88 17.84 9.67 14.53 nd nd 5.58 8.80 8.03 13.54 1 .84 3.17 0.06 0.66 0.80 2.89 0.04 0.29 nd nd nd nd nd nd nd nd nd nd nd nd *total Iron expressed as ferrous oxide; nd = not determined; Bg and 4999 are samples of dense glass; Bv and 5185 are samples of scorlaceous glass; 1) data analyzed for this study (Appendix C); 2) data are from W.G. Melson (1980), of the Smithsonian Institute, Washington DC; 3) Explorer Deep volcanic glass sample analyzed by Cousens (1982); 4) average basalt composition from Tureklan and Wedepohl (1961); 5) range In composition of volcanic glass from south Juan de Fuca RPdge from Melson et al . (1976). 1scorJaceous' samples (Bv and 5185) do appear chemically dist inct from the more dense samples (Bg and 4999); Bv and 5185 are low In Iron, potassium, titanium and possibly In phosphorus, and enriched In magnesium compared to the dense glass samples. The composition of sample 79-06-32-39 (Cousens, 1982) most c losely matches that of the dense glass samples (Bg and 4999) but, has somewhat lower s i l i con content and higher aluminium. Iron and magnesium contents (Table 4.8) . Explorer Deep Is located within the Ridge and Trough province of the northeast P a c i f i c . Basalts of th is region are typical ly h igh - s l l i ca and low-potassium tho le l l tes (Engle and Engle, 1963; Kay et a I., 1970), the Explorer Deep volcanic glass analyses are consistent with th is regional observation. For comparison, the average basalt elemental composition and the range In compositions for southern Juan de Fuca Ridge volcanic glass samples are Included In Table 4.8. Explorer Deep volcanic glass elemental contents generally l i e within the range of values for glass from southern Juan de Fuca Ridge. No further examination of the Explorer Deep volcanic glass was attempted In th i s study; however, In Chapter Five the volcanic glass chemical analyses are compared to the composition of sediments from the Explorer Deep area. -1 4 2 -5. THE HYDROTHERMAL COMPONENT IN EXPLORER DEEP SEDIMENTS Gr i l l at a l . (1981) described a nontronlte-oxlde crust (EDMS) of apparent hydrothermal or ig in which was recovered In dredge haul 69-11 from Explorer Deep. It Is possible that th is expression of hydrothermal act iv i ty In the area might also be reflected by a hydrothermal component In the local sediments. In th is section non-metal 11ferous sediments from the Explorer Deep area are compared to EDMS and to other hydrothermal deposits by employing techniques which u t i l i z e the chemical composition of different sediment types (Table 5.1) to distinguish hydrothermalIy-derlved sediments. The poss ib i l i ty that a hydrothermal component Is present In Explorer Deep sediments Is examined In d e t a i l . Dymond et a l . (1973) suggested use of an alumlnJum-lron-manganese ternary diagram (Figure 5.1) to distinguish between hydrothermal and other types of sediments; the low-alum!nJum portion of their diagram Is dominated by manganese nodules at the manganese apex and by hydrothermal metalliferous deposits at the Iron apex. In contrast, samples of EDMS (Gr i l l et a I.. 1981) exhibit a high degree of v a r i a b i l i t y , ranging over the entire low-alumlnlum portion of the diagram. Surface samples from the Explorer Deep area cores (analyzed In th is study) occupy the low-manganese area of an envelope which describes Pac i f i c pelagic sediments. This general composition ref lects a dominance of terrigenous material ; there Is no evidence In Figure 5.1 to suggest that a hydrothermal component Is present In Explorer Deep surface sediments. Recognizing the multi-phase nature of marine sediments, Bostrom -1 4 3 -Table 5 .1 Chemical composition of selected hydrothermal deposits plus metalliferous and non-metalliferous sediments from the northeast Pacif ic Ocean. SAMPLE ELEMENTAL CONCENTRATIONS SOURCE [weight percent] [ppm]  Si Al Fe Mn M9 Ti Ca Na K Ba Co Cu Ni Zn Domee 18B [34-36 cm] 23.4 4.64 9.09 4.32 2.56 0.30 1.66 0.55 1.93 nd nd 1280 630 nd Bischoff & Ro8enbauer, 1977 Domes 20 (13-18 cm) 24.5 8.56 5.23 0.85 1.90 0.47 0.91 2.00 2.85 nd nd 560 235 nd II II N.E. Pacific Sad. [avg. total) nd nd 5.3 0.21 nd nd 4.9 nd nd nd 23 68 75 136 Bo mho Id et a l . . 1981 N.E. Pacific Sed. [unit #4] nd nd 5.2 0.15 nd nd 5.4 nd nd nd 24 65 66 119 II II N.E. Pacific Sed. (unit 15) nd nd 12.2 2.95 nd nd 1.6 nd nd nd 490 1400 450 320 II II EPR [avg. heat flow; group a ) c f EPR [high heat flow; group b ) c f GR [todorokito-rich) 13.0 4.7 9.5 2.4 nd 0.17 nd nd nd 215 990 690 285 Boatrom & Peterson, 1969 6.1 0.50 18.0 6.0 nd 0.02 nd nd nd 105 730 430 380 II II 0.65 0.20 0.31 51.1 1.97 nd 1.19 2.29 0.55 2490 9 99 496 301 Corliss B t e l . , 1978 GR [blmessite-rich) 0.91 0.15 0.57 46.7 2.07 nd 1.82 2.28 1.17 1300 6 264 1430 1070 II II GR [nontronite-rich] 23.6 0.02 24.4 0.19 1.56 nd 0.64 1.11 1.80 72 1 5 17 28 II II ED MS (avg. #2, 6) B f * ED MS t#4)6f* ED MS ( « ) B f * ED MS [avg. #7,8,9)8 f* Bauer Deep MS c f a f Dellwood Seamount Fe-depoeit 22.7 1.26 17.9 0.16 2.36 0.14 0.70 0.89 2.00 700 3 16 12 50 Gri l l et e l . , 1981 5.14 <0.05 14.9 25.2 1.45 <0.03 1.22 1.27 0.13 1200 <1 <1 1 15 ti II 0.66 <D.05 1.95 44.3 2.18 <D.03 1.14 1.80 0.17 1900 2 6 6 13 II II 10.6 0.98 18.8 14.7 1.09 0.05 1.37 1.29 0.62 933 6 22 43 76 II II 20.6 2.34 13.5 3.70 2.32 0.12 1.40 0.74 0.80 15100 198 979 1000 321 Say lee & Bischoff, 1973 8.60 1.0 30.0 1.68 0.70 nd 1.30 nd 0.30 267 5 10 58 450 Piper et a l . , 1975 ED non-MS (avg. e l l samples)^ ED non-MS [avg. sfc. samp les] g^ Average Shale 25.9 8.05 5.13 0.09 1.87 0.51 3.1 2.82 1.70 1370 21 38 75 112 this study 26.5 7.55 5.06 0.16 1.72 0.48 2.04 2.89 1.54 2150 19 37 92 124 II II 7.30 8.00 4.72 0.08 1.50 1.38 2.21 0.95 2.66 580 19 45 68 95 Turekian & Wedepohl, 1961 Avg. Pacific Pelagic Clay c f 25.7 8.8 5.4 1.29 2.05 0.42 0.51 0.96 2.24 1200 150 560 210 85 Landergren, 1964; Landergren & Manheim [1963] cited In Savles & Bischoff [1973] EPR = East Pacific Rise; GR = Galapagos Rift hydrothermal mounds; ED = Explorer Deep; MS = Metalliferous sediment; cf = carbonate free; sf = salt free; nd = not determined; * described in Appendix A. Al F ig . 5.1 (after Dymond et a I.P 1973) Al-Fe-Mn ternary diagram relating Explorer Deep non-metaI 11ferous surface sediments (ED) to Paci f ic pelagic sediments, the Domes area sediments, Nazca Plate nodules, East Pac i f ic Rise metalliferous sediments,a Dellwood Seamount deep-sea Iron deposit (DSM), Bauer Deep metalliferous sediments, and Explorer Deep metalliferous sediments (1=sample #5; 2=sample #4; 3=average samples #7,8,9; 4=average #2,6). New data from Table 4.8 and Appendix C. et a l . (1972) advocated the use of an Iron/titanium versus aluminium/ alumlnlum+lron+manganese rat io to study component mixing relationships (Figure 5.2) . Surface sediments from the Explorer Deep cores plot at the terrigenous end of the diagram, between the curve defined by East Paci f ic Rise metalliferous sediments and average shale, and that defined by EDMS and Explorer Deep volcanic glass. The composition of non-metal I I ferous sediments from the Explorer Deep area can be derived by a mixture of terrigenous materials and volcanic debris; there Is no evidence In Figure 5.2 of the presence of a hydrothermal component. - 1 4 5 -1000 gh heat flow) 100 -Fe Ti 10 -BD EDMS(J7,8,9) \ \ "(#2,6) EDMS(#5) EPR(average heat flow) 0.1 "T -0.2 0.3 0.4 Q.5 I 0.6 Al Al+Fe+Mn Fig. 5.2 (after Bostrom et a l . , 1972) Fe/Al versus Al/Al +Fe+'Mn, demonstrating mixing relationships of non-metalliferous surface sediments from the Explorer' Deep area (ED), average Pacif ic pelagic clay (PPC), the Domes area sediments, East Pacif ic Rise average heat-flow area and high heat-flow area (metalliferous) sediments (EPR), Bauer Deep (BD), Explorer Deep metalliferous deposit (EDMS), Explorer Deep volcanic glass (Bg and Bv), and average shale (AS). Data are from Table 5.1 and Appendix C. -146-A graph of Iron/manganese versus copper+nickel was used by BIschoff and Rosenbauer (1977) to examine the compositional spectrum from pelagic sediments to ferromanganese nodules (Figure 5.3) . The diagram shows that ferromanganese nodules have low Iron/manganese ratios and high concentrations of trace metals. In contrast, hydrothermal deposits have quite variable iron/manganese compositions, and generally low trace metal contents. The rapid formation of hydrothermal minerals offers less opportunity for scavenging of trace metals from seawater, compared* to the slowly formed ferromanganese nodules of hydrogenous deposits (Chapter Two). Non-metalliferous sediments from the Explorer Deep area plot with other northeast Pac i f ic hemipelagic sediments, having high iron/manganese ratios and low nickel+copper contents. The composition of Explorer Deep sediment once again is between that of average shale and volcanic glass, with considerably lower trace metal content than that of Paci f ic pelagic sediments. This technique Is of limited use for distinguishing between hydrothermal and terrigenous sediments. BIschoff and Rosenbauer (1977) suggested that the contribution of pelagic clay to a mixed metalliferous-terrigenous sediment may be corrected for , thereby revealing a minor hydrothermal component. The procedure can be summarized as follows: 1) Assume the total sediment Is a mixture of metalliferous sediment and normal pelagic c lay , plus carbonate and Interst i t ial sa l t s . No corrections are made for the occurrence of biogenic s i l i c a or volcanic debris. 2) Assume al l aluminium Is bound within the terrigenous component ( le. pelagic c lay) . Then using major oxide to alumina ratios for typical "Paci f ic pelagic clay" (Table 5.2), the pelagic clay fraction can be calculated, Incorporating each sample's measured alumina content, and subtracted. 3) All CaO and Na20 are assumed to be present as carbonate and - 1 4 7 -200 100 80 60 40 20 10 _ EDMS (#2,6) -|- AVERAGE SHALE 1 \-.8 6 |-.4 DELLWOOD SEAMOUNT O Fe DEPOSIT l^-N.E. PACIFIC SEDIMENTS (unit.#4) y Q AVERAGE BASALT Bv ,« EXPLORER DEEP NON-METALLIFEROUS SEDIMENTS m + — N.E. PACIFIC ( a l l samples) f. AVERAGE PELAGIC SEDIMENT 9 DOMES 20 BASAL DSDP PACIFIC PELAGIC CLAY + N.E. PACIFIC (basal core #13)' EDMS (#7,8,9) EPR & S DOMES 18B X x PACIFIC FERROMANGANESE NODULES J ' i i I I i i J I i I I I II .001 .002 .004 .008.01 .02 .04 .06.08.1 .4 .6 .8 1 percent Cu+Ni Fig. 5.3 (modified after Bischoff and Rosenbauer, 1977) Fe/Mn versus Cu+Ni showing compositional relationship between Explorer Deep non-metalliferous sediments, average Paci f ic pelagic sediment and c lay , average shale, Explorer Deep volcanic glass (Bg and Bv), average basalt , Explorer Deep metalliferous deposit (.EDMS), other metalliferous sediments from East Pacif ic Rise (EPR), Bauer Deep (BD), basal DSDP, Domes 18B, and N.E. Pac i f ic basal core #13, plus Paci f ic ferromanganese nodules. New data are from Tables 4.8 and 5 .1 , and from Appendix C. -148-Interst i t ia l sa l t respectively, and are subtracted. 4) The remainder, In weight percent equivalent oxide, Is then recalculated to 100$. Samples of the Explorer Deep metalliferous deposit (Gr i l l et a I.f 1981) were partitioned using th is technique (Table 5.2) . The deposit has anomalously high non-terrigenous Iron, manganese and s i l i c a , plus s l ight enrichments of magnesium, titanium and potassium. Nontronlte-rlch samples (EDMS (#2,6)) contain 37.3 wt.$ non-terrigenous material , In contrast oxide-r ich samples contain about 60 wt.$ non-terrigenous material . The non-terrigenous contents of EDMS (#4) and EDMS (#5) are minimum estimates, calculated using 0.10 wt.$ AI2O3 (which Is l ikely an overestimate of the alumina content, as values quoted by Gr i l l et a I. (1981) are <0.10 wt.$ AI2O3); the true content could be considerably larger. Tremendous variation In composition of the non-terrigenous fraction Is evident; the non-terrigenous fraction In nontronlte-rlch samples (#2,6) contains no manganese, while In oxide-rich samples (#4, #5, and #7,8,9) It has between 30 and 88$ MnO. The non-terrigenous fraction In nontronlte Is composed of 56.8$ s i l i c a while only 1.7 to 26.7$ of the non-terrigenous fraction Is s i l i c a In oxide-rich samples. Iron accounts for 36.0$ of the non-terrigenous fraction In nontronlte r ich samples and from 4.2 to 42.2$ of the non-terrigenous fraction In oxide-r ich samples. A hydrothermal source Is l ikely for Iron, manganese and possibly potassium. Biogenic opal l ikely forms a s ignif icant part of non-terrigenous s i l i c a , however a hydrothermal source Is also possible. Magnesium may be scavenged from the water column and pore waters during formation of nontronlte. The non-terrigenous titanium content Is l ikely overestimated In the calculat ion (see below). -1 4 9 -Table 5.2 Major element composition of the non-terrigenous fraction in sediments from the Explorer Deep and Juan de Fuca Ridge areas. The terrigenous component was calculated using oxide/alumina ratios for average "Pacif ic pelagic clay" and subtracted; a l l CaO and Na^ O was assumed to be carbonate and i n t e r s t i t i a l - s a l t s and was subtracted. The remainder was recalculated to equal 100%. MAJOR TOPE/ALUMINA RATIOS SAMPLE SIC MnO NDN-TERRIGaOUS REMAINDER, [weight percent oxide] TOTAL SOURCE A L 2°3 A L2*3 M2O3 ALft EXCESS Si0 2 F e 2 ^ MnO MgO Ti0 2 KgO TOTAL 0.558 0.041 0.215 0.059 0.137 11.05 86.2 11.2 0 1.2 1.4 0 100 1 this study 0.464 0.005 0.198 0.056 0.137 7.26 98.2 0 0 0 1.8 0 100 11 II 0.513 0.023 0.212 0.062 0.134 10.42 90.5 6.5 0 1.0 2.0 0 100 it n 0.542 0.010 0.206 0.057 0.126 10.24 88.0 10.5 0 0.1 1.4 0 100 n n 0.516 0.012 0.212 0.057 0.143 6.91 84.4 11.0 0 1.4 3.2 0 100 11 •i 0.566 0.035 0.205 0.060 0.133 12.70 87.4 11.2 0 0 1.4 0 100 11 II 0.496 0.005 0.197 0.058 0.141 10.58 94.2 4.3 0 0 1.5 0 100 11 it 0.522 0.006 0.207 0.057 0.122 11.19 90.9 7.5 0 0.3 1.3 0 100 11 ti 0.421 0.018 0.148 0.042 0.114 12.20 100.0 0 0 0 0 0 100 11 ii 0.519 0.005 0.206 0.060 0.130 11.61 91.9 6.5 0 0.1 1.5 0 100 it II 0.536 0.005 0.209 0.060 0.140 12.46 91.3 6.0 0 0 0.7 0 100 11 II 0.462 0.006 0.182 0.053 0.108 6.74 98.7 0 0 0 1.3 0 100 11 II 0.500 0.006 0.211 0.057 0.140 8.82 91.5 5.9 0 1.0 1.6 0 100 11 II 0.507 0.008 0.211 0.057 0.140 7.53 88.6 B.2 0 1.2 2.0 0 100 n II 0.484 0.007 0.219 0.056 0.140 2.59 73.7 12.4 0 8.5 5.4 0 100 11 II 0.447 0.008 0.184 0.051 0.121 5.45 98.9 0 0 0 1.1 0 100 •1 II 0.462 0.006 0.202 0.055 0.128 0.95 86.3 0 0 0 13.7 0 100 11 II 0.576 0.023 nd 0.053 nd 6.16 75.9 22.9 0 nd 1.2 nd 100 Price, 1981 0.443 0.009 nd 0.055 nd 4.18 97.1 0 0 nd 2.9 nd 100 11 II 0.454 0.014 nd 0.048 nd 0.01 0 0 0 nd 100.0 nd 100 11 ti 6.11 0.054 0.865 0.058 0.627 37.3 56.8 36.0 0 4.2 0.1 2.9 100 Gr i l l et a l . , 1981* 213 325 24.0 0.3 1.6 67.0 15.9 31.7 48.5 3.6 0.1 0.2 100 II ii 27.9 572 36.1 0.3 2.0 64.8 1.7 4.2 88.3 5.5 0.0 0.3 100 II ii 14.48 10.21 0.97 0.041 0.405 61.6 26.7 42.2 30.4 0 0 P.7 100 II II 0.464 0.101 0.205 0.047 0.163 0 0 0 0 0 0 0 0 Landergren, 1964 79-06-01/0-2 79-06-02/0-2' 79-06-04/0-2 79-06-06/0-2 79-06-07/0-2 79-O6-O8/0-2 79-06-10/0-2 79-06-21/0-2 79-06-22/CM 79-06-29/0-6 79-06-30/0-2 Bf ! e f ! s f ! s f |sf B f ! 8 f ! 8 f B f ' B f j s f ! a f 79-06-31/0-2 79-06-06(we1ghted avg. ] B f 79-06-08(we1ghted avg. ) 8 f 79-06-10[weighted avg ." 8 f 79-06-22[weighted avg.) 8 f 79-06-31[weighted evg.) 8 f J de F [unit #1) J de F [unit 12) J de F [unit 1*3) EDMS (avg. #2,6) EDMS (#4) J sf ef 8 f EDMS (#5) EDMS lavgl"#7,8,9) Pacific pelagic cLay c f 4.03 3.79 3.99 3.96 3.71 4.11 4.01 4.02 4.12 4.09 4.13 3.74 3.87 3.77 3.43 3.66 3.36 3.68 3.58 3.26 12.21 110 14.1 12.18 3.31 nd = not determined; af = Bait - f r e e ; cf = carbonate-free; J de F = Juan de Fuca Ridge sediments; EDMS = Explorer Deep metalliferous sediments; 1) see Appendix C for coop late analyses; 2) see Appendix A for description of BampLes. The partit ioning technique recommended by BIschoff and Rosenbauer (1977) Ignores a possible hydrothermal source of calcium, assuming that a l l calcium Is present as biogenic carbonate. The calcium content of EDMS samples ranges between 0.50 and 1.96$ CaO (Gr i l l et a l . . 1981). The observed lack of biogenic debris (Gr i l l et a I . , 1981; Chapter Three this study) suggests that calcium Is associated with hydrothermal minerals. Dissolution of skeletal debris and hydrothermal solutions are the source of calcium. Part i t ioning the calcium data, using CaO/A1203=0.043 (from average "Pac i f ic pelagic c lay" ; Landergren, 1964) for the terrigenous component, results In a non-terrigenous calcium content of between 0.43 and 1.85 wt.$ CaO. Very l i t t l e of the calcium can be attributed to detr l tal Input. While It Is possible that calcium In EDMS Is present as exchangable cations In nontronlte, c lay - r i ch samples (EDMS #2,6) have lower calcium contents (0.50-1.45 wt.$ CaO; G r i l l et a I . , 1981) than oxlde-rlch samples (1.60-1.96 wt.$ CaO), suggesting that an alternate host-mineral Is present. Similarly the nontronIte-rIch sample from Galapagos Ridge hydrothermal mounds has a lower calcium content than +7 oxlde-rlch samples (Corl iss et a I.P 1973). Substitution of Ca for +7 Mn In the Mn-oxlde phase Is most l ikely case (E.V. G r i l l personal communication. University of Br i t ish Columbia). Sur f lc la l sediments from the Explorer Deep area are partitioned using the same technique; the results Indicate a non-terrigenous remainder forming between 6.7 and 12.7 wt.$ of the total sediment (Table 5.2) . The non-terrfgenous fraction Is composed predominately of s i l i c a (constituting up to 12 wt.$ of total sediment; Table 4.4) and Iron (forming upto 1.4 wt.$ of total sediment; Table 4.6) plus sl ight 'excess' titanium and magnesium. In surface sediments of cores 79-06-22 and 79-06-31 (from the flanks of Explorer Deep) and core 79-06-02 (from the floor) the non-terrigenous fraction is composed almost entirely of s i l i c a . There is considerable variation in the non-terrigenous iron content in sur f ic ia l sediments, but the three samples with >1.0 wt.$ non-terrigenous Fe20-j (Table 4.7) are a l l from the f loor . Titanium appears to be uniformly enriched in a l l samples, indicating that either a regional non-terrigenous source of titanium is present, or the ratio used for the terrigenous component (TiC^/AI203=0.047; Landergren, 1964) is smaller than is appropriate for the study area. The s imi lar i ty between titanium/alumina rat ios in nontronite-rich samples EDMS (#2,6) (TiO2/AI£0^=0.058; Table 5.2) , Explorer Deep sediments (average a l l samples; Ti 02^120-3=0.056), and Juan de Fuca Ridge sediments (Ti02/ A120^=0.48-0.55) suggests that the latter is the more l ike ly . Weighted average compositions of f ive cores are also partit ioned. Total non-terrigenous content is higher in cores from the floor of Explorer Deep (7.5 to 8.8 wt.$) than in cores from the flanks (0.9 to 5.5 wt.'$). Non-terrigenous s i l i c a content is between 6.7 and 8.1 wt.$ in cores from the f loor (derived from Table 5.2) , and between 0.8 and 5.4 wt.$ in cores from the flanks. Cores from the f loor contain between 0.5 and 0.6 wt.$ non-terrigenous Iron, while cores 79-06-22 and 79-06-31, from the flanks, contain no non-terrigenous Iron and core 79-06-10 is intermediate with 0.3 wt.$. In sediments from Juan de Fuca Ridge, units #2 and #3 (below the upper layer) contain no non-terrigenous iron. The partit ioning technique Indicates anomalously high non-terrigenous Iron and s i l i con contents in sediments from the floor of Explorer Deep. - 1 5 2 -Hydrothermal solutions recovered from vents In Galapagos R i f t supply s ignif icant amounts of barium, calcium, manganese, potassium and s i l i con to the water column (Edmond et a I.P 1979a, 1979b), providing direct evidence of hydrothermal solutions similar to those proposed as a source for EDMS. While hot springs sampled are e f f i c ient transporters of manganese they do not, with the exception of a single hot spring, supply much Iron. Inter - f ie ld Iron concentrations are highly var lb le , ref lect ing differences In Iron source material, water/rock ratios of Individual systems, and temperature of the exiting solutions. Magnesium concentrations decreased with increased temperatures, Indicating that hydrothermally active areas are sinks rather than sources for magnesium. Synthesis of smectite generally requires magnesium (Harder, 1972); how-+7 ever, nontronlte can form In the presence of Fe (Harder, 1978). The abundance of nontronlte in EDMS Implies that a source of magnesium (pos-sibly In sea water) adequate for formation of smectite, or more l ikely a +7 hydrothermal source of Fe , Is present In Explorer Deep. Hydrothermal solutions from Galapagos Ri f t are depleted In nickel and copper (Edmond et a I. P 1979a, 1979b), due to Incorporation In sulphides within the vent system; stripping of nickel and copper from pore waters was also In-dicated, and Is attributed to scavenging by newly formed Iron oxides. In non-metal 11ferous sediments from the Explorer Deep area barium correlates strongly with both nickel and zinc (r=0.87 and 0.89 respectively; Table 4.1) . Iron, when normalized to aluminium, correlates positively with barium, nickel and zinc (r=0.80, 0.63, and 0.67 respectively; Table 4.2) . When normalized to aluminium, s i l i con also correlates posit ively with a l l three minor elements (r=0.83, 0.73 and - 1 5 3 -0.67 respectively) . Si l icon and Iron correlate poorly (r=-0.23; Table 4.1) , but the correlation Improved sign i'f leant I y (r=0.37; Table 4.2) following normalization to aluminium, indicating an association that may ref lect di lut ion of a small phase by a much larger detrltal component. Barium, n icke l , zinc and non-l ithogenous iron and s i l i con are a l l enriched in cores from the floor of Explorer Deep compared to the flanks (Chapter Four). To show the relationship between these elements, iron/ manganese ratios were plotted against barium+nickel+zinc (Figure 5.4); similar to the iron/manganese versus nickel+copper diagram of Bischoff and Rosenbauer (1977). Tremendous var iab i l i t y is evident in the composition of samples from the same hydrothermal deposit and between different deposits; c lear l y , discrimination between hydrothermal and non-hydrothermaI sediments is not possible using the sediment bulk composition. There is however, a def inite separation between weighted average compositions of cores from the flanks of Explorer Deep (79-06-10, 79-06-22 and 79-06-31) and those from the floor (79-06-06 and 79-06-08). Weighted average composition of a l l f ive cores have iron/ manganese ratios similar to that of "average shale" (Turekian and Wedepohl, 1961). The Ba+Ni+Zn contents of cores from the flanks of Explorer Deep are similar to that of "average shale", while sur f ic ia l sediments and cores from the floor of Explorer Deep have Ba+Ni+Zn contents closer to that of "deep-sea clay" (Turekian and Wedepohl, 1961). Sur f lc la l sediments have higher manganese contents than down-core samples (ref lecting diagenetic enrichment of manganese in the oxidized surface layer; Chapter Four). If sediments recovered from the flanks of Explorer Deep represent the typical composition of hemlpelaglc - 1 5 4 -200 100 80 60 40 20 10 Ol 1 .8 .6 .4 .1 £ GR ( n o n t r o n i t e ) .01 Q EDMS (#2,6) 79-06-AVERAGE BASALT AVERAGE SHALE u X O O 79-06-08 T ^ 79-06-22 79-06-10 O 79-06-06 O SURFACE SAMPLES O °EEP SEA CLAY DELLWOOD SEAMOUNT Fe DEPOSIT % PACIFIC PELAGIC CLAY BDMS A • EDMS (#7,8,9) • EDMS (#4) ' * I I I I I A GR (b i rness i te ) — J ' * I I I I I .02 .04 .06 .08 .1 .2 .6 .8 1 percent Ba+Ni+Zn Fig 5.4 Fe/Mn versus Ba+Ni+Zn showing compositional relationship between: O Explorer Deep non-metalliferous sediments (weighted average values for f ive cores and average for twelve core surface samples); - f " a v e r a g e shale; O average 'deep sea c l a y 1 ; # average 'Pac i f i c pelagic c l a y 1 ; X average basalt ; A Bauer Deep metalliferous sediment (BDMS); A Galapagos Rift hydro-thermal mounds (GR); • Explorer Deep Metalliferous deposit (EDMS); • Dellwood Seamount iron deposit. Data are from Tables 4.8 and. 5.1. and Appendix C. -155-sediments In the area, then sur f lc la l sediments and sediments from the floor contain anomalously high concentrations of barium, nickel and zinc. Without the reference provided by down-core analyses of sediments from the flanks, the presence of an anomalous component In Explorer Deep sediments could not be distinguished. Barium Is of particular interest, as part it ioning of the mult i -modal distr ibution (Figure 4.30) Indicates two dist inct populations; high barium concentrations (mean 2050 ppm Ba) In sediments from the floor of Explorer Deep plus sur f lc la l samples, and low barium concentra-tions (mean 580 ppm Ba) in the flank sediments. EDMS samples show considerable variation in barium content (400 to 1900 ppm Ba; Gr i l l et a I., 1981); the highest concentration-Is similar to the high barium level In non-metaI I Iferous sediments. The low level (580 ppm Ba) Is the same as the barium content of "average shale" (580 ppm Ba; Tureklan and Wedepohl, 1961). These data are Interpreted to represent a regional background of terrigenous barium with sediments from the floor of Explorer Deep containing an anomalous barium-rich component, possibly of hydrothermal o r ig in . Barlte Is a common component In many hydrothermal deposits (Bonattl et a I.f 1972a; Bostrom et a I., 1973; Bertlne and Keene, 1975; Heath and Dymond, 1977; Lonsdale, 1979). While no barlte was found In either EDMS (Gri l l et a I.f 1981) or non-meta111ferous sediments (Chapter Three), small quantities of f ine-grained barlte may be present In amounts below detection l imits of the analytical technique used. Barium Is associated with both oxides and hydroxides, and smectites In a number of hydrothermal deposits (Bonattl et a I.f 1972a; Lonsdale, 1977; Cor 11 ss ejt_ai., 1978; Hoffert £ t _ a i . , 1978; Gr i l l - 1 5 6 -et a I.. 1981), although the oxide and hydroxide phase Is generally the principal barium host. Non-metal 11ferous sediments from the Explorer Deep area do not show s igni f icant correlation between barium and manganese (r=0.06; Table 4.1) ; s imi lar ! ly a poor correlation exists between barlum/alumlnlum and manganese/aluminium (r=0.19; Table 4.2) , Indicating that manganese oxides are not the primary host for barium. Significant posit ive correlations between smectite ratios and (normalized to aluminium) barium, Iron, nlcke ( l , s i l i c o n , and zinc (Table 4.3) , indicate an association between these elements and a smectite-bearing phase. The f ive elements, and smectite are enriched in sediments from the floor of Explorer Deep compared to those from the flanks (Chapters Three and Four); variations in smectite content and chemical composition may therefore have a common or ig in . Smectite composition In marine sediments however, can be quite complex: for example, Goulart (1976) identif ied four types of smectite In sediments from Atlantis II Deep, and proposed three modes of or ig in , de t r i ta l , submarine alteration of volcanic material , and precipitat ion from solution. In Explorer Deep at least three types of smectite are present: fine grained (dominating the <0.2 um fraction) smectite, l ikely detrltal montmor11lonlte; 11 IIte-smectlte and chlorlte-smectIte mixed-layer clays In clay (0.2 to 2 um) and very fine s i l t (2 to 5 um) fractions; and nontronlte In EDMS and .possibly non-metal 11ferous sediments (Chapter Three). Close examination of the smectite content In Explorer Deep sediments Is c lear ly required. The term smectite encompasses the group of 2:1 phyIloslIIcates Including montmor11lonlte, nontronlte, and related minerals (the terms -1 5 7 -montmor11lonoIds or montmorIIlonlte group are also commonly used). The swelling behavior character ist ic of smectites, occurs by expansion between adjacent tetrahedral layers. In smectites, component layers are not t ight ly bonded by K as In micas, or by Mg*- as In vermlcul Ites; Instead water molecules are present In Inter-layer s i tes . Isomorphous substitutions may occur In the tetrahedral layers (Fe 3 + and A l 3 + for S l ^ + ) , or more commonly In the octahedral layers (Mg 2 + , F e 2 + , F e 3 + , Z n 2 + , N l 2 + , L I + , M n 2 + , C r 2 + , C r 3 + , Cu + , V 4 + , etc . for A l 3 + ) , and lead to lat t ice charge deficiencies (Grim, 1968; MI I lot , 1970; Weaver and Pol lard , 1973; Sayles and Mangelsdorf, 1977). Net negative charges on adjacent component layers cause repulsion and separation; exchangable cations are sorbed between layers and balance the charge. The cation exchange capacity (CEC) of smectites Is high, between 0.7 to 1.3 meq/g*, of which about 80$ Is attributed Interlamellar cations, and 20$ results from edge-effects (Grim, 1968; Weaver and Pol lard, 1973). The l i s t of possible exchangeable cations Includes Na + , C a 2 + , Mg 2 + , H + , K + , L l + , NH 4 + , B a 2 + , S r 2 + , and Cs + (Jackson, 1956; MacEwan, 1961; Grim, 1968; MI I lot , 1970; Weaver and Pol lard , 1973; Sayles and Manglesdorf, 1977); organic molecules, aluminium and Iron oxides, and other hydrated Ions may also be present In Inter-layer positions (MacEwan, 1961; Grim, 1968; Weaver and Pol lard, 1973). The composition of smectites Is highly var iable, to the extent that they may be regarded as the "garbage-dump" of phyIloslIIcates (personal communication from L.M. Lavkul Ich, 1980). The smectite contents In clay and fine s l i t s ize - f ract ions of sur f l c la l sediments from the f loor and flanks of Explorer Deep are quite * 1 ml I Ilequlvalent (meq) = 0.001 g atom of H+ (or 6.023x10 2 0 lons) = 0.020 g atom of C a 2 + (or 3.01x10 2 0 Ions) - 1 5 8 -similar (Figures 3.7 and 3 .8 ) . In sediments from the flanks, the smectite content decreases dramatically at depth; in contrast In sediments from the f loor the smectite content remains constant or Increases s l ight ly at depth. The enrichment of smectite at depth In sediments from the f loor of Explorer Deep re lat ive to the flanks, may be accomplished In four ways: (1) winnowing of smectIte-rIch fines from the flanks; (2) Holocene sedimentation rates are higher for the floor than the flanks, which results In a thinner layer of possibly smectlte-rIch post-PIelstocene sediments on the flanks; (3) smectite formed by Insltu alteration of volcanic debris; and (4) Insltu formation of authlgenlc smectite by precipitat ion from hydrothermally enriched solutions. Each of the ways are c r i t i c a l l y examined below. Detrltal smectite Is common In marine sediments from the northeast Paci f ic (Rateev et a I. f 1969; Duncan et a I.', 1970; Stokke and Carson, 1974; Arcaro, 1978; Karl In, 1980; Cook, 1981; P r i ce , 1981), dominating the fine c lay , but present In decreasing quantit ies up to s i l t size (Arcaro, 1978; Chapter Three, this study). Cook (1981) suggested that winnowing of f ine-grained smectite from topographically high areas, presumably by deep-ocean currents, causes a concentration of smectite In depressions. Several factors Indicate that winnowing Is not responsible for the distr ibut ion of smectite In the Explorer Deep area. While the Cal i fornia Undercurrent may extend as far north as Vancouver Island (Reed and Halpern, 1976; Halpern et a I.P 1978; Karl In, 1980) and affect sediments on the upper slope (to depths of 200 to 800 m), deep-ocean currents, ef fect ive to depths of 2000 m, have not been reported In the Explorer Deep area. Furthermore, In th is study the distr ibution of clay - 1 5 9 -minerals Is examined as species rat ios within specif ic s ize- f ract ions (Chapter Three), rather than as total mineral concentrations. Both clay (0.2 to 2 um) and very f ine s i l t (2 to 5 um) show smectite enrichment below sur f l c la l samples of sediments from the floor of Explorer Deep (Figures 3.7 and 3.8 respectively) . To Invoke winnowing as the causa-t ive factor requires selective removal of a single component from both size ranges. Such a process cannot be attributed to current action. The role fecal pel lets play In the transport of sediment to the sea floor In the study area remains unclear. Honjo and Roman (1978) suggested that fine grained sediment, enclosed within a "protective" organic membrane, may be transported very rapidly through the water column and deposited on the sea f loor . Adundant pel letal material was observed In many of the cores recovered from the Explorer Deep area (Appendix A), suggesting that the volume of sediment contributed may be considerable. While It Is possible that organisms may selectively concentrate specif ic clay minerals, winnowing of pel let -s ized material (0.5 mm) from the flanks Is very unl ikely , and therefore does not explain the smectite d is t r ibut ion . Sediments In cores from the flanks of Explorer Deep have unusual character is t ics , which suggest that they may actually be older than those from the f loor . In core 79-06-10 a sharp geochemlcal break occurs at about 22 cm (Chapter Four), possibly indicating a dlsconformable contact; however, a corresponding sedlmentologlcal break Is not evident In the core (Figure A.7). The abundant coarse sediment (up to pebble size) In core 79-06-22 (Figure A.9) l ikely originated by gravity Induced - 1 6 0 -slumping of older material from the prominent escarpment of Paul Revere Ridge Into the valley at location 79-06-22 (see Figure 1.1). The geochemlcal var iab i l i t y In core 79-06-22 attests to the complex sediment composition (Chapter Four). Sediments In core 79-06-31 have features suggestive of turbidity current deposition (Figure A.12) Including si I ty laminations, some with sharp bases and graded bedding, and rare cross -lamlnatlons. During the Pleistocene high rates of sediment supply associated with the g lac ia l act iv i ty supported widespread turbidity current deposition, while during the Holocene a reduction In sediment supply has lead to predominately hemlpelaglc sedimentation, with only localized turbidity current act iv i ty (Duncan et a I.r 1970; Duncan and Kulm, 1970; Griggs and Kulm, 1970; Carson and McManus, 1971; Horn et a I.f 1972; McManus e ± _ g l . , 1972; Arcaro, 1978; Davis and RIddlhough, 1982). A decrease In the smectite content between Holocene and Late Pleistocene sediments has been reported by a number of authors (Duncan et a I.. 1970; Stokke and Carson, 1974; Cook, 1981). The difference In mlneraloglcal composition Is attributed to Increased chemical weathering ref lect ing the change In climate from cool glacial conditions during the Pleistocene to warmer Inter-gIacI a I Holocene conditions. Smectite content In clay and very fine s i l t s ize- f ract ions of sediments from the flanks Is maximum In su r f l c la l samples and decreases markedly at depth (Figures 3.7 and 3 .8 ) ; In contrast, In sediments from the f loor smectite content remains constant or Increases s l ight ly at depth. The Inference Is that sediments recovered from the floor of Explorer Deep (>120 cm) are entirely of Holocene age, whereas sediments recovered from the flanks are pr incipal ly of Pleistocene age with only a thin layer (<20 cm) of Holocene sediment. - 1 6 1 -The presence of a mlneraloglcal change at the PIelstocene-Holocene boundary has been disputed quite convincingly by Arcaro (1978) and Carson and Arcaro (1983), who concluded that variations In clay mineral content are primarily due to textural differences which ref lect selective transport and deposition of sediment. Clay mineral s i ze -dependency and grain -s ize distr ibution are the control l ing factors. Since In th is study, the distr ibutions of clay minerals are examined as relat ive variations within discrete size fractions (Chapter Three), • selective transport and deposition should not be factors. If sediment Is transported to the sea-f loor pr incipal ly by gravitational sett l ing of suspended part ic les and/or by entralnment In fecal pe l le ts , then deposi-tion should be fa i r l y uniform over the entire study area and a lack of Holocene sediment on the flanks becomes d i f f i c u l t to explain. In addition, If sediments from the flanks are Pleistocene or older In age, slow deposition of sediment during the Holocene should mean extended exposure to sea-water and lead to formation of fa i r l y thick oxidized surface layers. Such features are not evident (Appendix A); Indeed, core 79-06-31 has no oxidized (brown) surface layer. While the pos-s i b i l i t y exists that sediments from the flanks of Explorer Deep are older than those from the f loor , this cannot adequately be tested without age determinations. Regardless of the age of the sediment, the decrease In smectite at depth In sediments from the flanks does not require a change In mlneraloglcal composition, but can be attributed to dlagenetlc upgrading of 11 IIte-smectlte and chlorIte-smectlte mixed-layer clays (Chapter Three). In sediments from the f loor , high smectite contents at depth are not due to the presence of mixed-layer clays, 'and may represent a smectite component not present In the flank sediments. - 1 6 2 -Explorer Deep Is a volcanlcal ly active area (Chapter Two), and It Is well known that smectite may form during the alteration of volcanic material (Arrhenlus, 1963; Grim, 1968; MI I lot , 1970; Weaver and Pol lard, 1973; Goulart, 1976; Pr ice, 1976; E lder f le ld , 1976; Hume, 1978). The enrichment of smectite at depth In sediments from the floor of Explorer Deep could therefore be the result of alteration of dispersed volcanic debris. Explorer Deep volcanic glass has higher Iron but similar s i l i c a contents (Fe203/AI203=0.60-0.73; S10 2/A1 20 3 =3.1-3.6; Table 4.8) to non-metal 11 ferous sediments (average a l l samples: ?e2^^'2^3=^*4^» SIO2/ Al203=3.6; Table 5.1) . Alteration of volcanic debris could therefore provide Iron and si Icon for the formation of smectite. Dissolution of blologenlc skeletal remains Is also a source of s i l i c o n . The aluminium content of Explorer Deep volcanic glass (7.9-8.2$ A l ; Appendix C) Is similar to the average content of Explorer Deep sediments (8.05$ A l ; Table 5.1) , but Is higher than that of sediments from the floor (7.6$ A l ; Figure 4.2) . The low barium content of Explorer Deep volcanic glass (102 ppm Ba; Cousens, 1982) Indicates that the source for barium enrichment In smectite-rich sediments from the floor of Explorer Deep Is not In situ alteration of volcanic material . Another discordance concerns the character ist ic assemblage for altered volcanic material: pal agonIte-smectlte-zeolIte (Pr ice, 1976; E lder f le ld , 1976); neither palagonlte nor zeol i te were found In the sediments (Chapter Three). Sediments from the floor of Explorer Deep are quite homogeneous (for example cores 79-06-06 and 79-06-08; Figures A.4 and A.6 respectively) lacking g r i t zones that might contain unaltered volcanic glass shards. C lear ly , smectite distr ibution In Explorer Deep sediments cannot be attributed to In situ alterat ion of volcanic debris. -1 6 3 -Smectite Is a major component of many hydrothermal deposits (Bischoff, 1969, 1972; BonattI et a l . r 1972; Sayles and Bischoff , 1973; Dymond et a I.. 1973; Aokl et a l . r 1974; Goulart, 1976; Heath and Dymond, 1977; Cor l iss et a l . . 1978; Hoffert st_aL., 1978; Heklnlan et a l . . 1978; Rona, 1978; Williams et a I.. 1979). The EDMS deposit contains consider-able a IumInIum-poor Iron-rich smectite, Identified as nontronlte by Gr i l l et a l . (1981). Authlgenlc formation of th is mineral Is Implied, as there Is no known continental source for a IumlnIum-poor Iron-rich smectite (Sayles and Bischoff , 1973). Smectite In non-metal 11ferous sediments from the Explorer Deep area correlates negatively with aluminium (Table 4.3) Indicating that It Is a Ium!nIum-poor. Signif icant posit ive correlations between relat ive smectite concentration and barium, Iron, n icke l , s i l i c o n , and zinc suggest an association between these elements with the clay mineral (Chapter Four). Each of the five elements Is reported to be enriched In some hydrothermal deposits (Bischoff, 1969, 1972; BonattI et a l . P 1972; Sayles and Bischoff, 1973; Dymond et a I., 1973; Aokl et a I., 1974; Goulart, 1976; Heath and Dymond, 1977; Corl Iss e ± _ a ± . , 1978; Hoffert et a I,r 1978; Heklnlan et a I.. 1978; Rona, 1978; Edmond et a I.. 1979a; WlI 11ams e ± _ a l . , 1979; Gr i l l et a l . r 1981), and l ike smectite, a l l are In higher abundance In sediments from the floor of Explorer Deep, than In sediments from the flanks (Chapters Three and Four). These associations suggest that sediments from the floor of Explorer Deep contain a hydrothermal component, probably nontronlte, s imilar to that found In the hydrothermal EDMS deposit. Insight Into the formation of hydrothermal minerals In Explorer Deep may be gleaned from examination of EDMS and other hydrothermal -1 6 4 -deposits. Samples of EDMS exhibit highly variable mlneraloglcal and chemical compositions, Interpreted by G r i l l qt a I. (1981) to ref lect a complex deposltlonal history of localized mineral formation from sporadically ejected elementally-enriched hydrothermal solutions. Sub-surface mixing of the hydrothermal solutions and sea water occurs; the degree of mixing varies with strength and duration of discharge. Interaction between heated reducing hydrothermal solutions and actively c i rculat ing cool sea water results In rapid oxidation of Iron and leads to formation of hydroxides (Heath and Dymond, 1977; Edmond et a I.f 1979a). The newly formed hydroxides scavenge and sorb elements from sea water and hydrothermal solutions. Adsorbed manganese Is oxidized to form oxides and hydroxides. Some of the Iron hydroxide reacts with s i l i c a (of biogenic, hydrothermal and/or detr l tal origin) and other compatible elements to form nontronlte. Dissolution of carbonate and oxidation of organic matter In the sediment column supplies additional trace elements to pore waters. Composition of the primary hydrothermal solution and perhaps more Importantly, the degree of subsurface mixing strongly Influence the composition of f inal (ejected) solutions and pre-c ip i tates (Heath and Dymond, 1977; Cor IIss et a I.f 1978; Edmond et a I.P 1979a); If solutions cool slowly under reducing conditions nontronite forms, rapid cooling under oxidizing conditions favours formation of Iron and manganese oxides, and In areas of high discharge sulphides may form at or near the sediment-water Interface. Formation of hydrothermal minerals occurs In close proximity to discharge vents .(Lonsdale, 1977, 1979; CorlIss fi±_a±., 1978; Heklnlan et a l . r 1978; Hoffert s ± _ a l . , 1978; Williams et a I.P 1979); faults and fractures which cut the sediment cover are common sites of discharge owing to their high permeability. - 1 6 5 -In these areas, mounds or r idges, composed almost entirely of hydro-thermal minerals, may develop. The mounds or ridges are commonly underlain by and grade lateral ly Into "normal" pelagic sediments (CorlIss et a l . . 1978; Heklnlan et al . f 1978; Hoffert e ± _ a l . , 1978; Williams et a I.P 1979). A blanket of sediment of suf f ic ient thickness to insulate the system may be required to s tab i l i ze convectlve c e l l s and concentrate discharge Into discrete localized areas, before deposits can begin to form (Anderson and Hobart, 1976; Williams et a I., 1979). Hydro-thermal c i rculat ion occurs primarily within fractured volcanic basement rocks; however, secondary c i rculat ion c e l l s may occur within overlying sediments (CorlIss et a I.P 1978; Heklnlan et a I., 1978; Anderson et a I.f 1979). While the exact position of the EDMS s i te cannot be determined, due to poor navigational control during the recovery cruise (Gr11 I et a l . P 1981), the crust was recovered from a rugged area (Figure D.08) covered by a thick mantle of sediment up to 200 m thick (Enclosure Two). The EDMS deposit is envisioned as being part of one or more hydrothermal mounds, much l ike those described above. While the mantle of sediment In Explorer Deep acts as an Insulating blanket due to Its considerably lower permeability (compared to vent areas), slow percolation of hydrothermal solutions through the sediment may occur. Processes that are active tn discharge vent systems should also operate, at reduced rates, within the sedimentary column. Thus, subsurface mixing of hydrothermal solutions and sea water leads to oxldatl.on of Iron and formation of hydroxides. The newly formed hydr-oxides sorb elements enriched In hydrothermal solutions and scavenge elements from pore waters. Manganese Is oxidized to form hydroxides. - 1 6 6 -S i l i c a enriched In hydrothermal solutions and/or derived from d i s -solution of biogenic skeletal remains reacts with some of the Iron hydroxide to form smectite. High contents of smectite and low potassium and magnesium concentrations In sur f l c la l sediments ref lect an abundance of detr l tal 111Ite-smectlte and chI or Ite-smectIte mixed-layer clays (Chapter Three). The decrease In smectite and corresponding Increase In potassium and magnesium at depth In sediments from the flanks represents dlagenetlc upgrading of mixed-layer c lays ; In contrast, high smectite contents at depth In sediments from the f loor are Interpreted to ref lect Insltu formation of authlgenic smectite. Posit ive correlations between smectite rat ios and barium. Iron, n ickel , zinc and manganese (Table 4.3) are Interpreted to represent Fe**+, Fe^ + , N l ^ + , Zn^ + , and possibly Mn2+ substituting for A l ^ + In octahedral layers of authlgenic smectite, while barium Is present as exchangable cations, acting to balance the charge on the smectite structure. Barium Ions wi l l also react with sulphate to form barl te. Although no sulphides were Identif ied, small amounts of Iron, nickel and zinc sulphides could be present In the sediment. Reducing conditions are maintained within the sediment column by oxidation of organic matter, supplied by high rates of hemlpelaglc sedimentation, and by upward percolation of reducing hydrothermal solutions. The lower redox potentials encountered at depth cause d i s -solution of detr l ta l and authlgenic manganese oxides and hydroxides and to a lesser extent Iron oxides and hydroxides; the mobilized Ions migrate to the oxidizing layer near the sedlment-water Interface and upon encountering the higher redox potentials either precipitate as 9+ 3 + hydroxides or are lost to the water column. Mobilized Fe and Fe - 1 6 7 -Ions wil l combine with s i l i c a In the formation of authlgenlc smectite, or precipitate as hydroxides In the oxidizing layer. Trace metals enriched In the hydrothermal solutions and released by the dissolution of oxides and hydroxides are Incorporated In the formation of authlgenlc smectite, or migrate to the oxidized layer and there are sorbed by hydroxides. Manganese maxima are evident in sur f ic ia l sediments from most of the Explorer Deep cores (Figures 4.26 and 4.27). Surf ic ia l iron maxima are evident only in cores from the floor (Figure 4.22), indicating the presence of iron hydroxides and reflecting a possible influx of hydrothermal iron to Explorer Deep. Cores from the floor also have pronounced phosphorus maxima in sur f ic ia l sediments (Figure 4.10); the enrichment is l ikely due to the formation of ferriphosphate (Chapter Four). Enrichment of trace metals and manganese as a result of diagenetic recycling is common in sur f ic ia l samples of marine sediments (Lynn and BonattI, 1965; Bonatti et a I.f 1971; Hartmann, 1979; Pedersen, 1979; Bornhold et a I., 1981; Pr ice , 1981); enrichments of barium, manganese, nickel and zinc in surf ical sediments of the flank cores (Figures 4.31, 4.41 and 4.44 respectively) are quite l ikely due to diagenetic processes. In summary, hydrothermal c i rcu lat ion Is active in Explorer Deep. Faults which cut the thick mantle of turbldltes and hemlpelaglc sediment act as conduits for discharge of hydrothermal solutions. Mounds of hydrothermal minerals develop at the sediment surface in areas where hydrothermal solutions debouch into the water column. EDMS Is composed of nontronlte, iron and manganese oxides and hydroxides, and possibly barIte, and is interpreted as being part a mound of hydrothermal -1 6 8 -minerals from Explorer Deep. Hydrothermal solutions also percolate slowly through the sediment and promote formation of hydrothermal minerals within the sediment column. Processes active In the discharge vent system operate In the sediment column and lead to formation of a similar suite of minerals. With burial reducing conditions are established In the sediment column causing dissolution of the oxides and favouring formation of smectite. Manganese oxides and hydroxides are part icularly susceptible to dlagenetlc recycl ing, and therefore do not form part of the hydrothermal component In sediments from the floor of Explorer Deep. Hydrothermal solutions are a source of barium, Iron, manganese, s i l i c o n , and possibly calcium, n icke l , potassium and zinc In Explorer Deep. S i l i con and calcium are also supplied by dissolution of skeletal debris and oxidation of organic matter releases adsorbed trace elements which can be scavenged from pore waters by the hydrothermal minerals. Sediments from the floor of Explorer Deep are enriched In barium, Iron, s i l i c o n , nickel and zinc re lat ive to sediments from the flanks. The small hydrothermal component In sediments from the floor of Explorer Deep Is obscured by an abundance of terrigenous minerals, and Is evident only by comparison to sediments from the flanks and away from the hydrothermal Influence. -1 69-6. SUMMARY AND CONCLUSIONS During the joint s c i e n t i f i c cruise PGC-79-06 by the Geological Survey of Canada and University of Br i t ish Columbia approximately 515 km of acoustic prof i ler data, twelve gravity cores of sediments and one dredge haul of volcanic rocks were acquired from the Explorer Deep area (Figure 1.1). The prof i les (Appendix D) were used to construct bathy-metric, sediment thickness (isotime), and basement structure maps (Enclosures one and two, and Figure 2.3 respectively) . A total of eighty-eight samples of sediment and two samples of volcanic glass were chemically analyzed for sixteen elements, by X-ray fluorescence spectrometry (Appendix B). Surf ic ia l sediments from a l l twelve cores plus down-core samples from f ive cores were chemically analyzed (Appendix C). Mlneraloglcal compositions of total (bulk) sediment and of Individual s ize - f ract ions In f i f teen samples of hemlpelaglc sediment from f ive cores and one sample of Explorer Deep metalliferous sediment (EDMS) were examined by X-ray d i f f ract ion (XRD) (Chapter Three). Explorer Deep, a northeast trending trough 40 km In length with depths in excess of 3200 m, is part of the Explorer spreading centre (Chapter Two). Paul Revere Ridge forms the abrupt northeast l imit to Explorer Deep. While active seafloor spreading has Jumped to a position north of Explorer Deep, recovery of fresh extrusive volcanic rock Indicates that the area Is s t i l l volcanlcal ly act ive. In Explorer Deep much of the seafloor Is covered by sediment, which Is thin In the south and thickens northward toward the continent (up to 300 m thick; Chapter Two); locally areas of exposed volcanic rock are present. The acoustic - 1 7 0 -basement (Interpreted to be volcanic rock) Is highly dissected by an orthogonol system of faults (Figure 2.3) ; one set of faults paral le ls the trend of Explorer Deep, the other paral le ls Paul Revere Ridge. In areas with thin or no sediment cover, sea water may penetrate the fractured and faulted rock. As sea water percolates through the system It Is heated geothermally by volcanic act i v i t y , leaches elements from the substrate, and becomes reducing. In areas where the sediment cover Is suff ic ient ly thick to Insulate the system, convectlve c i rculat ion ce l l s are established. Discharge of hydrothermal solutions Is concentrated In areas of localized high permeability (vents), such as faults which cut the sediment cover. At discharge areas heated and reducing hydrothermal solutions mix with cool oxidizing sea water; Interaction between mixing f lu ids leads to formation of hydrothermal minerals (Chapter F ive) . In areas of repeated expluslon of hydrothermal solutions such as discharge vents, mounds or ridges of hydrothermal minerals wil l form. EDMS Is Interpreted to be part of a hydrothermal mound (or mounds) from Explorer Deep (Gri l l et a I . f 1981). Hemlpelaglc sediments from the study area are composed of quartz, opal, feldspar, amphlbole, carbonate, phyIlosiIIcates, poor Iy crystal 11 zed Iron and manganese hydroxides, plus trace amounts of Ilmenlte, ru t l le and hematite. Individual phyIlosiIIcates have d ist inct s ize distr ibut ions; f ine clay (<0.2 um) Is composed almost exclusively of smectite, In contrast clay (0.2 to 2 um) and fine s l i t (2 to 5 um) are composed of 11 l i t e , ch lo r i te , smectite, quartz, feldspar, amphlbole and possibly Iron and manganese hydroxides (Chapter Three). Three types of smectite are present In Explorer Deep: (1) very fine grained smectite (<0.2 um), l ikely - 1 7 1 -detr ltal montmorIIlonlte; (2) detr l tal 111Ite-smectlte and chlorI te-smectlte mixed-layer c lays ; (3) authlgenlc nontronlte. Quantitative estimates of mineral composition using XRD analyses are plagued by numerous problems; therefore, In th is study re lat ive variations In the mineral composition are examined using rat ios of areas of XRD peaks, rather than estimates of mineral concentrations. The distr ibut ion of smectite Is part icular ly Interesting. In clay and fine s i l t from the flanks of Explorer Deep, smectite content Is highest In su r f l c la l sediment and decreases at depth; In contrast, In sediments from the floor smectite abundance remains constant or Increases at depth. In the previous chapter, It was shown that the high relat ive abundance of smectite at depth In sediments from the floor of Explorer Deep cannot be attributed to winnowing of fines from the flanks nor to alterat ion of volcanic detr i tus. Pleistocene sediments reportedly contain less smectite than Holocene sediments (Duncan et a I.f 1970; Stokke.and Carson, 1974; Cook, 1981) therefore, If only a thin layer of smectIte-rlch Holocene sediment Is present on the f lanks, a much thicker section of Holocene sediments on the f loor could account for the smectite d is t r ibut ion . Existence of a d is t inct mlneraloglcal change at the Plelstocene-Holocene boundary has however, been strongly disputed by Arcaro (1978) and Carson and Arcaro (1983). Since th is hypothesis could not be adequately evaluated without age determinations (which are not avai lable) . It was not explored further. Upgrading of degraded 111Ite and ch lor i te In mixed-layer clays occured during sample preparation following K- and Mg-saturatIon respectively (Chapter Three); diagenetic upgrading of 11 l i t e and chlor i te may also occur, and be responsible for - 1 7 2 -the decrease of smectite at depth In-sediments from the flanks. Iron-rich smectite, nontronlte Is formed by precipitation from hydrothermal solutions, and Is a major component In EDMS. Insltu formation of authlgenic nontronlte In sediments from the f loor of Explorer Deep may account for the abundance of smectite at depth. The chemical composition of Explorer Deep hemlpelaglc sediments Is between that of "average shale" and average "Pac i f i c pelagic c lays" , and Is similar to other hemlpelaglc sediments from the northeast Paci f ic region (Chapter Four). Compared to average "Pac i f ic pelagic c lay" , the sediments are Co- , Cu - , Mn-, NI- and K-poor. Inter-element correlations for total element concentrations, for normalized to aluminium data, and between elemental concentrations and mineral rat ios proved very useful . The study area Is dominated by terrigenous sediment Influx, pr incipal ly due to proximity of the North American continental landmass and effects of Pleistocene glac I at I on. Not surpris ingly, chemical compositions of sediments from the study area are dominated by elements contained within detr l tal minerals. Most of the calcium Is present as carbonate, and some of the s i l i c a (upto 10$ S102) as opal . Distr ibution of calcium Is strongly controlled by water depth, which ref lects Increased dissolution of carbonate In the deeper parts of the study area. The carbonate compensation depth In the Explorer Deep area Is estimated to be at about -4280 m. Manganese and to a lesser extent Iron are enriched In sur f l c la l sediments due to dlagenetlc recycl ing, Involving dissolution of oxides and hydroxides In the reducing environment of the sediment column, with subsequent formation of Iron and manganese hydroxides In the oxidizing zone at or near the sedtment-water Interface. Barium, n icke l , phosphorus - 1 7 3 -and zinc are enriched In sur f lc la l sediments and appear to be associated with hydroxides. Posit ive correlations between smectite and barium, n icke l , z inc, "non-terrigenous" Iron and s i l i c o n , and possibly manganese suggest that these elements are associated with a smectIte-bearIng phase. Signif icant negative correlations exist between smectite and aluminium, and smectite and calcium Indicating that part of the smectite content Is In a phase other than alumlnlum-bearIng predominately detr l tal minerals, or biogenic carbonate. While mlneraloglcal and chemical compositions of hemlpelaglc sediments from the Explorer Deep area appear to be typical for sediments from the northeast Paci f ic region, subtle differences exist between sediments from the f loor , and those away from the Influence of hydro-thermal act iv i ty on the flanks. Relative to the f lanks, sediments from the floor have higher smectite content, are aluminium- and calcium-poor, and are enriched In barium, n icke l , z inc , and "non-terrigenous" Iron and s i l i c o n . These elements can be Incorporated In formation of authlgenlc smectite with F e 3 + and A l 3 + substituting for S i 4 + In the tetrahedral layer, and F e 2 + , F e 3 + , M n 2 + , Z n 2 + and N I 2 + substituting for A l 3 + In the octahedral layer, which leads to a net charge deficiency. Exchangable cations such as Ba , Na , K , Mg*- , Ca , organic molecules, and Iron hydroxides are adsorbed, pr incipal ly on Interlayer s i tes , to balance the net charge (dlsscussed In detail In previous chapter). Alternatively , the transit ion metals are adsorbed on Iron oxides and hydroxides which are present together with smectites, bar l te , and'opal In a common phase. vWhile no direct evidence exists for hydrothermal c i rculat ion In - 1 7 4 -Explorer Deep, the tectonic setting Is favorable, and recovery of a metalliferous deposit (EDMS), with characterist ics similar to other hydrothermal deposits, Indicates that at least localized hydrothermal mineral formation has occurred. A major component of EDMS Is a IumlnI urn-poor Iron-rich smectite, nontronlte, a mineral similar to that postulated to be present in sediments from the floor of Explorer Deep. Mounds of hydrothermal minerals l ike EDMS form near areas of localized high permeability, or discharge vents. In addition to rapid expulsion of solutions in discharge vents, slow percolation of heated hydrothermal solutions may occur through the sedimentary column. Processes active in vent areas should also operate in the sedimentary column, thus Inter-action between hot reducing hydrothermal solutions and cool oxidizing sea water leads to rapid oxidation of iron and formation of hydroxides. The hydroxides scavenge elements from enriched hydrothermal solutions and surrounding pore water. The sedimentary column Is reducing at depth due to oxidation of organic matter, supplied by continued hemipelagic sedimentation, which results In dissolution of oxides and hydroxides. Some of the released Iron reacts with s i l i con and other compatible elements to form smectite. The remaining mobilized iron, manganese, and previously sorbed elements migrate upward to the oxidizing layer at or near the sediment-water Interface, and upon encountering the higher redox potentials either precipitate as hydroxides which then sorb barium, n ickel , phosphorus, zinc and other elements, or diffuse Into the water column and are lost . The presence of a small hydrothermal component In sediments from the floor of Explorer Deep Is obscured by diagenetic recycling of elements and diluted by high rates of hemipelagic sedimentation. - 1 7 5 -RECOMMENDATIONS FOR FURTHER STUDY 1) The extent of hydrothermal act iv i ty and mineral formation In Explorer Deep cannot be properly evaluated using the remote sampling techniques employed In th is study. The localized nature of hydrothermal solution discharge requires that a more controlled means of selectively obtaining samples be used. Ocean bottom photography combined with deep-tow sonar and temperature sensors could be used to Identify anomalous areas for sampling; Ideally a manned submersible would be used. 2) Down-core samples were analyzed for only f ive of the twelve cores recovered from the Explorer Deep area during the PGC-79-06 cruise. The val id i ty of the differences In mineral and chemical composition of the sediments In the study area could be tested by analyses of the remaining cores. 3) In th is study only the uppermost 1 to 1.5 m of sediment from the Explorer Deep area was examined; using a piston corer, a considerably thicker Interval could be sampled. Examination of geochemlcal and mlneraloglcal distr ibut ions over the longer Interval could be very useful . 4) A more complete suite of major element chemical analyses, to augment those by Bornhold et a l . (1981), of sediments from the Explorer Ridge and Juan de Fuca Ridge areas would be useful tn determining a regional composition for the terrigenous component. 5) Results of th is study support the conclusion by Arcaro (1978) and - 1 7 6 -Carson and Arcaro (1983), that Individual clay mineral species are size spec i f i c , thereby precluding the use of a single size fraction (<2 um) to describe clay mineral d istr ibut ions. Future workers should separate sediment Into several c lay - and si I t -s ize fractions before attempting to determine the mineral d ist r ibut ions. 6) Grain size data In combination with detailed mlneralogJcal analyses would be very useful In defining the effect of textural variations on the composition of sediments from the Explorer Deep area. 7) The role of fecal pel lets In sediment transport In the Explorer Deep area should be studied. Questions needing answers: what Is the mineral composition and grain size of sediment contained within the pe l le ts , and what proportion of the total sediment Is Incorporated In the pel lets? 8) If end-members could be adequately defined, Q-mode factor analysis, l ikely using both major and minor element composition, would be of considerable value In determining the extent of hydrothermal act iv i ty and mineral formation In Explorer Deep. 9) SEM and MIcroprobe examination of sediments from the Explorer Deep area, part icular ly the c lay - and fine si I t -s ize fractions may Indicate the presence of several species of smectite, of bar l te , and of dispersed su l f ides . These data would be Invaluable In confirming the existence of a hydrothermal component In Explorer Deep sediments. - 1 7 7 -REFERENCES ABBEY, S. (1977) Studies In "Standard Samples" for use In the general analysis of s i l i c a t e rocks and minerals. Geological Survey  of Canada, paper 77-34, part 5, edition of "usable values". ALLMENDINGER, R.W.; RMS, F. (1979) The Galapagos Ri f t at 86°W; 1. Regional morphology and structural analysis. Journal of Geophysical Research, v. 84, #10, pp 5379-5389. ANDERSON, R.N. (1972) Petrologlcal signif icance of low heat flow on the flanks of slow-spreading mid-ocean ridges. Bui let In of the Geological Society of America, v. 83, pp 2947-2956. ANDERSON, R.N.; HOBART, M.A. (1976) The relation between heat flow, sediment thickness, and age In the Eastern P a c i f i c . Journal of Geophysical Research, v. 81, #17, pp 2968-2989. ANDERSON, R.N.; HOBART, M.A.; LANGSETH, M.G. (1979) Geothermal convection through oceanic crust and sediments In the Indian Ocean. Science, v. 204, pp 828-832. AOKI, S . ; KOHYAMA, N.; SUDO, T. (1974) An Iron-rich montmor11lonlte In a sediment core from the northeastern P a c i f i c . Deep-sea  Research f v. 21, pp 865-875. AOYAGI, K.; KAZAMA, T. (1980) Transformational changes of clay minerals, zeol i tes and s i l i c a minerals during dlagenesls. Sedlmentology f v. 27, pp 179-188. ARCARO, N.P. (1978) The control of lut l te mineralogy by selective transport, Late Pleistocene and Holocene sediments of Northern Cascadla Basin-Juan de Fuca Abyssal Plain (north-eastern Pac i f i c Ocean): a test of clay mineral size dependance. Unpublished M.Sc thesis , Lehigh University. ARCYANA (1975) Transform fault and Ri f t valley from bathyscaph and diving saucer. ScIence,. v. 190, pp 108-116. ARRHENIUS, G. (1963) Pelagic sediments, pp 665-727. La H i l l , M.N. (Ed.) The Sea r v. 3 , InterscIence, New York. ATWATER, T. (1970) Implications of plate tectonics for the Cenozolc tectonic evolution of western North America. Bui let In of the Geological Society of America, v. 81, pp 3513-3536. BALLARD, R.D. (1977) Notes on a major oceanographle f ind . Oceanusr v. 20, #3, pp 35-44. BALLARD, R.D.; H0LC0MB, R.T.; VAN ANDEL, T .H. (1979) The Galapagos Ri f t at 86°W: 3 . Sheet flows, collapse p i t s , and lava lakes of the Ri f t va l ley . Journal of Geophysical Research, v. 84, #B10, pp 5407-5422. -1 7 8 -BARNARD, W.D.; MCMANUS, D.A. (1973) Planktonlc foramlnlfera-radlolarlan stratigraphy and the Plefstocene-Holccene boundary In the north-east P a c i f i c . Bul let in of the Geological Society of  America, v. 84, pp 2097-2100. BARR, S.M. (1972) Geology of the northern end of the Juan de Fuca Ridge and adjacent continental slope. Unpublished Ph.D. thes is , University of Br i t i sh Columbia, Vancouver B . C . , Canada. BARR, S.M. (1974) Structure and tectonics of the continental slope west of Vancouver Island. Canadian Journal of Earth Sciences, v. 11, pp 1187-1199. BARR, S .M . ; CHASE, R.L. (1974) Geology of the northern end of Juan de Fuca Ridge and sea-f loor spreading. C a n a d i a n J o u r n a l of E a r t h $ g l e n s e s , v. 11, pp 1384-1406. BELAND, G. (In prep.) The tectonics and sediment geochemistry of the Explorer Ridge. Unpublished M.Sc. thesis , University of Br i t ish Columbia, Vancouver, B . C . , Canada. BENDER, M.; BROECKER, W.; GORNITZ, V. ; MIDDLE, U.; KAY, R.; SUN, S . S . ; BISCAYE, P. (1971) Geochemistry of three cores from the East Paci f ic Rise. Earth and Planetary Science Letters, v. 12, pp 424-433. BERGER, W.H. (1976) Blogenous deep sea sediments: production, preservation and Interpretation, i a Riley and Chester (Eds) Chemical Oceanography, second edi t ion, v. 5, pp 266-389, Academic Press, London. BERGER, W.H.; WINTERER, E.L. (1974) Plate stratigraphy and the fluctuating Carbonate l ine . Special Publication of the International Association of Sedlmentologlsts. v . 1 , pp 11-48. BERNER, R.A. (1973) Phosphate removal from sea water by adsorption on volcanogenlc fe r r ic oxides. Earth and Planetary Science Letters, v. 18, pp 77-86. BERRY, L .G . ; MASON, B. (1959) Mineralogy: concepts, descriptions, determinations. Published by W.H. Freeman and Company, San Francisco, U.S.A. , 630 p. BERTINE, K.K. ; KEENE, J .B . (1975) Submarine barlte-opal rocks of hydrothermal o r ig in . Sclence, v. 188, pp 150-152. BERTRAND, W.G. (1972) A geological reconnaissance of the Dellwood Sea-Mount area, northeast Pac i f ic Ocean, and Its relationship to plate tectonics. Unpublished M.Sc. thesis , University of Br i t ish Columbia, Vanouver, B .C . , Canada. BISCAYE, P.E. (1964) Distinction between kaol in l te and ch lor i te In recent sediments by X-ray d i f f rac t ion . The American Mineralogist, v. 49, pp 1281-1289. - 1 7 9 -BISCAYE, P.E. (1965) Mineralogy and sedimentation of Recent deep-sea clays In the Atlantic Ocean and adjacent seas and oceans. Bul let in of the Geological Society of America, v. 76, pp 803-832. BISCHOFF, J . L . (1969) Red Sea geothermal brine deposits: their mineralogy, chemistry and genesis, in. Degens and Ross (Eds) Hot brines and recent heavy metal deposits In the Red Sea. pp 368-401, Springer Verlag, New York. BISCHOFF, J . L . (1972) A ferroan nontronlte from the Red Sea geothermal system. Clays and Clay Minerals, v. 20, pp 217-223. BISCHOFF, J . L . ; ROSENBAUER, R.J . (1977) Recent metalliferous sediments in the North Pac i f ic manganese nodule area. Earth and Planetary Science Letters, v. 33, pp 379-388. BISCHOFF, J . L . ; SAYLES, F .L . (1972) Pore f luids and mlneraloglcal studies of Recent marine sediments: Bauer Depression region of East Pac i f i c Rise. Journal of Sedimentary Petrology, v. 42, pp 711-724. BONATTI, E. (1970) Deep sea volcanlsm. NaturwIssenschaften, v. 57, pp 379-384. BONATTI, E. (1975) Metallogenesls at oceanic spreading centres. In Annual Reviews Earth and Planetary Science, v. 3 , pp 401-431, Palo Al to , Ca l i fo rn ia , Annual Reviews Inc. BONATTI, E. (1978) The origin of metal deposits In the oceanic l l tho -sphere. Sc ient i f i c American, February, pp 54-61. BONATTI, E . ; FISHER, D.E . ; J0ENSUU, 0 . ; RYDELL, H.; (1971) Post-deposit iona I mobility of some transit ion elements, phosphorus, uranium, and thorium In deep-sea sediments. Geochlmlca et Cosmochlmlca Acta, v. 35, pp 189-201. BONATTI, E . ; FISHER, D.E . ; J0ENSUU, 0 . ; RYDELL, H.; BAYTH, M. (1972a) Iron-manganese-barlum deposit from the northern afar r i f t (Ethiopia). Economic Geology, v.67, pp 717-730. BONATTI, E . ; KRAMER, T . ; RYDELL, H.S. (1972b) C lass i f icat ion and genesis of submarine Iron-manganese deposits. in. Ferro-manganese Deposits on the Ocean Floor, pp 146-166, Lamont-Doherty Geological Observatory of Columbia University, Palisades, New York. B00THE, P .N . ; KNAUER, G.A. (1972) The possible Importance of fecal material In the biological amplification of trace and heavy metals. Limnology and Oceanography, v. 17, pp 370-374. B0RNH0LD, B.D.; TIFFIN, D.L. ; CURRIE, R.G. (1981) Trace metal geochemistry of sediments, northeast Paci f ic Ocean. Geological Survey of Canada, paper 80-25, 21 p. -1 8 0 -BOSTROM, K. (1970) Submarine volean Ism as a source of Iron. Earth and Planetary Science Letters, v. 9 , pp 348-354. BOSTROM, K. (1973) The origin and fate of ferromanganoan active ridge sediments. Stockholm Contributions to Geology, v. 27, #2, pp 149-243. BOSTROM, K. (1976) Part iculate and dissolved matter as sources for pelagic sediments. Stockholm Contributions to Geology, v.30, pp 15-79. BOSTROM, K.; FARQUHARSON, B.; EYL, W. (1971) Submarine hot springs as a source of active ridge sediments. Chemical Geology, v. 10, . pp 189-203. BOSTROM, K.; JOENSUU, 0 . ; BROHM, I. (1974) Plankton: Its chemical composition and Its signif icance as a source of pelagic sediments. Chemical Geology, v. 14, pp 255-271. BOSTROM, K.; JOENSUU, 0 . ; MOORE, C ; BOSTROM, B. ; DALZIEL, M.; H0K0WITZ, A. (1973) Geochemistry of barium In pelagic sediments. LIthos, v. 6, pp 159-174. BOSTROM, K.; JOENSUU, 0 . ; VALDES, S . ; CHARM, W.; GLACCUM, R. (1976) Geochemistry and origin of East Paci f ic sediments sampled during DSDP Leg 34. Init ial Reports of the Deep Sea DrllI In  Project, v. 34, pp 559-574, Washington U.S. Government Printing Of f ice . i BOSTROM, K.; PETERSON, M.N.A. (1966) Prectpltates from hydrothermal exhalations on the East Paci f ic Rise. Economic Geology, v. 61, pp 1258-1265. BOSTROM, K.; PETERSON, M.N.A. (1969) The origin of aluminum-poor ferromanganoan sediments In areas of high heat flow on the East Pac i f i c Rise. Marine Geology, v. 7, pp 427-447. BOSTROM, K.; PETERSON, M.N.A.; JOENSUU, 0 . ; FISHER, D.E. (1969) Aluminum-poor ferromanganoan sediments on active oceanic ridges. Journal of Geophysical Research, v. 74, pp 3261-3270. CALVERT, S .E . (1974) Deposition and dlagenesls of s i l i c a In marine sediments. International Association of Sedlmentologlsts Special Publ icat ion, v. 1, pp 273-299. CARROLL, D. (1969) Clay minerals: a guide to their X-ray Identi f icat ion. Geological Society of America, special paper 126, pp 1-77. CARSON, B. ; ARCARO, N.P. (.1983) Control of clay-mineral stratigraphy by selective transport In late Plelstocene-Holocene sediments of northern Cascadla Basin - Juan de Fuca abyssal p la in : Implications for studies of clay-mineral providence. Journal of Sedimentary Petrology, v. 53, #2, pp 395-406. - 1 8 1 -CARSON, B. ; MCMANUS, D.A. (1971) Analysis of turbidite correlation in Cascadia Basin, northeast Pacif ic Ocean. Deep-Sea Research, v. 18, pp 593-604. CHAN, L .H . ; DRUMMOND, D.; EDMOND, J . M . ; GRANT, B. (1977) On the barium data from the Atlantic GEOSECS expedition. Deep-Sea Research, v. 24, pp 613-649. CHASE, R.L . ; BARR, S . ; THOMLINSON, A.G. (1970) Deformation revealed by CSP on margins of the northern sector of the Juan de Fuca Litho-spheric Plate, northeast Pacif ic Ocean. Geological Society of  America, abstracts with programs for 1970, v. 2, pp 518. CHASE, R.L. ; TIFFIN, D.L. ; MURRAY, J.W. (1975) The western Canadian continental margin. j_n Yorath, C . J . ; Parker, E.R.; Glass, D.J. (Eds.) Canada's continental margins and offshore petroleum exploration. Canadian Society of Petroleum Geologists, Memoir 4, pp 701-721. CHAVE, K.E . ; MACKENZIE, F.T. (1961) A s ta t i s t i ca l technique applied to the geochemistry of pelagic muds. Journal of Geology, v. 69, pp 572-582. CHESTER, R.; ASTON, S.R. (1976) The geochemistry of deep-sea sediments, pp 281-390; in_ Ri ley, J . P . ; Chester, R. (Eds.) Chemical  Oceanography, second edi t ion, v. 6, 401 p. Academic Press, London. CHURCH, T .M. ; WOLGEMUTH, K. (1972) Marine barite saturation. Earth and  Planetary Science Letters, v. 15, pp 35-44. CLOWES, R.M.; MALECEK, S . J . (1976) Preliminary interpretation of a marine deep seismic sounding survey in the region of Explorer Ridge. Canadian Journal of Earth Sciences, v. 13, pp 1545-1555. CLOWES, R.M.; KNIZE, S. (1979) Crustal structure from a marine seismic survey off the west coast of Canada. Canadian Journal of .Earth Sciences, v. 16, pp 1265-1280. CLOWES, R.M.; THOREIFSON, A . J . ; LYNCH, S. (1981) Winona Basin, west coast Canada: crustal stucture from marine seismic studies. Journal  of Geophysical Research, v. 86, #B1, pp 225-242. COOK, H.E. (.1975) North American stratigraphic principles as applied to deep-sea sediments. Bul let in of the American Association of  Petroleum Geologists, v. 59, pp 817-837. COOK, R.A. (1981) Compositions and stratigraphy of Late Quaternary sediments from the northern end of Juan de Fuca Ridge. Unpublished M. Sc. thesis, University of Br i t ish Columbia, Vancouver B.C. , Canada. -182-CORLISS, J .B . (1971) The origin of metaI-bearIng submarine hydrothermal solutions. Journal of Geophysical Research, v. 76, pp 8128-8138. CORLISS, J . B . ; BALLARD, R.D. (1977) Oases of l i f e In Cold Abyss. National Geographic, v. 152, #4, pp 441-453. CORLISS, J . B . ; LYLE, M.; DYMOND, J . ; CRANE, K. (1978) The chemistry of hydrothermal mounds near the Galapagos R i f t . Earth and  Planetary Science Letters, v. 40, pp 12-24. COUCH, R.W.; CHASE, R.L. (1973) Site survey of Paul Revere Ridge west of northern Vancouver Island. I D , Kulm, L.D. et a I. (Eds.) Init ial report of the Deep Sea Dr i l l ing Project, v. 18, pp 987-995, Washington U.S. Government Printing Of f ice . COUSENS, B. (1982) Chemistry and petrology of Explorer Ridge basalts, northeast Pac i f i c Ocean. Unpublished M.Sc. thes is , University of Br i t ish Columbia, Vancouver B .C . , Canada. CRANE, K. (1979) The Galapagos Rift at 86°W: Morphological wave forms; evidence for a propagating r i f t . Journal of Geophysical  Research, v. 84, #311, pp 6011-6018. CRANE, K.; BALLARD, R.D. (1980) The Galapagos Ri f t at 86°W: 4. Structure and morphology of hydrothermal f ie lds and their relationship to the volcanic and tectonic processes of the Rift Valley. Journal of Geophysical Research, v. 85, pp 1443-1454. CRANE, K.; NORMARK, W.R. (1977) Hydrothermal act iv i ty and crestal structure of the East -Paci f ic Rise at 21°N. Journal of G e o p h y s i c a l R e s e a r c h , v. 82, #33, pp 5336-5348. CRONAN, D.S. (1969a) Inter-element association in some pelagic deposits. Chemical Geology, v. 5, pp 99-106. CRONAN, D.S. (1969b) Average abundances of Mn, Fe, N i , Co, Cu, Pb, Mo, V, Cr, T i , and P In Paci f ic pelagic c lays . Geochlmlca et Cosmochlmlca Acta, v. 33, pp 1562-1565. CRONAN, D.S. (1976) Basal metalliferous sediments from the eastern P a c i f i c . Bul let in of the Geological Society of America, v. 87, pp 928-934. CURRIE, R.G.; SEEMANN, D.A.; RI DDI HOUGH, R.P. (1982) Total f i e ld magnetic anomaly - offshore Br i t ish Columbia. Geo IogIcaI  Society of Canada, open f i l e #828. DARBY, D.A. (1975) Kaol lnl te and other clay minerals In Arct ic Ocean sediments. Journal of Sedlmentay Petrology, v. 45, #1, pp 272-279. -183-DAVIES, T . A . ; GORSLINE, D.S. (1976) Oceanic sediments and sedimentary processes, pp 1-80. in Ri ley, J . P . ; Chester, R. (Eds.) v Chemical Oceanography, second edi t ion , v. 5, 401 p. Academic Press, London. DAVIS, E .E . ; LISTER, C.R.B. (1977a) Heat flow measured over the Juan de Fuca Ridge; Evidence for widespread hydrothermal c i r cu la -tion in a highly heat transportive crust. Journal of  Geophysical Research, v. 82, pp 4845-4860. DAVIS, E .E . ; LISTER, C.R.B. (1977b) Tectonic structures on the Juan de Fuca Ridge. Bul let in of the Geological Society of America, v. 88, pp 346-363. DAVIS, E .E . ; LISTER, C .R.B. ; LEWIS, B.T.R. (1976) Seismic structure on Juan de Fuca Ridge: Ocean bottom seismometer results from the Median Valley. Journal of Geophysical Research, v. 81, pp 3541-3555. DAVIS, E .E . ; RIDDIHOUGH, R.P. (1982) The Winona Basin: structure and tectonics. Canadian Journal of Earth Sciences, v. 19, pp 767-788. DEHLINGER, P.; COUCH, R.W.; MCMANUS, D.A.; GEMPERLE, M. (1970) Northeast Paci f ic structure, pp 133-189. in_ Maxwell, A.E. (Ed.) The  Sea, part II, Wiley-Interscience,.New York. DELANEY, J . R . ; KOSKI, R.A.; CLAGUE, D.A.; BISCHOFF, J . L . ; NORMARCK, W.R. (1980) Massive zinc and i ron- r ich sulf ide deposits associated with hot springs, Juan de Fuca Ridge, (abstract) AAPG annual conference, 1982, Calgary, Alberta. DETRICK, R.S. ; SCLATER, J . G . ; THIEDE, J . (1977) The subsidence of aseismic ridges. Earth and Planetary Science Letters, v. 34, pp 185-196. DOWNING J r . , J . P . ; BAKER, E.T. (1977) Some implications of bottom nepheloid layer part ic le mineralogy, Barkley, Nitinat and Juan de Fuca canyons, northeast Pac i f i c , (abstract) Geological Society of America, abstracts with programs, v. 9, #7, pp 954-955. DUNCAN, J .R . ; KULM, L.D. (1970) Mineralogy, provenance, and dispersal history of late Quaternary deep-sea sands in Cascadia Basin and Blanco Fracture Zone off Oregon. Journal of Sedimentary  Petrology, v. 40, #3, pp 874-887. DUNCAN, J . R . ; KULM, L .D. ; GRIGGS, G.B. (1970) Clay mineral composition of late Pleistocene and Holocene sediments of Cascadia Basin, Northeastern Pacif ic Ocean. Journal of Geology, v. 78, pp 213-221. -184-DYMOND, J . ; CORLISS, J . B . ; HEATH, G.R.; FIELD, C.W.; DASH, E . J . ; VEEH, H.H. (1973) Origin of metalliferous sediments from the Paci f ic Ocean. Bul let in of the Geological Society of America, v.84, pp 3355-3372. DYMOND, J . ; CORLISS, J . B . ; STILLINGER, R. (1976) Chemical composition and metal accululatlon rates of metalliferous sediments from s i t 319, 320, 321. l a Init ial Reports of the Deep Sea  Dr11 11ng Project, v. 34, pp 575-588. Washington U.S. Government Printing Of f ice . DYMOND, J . ; EKLUND, W. (1978) A mlcroprobe study of metalliferous sediment components. Earth and Planetary Science Letters, v. 40, pp 243-251. EDMOND, J.M. (1974) On the dissolution of carbonate and s i l i c a t e In the deep ocean. Deep-Sea Research, v. 21, pp 455-480. EDMOND, J .M. ; MEASURES, C ; MANGUM, B.; GRANT, B.; SCLATER, F.R.; COLLIER, R.; HUDSON, A . ; GORDON, L. I . ; CORLISS, J .B . (1979a) On the formation of metal-r ich deposits at ridge crests . Earth and Planetary Science Letters, v. 46, pp 19-30. EDMOND, J .M . ; MEASURES, C ; MCDUFF, R.E. ; CHAN, L .H. ; COLLIER, R.; GRANT, B.; GORDON, L. I . ; CORLISS, J .B . (1979b) Ridge crest hydrothermal act iv i ty and the balances of the major and minor elements In the Ocean: the Galapagos data. Earth and Planetary Science  Letters, v. 46, pp 1-18. EINSELE, G . ; GIESKES, J .M . ; CURRAY, J . ; MOORE, D.M.; AGUAYO, E. ; AUBRY, M.P.; FORNARI, D.; GUERRERO, J . ; KASTNER, M.; KELTS, K.; LYLE, M.; MATOBA, Y . ; MOLINA-CRUZ, A . ; NIEMITZ, J . ; RUEDA, J . ; SAUNDERS, A . ; SCHRADER, H.; SIMONEIT, B.; VACQUIER, V. (1980) Intrusion of basalt ic s i l l s Into highly porous sediments, and resulting hydrothermal ac t i v i t y . Nature, v. 283, pp 441-445. ELDERFIELD, H. (1976) Hydrogenous material In marine sediments; excluding manganese nodules, pp 137-215, i n Ri ley, J . P . ; Chester, R. (Eds) Chemical Oceanography, second edit ion, v. 5, 401 p. , Academic Press, London. ELDERFIELD, H. (1977) Authlgenic s i l i ca te minerals and the magnesium budget In the Oceans. P h i l . Trans, of the Royal Society of London, v. (A)286, #1336, pp 273-281. EL WAKEEL, S .K . ; RILEY, J .P . (1961) Chemical and mlneralog lea I studies of deep-sea sediments. Geochlmlca et Cosmochlmlca Acta, v. 25, pp 110-146. ENGEL, A . E . J . ; ENGEL, C .G . ; HAVENS, R.G. (1965) Chemical characterist ics of oceanic basalts and the upper mantle. Bui let In of the  Geological Society of America, v. 76, pp 719-734. - 1 8 5 -ENGEL, C.G; ENGEL A . E . J . (1963) Basalts dredged from the northeastern Paci f ic Ocean. Science, v. 140, 1321-1324. FABBI, B.P. (1972) A refined fusion X-ray fluorescence technique and determination of major and minor elements In s i l i c a t e standards. The American Mineralogist, v. 57 pp 237-245. FEHN, U. CATHLES, L.M. (1979) Hydrothermal convection at slow-spreading mid-ocean r idges. J_o. Francheteau, J . (Ed) Processes at mid-ocean ridges. Tectonophyslcs, v. 55, pp 239-260. FLANAGAN, F . J . (1959) U.S. Geological Survey standards - II. F i rst compilation of data for the new U.S.G.S. rocks. GeochImlca et Cosmochimica Acta, v. 33, pp 81-120. FRANCHETEAU, J . ; NEEDHAM, H.D.; CH0UKR0UNE, P.; JUTEAU, T . ; SEGURET, M.; BALLARD, R.D.; FOX, P . J . ; NORMARK, W.; CARRANZA, A . ; CORDOBA, D.; GUERRERO, J . ; RANGIN, C ; BOUGAULT, H.; CAMBON, P. ; HEKINIAN, R. (1979) Massive deep-sea sulphide ore deposits discovered on the East Paci f ic Rise. Nature, v. 277, #15, pp 523-528. FROELICH, P.N. ; BENDER, M.L.; HEATH, G.R. (1977) Phosphorus accumulation rates In metalliferous sediments from the Paci f ic Ocean. Earth and Planetary Science Letters, v. 34, pp 351-359. FRYER, B . J . ; HUTCHISON, R.W. (1976) Generation of metal deposits on the sea f loor . Canadian Journal of Earth Science, v. 13, pp 126-135. FYFE, W.S. (1964) Geochemistry of so l ids . McGraw-Hill Inc., New York. GIBBS, R.J. (1967) Quatltatlve X-ray di f f ract ion analysis using clay mineral standards extracted from the samples to be analyzed. Clay Minerals, v. 7, pp 79-90. GIBBS, R.J. (1968) Clay mineral mounting techniques for X-ray di f f ract ion analysis . Journal of Sedimentary Petrology, v. 38, pp 242-243. GIBBS, R.J. (1977) Clay mineral segratlon In the marine environment. Journal of Sedimentary Petrology, v. 47, #1, pp 237-243. GODDARD, E.N. ; TRASK, P.D. ; DEFORD, R.K.; ROVE, O.N.; SINGEWALD, J .T . ; OVERBECK, R.M. (1975) Rock-color chart, (reprint) Geological Society  of America, Boulder, Colorado. GOLDBERG, E.D.; ARRHENI US, G.O.S. (1958) Chemistry of Pac i f ic pelagic sediments. Geochemlca et Cosmochimica Acta, v. 13, pp 153-212. GOULART, E.P. (1976) Different smectite types In sediments of the Red Sea. Geology Jahrb. Relhe D. #17, pp 135-149. -186-GRIFFIN, J . J . ; GOLDBERG, E.D. (1963) Clay-mfneral distr ibution in the Paci f ic Ocean, pp 728-741 . In HIM, M.N. (Ed) The S e a , v. 3 , 963 p. , Intersclence Publication, New York. GRIGGS, G.B. ; KULM, L.D. (1970) Sedimentation In Cascadla deep-sea channel. Bul let in of the Geological Society of America, v. 81, pp 1361-1384. GRILL, E.V.; CHASE, R.L . ; MACDONALD, R.D.; MURRAY, J.W. (1981) A hydrothermal deposit from the Explorer Ridge In the north-east Paci f ic Ocean. Earth and Planetary Science Letters, v. 52, pp 142-150. GRIM, R.E. (1968) Clay Mineralogy, second edit ion. 596 p. McGraw-Hill, New York. HALPERN, D.; SMITH, R.L . ; REED, R.K. (1978) On the Cal i fornia under-current over the continental slope off Oregon. Journal of  Geophysical Research, v. 83, #C3, pp 1366-1372. HARDER, H. (1972) The role of magnesium In the formation of smectite minerals. Chemical Geology, v. 10, pp 31-39. HARDER, H. (1978) Synthesis of Iron layer s i l i c a t e minerals under natural conditions. Clays and Clay Minerals, v. 26 pp 65-72. HART, R. (1970) Chemical exchange between sea water and deep ocean basalts. Earth and P l a n e t a r y Science Letters, v. 9, pp 269-279. HARTMANN, M. (1979) Evidence for early dlagenetlc mobilization of trace metals from discolorations of pelagic sediments. Chemical Geology, v. 26, pp 277-293. HARVEY, P.K.; TAYLOR, D.M.; HENDRY, R.D.; BANCROFT, F. (1973) An accurate fusion method for the analysis of rocks and chemically related materials by X-ray fluorescence spectrometry. X-ray Spectrometry, v. 2, pp 33-44. HAYES, D.E. ; EWING, M. (1970) Paci f ic boundary structure, pp 29-72, i a Maxwell, A .E . (Ed) The Sea: part I I, v. 4, Wlley-Intersclence, New York. HEATH, G.R.; DYMOND, J . (1977) Genesis and transformation of metal-l iferous sediments from the East Pac i f i c Rise, Bauer Deep and Central Basin, northwest Nazca Plate . Bui let ln of the Geological Society of America, v .88, pp 723-733. HEATH, G.R.; MOORE, J r . , T . C . ; DAUPHIN, J .P . (1976) Late Quaternary accumulation rates of opal , quartz, organic carbon and calcium carbonate in Cascadla Basin area, northeast Pac i f i c . Geological Society of America, memoir 145, pp 393-409. -1 8 7 -HEATH, G.R.; PISIAS, N.G. (1979) A method for the quantitative estimation of clay minerals in North Pacif ic deep-sea sediments. Clays  and Clay Minerals, v. 27, #3, pp 175-184. HEKINIAN, R.; ROSENDAHL, B.R.; CRONAN, D.S. ; DMITRIEV, Y . ; FODOR, R.V.; GOLL, R.M.; HOFFERT, M.; HUMPHRIS, S . E . ; MATTEY, D.P. ; NATLAND, J . ; PETERSON, N.; ROGGENTHEN, W.; SCHRADER, E .L . ; STRIVASTAVA, R.K.; WARREN, N. (1978) Hydrothermal deposits and associated basement rocks from the Galapagos spreading center. Oceanologica Acta, v. 1, #4, pp 473-482. HERSHEY, J .B. (1965) Sediment ponding in the deep-sea. Bulletin of the  Geological Society of America, v. 76, pp 1251-1260. HEY, R.N. (1977a) Evidence for spreading center jumps from f ine-scale bathymetry and magnetics, (abstract) EOS Transactions of  the American Geophysical Union, v. 58, #12, pp 1230. HEY, R.N. (1977b) A new class of pseudofaults and their bearing on plate tectonics, (abstract) EOS Transactions of the  American Geophysical Union, v. 58, #6, pp 511. HEY R.N.; DUENNEBIER, F.K. ; MORGAN, J.W. (1980) Propagating r i f t s on midocean ridges. Journal of Geophysical Research, v. 35, pp 3647-3658. HOFFERT, M.; PERSEIL, A . ; HEKINIAN, R.; CHOUKROUNE, P. ; NEEDHAM, H.D.; FRANCHETEAU, J . ; LE PICHON, X. (1978) Hydrothermal deposits sampled by diving saucer in Transform Fault "A" near 37 N on the Mid-Atlantic Ridge, Famous area. Oceanologica Acta, v. 1, #1, pp 73-86. H0NJ0, S . ; EREZ, J . (1978) Dissolution rates of calcium carbonate in the deep ocean; an insi tu experiment in the North Atlantic Ocean. Earth and Planetary Science Letters, v. 40, pp 287-300. HONJO, S . ; ROMAN, M.R. (1978) Marine copepod fecal pe l le ts : production, preservation, and sedimentation. Journal of Marine Research, v. 36, pp 45-57. HORN, D.R.; DELACH, M.N.; HORN, B.M. (1974) Physical properties of sedimentary provinces, North Pacif ic and North Atlantic Oceans, pp 417-442. i_n Inderbitzen, A.L. (Ed.) Deep-sea sediments. Marine Science, v. 2, 497p. , Plenum Press, New York. HORN, D.R.; EWING. M.; DELACH, M.N.; HORN, B.M. (1971) Turbidites of the northeast Pac i f i c . Sedimentology, v. 16, pp 55-69. HORN, D.R.; EWING, J . I . ; EWING, M. (1972) Graded-bed sequences emplaced by turbidity currents north of 20 N in the Pac i f i c , At lant ic , and Mediterranean. Sedimentology, v. 18, pp 247-275. -188-HOROWITZ, A. (1970) The distr ibution of Pb, Ag, Sn, TI and Zn In sediments on active oceanic ridges. Marine Geology, v. 9, pp 241-259. HOROWITZ, A . ; CRONAN, D.S. (1976) The geochemistry of basal sediments from the north Atlantic Ocean. Marine Geology, v. 20, pp 205-228. HOWER, J . (1981) X-ray d i f f ract ion Identification of mixed-layer clay minerals, pp 39-59. I a Longstaffe, F . J . (Ed.) Clays and the resource geologist . Mlneraloglcal Assoc. of Canada, short course handbook, v. 7. HUME, T.M. (1978) Clay petrology of Mesozolc to Recent sediments of central western North Island, New Zealand. Unpublished Ph.D. thesis . University of Walkata, New Zealand. HYNDMAN, R.D.; ROGERS, G.C . ; BONE, M.N.; LISTER, C .R.B . ; WADE, U.S.; BARRETT, D.L. ; DAVIS, E .E . ; LEWIS, T . ; LYNCH, S . ; SEEMANN, D. (1978) Geophysical measurements In the region of the Explorer Ridge off Western Canada. Canadian Journal of Earth Science, v. 15, pp 1508-1525. JACKSON, M.L. (1956) Soil chemical analysis -advanced course. Published by Professor Jackson, Madison Wisconsin. JACOBS, M.B.; HAYES, J .D. (1972) Pa Ieo-cIImatic events Indicated by mlneraloglcal changes In deep-sea sediments. Journal of  Sedimentary Petrology, v. 42, pp 889-898. KAPLAN, I.R.; RITTENBERG, S .C . (1963) Basin sedimentation and dlagenesis. pp 583-616. l a HIM, M.N. (Ed.) The sea, v. 3, Intersclence Publishers, New York. KARLIN, R. (1980) Sediment sources and clay mineral distr ibutions off the Oregon coast. Journal of Sedimentary Petrology, v. 50, #2, pp 543-560. KAY, R.; HUBBARD, M.J . ; GAST, P. (1970) Chemical character ist ics and origins of oceanic ridge volcano rocks. Journal of Geophysical Research, v. 75, pp 1585-1613. KEEN, C . E . ; HYNDMAN, R.D. (1979) Geophysical review of the continental margins of Eastern and Western Canada. Canadian Journal of Earth Science, v. 16, pp 712-747. KELLER, W.D. (1970) Environmental aspects of clay minerals. Journal of Sedimentary Petrology, v. 40, #3, pp 788-811. KRAUSK0PF, K.B. (1957) Separation of manganese from Iron In sedimentary processes. Geochlmlca et Cosmochlmlca Acta, v. 12, pp 61-64. -1 8 9 -KRAUSKOPF, K.B. (1959) The geochemistry of s i l i c a in sedimentary environments. JJQ. S i l i c a In Sediments. Society of Econ. Paleontol. M inera l . r special publication #7, pp 4-19. KRUMBEIN, W.C.; GRAYBILL, F.A. (1965) An Introduction to s ta t i s t i ca l models In geology. 475p. Mcgraw-HHI Book Co. , New York. KULM, L.D. ; VON HUENE, R.; DUNCAN, J .R . ; INGLE, J . C . ; KLING, S . A . ; PIPER, D.J.W.; PRATT, R.M.; SCHRADER, H.J . ; WESER, 0; WISE J r . , S.W. (1973) Si te 177: the shipboard sc ien t i f i c party, l a Init ial reports of the Deep Sea Dr i l l ing Project, v. 18, pp 233-243, Washington U.S. Government Printing Of f ice . LANDERGREN, S. (1964) On the geochemistry of deep-sea sediments, l a Jerlov, N. and Kullenberg, B. (Eds.) Reports of the Swedish  Deep-Sea Expedition, 1947-1948. v. 10, #5, pp 61-154. LAVKULICH, L.M. (1978) Methods manual: Pedology laboratory. Unpublished laboratory manual, Department of Soil Science, University of Br i t i sh Columbia, Vancouver, B .C. , Canada. LEINEN, M.S. (1979) Pa IeochemicaI signatures In Cenozoic Pac i f ic sediments. Unpublished Ph.D; thesis , Rhode Island University, New York. LEPICHON, X. (1958) Sea-f loor spreading and continental d r i f t . Journal of Geophysical Research, v. 73, pp 3661-3698. LI, Y .H . ; KU, T . L . ; MATHIEU, G.G. ; WOLGEMUTH, K. (1973) Barium In the Anarctlc Ocean and Implications regarding the marine geochemistry of Ba and 2 2 6 R a . Earth and Planetary Science  Letters, v.. 19, pp 352-358. LISTER, C.R.B. (1970) Heat flow and sea floor spreading off the coast. In Moen, A.D. (Ed.) Symposium on tectonism of the Pac i f ic northwest. EOS Transactions of the American Geophysical  Union, v. 52, pp 628-630. LISTER, C.R.B. (1972) On the thermal balance of a mid-ocean ridge. Geophysical Journal of the Royal Astron. Society, v. 25, pp 515-535. LISITSYN, A.P. (1967) Basic relationships In distribution of modern s l l l c lous sediments and their connection with cl imatic zonatlon. International Geology Review, v. 9, #5, pp 631-652. LISITZIN, A.P. (1972) Sedimentation In the World Oceans: with emphasis on the nature, distr ibution and behavior of marine suspensions. Society of Econ. Paleontol. Mineral . , special paper #17, 218 p. -190-LOGANATHAN, P. ; BURAU, R.G. (1973) Sorption of heavy metal Ions by a hydrous manganese oxide. Geochimica et Cosmochimica Acta, v. 37, pp 1277-1293. LONGSTAFFE, F . J . (Ed.) (1981) Short course in clays and the resource geologist. Mlneraloglcal Assoc. of Canada, short course handbook, v. 7. LONSDALE, P. (1977) Deep-tow observations at the mounds abyssal hydrothermal f i e l d , Galapagos R i f t . Earth and Planetary  Science Letters,, v. 36, pp 92-110. LONSDALE, P. (1979) A deep-sea hydrothermal s i te on a s t r ike - s l ip fau l t . Nature, v. 281, pp 531-534. LONSDALE, P.; BATIZA, R. (1980) HyalocIastite and lava flows on young seamounts, examined with a submersible. BuI let In of the  Geological Society of America, part 1, v. 91, pp 545-554. LONSDALE, P.; LAWVER, L.A. (1980) Immature plate boundary zones studied with a submersible In the Gulf of Ca l i fo rn ia . Bui let in of  the Geological Society of America, part 1, v. 91, pp 555-569. LYLE, M.; DYMOND, J . ; HEATH, G.R. (1977) Copper-nickel-enriched ferro-manganese nodules and associated crusts from the Bauer Basin, northwest Nazca Plate. Earth and Planetary Science Letters, v. 35, pp 55-64. LYNN, D . C ; BONATTI, E. (1965) Mobility of manganese In d I agenesis of deep-sea sediments. Marine Geology, v. 3, pp 457-474. MACEWAN, D.M.C. (1961) MontmorI I I onite mineraIs. pp 143-207, Chapter IV In Brown, G. (Ed.) The x-ray identif ication and crystal structures of clay minerals. Mlneraloglcal Society of London publIcatlon, 544 p. \ MALECEK, S . J . ; CLOWES, R.M. (1978) Crustal structure near Explorer Ridge from a marine deep seismic sounding survey. Journal of Geophysical Research, v. 83, pp 5899-5912. MAMMERICKX, J . ; TAYLOR, L .L . (1971) Bathymetry of the Pioneer Survey Area, north of 45° latitude. Scrlpps Institute of Oceanography, special chart #1. MARTIN, J . H . ; KNAUER, G.A. (1973) The elemental composition of plankton Geochimica et Cosmochimica Acta, v. 37, pp 1639-1651. MATHEWS, D.J. (1939) Tables for the velocity of sound In pure water and sea water. Hydrographlc Department, Admiralty, London. MCMANUS, D.A.; HOLMES, M.L.; CARSON, B.; BARR, S.A. (1972) Late Quaternary tectonics, northern end of Juan de Fuca Ridge (northeast P a c i f i c ) . Marine Geology, v. 12, #2, pp 141-164. -191-MEHRA, D.P.; JACKSON, M.L. (1960) Iron oxide removal from soi ls and clays by a dithionate-citrate system buffered with sodium • bicarbonate. Clays and Clay Minerals, v. 7, pp 319-327. MELSON, W.G.; VALLIER, T . L . ; WRIGHT, T . L . ; BYERLY, G . ; NELEN, J . (1976) Chemical diversity of abyssal volcanic glass erupted along P a c i f i c , At lantic and Indian Ocean sea-f loor spreading centers, pp 351-368. in_ The Geophysics of the Paci f ic Ocean Basin and i t s margin, Geophysical Monograph #19, American Geophysical  Union. MENARD, H.W. (1964) Marine geology of the Pac i f i c . 271 p. McGraw-Hill, New York. MILLOT, G. (1970) Geology of clays. 429 p. Mason et Cie, Paris. MILNE, W.G.; ROGERS, G.C. ; RIDDIHOUGH, R.P. ; MCMECHAN, G.A.; HYNDMAN, R.D. (1978) Seismicity of Western Canada. Canadian Journal of  Earth Sciences,, v. 15, pp 1170-1193. MIZUTANI, S. (1970) S i l i c a minerals in the early stages of diagenesis. Sedimentology, v. 15, pp 419-436. MOEN, A.D. (Ed.)(1971) Symposium on tectonism of the Pacif ic Northwest. EOS, Transactions of the American Geophysical Union, v. 52, pp 628-645. MOORE J r . , T.C. (1973) Late Pleistocene-Holocene oceanographic changes in the northeastern Pac i f i c . Quaternary Research, v. 3, pp 99-109. MOORE, W.S.; VOGT, P.R. (1976) Hydrothermal manganese crusts from the s i te near the Galapagos spreading axis. -Earth and Planetary  Science Letters, v. 29, pp 349-356. MORGAN, W.J. (1968) Rises, trenches, great faults and crustal blocks. Journal of Geophysical Research, v. 73, pp 1959-1982. MURRAY, J . ; RENARD, A.F . (1891) Deep sea deposits. Reports of the Sc ient i f i c Results of the Voyage of the H.M.S. Challenger, 425 p. MURRAY, J.W.; BREWER, P.G. (1977) Mechanisms of removal of i ron , manganese and other trace metals from sea water, pp 291-325. in_ Glasby, G.P. (Ed.) Marine Manganese Deposits, E lsevier , Amsterdam. MURRAY, J .W.; TIFFIN, D.L. (1969) Structure of the continental margin west of Vancouver Island, B.C. Geological Survey of Canada, paper 69-1A, pp 14. NORRISH, K.; HUTTON, J .T. (1969) An accurate X-ray spectographic method for the analysis of a wide range of geological samples. Geochimica et Cosmochimica Acta, v. 33, pp 431-453. -192-PARSONS, B. ; SCLATER, J .G . (1977) An analysis of the variation of ocean-f loor bathymetry and heat flow with age. Journal of  Geophysical Research, v. 82, pp 803-827. PEARSON, M.J. (1978) Quantitative clay mlneraloglcal analyses from the bulk chemistry of sedimentary rocks. Clays and Clay Mineral P v. 26, pp 423-433. PEDERSEN, T . F . (1979) The geochemistry of sediments of the Panama Basin, Eastern Equatorial Pac i f ic Ocean. Unpublished Ph.D. thesis , University of Edinburgh, Scotland. PICKARD, G.L. (1975) Descriptive physical oceanography: an Introduction, second edi t ion . 214 p. , Pergamon Press, Oxford. PIPER, D.Z. (1973) Origin of metalliferous sediments from the East Paci f ic Rise. Earth and Planetary Science Letters, v. 19, pp 75-82. PIPER, D.Z.; VEEH, H.H.; BERTRAND, W.G.; CHASE, R.L. (1975) An Iron-rich deposit from the northeast P a c i f i c . Earth and Planetary Science Letters , v. 26, pp 114-120. PRICE, N.B. (1976) Chemical dlagenesls In sediments, pp 1-58 i n Ri ley, J . P . ; Chester, R. (Eds) Chemical Oceanography, second  edIt Ion, v. 6, 401 p. Academic press, London. PRICE, M.G. (1981) A study of sediments from the Juan de Fuca Ridge, northeast Paci f ic Ocean: with special reference to hydrothermal and diagenetic components. Unpublished M.Sc. thes is , University of Br i t ish Columbia, Vancouver, B .C . , Canada. , R.G. (1961) Magnetic survey off the west coast of North America, 40°N latitude to 526N latitude. Bulletin of RAFF, A .D . ; MASON the Geological Society of America, v. 72, pp 1267-1270 RATEEV, M.A.; G0RBUN0VA, Z . N . ; LISTIZYN, A . P . ; N0S0V, G.L. (1969) The distr ibution of clay minerals In the oceans. Sedimentology. v. 13, pp 21-43. RE ID, R.K.; HALPERN,D. (1976) Observations of the CalIfornla Undercurrent off Washington and Vancouver Island. Limnology Oceanography, v. 21, pp 389-399. REYNOLDS, J r . , R.C. (1963) Matrix corrections In trace element analysis by X-ray fluorescence: estimation of the mass adsorption coeff ic ient by Compton Scattering. American Mineralogist, v. 48, pp 1133-1143. RIDDIHOUGH, R.P. (1977) A model for recent plate Interactions off Canada's west coast. Canadian Journal of Earth Sciences, v. 14, pp 384-396. -1 9 3 -RIDDIHOUGH, R.P. (1979) Gravity and structure of an active margin- -Br i t ish Columbia and Washington. Canadian Journal of Earth  Sciences, v. 16, pp 350-363. RIDDIHOUGH, R.P. ; CURRIE, R.G.; DAVIS, E .E . ; ROGERS, G.C. ; HYNDMAN, R.D. (1978) The Dellwood Knolls - the l ink between the Explorer Ridge and the Queen Charlotte fau l t , (abstract) EOS,  Transactions of the American Geophysical Union, v. 59, pp 1197. RIDDIHOUGH, R.P. ; CURRIE, R.G.j HYNDMAN, R.D. (1980) The Dellwood Knolls and their role in t r ip le junction tectonics off northern Vancouver Island. Canadian Journal of Earth Sciences, v. 17, pp 577-593. RIDDIHOUGH, R.P. ; HYNDMAN, R.D. (1976) Canada's active western margin -the case for subduction. Geoscience Canada, v. 3, pp 269-278. RIEDEL, W.R. (1959) Sil iceous organic remains in pelagic sediments. i_n_ S i l i c a in sediments. Society of Econ. Paleontol. Mineral . , special publication #7, pp 80-91. RILEY, J . P . ; CHESTER, R. (1971) Introduction to marine chemistry. 465 p. Academic Press, London. RODEN, G.I. (1967) On r iver discharge into the northeastern Pacif ic Ocean and the Bering Sea. Journal of Geophysical Research, v. 72, #22, pp 5613-5629. RONA, P.A. (1976) Pattern of hydrothermal mineral deposition: Mid-At lant ic Ridge crest at latitude 26°N. Marine Geology, v. 21, pp M59-M66. RONA, P.A. ( 1977) TAG hydrothermal f i e l d : Mid-Atlantic Ridge crest ( lat . 26°N). (abstract) Geological Society 6f America, abstracts with programs, v. 9 , #7, pp 1146-1147. RONA, P.A. (1978) Cr i ter ia for the recognition of hydrothermal mineral deposits in oceanic crust. Economic Geology, v. 73, #2, pp 135-160. ROWE, G.T. (1974) The effects of the benthic fauna on the physical properties of deep-sea sediments, pp 381-395. i_n_ Inderbitzen, A .L . (Ed.) Deep-sea sediments. Marine Science, v. 2, 497 p. Plenum Press, New York. SAYLES, F .L . ; BISCHOFF, J . L . .(1973) Ferromanganoan sediments in the Equatorial East Paci f ic Rise. Earth and Planetary Science  Letters, v. 19, pp 330-336. SAYLES, F .L . ; KU, T . L . ; BOWKER, P.C. (1975) Chemistry of ferromanganoan sediments of the Bauer Deep. Bulletin of the Geological  Society of America, v. 86, pp 1423-1431. -194-SAYLES, F . L . ; MANGELSDORF, P.C. (1977) The equil ibration of clay minerals with sea water: exchange reactions. Geochimica et Cosmochimica  Acta, v. 41, pp 951-960. SCHINK, D.R.; GUINASSO J r . , N.L. (1977) Effects of bioturbation on sediment-sea water interaction. Marine Geology, v. 23, pp 133-154. SCHRADER, H.J. (1971) Fecal pe l le ts : role in sedimentation of pelagic diatoms. Science, v. 174, pp 55-57. SCLATER, F.R.; BOYLE, E . ; EDMOND, J .M. (1976) On the marine geochemistry of n ickel . Earth and Planetary Science Letters, v. 31, pp 119-128. SCLATER, J . G . ; CROWE, J . ; ANDERSON, R.N. (1976) On the r e l i a b i l i t y of oceanic heat flow averages. Journal of Geophysical Research, v. 81, pp 2997-3006. SCOTT, M.R.; SCOTT, R.B. ; MORSE, J .W.; BETZER, P.R.; BUTLER, L.W.; RONA, P.A. (1978) Metal-enriched sediments from the T.A.G. hydrothermal f i e l d . Nature, v. 276, pp 811-813. SCOTT, M.R.; SCOTT, R.B. ; RONA, P.A. ; BUTLER, L.W.; NALWALK, A . J . (1974) Rapidly accumulating manganese deposit from the median valley of the Mid-Atlantic Ridge. Geophysical Research Letters, v. 1, pp 355-358. SCOTT, R.B. ; RONA, P.A. ; MCGREGOR, B.A. ; SCOTT, M.R. (1974) The T.A.G. hydrothermal f i e l d . Nature, v. 251, pp 301-302. SEYFRIED, W.; BISCHOFF, J . L . (1977) Hydrothermal transport of heavy metals by seawater: the role of seawater/basalt rat io . Earth and Planetary Science Letters, v. 34, pp 71-77. SHEPARD, F.P. (1978) Currents in submarine canyons and other types of slope val leys, (abstract) Bulletin of the American  Association of Petroleum Geologists, v. 62, #3, pp 561. SILVER, E.A. (1971) Small plate tectonics in the northeastern Pac i f ic . Bulletin of the Geological Society of America, v. 82, pp 3491-3496. SINCLAIR, A . J . (1976) Applications of Probability Graphs in mineral exploration. The Association of Exploration Geochemists, special volume #4, 95p. SKORNY/AKOYA, I.S. (1964) Dispersed iron and manganese in Pacif ic Ocean sediments. International Geology Review, v. 7, pp 2161-2174. SRIVASTAVA, S.P. (1973) Interpretation of gravity and magnetic measure-ments across the continental margin of Br i t ish Columbia, Canada. Canadian Journal of Earth Sciences, v. 10, #11, pp 1664-1667. -195-SRIVASTAVA, S . P . ; BARRETT, D .L . ; KEEN, C . E . ; MANCHESTER, K.S. ; SHIH, K.G.; TIFFIN, D.L. ; CHASE, R .L . ; TOMLINSON, A . G . ; DAVIS, E .E . ; LISTER, C.R.B. (1971) Preliminary analysis of geophysical measurements north of Juan de Fuca Ridge. Canadian Journal of Earth Sciences, v. 8, pp 1265-1281. STERN, W.B. (1976) On trace element analysis of geological samples by X-ray fluorescence. X-ray Spectrometry, v. 5, pp 56-60. STOKKE, P.R.; CARSON, B. (1973) Variation in clay mineral X-ray d i f -fraction results with the quantity of sample mounted. Journal of Sedimentary Petrology, v. 43, pp 957-964. STOW, D.A.V.; AKSU, A .E . (1978) Disturbances in soft sediments due to piston coring. Marine Geology, v. 28, pp 135-144. STRAKHOV, N.M. (1966) Types of manganese accumulation in present day basins: their signif icance in understanding of manganese mineralization. International Geology Review, v. 8 , pp 1172-1196. ' TEMPLE, D.G.; SCOTT, R.B. ; RONA, P.A. (1979) Geology of a submarine hydrothermal f i e l d , Mid-Atlantic Ridge, 26 N lat i tude. Journal of Geophysical Research, v. 84, #B13, pp 7453-7466. THOMPSON, G . ; WOO, C . C ; SUNG, W.Y. (1975) Metalliferous deposits on the Mid-Atlantic Ridge. Geological Society of America, abstracts with programs, pp 1297. ogy. n i i . i i (J| u y i u n i o , X C J I . THOMPSON, P.R.; TSUNEMASA, S. (1974) Pacif ic Pleistocene sediments: planktonic foraminifera dissolution cycles and geochronol Geology, v. 2, pp 333-335. TIFFIN, D.L. (1973a) Marine geophysical act iv i t ies on the Paci f ic margin. Geological Survey of Canada, paper 73-1A, pp 127. TIFFIN, D.L. (1973b) Regional tectonic and sedimentary basin studies on the continental margin of f Br i t ish Columbia. EOS, Transactions  of the American Geophysical Union, v. 54, #3, pp 140-141. TIFFIN, D.L. (1974) Marine geophysical and geological studies on the Pacif ic margin. Geological Survey of Canada, paper 74-1A, pp 127. TIFFIN, D.L. ; BORNHOLD, B.D. ; YORATH, C . J . ; HERZER, R.H. ; TAYLOR, G.C. (1978) Bottom sediments-vicinity of Juan de Fuca and Explorer Ridges, northeast Paci f ic Ocean. Geological Survey of Canada, paper 78-1A, pp 533-537. TIFFIN. D.L. ; CAMERON, B .E .B . ; MURRAY, J.W. (1972) Tectonics and depositional history of the continental margin off Vancouver Island, Br i t ish Columbia. Canadian Journal of Earth Sciences, v. 9, pp 280-296. -196-TIFFIN, D.L.;SEEMANN, D. (1975) Bathymetric map of the continental margin of western Canada. Geological Survey of Canada, open f i l e report 75-301. TOBIN, D.G.; SYKES, L.R. (1968) Seismicity and tectonics of the north-eastern Paci f ic Ocean. Journal of Geophysical Research, v. 73, #12, pp 3821-3845. TOWE, K.M. (1974) Quantitative clay petrology: The trees but not the forest . Clays and Clay Minerals, v. 22, pp 375-378. TUREKIAN, K.K.; WEDEPOHL, K.H. (1961) Distribution of the elements in some major units of the earth's crust. Bul let in of the  Geological Society of America, v. 72, pp 175-192. TURNER, J . S . ; GUSTAFSON, L.B. (1978) The flow of hot saline solutions from vents in the sea f loor - some implications for exhalative massive sulf ide and other ore deposits. Economic Geology, v. 73, pp 1082-1100. VAN ANDEL, T . H . ; BALLARD, R.D. (1979) The Galapagos Rift at 86°W: 2. Volcanism, structure and evolution of the r i f t valley. Journal of Geophysical Research, v. 84, #B10, pp 5390-5406. VEEVERS, J . J . (1976) PaTeobathymetry of the crest of spreading ridges related to the age of ocean basins. Earth and Planetary  Science Letters, v. 34, pp 100-106. VINE, F.J . (1966) Spreading of the ocean f loor : New evidence. Science, v. 154, pp 1405-1415. VINE, F . J . ; WILSON, J .T . (1965) Magnetic anomalies over a young oceanic ridge of f Vancouver Island. Science, v. 150, pp 485-489. WALKER, R.G.; MUTTI, E. (1973) Turbidite facies and facies associations. in Middleton, G.V.; Bouma, A.H. (Eds.) Turbidites and deep-water sedimentation. Society of Econ. Paleontol. Mineral . , Paci f ic sect ion, short course notes, pp 119-157. WEAVER, C . E . ; POLLARD, L.D. (1973) The chemistry of clay minerals. Developments in Sedimentology, v. 15, 213 p. Elsevier Publishers, Amsterdam. WEAVER, C . E . ; WAMPLER, J.M. (1972) The i11ite-phosphate association. Geochimica et Cosmochimica Acta, v. 36, pp 1-13. WEBBER. G.R.; NEWBERRY, M.L. (1971) X-ray fluorescence determinations . of minor and trace elements in s i l i c a t e rocks. Canadian  Spectroscopy, v. 16, #4, pp 3-7. WEISS, R.F. ; LONSDALE, 0 . ; LUPTON, J . E . ; BAINBRIDGE, A . E . ; CRAIG, H. (1977) Hydrothermal plumes in the Galapagos R i f t . Nature, v. 267, pp 600-603. -197-WILLIAMS, D.L. ; GREEN, K.; VAN ANDEL, T . H . ; VON HERZEN, R.P. ; DYMOND, J.R. CRANE, K. (1979) Hydrothermal mounds of the Galapagos R i f t : observations with DSRV Alvin and detailed heat flow studies. Journal of Geophysical Research, v. 84, #B13, pp 7467-7484. WILLIAMS, D.L. ; VON HERZEN, R.P. ; SCLATER, J . G . ; ANDERSON, R.N.(1974) The Galapagos spreading center: l ithospheric cooling and hydrothermal c i rcu lat ion . Geophysical Journal of the Royal  Astro. Society, v. 38, pp 587-608. WILSON, J .T. (1965) Transform fau l ts , ocean ridges and magnetic anomalies southwest of Vancouver Island. Science, v. 150, pp 482-485. WINDOM, H.L. (.1975) Eolian contributions to marine sediments. Journal of Sedimentary Petrology, v. 45, #2, pp 520-529. WINDOM, H.L. (.1976) Lithogenous material in marine sediments, pp 103-136. in_ Ri ley , J . P . ; Chester, R. (Eds.) Chemical Oceanography, second edi t ion , v: 5, 401 p, Academic Press, London. ZEMMELS, I.; COOK, H.E. (1973) X-ray mineralogy of sediments from the northeast Pacif ic and Gulf of Alaska - leg 18 Deep Sea Dr i l l ing Project. jn_ Kulm, et a l . In i t ial Reports of the Deep Sea  Dr i l l ing Project, v. 18, pp 1015-1019, Washington U.S. Government Printing Off ice. -198-APPENDIX A SAMPLE COLLECTION METHODS AND SAMPLE DESCRIPTIONS -199-A.1 SAMPLE COLLECTION In order to define desirable coring posit ions, stations were surveyed using 12 kHz and 3.5 kHz acoustic sounding and single channel contluous seismic p r o f i l i n g . Navigation was by Loran-C, with an estimated accuracy of 30 m. Both gravity and Benthos Boomerang corers were used to obtain sediment cores for th is study. The longest core recovered, 79-06-31, was 1.64 m. The gravity cores were generally longer than the Boomerang cores (Table 1.1). Two types of gravity corers were used, both with plast ic l iners , one with carbon steel weights and barrel (10.2 cm In diameter), the other with stainless steel barrel (15.2 cm In diameter). The advantage of a larger diameter corer Is obvious; It retrieves more sample, with less deformation of the sediment In the centre of the core. The disadvantage of the larger barrel diameter, stainless steel corer (designed by R.D. MacDonald, University of Br i t ish Columbia Geology Department, referred to as the modified gravity corer In thesis text) was Its poorer penetration. The gravity corers were lowered on a 1.3 cm diameter steel wire to about 100 m above bottom, then allowed to free fa l l to the sea f loor . After penetration the corer was raised to the surface, the plast ic core liner (and sediment contained therein) was removed, and weight-stand, barre l , core cutter and core catcher used repeatedly (with a new plast ic l iner each time). The Boomerang corers were released at the surface, f e l l freely and penetrated the bottom. Following penetration, two glass ' - 2 0 0 -globes were automatically released and floated the plast ic l iner with sediment core to the surface. Recovery of the f loats and core was accomplished at night, sighting being fac i l i ta ted by flashing strobe- l ights within the glass-spheres. The weight-stand, barrel and core cutter remained on the sea floor and were lost . The cores were s p l i t at sea, using a Skll-saw and spIIttlng-box; a nylon line was used to cut the sediment. The cores were photographed and described prior to sampling. Samples for chemical analysis were taken at 10 cm intervals down the core, placed Into plast ic culture-/ dishes and allowed to a i r -d ry . The sp l i t cores were then placed Into plast ic "D-tubes n , labelled and stored horizontally at 4°C. One half of each core was sampled and the other half preserved as an archival sp l i t (later X-rayed for study of sedimentary structures). Dredge samples were obtained using a chain-bag dredge, with a leader of heavy anchor chain. The dredge was typ ica l ly lowered to the base of a submarine slope, cable laid out, and the dredge dragged upslope. The contents of the single successful haul obtained were photographed, described b r ie f l y , then stored In f ive -gal lon metal p a l l s . Pillow basalts recovered from dredge PGC-79-06-32 (see Table 1.1 and Figure 1.1) form part of the study by Cousens (1982). - 2 0 1 -A.2 CORE DESCRIPTIONS X-radlographs of satisfactory quality were taken of the archival halves by INS Technologies L t d . , Vancouver, B.C. Recoglzable sediment-ary features Include bloturbated Intervals, paral lel and cross laminations, graded bedding and g r i t zones. Core descriptions (Including X-radlograph Interpretations and v i s ib le structures), MunselI colour (Goddard et a I.P 1975), and the resulting st r ip - logs are presented for each core taken (Figures A.1 to A.12). The s t r ip - logs are scaled In centimetres of sediment recovered with the top of each core at depth=0. No adjustment of depth was made for suspected core loss during recovery (see text for discussion). Table A.1 Is a legend for the symbols used In the s t r ip - logs . A.3 EXPLORER DEEP METALLIFEROUS SEDIMENT (EDMS) DESCRIPTION The deposits were col lected during dredge haul 69-11, by dredging the small ridge that Juts Into the deepest part of Explorer Deep (Figure 1.1). Varicoloured deposits were recovered from the surface of the ol ive-gray muds which f i l l e d the bottom two thirds of the pipe dredge. Exact positioning of the station Is somewhat questionable since It was derived from a single s a t e l l i t e navigation f i x at 50°05.5 'N , 139°46.0»W (In 2800 m water depth). G r i l l et a l . (1981) Indicated that It l ikely originated from the crest of the medial r idge. - 2 0 2 -The Explorer Deep metalliferous deposit was not described In detail at the time of recovery. The following Is a description of the present state of the sample by Gr i l l et a l . (1981): " . . . It consists of about 10 Irregularly shaped pieces of crust -like material that linear dimensions ranging between 1 and 15 cm and are composed of soft yellow-green clays and f r iable orange to black ferromanganese oxides. Included among these are several f la t slabs In which c lay - and oxlde-rlch portions are Joined along a boundary paral le l ing the flattened faces; a well-defined Internal layering, normally found In both the clay and oxide portions, generally, but not always, paral le ls the boundary and is marked at irregular intervals by thin (<1 mm) laminae of orange material. The holdfast of a s i l iceous sponge is attached to the black oxide face of one such piece, marking It as a surface that had been exposed to the sea. The remaining pieces in the sample outwardly appear to consist of orange-brown to black ferromanganese minerals, but on fracturing often are found to contain much Intimately Inter-mixed yellow-green c lay . " Samples of the Explorer Deep metalliferous deposit were chemically analyzed by Gr i l l et al . (1981); several of their results were used In this study: EDMS (#2,6).. . .average of samples #2 and #6, predominately composed of nontronlte EDMS (#4) sample #4, oxlde-rlch both todoroklte and birnessite EDMS (#5) sample #5, predominately todorokite EDMS (#7,8,9)..average samples #7, #8 and #9, predominately composed of birnessite. The mineralogy of two samples was also examined in this study: EDMS a sample of soft yellow-green c lay - r ich sediment EDMS-b...a sample of black ferromanganese oxlde-rlch sediment. -203-Table A .1 Legend of symbols for s t r ip - logs . Li thiol ogy | j clay-mud of uniform texture | .j • j si Ity zone |-!:';-:.-V:.v gr i t zone (sand-size grains) Sedimentary Structures = | parallel laminations jzi777r. | cross laminations \(?t£S | bioturbation j — | carbonaceous material -204-sediment Munsell structures colours 20 40 60 S o 3: a. Q 80 100 120 140 160 L_ 5YR4/4 10Y4/2 description & comments 0- 1 cm moderate brown 1- 125 cm grayish olive with gradational upper contact. Several greenish streaks, irregular in nature are distributed down core. Core exhibits a strong pel letoid texture continuing from top to 100 cm. A s l ight ly s i l t y zone occurs at 85-87 cm, the remainder of the core appears uniformly fine grained. An angular contact (unconformity) is v is ib le in X-radiographs at 100-110 cm, below which a laminated nature becomes increasingly evident. Blueish streaks noted at 100-106 cm correspond well with X-ray laminated texture. Slight bioturbation is evident from 6-10 cm and a single burrow at 34-40 cm. Total length = 125 cm. Fig. A . l Core 79-06-01: s t r ip - log and description. -205-0 t-sediment Munsell structures colours 160 L 10Y5/4 — 5GY5/2 5GY5/2 (5B5/1 streaks) description & comments 0-63 cm grayish ol ive 63-108 cm dusky yellow green, mottled with patches of greener sediment. Gradational upper contact. 108-122 cm dusky yellow green with bands of medium blueish gray. Overall somewhat l ighter than above unit. Streaks appear to be s i I ty . Strongly burrowed from 0-48 cm (diameter of burrows average 4 mm). A second zone of s l ight bioturbation is evident from 63-72 cm. The intensity of bioturbation decreases downward from 63 cm. Several s i l t y lenses v is ib le at 51 and at 58 cm. These lenses exhibit no dist inct ive colouration. Streaks of blueish sediment at 112 and 126 cm correspond well with s i l t y streaks seen in the X-radiographs. Laminations scattered throughout core from 86 cm to 122 cm, increase in intensity below contact at 108 cm. Total length = 122 cm. Fig. A.2 Core 79-06-02: s t r ip - log and description. -206-0 t — sediment Munsell structures colours \ 10YR4/2 56Y5/2 5GY3/2 5G4/1 description & comments 0- 1 cm dark yellowish brown 1- 38 cm dusky yellow green, with gradational upper contact. 38-120 cm grayish olive green, with gradational upper contact. Streaks of grayer sediment becoming increasingly frequent toward base of unit. 120-134 cm dark greenish gray, with several brownish streaks, irregular in thickness (less than 1 cm thick). Pel letoid texture v is ib le down to 120 cm, the abundance of pellets decreasing sharply at 38 cm. A wood fragment (dark bleb in section) with dimensions 2.7 cm in length and 0.5 cm in width found at 27 cm. Bioturbated from 5 cm to 25 cm, increasing in intensity downward from 5 cm. A zone of s l ight bioturbation at 58-72 cm. SiIty lenses at 26 cm and at 29 cm (Holothurioid grazing?) and at 115 and 121 cm. Laminated nature evident below 85 cm. Numerous horizontal and cross-laminations from 85-100 cm, decreasing in frequency from 100-120 cm, then strongly laminated from 120 cm to T .D . . Total length = 134 cm. 160 «-Fig. A.3 Core 79-06-04: s t r ip - l og and description. -207-sediment Munsell structures colours 20 -40 60 o 80 UJ Q 700 720 740 760 L-\5Y4/4 10Y4/2 5Y3/2 description & comments 0-1 cm moderate olive brown, gradational lower contact (down to 5 cm). 5-127 cm grayish ol ive. 127-132 cm l ight o l ive. Pel let i ferous from surface to 127 cm. Below 127 cm pellet structure is no longer v is ib le . Pellets are oblong (approximately 0.50 mm in diameter). A chitinous worm tube vis ible in surface sample (about 3 cm in length and very thin) . Slight bioturbation noted from 17-27 cm. Very uniform texture and colour from 30-127 cm. The l ighter colour and X-radiograph signature indicate a sl ight coarsening of sediment below 127 cm. Total length = 132 cm. Fig. A.4 Core 79-06-06: s t r i p - l o g and description. -208-sediment Munsell structures colours 0 r-20 40 60 E o i : Uj Q 80 100 120 140 160 \ 5Y4/2 10Y5/2 to 5GY5/2 10Y5/2 8Y5/2 7GY5/2 8Y5/2 description & comments 0- 1 cm l ight olive gray. 1- 20 cm l ight o l i ve , interlaminated every few millimeters with more or less yellow or blackish coloured sediment. 20-23 cm brownish smear. 23-35 cm l ight ol ive (uniformly olive coloured). 35-70 cm moderate gray o l i ve , with several blackish smears. 70-73 cm moderate yellow gray green. 73-85 cm moderate gray o l i ve , highly mottled with greenish and blackish streaks. There is a hint of lamination throughout the upper zones down to 20 cm. Laminated further down core at 53 cm and below 74 cm. The two grit zones at 70 cm contain grains upto greater than 2 mm. Total length = 85 cm. Fig. A.5 Core 79-06-07: s t r ip - log and description. *note: most of the structure has been destroyed prior to X-raying due to improper storage of core after sp l i t t ing ( ie. desiccation) -209-sediment Munsell structures colours 20 40 60 o a . Uj Q 80 100 120 140 160 i \ 5YR4/4 5GY5/2 5GY5/2 10Y4/2 description & comments 0-0.5 cm moderate brown. 0.5-22 cm dusky yellow green. 22-148 cm s l ight ly l ighter dusky yellow green. Sharp' upper contact. Layering evident throughout unit , predominately as l ighter shades of green. Abundant black smears. 148-158 cm grayish olive with patches of dusky yellow green. Pel letoid texture dist inct from surface down to 148 cm. Occasional burrows from 0-40 cm. Rare laminations between 0-35 cm. Very uniform colour and texture from 40-148 cm. Sharp contact at 148 cm. Total length = 158 cm. Fig. A.6 Core 79-06-08: s t r ip - log and description. -210-sediment Munsell structures colours 0 r-20 40 60 5 o 80 Uj Q 100 120 140 160 L-\ 5Y4/4 10Y4/2 10Y4/2 & 5GY4/1 5GY4/1 5GY4/1 & 5G4/1 5GY4/1 & 5G4/1 description & comments 0-2 cm moderate olive brown. 2-20 cm grayish o l i ve , with gradational upper contact. 20-28 cm strongly mottled zone, predominately grayish ol ive with pockets of l ighter coloured sediment. Sharp basal contact. 28-33 cm almost medium bluish gray, with irregular streaks of greener sediment. 33-133 cm predominately dark greenish gray with abundant streaks of greener sediment. Slight brown tinge to zone from 35-55 cm. Sl ightly bioturbated from 0-15 cm. Highly bioturbated from 20-28 cm, with a decrease in intensity from 28-45 cm. Several laminations v is ib le at 45 and 48 cm, again from 60-80 cm. A f inal lamination at 131 cm (may be due to sea water-sediment interaction during coring). Total length = 133 cm. Fig. A.7 Core 79-06-10: s t r ip - log and description. -211-sediment Munsell structures colours 20 40 60 s o 2: Q 80 100 120 140 160 «— 10Y4/2 10Y4/2 description & comments 0-38 cm grayish o l ive . 38-43 cm grayish olive with sand grains from clear to white to black in a grayish olive mud matrix. 43-91 cm grayish ol ive. Sediment appears to be composed predominately of oblong pel lets (upto 1 mm in length), except for the gr i t section from 38-43 cm. Pellets are extremely soft and easi ly destroyed, yet maintain their form to T .D . . The upper sediment contains numerous foraminifera tests. Bioturbation evident in the upper 34 cm, decreasing in intensity toward base of unit. SiIty layer overlying gr i t zone from 38-43 cm. Grains upto greater than 5 mm . in diameter. Very uniform (structureless) from 43 cm to T .D . . Total length = 91 cm Fig. A.8 Core 79-06-21: s t r ip - log and description. -212-sediment structures Munsell colours 0 r -20 40 60 6 o i— a . Q 80 100 120 140 -160 *— \ 10YR4/2 5Y5/2 5Y6/2 .5B5/1 5GY5/1 description & comments 0- 1 cm dark yellowish brown. 1- 10 cm l ight ol ive gray. 10-21 cm yellowish ol ive gray. 21-35 cm medium blueish gray. 35-69 cm medium greenish gray. Pelletiferous zones at 23 cm, 27 cm, 31 cm, and from 32-40 cm. Pellets are oblong, about 0.5 mm in length. Foraminifera rich zone from 10-13 cm, with abundant foraminifera at surface, at 5 cm, at 19 cm, and at 48 cm. Also a bivalve shell fragment at 48 cm. Minor bioturbation evident from 49 cm to 62 cm. , S i l ty zones from 0-21 cm, 26-29 cm, 31-32 cm, 40-47 cm, and 49-63 cm. Clay rich zone from 22-24 cm. Grit zones from 21-22 cm, 24-26 cm, 29-31 cm, 32-33 cm, 38-40 cm (fragments upto 5 mm), and from 47-49 cm. Grit includes glass shards, pebbles of various composition, sand size quartz and rock fragments. Several of the zones show apparent f ining upwards sequences, particularly 24-26 cm, 29-31 cm, 33-40 cm (this character is part icular ly noticable in the X-radiographs). Total length = 69 cm. Fig. A.9 Core 79-06-22: s t r ip - log and description. -213-sediment Munsell structures colours 0 r-20 40 60 5 o 1 Q. Uj Q 80 100 120 140 160 5Y5/2 10Y5/2 description & comments 0-5 cm l ight ol ive gray. 5-102 cm l ight o l i ve , with rare black streaks, otherwise very uniform in colour. Well developed, pelletiferous texture, part icular ly near the top, though s t i l l d ist inct at base. Foraminifera rich zone from 1-2 cm. Upper sediment very soft . X-radiographs indicate several weakly defined laminations throughout the length of the core. Several sharp contacts are v is ible at 15 cm, 63 cm, 95 cm and at 100 cm. SiIty zones at 18 cm, 53 cm, and at 94 cm. Total length = 102 cm. Fig. A.10 Core 79-06-29: s t r ip - log and description. -214-sediment Munsell structures colours 0 r-20 40 60 o a: »— CL UJ Q 80 100 120 140 4 ? \10YR4/2 10Y5/2 10Y5/2 description & comments 0-2 cm dark yellowish brown, with streak of underlying green sediment. 2-19 cm l ight o l i ve , with s l ight colour mottling from 1-10 cm. Brownish streak from. 19-20 cm. 20-98.5 cm l ight o l i ve , with s l ight colour mottling from 50-55 cm. Pelletiferous texture very prominent at top, becoming indistinguishable at 80 cm. Slight bioturbation evident above 30 cm, with sections of very uniform colour and texture. Slight laminated nature evident from 33 cm to T .D . , with thick uniform sections part icularly below 53 cm. Total length = 98.5 cm. 160 *— Fig. A.11 Core 79-06-30: s t r ip - log and description. -215-0 r -sediment Munsell structures colours 20 40 60 E u Q. Uj Q 80 100 120 140 160 '///to/,,;. 5Y5/2 5B6/2 10YR6/4 5GY6/2 description & comments 0-3 cm l ight olive gray. 3-10 cm l ight olive gray interlaminated with greenish layers. 10- 11 cm brownish zone. 11- 29 cm zone exhibiting extreme mottling, with colours ranging from greens to blue-grays to yellowish browns. 29- 30 cm brownish zone. 30- 103 cm blue-green mottled zone, with brownish streaks at 43 and 48 cm, and from 63-74 cm. 103-108 cm l ight yellowish brown. 108-134 cm mottled blue-grays, with a brownish smear at 130-131 cm. 134-160 cm mottled grayish greens and blues, with brownish smear at 143-145 cm. Slight darkening at 152 cm. 160-164 cm yellowish gray green (altered by contact with seawater ?) Pellets v is ib le at 22 cm. Foraminifera rich zone at 82 cm (about 0.5 cm below gr i t zone), and from 107-109 cm. Mildly bioturbated zone from 38-53 cm. Abundant s i l t lenses and grits throughout core length. Many of the s i l t s show fining upwards sequences. Laminations well developed from 10-30 cm, from 55-65 cm, from 90-108 cm, and from 140-145 cm. Throughout length of core single lamina occur. Total length = 164 cm. Fig. A.12 Core 79-06-31: s t r ip - lpg and description, -216-APPENDIX B ANALYTICAL METHODS - 2 1 7 -B.I MINERALOGY; X-RAY PIFFRACTIQN Sample preparation was performed following techniques described by Lavkullch (1978). A summary of the method Is presented below. I 5 g of a i r -dr ied sample was l ightly ground using a mortar and pest le . Excessive grinding was avoided, In order to preserve the original par t lc le -s l ze relationships and to prevent fraying at the edges of the clay par t ic les . Carbonates and soluble salts were removed using a sodium acetate solution (82 g NaOAc*3H20, 27 ml glacial acetic ac id , made to 1- l i t r e with d i s t i l l e d water, pH adjusted to 4.5 prior to use) In a 100 ml centrifuge tube. The mixture was heated at 80°C In a water bath for 30 minutes, allowed to coo l , then centrlfuged at 1500 rpm for 5 minutes. The supernatant l iquid was decanted and discarded. The sediment was then washed with 20 ml of sodium acetate solut ion. Organic matter was oxidized by the addition of sodium hypochlorite (5$), to the carbonate- and sa l t - f ree sediment. After 15 minutes In an 80°C water bath, the mixture was allowed to coo l , then centrlfuged at 2400 rpm for 10 minutes. The supernatant l iquid was discarded. This treatment was repeated three times to ensure complete oxidation. Free Iron oxides were removed using citrate-buffered sodium dlthlonlte solution (Mehra and Jackson, 1960). The sediment was dispersed In saturated NaCl solut ion, centrlfuged to remove the l iqu id , then redlspersed In 80 ml of c i t ra te buffer. The c i t ra te buffer mixture was heated In a water bath to 75-80°C. After the temperature had been reached, 3 g of sodium dlthlonlte was slowly added while s t i r r i n g . - 2 1 8 -Heating was continued for 15 minutes, followed by cooling and c e n t r l -fuglng as 2100 rpm for 20 minutes. The l iquid was discarded and the residue washed with c i t rate buffer. Part Ic le -s lze separation was completed using a progressive sedimentation technique. The f i r s t fraction removed was the less than 0.2 um size range. The sediment was dispersed in d i s t i l l ed water (to a depth of 10 cm), then centrlfuged at 2125 rpm for 49.6 minutes. The suspended material was saved and the procedure repeated f ive times. Following the size separation, the suspension was flocculated by the addition of 10$ MgCI2*6H20 (50 ml), and left to sett le overnight. The sediment was then Mg-saturated by centrifuge washing three times with 50 ml portions of )0% MgCI2*6H20. The clays were f inal ly washed twice with acetone to remove any excess MgCI2, then oven-dried at 60°C. The 0.2 to 2 um size fraction was separated by centrlfuging at 500 rpm for 9.1 minutes. The procedure was repeated three times to obtain a l l material less than 2 um. The clays were then flocculated and Mg-saturated as described above. After actone washing, the sample was oven-dried at 60°C. Separation of the 2 to 5 um size fraction Involved centrlfuging at 300 rpm for 4.1 minutes. After centrlfuging at 300 rpm the suspended sediment was removed, and the suspension centrlfuged at 2100 rpm for 10 minutes. The supernatant l iquid was discarded. This procedure was repeated three times. Mg-saturatIon and washings were done as.desert bed above, and the sediment again dried at 60°C. -219-For separation of the 5 to 20 um size f ract ion, the sediment was dispersed In d i s t i l l e d water to a depth of 10 cm, and allowed to stand for 4.3 minutes. The supernatant suspension was decanted, centrlfuged at 2100 rpm, and the l iquid discarded, as before. This prodedure was repeated three times. The sediment fraction was then dried at 60°C. There Is no need for Mg-saturatlon In th is size f ract ion. The remaining sediment was also dried at 60°C and was simply considered as the >20 um size f ract ion. Having now separated the sediment Into Its various size fract ions, samples were prepared for X-ray dlffratometry by two techniques. The 5 to 20 um, >20 um and " to ta l " (or bulk) samples were prepared as unorlented mounts, while the <0.2 um, 0.2 to 2 um and 2 to 5 um size fractions were prepared as oriented s l ides . Unorlented mounts were prepared In aluminium holders as loose packed powders, having f i r s t been ground to Insure uniform mineral s i ze . In some cases there was Insuf-f i c ient sample to permit mounting In the aluminium holder; In th is situation a random mount was prepared using an acetone slurry on a glass s l i d e . The two techniques seemed to produce comparable results (although Intensity of X-ray d i f f ract ion peaks for the latter were somewhat lessened). Oriented mounts were prepared of K-saturated, Mg-saturated, and Mg-saturated glycerol solvated samples. In each case 25 mg of the sample was used In the preparation. For the K-saturated al iquot, the sediments were centrifuge-washed four times with 1.0 N KCI. The sediment was centrifuge-washed twice with ethanol-water (50-50), twice - 2 2 0 -with ethanol then twice with d i s t i l l e d water, and the s l ide made Immediately. The Mg-saturated mounts were prepared by f i r s t washing with d i s t i l l e d water Into which one drop of 0.1 N HCI had been added. The sediment was then centrifuge-washed once with 1.0 N magnesium acetate, twice with 1.0 N MgC^, and then washed with ethanol-water, ethanol and f ina l l y with water as described for the K-saturated sample. For the g lycero l - solvated sample two drops of 10$ glycerol solution were added to a 5 ml portion of the Mg-saturated sample. Glass sl ides used for the oriented sample mounts were f i r s t cleaned with ethanol, then marked with two paral lel lines (across the s l ide at about 1 cm and 1.5 cm from the ends) using an enamel pen. The sample was welTmlxed and then with a pipette-dropper, a sample was taken and poured In between the lines on the s l i de . The sl ides were allowed to dry at room temperature, under a dust cover. The glycerol-solvated sample was stored In a glycerol-saturated desslcator. K-saturated samples were run at room temperature, after heating to 300°C for four hours, and to 550°C for four hours. The sl ides were run from 3° to 33° 29 for the oriented mounts, and from 3 ° to 60° 20 for for the unorlented mounts. The X-ray d i f f ract ion analyses were performed with a Phi l ips PW4280 amplifier analyser, PW1365 pulse shaper, PW1011/60 X-ray generator, and 1050/65 Goniometers. The analytical conditions used were as follows: CuK©< radiation at 30 kV, 20 mA; NI f i l t e r ; dispersion s l i t s at 1° -0 .2 mm-1°; variable scanning speeds, at 2° 20/mInute and 1/2° 29/mInute; variable scale (typically 1000 counts/Inch); variable time constant (typically 1 second). - 2 2 1 -B.2 CHEMICAL ANALYSIS: X-RAY FLQURESCENCE SPECTROMETRY Major elements The analysis of major elements was performed on fused discs (30.5 mm diameter), prepared by a method similar to that of Pedersen (1979). The technique Is based on that described by Norrlsh and Hutton (1969), later modified by Harvey et a l . (1973). About 5 g of each sediment sample was ground with a mortar and pestle, then dried at 60°C. Approximately 2.0 g of X-ray fusion flux, Complex (Grade III) was weighed Into a 95? Pi/5% Au crucib le , then fused over a Meker burner. The flux is composed of lithium tetraborate (47$), lithium carbonate (37$) and lanthanum oxide (16$). Fusion of the flux was necessary as Chemplex (Grade III) Is not pre-fused. A number of fused beads were made at one time, then stored. In a dessicator until they were needed. A flux bead was accurately weighed (to ±0.0001 g) Into a Pt/Au crucible, then a sediment sample was added at a rat io of 6.0000:1 (flux-sample, by weight). The crucible was then placed oyer a Meker burner for 20 minutes. The crucible with sample was then rewelghed and loss-on-Ignltlon was calculated. The .loss In weight was made up with lithium tetraborate ('spec grade') , which had been dried at 400°C prior to use. Use of a La-bearing flux to replace the weight loss would considerably Increase the proportion of heavy adsorber (La), alter ing the heavy adsorber (La)/element rat io for each sample; therefore a flux containing only lithium tetraborate was used. The crucible (containing both the flux and sample) was again placed -222-over a Meker burner and re-fused. Disc-shaped, concave, duraluminlum moulds and plunger were kept on a hotplate at 220°C (for detai ls of design see Harvey et a I.f 1973). The molten glass was poured Into the mould and pressed Into a disc with the plunger. The disc was 'cured' for about one hour at 220°C, then labelled and stored In a desslcator until It was ready for Introduction to the X-ray beam. A graph of sample weight-loss versus temperature (Figure B.1) shows that weight-loss would s t i l l occur at temperatures greater than 1000°C, Indicating that the furnace temperature readings were probably too low. Examination of the furnace revealed defective heating elements, so the furnace could not be used. Meker, burners were used for both the Inltal 20 minute sample-flux fusion as well as the f inal fusion for disc moulding. Fusion of the samples using only Meker burners had two disadvantages: 1) the process was very time consuming as only two samples could be prepared at a time; 2) the temperature of fusion was limited to 1000°C whereas Pedersen (1979) recommends fusion at 1100°C. Norrlsh and Hutton (1969) discuss the negative effects of fusion at temperatures below 950°C (considered In the next sect ion) . Addition of large quantities of La-bearing flux to the sample considerably Increased the total mass adsorption of the glass discs after fusion. This overall Increase tends to buffer the effect of elemental mass adsorption differences from sample to sample, thus pract ica l ly eliminating the matrix adsorption effects between the samples and standards. Hence no matrix coef f ic ients were calculated for the major elemental analyses. - 2 2 3 -0 0 2 4 6 8 10 12 T (X 100) °C Fig. B.l Graph showing weight-loss during heating of sediments from Explorer Deep, in muffle furnace. Each point represents 20 minute continuous heating at the indicated stabi l ized temperature. -224-Three International rock standards were used for cal ibrat ion In th is study: AGV-1, BCR-1 and SY-3. Two samples were prepared for each standard. A comparison of the determined values with recommended values (Abbey, 1977) are l isted In Table B.1. Five synthetic standards were also used In the ca l ibrat ion . The synthetic standards were prepared by adding varying quantities of CaC0 3, S10 2 , Mn02, KH 2 P0 4 , F e ^ , NaCl, and MgO (al l Johnson-Matthey Specpure chemicals); analyzed and suggested concentrations are l isted In Table B.I. The synthetic standards, prepared by T. Pedersen for analyses of sediments from the Panama Basin, were kindly loaned for this study (Pedersen, 1979). The compositions of International rock standards plus synthetic standards generally span the range In elemental concentrations of sediments from the Explorer Deep area. The exception Is calcium; low-calcium samples are outside the cal ibrat ion range. However, the calcium cal ibrat ion line Is well defined by the standards. Agreement of the International rock standards cal ibrat ion with that of the synthetic standards was generally very good (Table B.1). The exception Is potassium, for which the International rock standards analyzed consistently high. The f ive synthetic standards form a well defined potassium cal ibrat ion l ine, while the International rock standards form a trend paral lel to the synthetic standard l ine . In th is study the synthetic standard line was used, so than potassium content may have a systematic overestImatIon of 0.20$ K 2 0. ^ The analyses for chlorine were performed on fused discs, and the values used In corrections for salt contribution. Sample preparation - 2 2 5 -STANDARD S i0 2 A1 2 0 3 Fe 2 0 3 MgO MnO T i0 2 CaO Na20 K20 P 2 0 5 CI AGV-1 59.93 17.62 6.99 1.48 0.09 1.10 5.05 4.37 3. 18 0.49 less than 0.02 AGV-1* 59.72 17.22 6.92 1.55 0.10 1.05 5.00 4.31 2. 93 0.50 0.02 BRC-1 54.22 13.71 13.37 3.27 0.19 2.09 6.95 3.21 1. 86 0.33 less than 0.02 BRC-1* 54.85 13.68 13.51 3.48 0.19 2.22 6.98 3.29 1. 68 0.33 0.01 SY-3 60.53 11.62 6.58 2.55 0.35 0.16 8.02 3.98 4. 60 0.54 less than 0.02 SY-3* 59.68 11.80 6.47 2.64 0.33' 0.15 8.26 4.15 4. 24 0.54 0.01 TFP-1 7.57 1.81 0.50 5.19 0.206 0.087 47.97 1.42 0. 60 0.021 ' 1.30 TFP-1** 7.21 1.62 0.46 5.06 0.213 0.072 46.18 1.40 0. 59 0.030 1.26 TFP-2 22.22 5.04 1.37 4.15 0.576 0.217 33.37 2.97 1. ,83' 0.272 2.04 TFP-2** 21.92 4.95 1.42 4.18 0.568 0.217 33.58 3.02 1. 90 0.247 2.02 TFP-3 31.55 7.10 1.95 2.72 0.942 0.300 . 26.80 3.19 2. 64 0.121 2.19 TFP-3** 32.13 7.25 2.07 2.49 0.930 0.317 26.78 3.09 2. 64 0.131 2.42 TFP-4 44.47 10.01 2.79 1.89 .2.81 0.450 13.47 4.81 4. 19 0.999 3.51 TFP-4** 44.79 10.11 2.89 1.91 2.81 0.442 14.06 4.69 4. 15 0.893 3.25 TFP-5 51.70 11.56 3.32 0.83 5.70 0.517 6.27 6.97 4. 13 0.158 5,13 TFP-5** 52.06 11.75 3.35 0.75 5.49 0.517 6.30 6.98 4. 17 0.213 5.21 Table B. 1 Standards used for calibration in major element analyses, and recommended values. *values from Abbey, 1977 **values from Pedersen, 1979 for chlorine analysis poses several problems which may lead to a loss of chlor ine. Reaction with organic matter may, due to Its high react iv i t y , lead to the hydrolIzatlon of magnesium and sodium chorldes and subsequent loss of CI as vo lat i le HCI. Chlorine may also by lost through evaporation, as the melting point of NaCl (about 800°C) Is below the fusion temperature (1000°C). Possible loss of chlorine during sample fusion was countered by use of a flux with a low melting point; the Chemplex (Grade III) mixture used has a melting point at about 700°C (Norrlsh and Hutton, 1969). By Igniting the sediment In the presence of the flux It Is hoped that the blanket of f lux wi l l 'protect ' the sediment and allow the vo la t i le evolution to precede at a slower and more control led pace, thereby preventing excessive loss of ch lor ine . The methods used were not entirely successful , as Indicated by the difference between values obtained Independently by E.V. G r i l l (of the University of B r i t i sh Columbia) and those of th is study (Table B.2) . The chlorine problem was dealt with In detail by Pedersen (1979). Table B.2 Analyses of chlorine contents In Explorer Deep sediments. Sample / Chlorine concentration (wt. percent)  E.V. G r i l l * this study** 8/50-52 2.70 0.72 10/50-52 3.19 1 .18 22/5-6 2.98 0.30 22/30-31 2.09 0.48 31/110-112 3.19 0.92 * (of the University of Br i t ish Columbia) values obtained by leaching the sediment and t i t ra t ing the C l~ ; ** values obtained by XRF analysis on fused glass disks. - 2 2 7 -Calculation of Totals; As Weight Percent Oxides The overall quality of major elemental analyses performed Is measured roughly by the summation of equivalent weight percent oxides for each element, plus loss-on- lgnlt lon (Table C.1). A correction for oxygen excess due to chloride compounds (CI=0) was subtracted from the to ta ls . The totals range from 98.3$ to 102.7$, with the majority of the totals being greater than 100$. Several factors may contribute to the high summations: a possible overestI mat I on of K20 content (previously discussed); the flux may contain a vo lat i le component, which, when lost during sample fusion resulted in lower flux/sample rat ios , and thus an overestimat Ion of the elemental contents; the L i 2 B 4 O 7 flux was likely to have contained some water> adsorbed after the pre-Ignition at 400°C (Harvey et a I., 1973); the low-temperature of fusion used (1000°C) may be a factor as Norrish and Hutton (1969) showed that the fusion technique is sensitive to the temperature of fusion and that micro-segregation of elements occured if fusion temperature was below 950°C, resulting In Increased count rates (hence overestImat Ion of elemental contents). -228-Minor Elements Analyses of minor elements were performed on pressed powder discs (30.5 mm diameter). The discs were prepared by f i r s t l ightly grinding a i r -dr ied sediment with a mortar and pest le. 4 g of sediment was mixed with one drop of binding agent {2% poly vinyl alchohol: hydrollzed), then poured Into a stainless steel sleeve onto a highly polished tungsten-carbide d isc . The sleeve and disc were within a stainless steel powder press. Using a leuclte plunger, the sediment was compressed by hand Into a pe l le t . One tablespoon of sieved boric acid (analytical grade) was poured over the sediment pe l le t , a stainless steel plunger Inserted and the sample pressed In a hydraulic ram at 13 tons per square Inch for one minute. The pressure was released slowly and the sample removed, labelled, and stored In a dust-free container with the analytical face upwards. The matrix absorption coeff ic ient C u ' ) was determined after the method described by Reynolds (1963), In which the time taken to reach a speci f ic number of counts Is proportional to ' u f . In th is study ' u' was calculated at the SrKo<. radiation wavelength; four 20 second counts were averaged and the Inverse of the average counts/second (c .p .s . ) was calculated. The cal ibrat ion curve was constructed by plotting average c . p . s . versus ' u ' values for International rock standards; a b e s t - f i t l ine was determined by least-squares linear regression. The Reynolds method only applies to elements with K ot radiation line wavelengths shorter than the Iron absorption edge, which Includes a l l the minor elements analyzed except barium. - 2 2 9 -Reynolds method worked well for the calculation of Co, Cu and Zn concentrations. Calibration curves were a l l l inear, with correlation coeff ic ients close to one; equations for the b e s t - f i t lines were determined. The following format was used for calculation of element concentrations: X = Y - b m where X = elemental concentration Y = (element net c . p . s . ) sample - ' u ' sample (element net c . p . s . ) monitor - ' u ' monitor (net c . p . s . = peak c . p . s . - background c .p . s . ) b = Y Intercept for cal ibrat ion curve m = slope of cal ibrat ion l ine The calculation of nickel concentration Involved the use of the plain net counts/second ra t io , without the use of a mass absorption coef f i c ient . Without applying the ' u ' correction a linear cal ibrat ion curve was constructed using International rock standards, yet It proved to be quite Impossible to do so If a mass absorption correction was applied. This may be due to the closeness of the Nl Ko< wavelength to the Iron absorption edge; Reynolds (1963) considered nickel to be the cutoff . Barium concentrations were calculated without correcting for mass absorption. The Ba line was used for the Ba analyses, but because the Ba L X J l ine l ies on the shoulder of the TI K„< peak, the TI K « peak was also measured. The barium concentration was determined by: X = Y - b m where X = elemental concentration - 2 3 0 -Y = Ba c . p . s . Ba c . p . s . _ (TI c . p . s . ) (Ba c . p . s . ) _ (Ti c . p . s . ) (Ba c . p . s . ) mon i tor sample b = Y Intercept for barium cal ibrat ion curve m= slope of cal ibrat ion line The X-ray fluorescence analyses were performed at the University of Br i t ish Columbia, Department of Geological Sciences, on the following Instruments: Phi l ips PW 1410 X-ray Spectrometer, PW 1390 Channel Control , PW 8203 Single-pen Recorder, PW 1140/96 X-ray Generator. The X-ray Spectrometer has a four-posit ion sample holder (one posit ion was usually used for a monitor), and four analytical c rys ta ls : LIF200, LIF220, TLAP and PET. The operating conditions are l isted In Table B.3 for both the major and minor elements. No Independent chemical analyses were performed on sediments from the Explorer Deep area however, In a study of sediments from the Panama Basin, Pedersen (1979) estimated the analytical precision of X-ray fluorescence analyses for major and minor elements (Table B.4) . Chemical analyses performed In th is study used the same standards and a very s imilar sample preparation to that of Pedersen (1979), therefore the estimated total precision should be comparable. - 2 3 1 -ELEMENT TUBE kV ma CRYSTAL COUNTER COUNT TIME PEAK BACKGROUND PULSE HEIGHT COLLIMATOR VACUUM Al SAMPLE PREP. COMMENTS . & LINE (s) °2e °2S L.L. WINDOW FILTER A1K- Cr 50 40 TLAP f 3 X 10 37.56 39.50 240 600 coarse on out fused disk BaL-[ Cr 50 40 L1F200 F 3 X 10 87.19 91.20 300 500 f ine on out powder disk also measure TiKBi at 86.07° CaK« Cr 50 40 L1F200 F 3 X 4 113.17 116.50 220 700 f ine on out fused disk C1K» Cr 50 40 PET F 3 X 10 65.54 67.50 300 400 coarse on out fused disk CoK« W 50 40 LiF200 F 100 52.82 53.15 52.50 200 1 600 f ine on out powder disk on shoulder of FeKBi at 51.73° CuK« w 50 40 L1F200 F 3 X 40 45.06 45.60 44.70 200 600 f ine on out powder disk avoid WL«i at 43.02° FeK« Cr 50 40 Li F200 F 3 X 10 57.58 60.00 360 400 coarse on out fused disk KK« Cr 50 40 L1F200 F 3 X 10 136.70 133.80 200 .700 f ine on out fused disk MgK« Cr 50 40 TLAP F 100 44.95 43.85 250 450 coarse on out fused disk MnK« W 50 40 Li F200 . F 3 X 10 63.03 65.60 350 400 f ine on out fused disk MoK- W 50 40 Li F200 F 100 20.32 19.50 350 350 f ine on out powder disk avoid ZrKBi at 28.33° NaK« Cr 50 40 TLAP F 100 54.89 53.30 250 500 coarse on out fused disk NiK« W 50 40 L1F200 F 3 X 10 48.69 48.00 250 500 f ine on out powder disk PK« Cr 50 40 PET F 3 X 10 89.55 91.20 300 400 coarse on out fused disk S iK« Cr 50 40 TLAP F 3 X 10 31.88 29.00 240 600 coarse on out fused disk TiK- Cr 50 40 LiF200 F 3 X 10 86.22 88.60 300 560 coarse on out fused disk ZnK« w 50 40 HF200 F&S 3 X 10 41.83 42.40 41.30 300 400 f ine on out powder disk avoid CuKB at 40.45° and W at 43.36° compton Ho 60 40 LiFZOO S 4 X 20 21.13 none 200 600 f ine on out powder disk calculated at SrK« scatter & BaLB 2 wavelengths (MoK«) Table B.3 Analytical operating conditions used for XRF analysis of major and minor elements, F = flow; S = sc int i l la t ion counter; L.L. = lower leve l . Table B.4 (after Pedersen, 1979) X-ray fluorescence analytical precision for major and minor elements In Panama Basin sediments. ELEMENT ESTIMATED TOTAL PRECISION2 (as percent re lat ive standard deviation. 1o-) Al 0.6 Ba 2.5 Ca 0.7 CI 2 . 0 3 Co 4.0 Cu 2.5 Fe 0.5 K 0.8 Mg 1.2 Mn 2.0 Mo 6 . 0 4 Na 3.2 NI 3.0 P 2.5. SI 0.5 TI 3.0 Zn 3.0 The analyt ical precision for sediments from the Explorer Deep area should be similar to that for sediments from the Panama Basin. Includes counting error, disc reproducib i l i ty , error In choice and slope of each regression l ine, and error In mass absorption determinations (minor elements). Major element precision Is based mainly, on analyses by J .G . FItton of three duplicate discs of a wet chemically-analyzed sample. The large difference between chlor ine contents derived by leaching and t i t ra t ing the CI" and those obtained by XRF In th is study (Table B.2), Indicate that the chlorine precision quoted Is suspect. Increasing to about 30$ for concentrations <5 ppm Mo. - 2 3 3 -Corrections For Salt Contribution The presence of salt In marine sediments Interferes with chemical assays In two ways; sa l t acts to direct ly di lute the sediment, as well as contributing certain elements to the sediment. It Is therefore desirable to correct for the sal t content In the sediment samples. The technique for salt correction used In th is study was described by Pedersen (1979) and assumes that the chlorine content In the samples Is entirely due to the salt contribution (hence the CI content Is a measure of the sa l t content), and that the Interst i t ia l water sa l in i ty was 35 parts per m i l . Two samples were centrifuge-washed with d i s t i l l e d water (100 times the sediment weight) and analyzed for chlor ine; the chlorine concentration was below the detection l imit ( le . <0.02% CI), Indicating that Indeed sea water sa l t Is the main source of chlor ine. Sa l t - f ree elemental concentrations were calculated as follows: (wt. % N a ) s e d = (wt. % N a ) s e d + s a | + - 0.556(wt. % CI) 1 (wt. % Mg) s e ( J = (wt. % M g ) s e d + s a | + - 0.067(wt. % CI) (wt. % C a ) s e d = (wt. % C a ) s e d + s a | + - 0.021(wt. % CI) (wt. % K ) s e d = (wt. % K ) s e d + s a | + - 0.020(wt. % CI) The remaining elemental concentrations were then corrected for di lut ion using the following equation: ( W + * % X ) s e d = ( W + * % X ) s e d + sa l t (100 - 1 .82°(wt . % CI)' 1. Factors used were calculated by Pedersen (1979) using the composition of sea water calculated by Home (1969, p. 151). - 2 3 4 -APPENDIX C MlNERALOGICAL AND CHEMICAL DATA Sample names are In the form 1/40-42; which refers to core PGC 79-06-01 and sample Interval at 40 to 42 cm from top of core. Mlneraloglcal data l isted are areas of X-RD peaks In pre-treated oriented samples of <0.2 um, 0.2 to 2 um and 2 to 5 um size-fractIons, and In unorlented powder mounts of coarser s ize - f ract ions and total (bulk) samples of sediments from the Explorer Deep area. Major element analyses of sediments and volcanic glass from the Explorer Deep area are l isted on an uncorrected basis, as weight percent oxide equivalent, on a sa l t - f ree basis, and as element/aluminium ratios (of sa l t - f ree concentrations). Al l values are In weight percent. Minor element analyses of sediments and volcanic glass from the Explorer Deep area are l isted on an uncorrected basis, on a sa l t - f ree basis, and as element/aluminium rat ios (of sa l t - f ree concentrations). Al l values are In parts-per-ml11 Ion (ppm). - 2 3 5 -TABLE C.1 MINERALOGICAL DATA Areas of X-ray di f f ract ion peaks (mm ) for II l i t e , ch lor i te , quartz and smectite in oriented mounts of K-saturated, and Mg-saturated glycerol -solvated samples of <0.2 um, 0.2 to 2 um and 2 to 5 um s ize - f ract ions In sediments from the Explorer Deep area. Areas of X-ray di f f ract ion peaks (mm ) for total phyIloslIIcates, feldspars, and quartz In 5 to 20 um and >20 um s ize - f ract ions , and In total (bulk) sediments from the Explorer Deep area. -236-AREAS OF X-RAY DIFFRACTION PEAKS FOR K-SATURATED ORIENTED SAMPLES AREAS OF X-RAY DIFFRACTION PEAKS (mm2) <0.2 um FRACTION 0.2 to 2 um FRACTION 2 to 5 um FRACTION K+C 1 0 K+C 1 0 K+C I 0 SAMPLE (7ft) (10ft) (3.34ft) (7ft) (10ft) (3.34ft) (7ft) (10ft) (3.34ft) EDMS 0 0 0 60 0 t r 50 19 31 6/4-8 60 t r 0 178 139 127 158 132 124 6/20-24 na na na na na na 184 114 108 6/60-64 na na na na na na 182 132 132 6/120-124 96 t r 0 196 100 102 182 140 178 8/4-8 36 0 0 137 122 86 na na na 8/60-64 47 t r 0 137 83 83 na na na 10/4-8 79 0 0 153 117 108 181 150 167 10/20-24 na na na 162 144 97 191 94 143 10/60-64 na na na na na na 305 343 195 10/120-124 74 0 0 178 130 98 234 244 181 22/0-4 92 23 38 127 110 60 na na na 22/60-64 114 t r 0 188 273 130 na na na 31/4-8 na na na 120 127 64 na na na 31/66-70 na na na i 194 140 104 na na na 31/120-124 69 t r t r 165 330 154 na na na K+C=kaolInlte+chlorlte; l= I l l l te ; Q=quartz; tr=trace;na=not analyzed. AREAS OF X-RAY DIFFRACTION PEAKS FOR Mg-SATURATED, GLYCEROL SOLVATED ORIENTED SAMPLES AREAS OF X-RAY DIFFRACTION PEAKS (mm2) ; <0.2 um FRACTION 0 ,2 to 2 um FRACTION 2 to 5 urn FRACTION K+C I S 0 K+C I S Q K+C I S Q SAMPLE <7R> (10ft) (187?) (3.34ft) (7ft (10$) (18ft) (3.34ft) <7ft> (10ft) (18ft) (3.341 EDMS 0 0 1100 0 45 0 527 37 30 25 85 50 6/4-8 47 t r 295 0 192 85 320 110 120 52 59 90 6/20-24 260 t r 1910 0 137 72 118 59 140 57 t r 209 6/60-64 54 t r 870 0 98 36 196 51 160 72 93 134 6/120-124 39 t r 552 0 207 91 360 84 164 91 105 133 8/4-8 82 t r 1875 t r 89 52 159 86 97 43 36 66 8/60-64 92 t r 2400 0 166 77 320 54 136 60 60 84 10/4-8 79 0 1075 0 152 52 297 83 180 70 79 125 10/20-24 88 0 1368 0 155 48 167 67 165 77 38 96 10/60-64 130 34 1094 0 230 67 88 60 288 71 36 111 10/120-124 89 0 607 0 255 114 165 72 262 101 28 148 22/0-4 92 t r 1892 t r 115 42 248 73 104 41 61 86 22/60-64 160 t r 1116 0 222 68 53 59 180 53 12 118 31/4-8 218 t r 1732 32 124 42 164 58 127 61 86 73 31/66-70 254 53 3041 26 184 74 162 56 222 113 40 128 31/120-124 na na na na 174 40 t r 23 140 32 0 100 K+C=kaol Inlte+chlorlte; l = IIIIte; S=smectlte; Q=quartz; tr=trace; na=not analyzed. AREAS OF X-RAY DIFFRACTION PEAKS FOR UNORIENTED SAMPLES AREAS OF X-RAY DIFFRACTION PEAKS [mm2) 5 to 20 um FRACTION [0.2 to 2 um) FRACTION TOTAL [UNTREATED) clays F F Q Q clays F F Q a clay6 F F Q a SAMPLE [4.468] ( 3 . 2 0 8 ) (4.048) [3.348] [ 4 . 2 0 8 ] [4.468] [ 3 . 2 0 8 ) [4.048] [3.348] [4.268) [4.468] [ 3 . 2 0 8 ] (4.048) [3.348] [4.268] EDMS 174 189 76 165 50 318 100 35 154 47 420 114 19 185 42 6/4-8 30 331 94 508 106 tr 245 55 370 71 95 236 67 298 60 6/20-24 34 368 95 680 109 na na na na ne 111 197 60 270 58 6/60-64 8 415 116 355 107 na na na na na 82 209 64 239 97 8/120 -124 na na na na na na na na na na 75 190 70 304 64 8/4-8 30 352 104 555 104 18 445 97 530 137 62 164 55 230 55 8/20-24 na na na na na na na na na na 46 180 46 212 79 8/60-64 41 340 92 541 104 26 441 110 485 120 46 105 37 156 40 10/4-8 19 370 104 727 111 na na na na na 59 180 65 243 50 10/20-24 18 313 78 393 98 na na na na na 42 254 55 272 56 10/60-64 28 450 130 512 120 na na na na na 50 327 75 308 57 10/120-124 23 472 140 674 133 20 497 105 840 99 54 331 76 372 68 22/0-4 21 396 107 497 109 tr 401 52 395 101 na na na na na 22/10-12 na na na na na na na na na na 14 270 34 249 68 . 22/60-64 28 528 130 522 118 na na na na na 10 326 53 301 55 31/4-B 22 409 96 520 98 10 920 113 716 124 52 402 75 320 113 31/20-24 na na na na na na na na na na 27 361 76 312 52 31/66-70 35 387 80 476 100 21 648 96 650 140 33 224 58 341 56 31/103-105 na na na na na na na na na na 53 223 40 505 86 31/120-124 18 553 115 439 90 na na na na na 36 413 103 299 80 clBys=total phy I IOB 111 cat as; F=feldeper; Q=quartz; tr= trace; na=not analyzed. TABLE C.2 MAJOR ELEMENTAL COMPOSITION Data are expressed on an uncorrected basis, as equivalent weight percent oxides, on a sa l t - f ree basis, and as element/aluminium ratios (of s a l t -free concentrations). Al l values are In weight percent. LOI Is loss on Ignition. CI=0 Is correction for the addition of excess oxygen for the totals ca lcu lat ion . Bg Is a sample of dense volcanic glass (of the c h i l l margin on a basalt pillow) In dredge haul PGC-79-06-32 from Explorer Deep. Bv Is a sample of scorlaceous volcanic glass (of the c h i l l margin on a basalt pillow) In dredge haul PGC-79-06-32 from Explorer Deep. -240-SURFACE SEDIMENTS: UNCORRECTED MAJOR ELEMENT DATA, WEIGHT PERCENT ELEMENT. SAMPLE Si Al Fe Mg Mn Ti Na Ca K P CI LOI 1/0-2 23.88 6.72 4.95 1.85 0 .400 0 .450 4.68 1.60 1.51 0.067 2.97 11.97 2/0-2 25.40 7.58 4:65 1.85 0 .054 0 .481 3.70 1.62 1.66 0.034 1.93 10.39 4/0-2 24.91 7.08 4.80 1.85 0 .246 0 .493 3.78 2.11 1.52 0.055 2.00 11.68 6/0-2 24.49 7.00 5.01 1.81 0, .102 0 .454 4.71 1.63 1.43 0.050 2.50 12.47 7/0-2 25.06 7.63 5.19 1.93 0 .126 0 .495 3.46 1.95 1.73 0.045 1.21 9.63 8/0-2 24.97 6.88 5.15 1.85 0 .351 0 .469 4.20 1.90 1.50 0.063 3.54 8.84 10/0-2 25.28 7.15 4.68 1.80 0 .059 0 .473 3.67 2.01 1.64 0.044 2.87 10.31 21/0-2 25.58 7.20 4.96 1.89 0 .066 0 .467 4.59 1.75 1.45 0.053 2.80 9.53 22/0-1 28.97 7.96 4.42 1.35 0 .217 0 .378 2.78 2.74 1.42 0.041 0.08 5.07 29/0-5 24.76 6.86 4.70 1.80 0 .055 0 .467 4.33 2.05 1.46 0.038 2.87 11.82 30/0-2 25.74 7.04 4.99 1.79 0 .056 0 .482 3.95 1.83 1.57 0.041 1.64 11.28 31/0-2 26.43 8.02 4.89 1.73 0 .069 0 .480 3.60 2.91 1.37 0.045 1.08 7.85 SURFACE SEDIMENTS: UNCORRECTED MAJOR ELEMENT DATA, WEIGHT PERCENT OXIDE EQUIVALENT. SAMPLE S i0 2 A1 20 3 Fe ' 2 0 3 MgO MnO T i0 2 Na20 CaO K2 :0 P2 o 5 CI LOI C1=0 TOTAL 1/0-2 51.08 12.69 7. 08 3.07 0 .516 0.751 6.31 2.24 1. 82 0. 153 2 .97 11.97 0.67 99.98 2/0-2 54.33 14.32 6. 65 3.07 0 .070 0.802 5.00 2.27 2. 00 0. 078 1 .93 10.39 0.44 100.47 4/0-2 53.28 13.37 6. 86 3.07 0 .318 0.822 5.10 2.95 1. 83 0. 126 2 .00 11.68 0.45 100.96 6/0-2 52.38 13.21 7. 16 3.00 0 .132 0.758 6.35 2.28 1. 72 0. 115 2 .50 12.47 0.56 101.51 7/0-2 53.60 14.41 7. 42 3.20 0 .163 0.826 4.66 2.73 2. 08 0. 103 1 .21 9.63 0.27 99.76 8/0-2 53.41 13.00 7. 36 3.07 0 .453 0.782 5.66 2.66 1. 81 0. 144 3 .54 8.84 0.80 99.93 10/0-2 54.07 13.51 6. 69 2.98 0 .076 0.789 4.95 2.81 1. 98 0. 101 2 .87 10.31 0.65 100.49 21/0-2 54.72 13.60 7. 09 3.13 0 .085 0.779 6.19 2.45 1. 75 0. 121 2 .80 9.53 0.63 101.61 22/0-1 61.97 15.03 6. 32 2.20 0 .280 0.631 3.75 3.83 1. 71 0. 108 0 .08 5.07 0.02 100.96 29/0-5 52.96 12.96 6. 72 2.98 0 .071 0.779 5.84 2.87 1. 76 0. 087 2 .87 11.82 0.65 101.07 30/0-2 55.06 13.30 7. 14 2.97 0 .072 0.804 5.32 2.56 1. 89 0. 094 1 .64 11.28 0.37 101.76 31/0-2 56.53 15.15 6. 99 2.87 0 .089 0.801 4.85 4.07 1. 65 0. 103 1 .08 7.85 0.24 101.79 SURFACE SEDIMENTS: SALT-FREE MAJOR ELEMENT DATA, WEIGHT PERCENT. SAMPLE Si Al Fe Mg Mn Ti Na Ca K P CI LOI 1/0-2 25.24 7.10 5.23 1.74 0.423 0.476 3.20 1.63 1.53 0.071 2.97 11.97 2/0-2 26.32 7.86 4.82 1.78 0.056 0.499 2.73 1.68 1.68 0.035 1.93 10.39 4/0-2 25.85 7.35 4.98 1.78 0.246 0.512 2.79 2.15 1.54 0.057 2.00 11.68 6/0-2 25.66 7.33 5.25 1.72 0.107 0.476 3.48 1.66 1.45 0.052 2.50 12.47 7/0-2 25.62 7.80 5.31 1.89 0.129 0.506 2.85 1.96 1.75 0.046 1.21 9.63 8/0-2 26.69 7.35 5.50 1.72 0.375 0.501 2.38 1.96 1.53 0.067 3.54 8.84 10/0-2 26.67 7.54 4.94 1.70 0.062 0.499 2.18 2.06 1.67 0.046 2.87 10.31 21/0-2 26.95 7.59 5.23 1.79 0.070 0.492 3.19 1.78 1.46 0.056 2.80 9.53 22/0-1 29.01 7.97 4.43 1.35 0.217 0.379 2.78 2.74 1.42 0.041 0.08 5.07 29/0-5 26.12 7.24 4.96 1.70 0.058 0.493 2.88 2.10 1.48 0.040 2.87 11.82 30/0-2 26.53 7.26 5.14 1.73 0.058 0.494 3.13 1.86 1.59 0.042 1.64 11.28 31/0-2 26.96 8.18 4.99 1.69 0.070 0.490 3.06 2.95 1.38 0.046 1.08 7.85 SURFACE SEDIMENTS: MAJOR ELEMENT RATIOS TO ALUMINUM (SALTFREE). SAMPLE Si/Al Fe/Al Mg/Al Mn/Al Ti/Al Na/Al Ca/AI K/Al P/AI 1/0-2 3.555 0.737 0.245 0.060 0.067 0. 451 0.229 0. .215 0.010 2/0-2 3.349 0.613 0.226 0.007 0.063 0. 347 0.214 0. .214 0.004 4/0-2 3.517 0.678 0.242 0.033 0.070 0. 380 0.293 0. ,210 0.008 6/0-2 3.501 0.716 0.235 0.015 0.065 0. 475 0.226 0. ,198 0.007 7/0-2 3.285 0.681 0.242 0.017 0.065 0. 365 0.251 0. ,224 0.006 8/0-2 3.631 0.748 0.234 0.051 0.068 0. 324 0.267 0. ,208 0.009 10/0-2 3.537 0.655 0.225 0.008 0.066 0. 289 0.273 0. ,221 0.006 21/0-2 3.551 0.689 0.236 0.009 0.065 0. 420 0.235 0. ,192 0.007 22/0-1 3.640 0.556 0.169 0.027 0.048 0. 349 0.344 0. ,178 0.005 29/0-5 3.608 0.685 0.235 0.008 0.068 0. 398 0.290 0. ,204 0.006 30/0-2 3.654 0.708 0.238 0.008 0.068 0. 431 0.256 0. ,219 0.006 31/0-2 3.296 0.610 0.207 0.009 0.060 0. 374 0.361 0. ,169 0.006 CORE 79-06-06: UNCORRECTED MAJOR ELEMENT DATA, WEIGHT PERCENT ELEMENT. SAMPLE Si Al Fe Mg Mn Ti Na Ca K P CI LOI 6/0-2 24.49 7.00 5.01 1.81 0.102 0.454 4.71 1.63 1.43 0. 050 2.50 12.47 6/5-7 24.92 6.90 4.51 1.79 0.056 0.465 4.38 1.65 1.56 0. 032 1.30 12.10 6/10-12 25.13 7.29 4.77 1.81 0.044 0.473 4.46 1.63 1.68 0. 036 3.44 10.12 6/20-22 25.38 7.19 4.70 1.88 0.049 0.474 3.81 1.73 1.68 0. 037 2.25 10.16 6/30-32 25.29 6.89 4.72 1.81 0.059 0.455 4.59 1.68 1.52 0. 035 2.02 10.55 6/40-42 25.13 7.01 4.66 1.83 0.069 0.461 4.40 1.72 1.68 0. 041 2.03 10.84 6/50-52 25.15 7.25 4.87 1.85 0.066 0.470 4.05 1.71 1.68 0. 031 1.76 11.23 6/60-62 25.09 7.49 4.94 1.84 0.062 0.486 3.83 1.80 1.65 0. 026 1.64 10.26 6/70-72 25.62 7.43 4,. 91 1.93 0.067 0.482 4.03 1.87 1.71 0. 035 1.76 9.88 6/80-82 25.31 7.58 5.06 1.89 0.061 0.496 3.82 1.72 1.67 0. 041 1.00 11.36 6/90-92 25.11 7.55 5.02 1.89 0.066 0.495 3.71 1.86 1.77 0. 034 1.40 10.31 6/100-102 25.18 7.78 5.16 1.93 0.070 0.493 3.72 1.85 1.78 0. ,033 2.04 9.57 6/110-112 25.35 7.66 5.16 . 1.96 0.076 0.505 3.46 1.87 1.73 0. ,038 1.44 9.84 6/120-122 25.30 7.76 4.99 1.97 0.094 0.507 3.67 1.81 1.88 0. ,046 1.28 9.98 CORE 79-06-06: UNCORRECTED MAJOR ELEMENT DATA, WEIGHT PERCENT OXIDE EQUIVALENT. SAMPLE S i0 2 A1 2 0 3 Fe 2 0 3 MgO MnO T i0 2 Na20 CaO iO P2 >o5 CI LOI C1=0 TOTAL 6/0-2 52. 38 13.21 7.16 3.00 0 .132 0. 758 6.35 2 .28 1 .72 0. 115 2 .50 12. 47 0.56 101.51 6/5-7 53. 30 13.04 6.45 2.97 0 .072 0. 776 5.90 2 .31 1 .88 0. 073 1 .30 12. 10 0.29 99.88 6/10-12 53. 75 13.78 6.82 3.00 0 .057 0. 789 6.01 2 .28 2 .02 0. 082 3 .44 10. 12 0.78 101.37 6/20-22 54. 29 13.58 6.72 3.12 0 .063 0. 791 5.14 2 .43 2 .02 0. 085 2 .25 10. 16 0.51 100.14 6/30-32 54. 10 13.02 6.75 3.00 0 .076 0. 759 6.19 2 .35 1 .83 0. 080 2 .02 10. 55 0.46 100.26 6/40-42 53. 75 13.24 6.66 3.03 0 .089 0. 769 5.93 2 .41 2 .02 0. 094 2 .03 10. 84 0.46 100.40 6/50-52 53. 80 13.70 6.96 3.07 0 .085 0. 784 5.46 2 .39 2 .02 0.071 1 .76 11. 23 0.40 100.93 6/60-62 53. 67 14.14 7.06 3.05 0 .080 0. 811 5.16 2 .51 1 .99 0. 060 1 .64 10. 26 0.37 100.06 6/70-72 54. 82 14.03 7.02 3.20 0 .086 0. 812 5.43 2 .63 2 .06 0. 080 1 .76 9. 88 0.40 101.41 6/80-82 54. 14 14.32 7.24 3.13 0 .079 0. 827 5.15 2 .41 2 .01 0. 094 1 .00 11. 36 0.23 101.53 6/90-92 53. 71 14.26 7.18 3.13 0 .085 0. 826 5.00 2 .60 2 .13 0. 078 1 .40 10. 31 0.32 100.39 6/100-102 53. 86 14.70 7.38 3.20 0 .090 0. 822 5.01 2 .59 2 .14 0. 076 2 .04 9. 57 0.46 101.02 6/110-112 54. 22 14.47 7.38 3.25 0 .098 0. 842 4.66 2 .62 2 .08 0. 087 1 .44 9. 84 0.32 100.67 6/120-122 54. 12 14.66 7.14 3.27 0 .121 0. 846 4.95 2 .53 2 .27 0. 105 1 .28 9. 78 0.29 100.78 CORE 79-06-06: SALT-FREE MAJOR ELEMENT DATA, WEIGHT PERCENT. SAMPLE 6/0-2 6/5-7 6/10-12 6/20-22 6/30-32 6/40-42 6/50-52 6/60-62 6/70-72 6/80-82 6/90-92 6/100-102 6/110-112 6/120-122 Si 25.66 25.52 26.81 26.46 26.26 26.09 25.98 25.86 26.47 25.78 25.77 26.15 26.03 25.90 Al 7.33 .07 78 .50 15 7.28 7.49 7.72 7.68 7.72 7.75 8.08 7.87 7.95 Fe 5.25 4.62 5.09 4.90 4. 4. 5. 5. 5. 5. 5. 5. 90 84 03 09 07 15 15 36 Mg 1.72 1.74 1.69 1.80 5.30 5.11 .73 75 79 78 .87 1.85 1.85 1.86 1.91 1.92 Mn 0.107 0.057 0.047 0.051 0.061 0.072 0.068 0.064 0.069 0.062 0.068 0.073 0.078 0.096 Ti 0.476 0.476 0.505 0.494 0.472 0.479 0.486 0.501 0.498 0.505 0.508 0.512 0.519 0.519 Na 3.48 3.75 2.72 2.67 60 40 17 01 15 32 3.01 2.69 2.73 3.03 Ca 1.66 1.66 1.66 1.75 1.70 1.74 1.73 1.82 1.89 1.73 1.88 1.87 1.89 1.82 _K 1.45 1.57 1.72 1.71 1.54 1.70 1.69 1.67 1.73 1.68 1.79 1.81 1.75 1.89 0.052 0.033 0.038 0.039 0.036 0.043 0.032 0.027 0.036 0.042 0.035 0.034 0.039 0.047 CI 2.50 30 44 25 02 03 76 64 1.76 1.00 1.40 2.04 1.44 1.28 LOI 12.47 12.10 10.12 10.16 10.55 10.84 11.23 10.26 9.88 11.36 10.31 9.57 9.84 9.98 CORE 79-06-06: MAJOR ELEMENT RATIOS TO ALUMINUM (SALTFREE) SAMPLE Si/Al Fe/AI Mg/AI Mn/AI Ti/Al Na/AI Ca/AI K/AI P/AI 6/0-2 3..501 0.716 0.235 0.015 0.065 0. 475 0 .226 0 .198 0.007 6/5-7 3.610 0.653 0.246 0.008 0.067 0. 530 0 .235 0 .222 0.005 6/10-12 3.446 0.654 0.217 0.006 0.065 0. 350 0 .213 0 .221 0.005 6/20-22 3.528 0.653 0.240 0.007 0.066 0. 356 0 .233 • 0 .228 0.005 6/30-32 3.673 0.685 0.242 0.009 0.066 0. 503 0 .238 0 .215 0.005 6/40-42 3.584 0.665 0.240 0.010 0.066 0. 467 0 .239 0 .234 0.006 6/50-52 3.469 0.672 0.239 0.009 0.065 0. 423 0 .231 0 .226 0.004 6/60-62 3.350 0.659 0.231 0.008 0.065 0. 390 0 .236 0 .216 0.003 6/70-72 •3.447 0.660 0.243 0.009 0.065 0. 410 0 .246 0 .225 0.005 6/80-82 3.339 0.667 0.240 0.008 0.065 0. 430 0 .224 0 .218 0.005 6/90-92 3.325 0.665 0.239 0.009 0.066 0. 388 0 .243 0 .231 0.005 6/100-102 3.236 0.663 0.230 0.009 0.063 0. 333 0 .231 0 .224 0.004 6/110-112 3.307 0.673 0.243 0.010 0.066 0. 347 0 .240 0 .222 0.005 6/120-122 3.258 0.643 0.242 0.012 0.065 0. 381 0 .229 0 .238 0.006 CORE 79-06-08: UNCORRECTED MAJOR ELEMENT DATA, WEIGHT PERCENT ELEMENT. SAMPLE Si Al Fe Mg Mn Ti Na Ca K P CI LOI 8/0-2 24.97 6.88 5. 15 1.85 0.351 0.469 4. .20 1. 90 1 .50 0.063 3 .54 8. 84 8/5-7 25.69 7.36 4. 63 1.77 0.048 0.479 3. 98 2. 13 1 .60 0.037 1 .71 11. 34 8/10-12 25.46 7.04 4. 55 1.78 0.064 0.470 3. 88 2. 34 1 .56 0.033 2 .33 11. 49 8/20-22 24.46 6.40 4. 31 1.70 0.057 0.435 4. 20 2. 82 1 .42 0.024 2 .11 11. 54 8/30-32 25.27 7.19 4. 77 1.80 0.065 0.469 3. 45 2. 42 1 .65 0.041 1 .16 11. 25 8/40-42 25.26 7.44 5. 12 1.95 0.069 0.489 3. .91 2. 09 1 .68 0.037 2 .39 9. 47 8/50-52 25.22 7.42 4. 78 1.85 0.052 0.493 3. 52 2. 18 1 .67 0.034 0 .72 9. 12 8/60-62 25.09 7.59 5. 07 1.9.5 0.070 0.490 3. 77 2. 39 1 .72 0.049 1 .39 10. 84 8/70-72 24.56 7.48 4. 86 1.88 0.073 0.475 3. 26 2. 54 1 .65 0.042 0 .56 12. 27 8/80-82 25.35 7.75 5. 00 1.91 0.076 0.495 3. 63 2. 22 1 .75 0.024 1 .10 10. 74 8/90-92 25.37 7.74 5. 25 1.91 0.073 0.496 3. 54 2. 22 1 .77 0.042 1 .54 9. 98 8/90-92' 25.14 7.84 5. 10 1.90 0.073 0.496 3. 20 2. 21 1 .82 0.047 1 .23 9. 92 8/100-102 24.59 7.61 4. 97 1.92 0.072 0.501 3. 32 2. 64 1 .81 0.048 1 .95 9. 69 8/110-112 24.39 7.69 5. 34 1.92 0.065 0.508 3. 35 • 2. 68 1 .75 0.037 1 .29 10. 52 8/120-122 24.50 7.80 5. 33 1.97 0.069 0.498 3. .01 2. 95 1 .83 0.057 1 .86 9. 37 8/130-132 23.99 7.88 5. 31 2.02 0.072 0.503 3. 30 3. 02 1 .75 0.057 1 .84 10. 15 8/140-142 23.20 7.66 5. 24 2.04 0.093 0.467 3. 54 3. 95 1 .64 0.052 1 .06 11. 84 8/150-152 22.82 7.59 5. 03 2.00 0.100 0.469 3. 24 4. 60 1 .62 0.053 1 .15 11. 59 CORE 79-06-08: UNCORRECTED MAJOR ELEMENT DATA, WEIGHT PERCENT OXIDE EQUIVALENT. SAMPLE S i0 2 A1 2 0 3 Fe 2 0 3 MgO MnO T i0 2 Na20 CaO K20 P 2 0 5 CI LOI C1=0 TOTAL 8/0-2 53.41 13.00 7. 36 3.07 0 .453 0. 782 5. 66 2. 66 1 .81 0. 144 3 .54 8.84 0. 80 99. 93 8/5-7 54.95 13.90 6. 62 2.93 0 .062 0. 799 5. 36 2. 98 1 .93 0. 085 1 .71 11.34 0. 39 102. 28 8/10-12 54.46 13.30 6. 51 2.95 0 .083 0. 784 5. 23 3. 27 1 .88 0. 076 2 .33 11.49 0. 53 101. 83 8/20-22 54.46 12.09 6. 16 2.82 0 .074 0. 726 5. 66 3. 95 1 .71 0. ,055 2 .11 11.54 0. 48 100. 88 8/30-32 54.05 13.58 6. 82 2.98 0 .084 0. 782 4. 65 3. 39 1 .99 0. ,094 1 .16 11.25 0. 26 100. 57 8/40-42 54.03 14.05 7. 32 3.23 0 .089 0. 816 5. 27 2. 92 2 .02 0. 085 2, .39 9.47 0. 54 101. 15 8/50-52 53.95 14.03 6. 84 3.06 0 .067 0. 822 4. 74 3. 05 2 .01 0. 078 0 .72 9.12 0. 16 98. 33 8/60-62 53.66 14.34 7. 25 3.23 0.090 0. 817 5. 08 3. 34 2 .07 0. 112 1 .39 10.84 0. 31 101. 91 8/70-72 52.53 14.13 6. 95 3.12 0 .094 0. 792 4. 39 3. 55 1 .99 0. 096 0.56 12.27 0. 13 100. 34 8/80-82 54.22 14.65 7. 15 3.17 0 .098 0. 826 4. 89 3. 11 2 .10 0. 055 1. .10 10.74 0. 25 101. 86 8/90-92 54.28 •14.62 7. 51 3.17 0. .094 0. 827 4. 77 3. 11 2 .13 0. 096 1 .54 9.98 0. 35 101. 77 8/90-92' 53.77 14.81 7. 29 3.15 0. .094 0. 827 4. 31 3. 09 2 .19 0. 108 1 .23 9.92 0.28 100. 50 8/100-102 52.60 14.38 7. 11 3.18 0 .093 0. 836 4. 46 3. 69 2 .18 0. 110 1 .95 9.69 0. 44 99. 84 8/110-112 52.17 14.53 7. 64 3.18 0. .084 0.847 4. 52 3. 75 2 .11 0. 085 1, .29 10.52 0. 29 100. 44 8/120-122 52.41 14.73 7. 62 3.27 0 .089 0. 831 4. 07 4. 06 2 .20 0. 130 1. .86 9.37 0. 42 100. 22 8/130-132 51.31 14.89 7. 59 3.35 0 .093 0. 839 4. 45 4. 22 2 .11 0. 130 1, .84 10.15 0. 42 100. 55 8/140-142 49.62 14.47 7. 49 3.38 0 .120 0. 779 4. 77 5. 53 1 .98 0. 119 1 .06 11.84 0. 24 100. 92 8/150-152 48.81 14.34 7. 19 3.32 0 .129 0. 782 4. 37 6. 45 1 .95 0. 121 1 .15 11.59 0. 26 99. 94 CORE 79-06-08: SALT-FREE MAJOR ELEMENT DATA, WEIGHT PERCENT ELEMENT. SAMPLE Si Al Fe Mg Mn Ti Na Ca K P CI LOI 8/0-2 26.69 7.35 5.50 1.72 0.375 0. 501 2. 38 1, .96 1, .53 0 .067 3. 54 8. 84 8/5-7 26.52 7.60 4.79 1.71 0.050 0. 494 3. 13 2, .16 1. ,62 0 .038 1. 71 11. 34 8/10-12 26.59 7.35 4.75 1.69 0.067 0. 491 2. 69 2, .39 1. .58 0 .034 2. 33 11. 49 8/20-22 26.48 6.66 4.48 1.62 0.059 0. 452 3. 15 2, .89 1, .44 0 .025 2. 11 11. 54 8/30-32 25.81 7.34 4.87 1.77 0.066 0. 479 2. 87 2 .45 1, .67 0 .042 1. 16 11. 25 8/40-42 26.41 7.78 5.35 1.96 0.072 0. 511 2. 70 2, .13 1, .70 0 .039 2. 39 9. 47 8/50-52 25.55 7.52 4.84 1.82 .0.053 0. 500 3. 15 2, .19 1, .64 0 .034 0. 72 9. 12 8/60-62 25.74 7.79 5.20 1.91 0.072 0. 503 3. 08 2, .42 1. ,73 0 .050 1. 39 10. 84 8/70-72 24.81 7.56 4.91 1.86 0.074 0. 480 2. 98 2, .56 1, .66 0 .042 0. 56 : 12. 27 8/80-82 25.87 7.91 5.10 1.88 0.078 0. 505 3. 08 2, .24 1. ,77 0 .024 1. 10 10. 74 8/90-92 26.10 7.96 5.40 1.86 0.075 0. 510 2. 76 2, .25 1. .79 0 .043 1. 54 9. 98 8/90-92' 25.72 8.02 5.22 1.86 0.075 0. 507 2. 58 2, .23 1, .84 0 .048 1. 23 9. 92 8/100-102 25.49 7.89 5.15 1.86 0.075 0. 519 2. 32 2, .70 1. ,84 0 .050 1. 95 9. 69 8/110-112 24.98 7.87 5.47 1.87 0.067 0. 520 2. 69 2, .71 1, ,76 0 .038 1. 29 10. 52 8/120-122 25.36 8.07 5.52 1.91 0.071 0. ,515 2. 05 3, .01 1, .85 0 .059 1. 86 9. 37 8/130-132 24.82 8.15 5.49 1.97 0.074 0. 520 2. 36 3, .08 1, ,77 0 .059 1. 84 10. 15 8/140-142 23.66 7.81 5.34 2.01 0.095 0. 476 3. 01 4, .01 1, .65 0 .053 1. 06 11. 84 8/150-152 . 23.31 7.75 5.14 1.96 0.102 0. 479 2. 66 4, .68 1. ,63 0 .054 1. 15 11. 59 CORE 79-06-08: MAJOR ELEMENT RATIOS TO ALUMINUM (SALTFREE) SAMPLE Si/Al Fe/AI Mg/AI Mn/AI Ti/Al Na/AI Ca/AI K/AI P/AI 8/0-2 3.631 0.748 0.234 0.051 0.068 0. 324 0 .267 0 .208 0.009 8/5-7 3.489 0.630 0.225 0.007 0.065 0. 412 0 .284 0 .213 0.005 8/10-12 3.618 0.646 0.230 0.009 0.067 0. 366 0 .325 0 .215 0.005 8/20-22 3.976 0.673 0.243 0.009 0.068 0.473 0 .434 0 .216 0.004 8/30-32 3.516 0.663 0.241 0.009 0.065 0. 391 0 .334 0 .228 0.006 8/40-42 3.395 0.688 0.252 0.009 0.066 0. 347 0 .274 0 .219 0.005 8/50-52 3.398 0.644 0.242 0.007 0.066 0. 419 0 .291 0 .218 0.005 8/60-62 3.304 0.668 0.245 0.009 0.065 0. 395 0 .317 0 .222 0.006 8/70-72 3.282 0.649 0.246 0.010 0.063 0. 394 0 .339 0 .220 0.006 8/80-82 3.271 0.645 0.238 0.010 0.064 0. 389 0 .283 0 .224 0.003 8/90-92 3.279 0.678 0.234 0.009 0.064 0. 347 0 .283 0 .225 0.005 8/90-92' 3.207 0.651 0.232 0.009 0.063 0. 322 0 .278 0 .229 0.006 8/100-102 3.231 0.653 0.236 0.010 0.066 0. 294 0 .342 0 .233 0.006 8/110-112 3.174 0.695 0.238 0.009 0.066 0. 342 0 .344 0 .224 0.005 8/120-122 3.143 0.684 0.237 0.009 0.064 0. 254 0 .373 0 .229 0.007 8/130-132 3.045 0.674 0.242 0.009 0.064 0. 290 0 .378 0 .217 0.007 8/140-142 3.029 0.684 0.257 0.012 0.061 0. 385 0 .513 0 .211 0.007 8/150-152 3.008 0.663 0.253 0.013 0.062 0. 343 0 .604 0 .210 0.007 CORE 79-06-10: UNCORRECTED MAJOR ELEMENT DATA, WEIGHT PERCENT ELEMENT. SAMPLE Si Al Fe Mg Mn Ti Na Ca K P CI LOI 10/0-2 25.28 7.15 4.68 1.80 0.059 0.473 3.67 2.01 1.64 0 .044 2.87 10.31 10/5-7 25.92 7.22 4.57 1.66 0.046 0.470 3.89 2.32 1.68 0 .045 1.84 10.35 10/5-7' 25.73 7.15 4.61 1.79 0.056 0.461 3.86 2.56 1.60 0 .041 1.55 11.05 10/10-12 25.42 7.37 4.93 1.89 0.052 0.487 3.47 2.54 1.74 0 .031 1.99 9.41 10/15-17 25.83 7.09 4.76 1.78 0.048 0.473 3.44 2.45 1.64 0 .037 1.42 10.06 10/20-22 25.08 7.64 4.97 1.93 0.072 0.493 3.22 2.71 1.68 0 .049 0.97 9.16 10/25-27 24.76 8.17 4.59 2.17 0.094 0.534 2.99 3.81 1.73 0 .064 1.52 6.92 10/30-32 24.80 8.74 5.60 2.23 0.058 0.552 3.60 3.80 1.68 0 .068 0.37 6.72 10/40-42 24.31 8.21 5.28 2.07 0.092 0.499 2.84 4.38 1.85 0 .056 1.24 7.78 10/50-52 24.31 8.18 5.26 2.13 0.087 0.501 2.96 4.52 1.85 0 .063 1.18 8.32 10/60-62 no data due to error during sample preparation 10/70-72 24.74 8.57 5.60 2.30 0.113 0.560 3.16 3.60 1.82 0 .074 0.51 5.04 10/80-82 25.27 8.84 5.58 2.22 0.115 0.555 3.30 3.65 1.86 0 .060 0.83 5.45 10/90-92 24.67 8.58 5.40 2.12 0.077 0.510 2.73 3.66 2.06 0 .053 1.00 7.40 10/100-102 24.77 8.30 5.54 2.07 0.072 0.502 3.23 3.83 1.88 0 .053 0.88 8.37 10/110-112 24.58 8.39 5.19 2..11 0.073 0.518 2.88 3.89 1.81 0 .044 0.80 7.40 10/120-122 25.07 8.52 5.33 2.14 0.081 0.536 2.82 3.41 1.84 0 .053 0.98 7.20 10/130-132 24.88 8.63 5.73 2.21 0.079 0.532 2.88 3.10. 1.91 0 .065 0.96 5.88 CORE 79-06-10: UNCORRECTED MAJOR ELEMENT DATA, WEIGHT PERCENT OXIDE EQUIVALENT. SAMPLE S i0 2 A1 2 0 3 Fe 2 0 3 MgO MnO T i0 2 Na20 CaO K2 o P2 o 5 CI LOI C1=0 TOTAL 10/0-2 54.07 13.51 6.69 2.98 0.076 0.789 4.95 2. 81 1. 98 0. 101 2 .87 10.31 0.65 100.49 10/5-7 55.44 13.64 6.54 2.75 0.059 0.784 5.24 3. 25 2. 02 0. 076 1 .84 10.35 0.42 101.57 10/5-7' 55.04 13.51 6.59 2.97 0.072 0.769 5.20 3. 58 1. 93 0. 103 1 .55 11.05 0.35 102.01 10/10-12 54.37 13.92 7.05 3.13 0.067 0.812 4.68 3. 55 2. 10 0. 094 1 .99 9.41 0.45 100.72 10/15-17 55.26 13.39 6.81 2.95 0.062 0.789 4.64 3. 43 1. 98 0. 071 1 .42 10.06 0.32 100.54 10/20-22 53.65 14.43 7.11 3.20 0.093 0.822 4.34 3. 79 2. 02 0. 085 0 .97 9.16 0.22 99.45 10/25-27 52.96 15.43 6.56 3.59 0.121 0.891 4.03 5. 33 2. 08 0. 112 1 .52 6.92 0.34 99.20 10/30-32 53.05 16.51 8.01 3.69 0.075 0.921 4.85 5. 32 2. 02 0. 147 0 .37 6.72 0.08 101.60 10/40-42 52.00 15.51 7.55 3.43 0.119 0.832 3.83 6. 13 2. 23 0. 156 1 .24 7.78 0.28 100.53 10/50-52 52.00 15.45 7.52 3.53 0.112 0.836 3.99 6. 32 2. 23 0. 128 1 .18 8.32 0.27 101.35 10/60-62 no data 10/70-72 52,92 16.19 8.01 3.81 0.146 0.934 4.26 5. 04' 2. 19 0. 169 0 .51 5.04 0.12 99.10 10/80-82 54.05 16.70 7.98 3.67 0.148 0.926 4.45 5. 11 2. 24 0. 137 0 .83 5.45 0.19 101.50 10/90-92 52.77 16.21 7.72 3.51 0.099 0.851 3.68 5. 12 2. 48 0. 121 1 .00 7.40 0.23 100.73 10/100-102 52.98 15.68 7.92 3.43 0.093 0.837 4.35 5. 36 2. 26 0. 121 0 .88 8.37 0.20 102.08 10/110-112 52.58 15.85 7.42 3.49 0.094 0.864 3.88 5. 39 2. 18 0. 101 0 .80 7.40 0.18 99.87 10/120-122 53.62 16.09 7.62 3.54 0.105 0.894 3.80 4. 78 2. 22 0. 121 0 .98 7.20 0.22 100.75 10/130-132 53.22 16.30 8.19 3.66 0.102 0.887 3.88 4. 35 2. 30 0. 149 0 .96 5.88 0.22 99.66 CORE 79-06-10: SALT-FREE MAJOR ELEMENT DATA, WEIGHT PERCENT ELEMENT. SAMPLE Si Al Fe Mg Mn Ti Na Ca K P CI LOI 10/0-2 26.67 7.54 4.94 1.70 0.062 0.499 2.18 2.06 1.67 0.046 2.87 10.31 10/5-7 26.82 7.47 4.73 1.59 0.048 0.486 2.97 2.36 1.70 0.047 1.84 10.35 10/5-7' 26.48 7.36 4.74 1.74 0.058 0.474 3.09 2.60 1.62 0.042 1.55 11.05 10/10-12 26.38 7.65 5.12 1.83 0.054 0.505 2.45 2.59 1.76 0.032 1.99 9.41 10/15-17 26.52 7.28 4.89 1.72 0.049 0.486 2.72 2.48 1.65 0.038 1.42 10.06 10/20-22 25.53 7.78 5.06 1.89 0.073 0.502 2.73 2.74 1.70 0.050 0.97 9.16 10/25-27 25.46 ~ 8.40 4.72 2.13 0.097 0.549 2.20 3.89 1.75 0.066 1.52 6.92 10/30-32 24.97 8.80 5.64 2.22 0.058 0.556 3.41 3.82 1.68 0.068 0.37 , 6.72 10/40-42 24.87 8.40 5.40 2.04 0.094 0.511 2.20 4.45 1.87 0.057 1.24 7.78 10/50-52 24.84 8.36 5.38 2.09 0.089 0.512 2.35 5.11 1.87 0.064 1.18 8.32 10/60-62 no data 10/70-72 24.97 8.65 5.65 2.29 0.114 0.565 2.91 3.62 1.83 0.075 0.51 5.04 10/80-82 25.66 8.98 5.67 2.19 0.117 0.564 2.88 3.69 1.87 0.061 0.83 5.45 10/90-92 25.13 8.74 5.50 2.09 0.078 0.519 2.21 3.71 2.08 0.054 1.00 7.40 10/100-102 25.17 8.44 5.63 2.04 0.073 0.510 2.78 3.87 1.89 0.054 0.88 8.37 10/110-112 24.94 8.51 5.27 2.09 0.074 0.526 2.48 3.93 1.82 0.045 0.80 7.40 10/120-122 25.53 8.67 5.43 2.14 0.082 0.546 2.32 3.46 1.85 0.054 0.98 7.20 10/130-132 25.32 8.78 5.83 2.19 0.080 0.541 2.39 3.13 1.92 0.066 0.96 5.88 CORE 79-06-10: MAJOR ELEMENT RATIOS TO ALUMINUM (SALTFREE) SAMPLE Si/Al Fe/AI Mg/AI Mn/AI Ti/Al Na/AI Ca/AI K/AI P/AI 10/0-2 3.537 0.655 0.225 0.008 0. .066 0. 289 0 .273 0.221 0,.006 10/5-7 3.590 0.633 0.213 0.006 0, .065 0. 398 0 .316 0.228 0.006 10/5-7' 3.598 0.644 0.236 0.008 0, .064 0. 420 0 .353 0.220 0.006 10/10-12 3.448 0.669 0.239 0.007 0. .066 0. 320 0 .339 0.230 0.004 10/15-17 3.643 0.672 0.236 0.007 0. .067 0. 374 0 .341 0.227 0.005 10/20-22 3.281 0.650 0.243 0.009 0, .065 0. 351 0 .352 0.219 0.006 10/25-27 3.031 0.562 0.254 0.012 0. .065 0. 262 0 .463 0.208 0.008 10/30-32 2.838 0.641 0.252 0.007 0. .063 0. 388 0 .434 0.191 0.008 10/40-42 2.961 0.643 0.243 0.011 0. .061 0. 262 0 .530 0.223 0.007 10/50-52 2.971 0.644 0.250 0.011 0. .061 0. 281 0 .611 0.224 0.008 10/60-62 no data 10/70-72 2.887 0.653 0.265 0.013 0. .065 0. 336 0 .418 0.212 0.009 10/80-82 2.857 0.631 0.244 0.013 0. .063 0. 321 0 .411 0.208 0.007 10/90-92 2.875 0.629 0.239 0.009 0. .059 0. 253 0 .424 0.238 0.006 10/100-102 2.982 0.667 0.242 0.009 0, .060 0. 329 0 .459 0.224 0.006 10/110-112 2.931 0.619 0.246 0.009 0, .062 0. 291 0 .462 0.214 0.005 10/120-122 2.945 0.626 0.247 0.009 0, .063 0. 268 0 .399 0.213 0.006 10/130-132 2.884 0.664 0.249 0.009 0. .062 0. 272 0 .356 0.219 0.008 CORE 79-06-22: UNCORRECTED MAJOR ELEMENT DATA, WEIGHT PERCENT ELEMENT. SAMPLE Si Al Fe Mg Mn Ti Na Ca K P CI LOI 22/0-1 28.97 7.96 4.42 1.35 0.217 0, .378 2.78 2.74 1.42 0 .041 0.08- 5.07 22/5-6 28.44 8.07 4.67 1.44 0.108 0, .421 3.02 2.53 1.53 0 .043 0.30 6.14 22/10-11 19.46 5.97 4.12 1.59 0.095 0, .347 2.60 "12.46 1.18 0 .046 0.96 17.39 22/15-16 25.76 7.94 4.76 1.69 0.063 0, .466 3.30 4.98 1.49 0 .052 0.67 7.89 22/20-21 26.24 8.19 5.74 2.00 0.101 ' 0. .493 3.64 3.51 1.55 0 .071 0.61 5.01 22/25-26 26.12 8.96 5.22 2.04 0.097 0, .535 3.29 3.74 1.55 0 .070 0.46 4.69 22/30-31 27.48 8.36 4.44 1.70 0.075 0, .480 3.13 3.77 1.57 0 .052 0.48 4.46 22/35-36 25.56 8.26 4.86 1.92 0.074 0, .531 2.68 4.39 1.79 0 .063 0.62 7.71 22/40-41 27.32 7.86 3.97 1.51 0.052 0, .444 3.22 4.26 1.48 0 .028 0.55 5.83 22/45-46 26.09 8.13 4.51 1.64 0.055 0, .453 2.69 3.86 1.49 0 .051 0.52 9.25 22/50-51 . 25.54 8.17 4.96 1.92 0.081 0, .514 2.75 4.95 1.53 0 .081 0.57 6.39 22/60-61 26.32 8.54 4.81 1.84 0.077 0, .514 2.65 3.84 1.66 0 .059 <0.02 6.51 CORE 79-06-22: UNCORRECTED MAJOR ELEMENT DATA, WEIGHT PERCENT OXIDE EQUIVALENT. SAMPLE S i0 2 A1 2 0 3 Fe 2 0 3 MgO MnO T i0 2 Na20 CaO K2 0 P2 o 5 CI LOI CI =0 TOTAL 22/0-1 61.97 15.03 6.32 2.20 0.280 0.631 3.75 3. .83 1. 71 0. 108 0 .08 5. 07 0. 02 100.96 22/5-6 60.83 15.24 6.68 2.38 0.139 0.702 4.07 3. .54 1. 84 0. 096 0 .30 6. 14 0. 07 101.89 22/10-11 41.62 11.28 5.89 2.63 0.123 0.579 3.50 17. ,44 1. 42 0. 105 0 .96 17. 39 0. 22 102.72 22/15-16 55.10 14.99 6.81 2.80 0.081 0.777 4.45 6. .97 1. 80 0. 119 0 .67 7. 89 0. 15 102.31 22/20-21 56.13 15.48 8.21 3.30 0.130 0.822 4.91 4. ,91 . 1. 87 0. 163 0 .61 5. 01 0. 14 101.41 22/25-26 55.87 16.93 7.46 3.38 0.125 0.892 4.43 5. .23 1. 87 0. 160 0 .46 4. 69 0. 10 101.40 22/30-31 58.78 15.78 6.35 2.82 0.097 0.801 4.22 5. ,27 1. 89 0. 119 0 .48 4. 46 0. 11 100.96 22/35-36 54.67 15.61 6.95 3.18 0.096 0.886 3.61 6. ,14 2. 16 0. 144 0 .62 7. 71 0. 14 101.64 22/40-41 58.44 14.85 5.68 2.50 0.067 0.741 4.34 5. ,96 1. 78 0. 064 0 .55 5. 83 0. 12 100.68 22/45-46 55.81 15.36 6.45 2.72 0.071 0.756 3.63 5. ,40 1. 80 0. 117 0 .52 9. 25 0. 12 101.76 22/50-51 54.63 15.44 7.09 3.18 0.105 0.857 3.71 6. ,93 1. 84 0. 185 0 .57 6. 39 0. 13 100.80 22/60-61 56.30 16.14 6.88 3.05 0.099 0.857 3.57 5. ,37 2. 00 0. 135. <0 .02 6. 51 0 100.91 CORE 79-06-22: SALT-FREE MAJOR ELEMENT DATA, WEIGHT PERCENT ELEMENT. SAMPLE Si Al Fe Mg Mn Ti Na Ca K P CI LOI 22/0-1 29.01 7.97 4.43 1.35 0.217 0.379 2.78 2.74 1.42 0.041 0.08 5.07 22/5-6 28.60 8.11 4.70 1.43 0.109 0.423 2.86 2.53 1.53 0.043 0.30 6.14 22/10-11 19.81 6.08 4.19 1.56 0.097 0.353 2.10 12.66 1.18 0.047 0.96 17.39 22/15-16 26.08 8.04 4.82 1.67 0.064 0.472 2.97 5.05 1.50 0.053 0.67 7.89 22/20-21 26.53 8.28 5.80 1.98 0.102 0.499 3.34 3.54 1.56 0.072 0.61 5.01 22/25-26 26.34 9.04 5.26 2.03 0.098 0.540 3.06 3.76 1.55 0.071 0.46 4.69 22/30-31 27.72 8.43 4.48 1.68 0.076 0.484 2.89 3.79 1.57 0.052 0.48 4.46 22/35-36 25.85 8.35 4.92 1.90 0.075 0.537 2.37 4.43 1.80 0.064 0.62 7.71 22/40-41 27.60 7.94 4.01 1.48 0.053 0.448 2.94 4.29 1.48 0.028 0.55 5.83 22/45-46 • 26.34 8.21 4.55 1.63 0.056 0.457 2.42 3.89 1.49 0.051 0.52 9.25 22/50-51 25.81 8.26 5.01 1.90 0.082 0.519 2.46 4.99 1.54 0.082 0.57 6.39 22/60-61 26.32 8.54 4.81 1.84 0.077 0.514 2.65 3.84 1.66 0.059 <0.02 6.51 CORE 79-06-22: MAJOR ELEMENT RATIOS TO ALUMINUM (SALTFREE) SAMPLE Si/Al Fe/Al Mg/Al Mn/Al Ti/Al Na/Al Ca/AI K/Al P/AI 22/0-1 3.640 0.556 0. 169 0.027 0.048 0.349 0 .344 0. 178 0.005 22/5-6 3.527 0.580 0. 176 0.013 0.052 0.353 0 .312 0. 189 0.005. 22/10-11 3.258 0.689 0. 257 0.016 0.058 0.345 2 .082 0. 194 0.008 22/15-16 3.244 0.600 0. 208 0.008 0.059 0.369 0 .628 0. 187 0.007 22/20-21 3.204 0.700 0. 239 0.012 0.060 0.403 0 .428 0. 188 0.009 22/25-26 2.914 0.582 0. 225 0.011 0.060 0.338 0 .416 0. 171 0.008 22/30-31 3.288 0.531 0. 199 0.009 0.057 0.343 0 .450 0. 186 0.006 22/35-36 3.096 0.589 0. 228 0.009 0.064 0.284 0 .531 0. 216 0.008 22/40-41 3.476 0.505 0. 186 0.007 0.056 0.370 0 .540 0. 186 0.004 22/45-46 3.208 0.554 0. 199 0.007 0.056 0.295 0 .474 0-. 181 0.006 22/50-51 3.125 0.607 0. 230 0.010 0.063 0.298 0 .604 0. 186 0.010 22/60-61 3.082 0.563 0. 215 0.009 0.060 0.310 0 .450 0. 194 0.007 CORE 79-06-31: UNCORRECTED MAJOR ELEMENT DATA, WEIGHT PERCENT ELEMENT. SAMPLE Si Al Fe Mg Mn Ti Na Ca K P CI LOI 31/0-2 26. 43 8.02 4. .89 1 .73 0 .069 0 .480 3. 60 2. 91 1 .37 0, .045 1 .08 7. 85 31/5-7 25. 18 8.36 5. .28 2 .12 0 .077 0 .534 3. 25 3. 82 1 .64 0, .076 1 .28 5. 78 31/10-12 24. 93 8.88 5. .43 2 .17 0 .081 0 .570 3. 79 3. 52 1 .77 0. .085 1 .13 5. 22 31/20-22 25. 03 8.69 5, .55 2 .23 0 .084 0 .556 3. 51 3. 42 1 .77 0, .073 0 .80 5. 33 31/30-32 23. 71 8.34 5. .21 2 .07 0 .080 0 .527 3. 26 3. 94 1 .76 0. .077 1 .38 7. 59 31/40-42 25. 44 8.51 5. .44 1 .98 0 .080 0 .535 3. 40 2. 87 1 .98 0. ,077 0 .88 5. 93 31/50-52 25. 57 8.47 5. .52 1 .96 0 .078 0 .527 3. 08 3. 15 1 .84 0, .082 0 .73 5. 52 31/60-62 24. 38 8.22 5. .23 2 .00 0 .088 0 .508 3. 27 4. 38 1 .72 0. .057 0 .21 •8. 32 31/65-67 24. 77 8.44 4. .91 1 .79 0 .049 0 .553 2. 73 4. 25 2 .06 0. .060 1 .32 8. 80 31/70-72 25. 44 8.46 5. .01 1 .91 0 .081 0 .498 3. 02 3. 92 1 .78 0. .072 0 .63 6. 77 31/80-82 26. 27 8.61 5. .10 1 .99 0 .078 0 .516 3. 66 3. 75 1 .61 0. .067 0 .52 4. 47 31/90-92 27. 14 8.58 4. .61 1 .73 0 .069 0, .489 3. 18 3. 78 1 .58 0. ,061 1 .02 4. 22 31/100-102 26. 03 8.77 5. ,39 2 .13 0 .088 0 .549 3. 48 3. 73 1 .59 0. ,086 0 .84 3. 99 31/103-105 26. 07 8.89 4. ,65 1 .69 0 .038 0, .571 1. 96 2. 38 2 .64 0, ,054 0 .40 9. 21 31/110-112 25. 50 8.80 5. ,59 2 .20 0 .086 0 .559 3. 66 3. 66 1 .66 0. ,076 0 .92 4. 54 31/120-122 26. 41 8.65 5. ,09 1 .94 0 .089 0, .502 3. 57 3. 65 1 .57 0. ,067 0 .44 4. 25 31/130-132 25. 10 8.58 5. .28 2 .06 0 .080 0 .542 3. 44 4. 02 1 .64 0. ,085 0 .58 4. 96 31/140-142 26. 48 8.79 5. .17 1 .93 0 .083 0-.519 3. 18 3. 60 1 .73 0, ,077 0 .49 4. 44 31/150-152 25. 23 8.61 5, .44 2 .11 0 .098 0 .538 3. 26 3. 38 1 .72 0, ,087 0 .31 4. 88 31/160-162 25. 03 8.56 4. ,86 1 .94 0 .060 0 .542 2. 49 4. 47 1 .96 0, ,078 0 .61 7. 77 CORE 79-06-31: UNCORRECTED MAJOR ELEMENT DATA, WEIGHT PERCENT OXIDE EQUIVALENT. SAMPLE S i0 2 A1 2 0 3 Fe 2 0 3 MgO MnO T i0 2 Na i20 CaO K; ?o P2 o 5 CI LOI C1=0 TOTAL 31/0-2 56.53 15.15 6.99 2.87 0.089 0 .801 4. 85 4. 07 1 .65 0. 103 1 .08 7.85 0.24 101.79 31/5-7 53.86 .15.79 7.55 3.51 0.099 0 .891 4. 38 5. 34 1 .98 0. 174 1 .28 5.78 0.29 100.34 31/10-12 53.33 16.77 7.76 3.60 0.105 0 .951 5. 11 4. 94 2 .13 0. 195 1 .13 5.22 0.25 100.99 31/20-22 53.54 16.42 7.94 3.70 0.108 0 .927 4. 73 4. 78 2 .13 0. 167 0 .80 5.33 0.18 100.39 31/30-32 50.72 15.75 7.45 3.43 0.103 0 .879 4. 39 5. 51 2 .12 0. 176 1 .38 7.59 0.31 99.19 31/40-41 54.42 16.08 7.78 3.28 0.103 0 .892 4. 58 4. 02 2 .39 0. 176 0 .88 5.93 0.20 100.33 31/50-52 54.69 16.00 7.89 3.25 0.101 0 .879 4. 15 4. 41 2 .22 0. 188 0 .73 5.52 0.16 99.87 31/60-62 52.15 15.53 7.48 3.32 0.114 0 .847 4. 41 6. 13 2 .07 0. 131 0.21 8.32 0.05 100.66 31/65-67 52.98 15.94 7.02 2.97 0.063 0 .922 3. 68 5. 95 2 .48 0. 137 1 .32 8.80 0.30 101.96 31/70-72 54.42 15.98 7.16 3.17 0.105 0 .831 4. 07 5. 48 2 .14 0. 165 0 .63 6.77 0.14 100.78 31/80-82 56.19 16.26 7.29 3.30 0.101 0 .861 4. 93 5. 25 1 .94 0. 153 0 .52 4.47 0.12 101.14 31/90-92 58.05 16.21 6.59 2.87 0.089 0 .816 4. 29 5. 29 1 .90 0. 140 1 .02 4.22 0.23 101.25 31/100-102 ' 55.68 16.57 7.71 3.53 0.114 0 .916 4. 69 5. 22 1 .92 0. 197 0 .84 3.99 0.19 101.19 31/103-105 55.76 16.79 6.65 2.80 0.049 0 .952 2. 64 3. 33 3 .18 0. 124 0 .40 9.21 ' 0.09 101.79 31/110-112 54.54 16.62 7.99 3.65 0.111 0 .932 4. 93 5. 12 2 .00 0. 174 0 .92 4.54 0.21 101.32 31/120-122 56.49 16.34 7.28 3.22 0.115 0 .837 4. 81 5. 11 1 .89 0. 153 0 .44 4.25 0.10 100.83 31/130-132 53.69 16.21 7.55 3.42 0.103 0 .904 4. 64 5. 62 1 .98 0. 195 0 .58 4.96 0.13 99.72 31/140-142 56.64 16.60 7.39 3.20 0.107 0 .904 4. 29 5. 04 2 .08 0. 176 0 .49 4.44 0.11 101.25 31/150-152 53.97 16.26 7.78 3.50 0.127 0 .897 4. 39 4. 73 2 .07 0. 199 0 .31 4.88 0.07 99.04 31/160-162 53.54 16.17 6.95 3.22 0.077 0 .904 3. 36 6. 27 2 .36 0. 179 0 .61 7.77 0.14 101.27 CORE 79-06-31: SALT-FREE MAJOR ELEMENT DATA, WEIGHT PERCENT ELEMENT. SAMPLE Si Al Fe Mg Mn Ti Na Ca K P CI LOI 31/0-2 26. 96 8.18 4. 99 1. .69 0 .070 0 .490 3, .06 2, .95 1, .38 0, .046 1 .08 7. 85 31/5-7 25. 78 8.56 5. 41 2. .08 0 .079 0 .547 2. .60 3. ,88 1. .65 0, .078 1 .28 5. 78 31/10-12 25. 45 9.07 . 5. 54 2, .13 0 .083 0 .582 3. .23 3. .57 1. .79 0. .087 1 .13 5. 22 31/20-22 25. 40 8.82 5. 63 2. .21 0 .085 0 .564 3. .12 3. ,45 1. .78 0. .074 0 .80 5. 33 31/30-32 24. 32 8.55 5. 34 2. .03 0 .082 0 .541 2. ,55 4. ,01 1. .77 0. .080 1 .38 7. 59 31/40-42 25. 85 8.65 5. 53 1, .95 0 .081 0 .544 2. ,96 2. ,90 1. .99 0, .078 0 .88 5. 93 31/50-52 25. 91 8.58 5. 59 1. .94 0 .079 0 .534 2. .71 3. ,17 1. .84 0. .083 0 .73 5. 52 31/60-62 24. 47 8.25 5. 25 2. .00 0 .088 0 .510 3. .16 4. ,40 1. .73 0. .057 0 .21 8. 32 31/65-67 25. 38 8.65 5. 03 1, .74 0 .050 0 .567 2. ,05 4. ,32 2. .08 0. .061 1 .32 8. 80 31/70-72 25. 73 8.56 5. 07 1. .89 0 .082 0 .504 2. .70 3. 96 1. ,79 0. .073 0 .63 6. 77 31/80-82 26. 52 8.69 5. 15 1, .98 0 .079 0 .521 3. .40 3. ,78 1. .62 0, .068 0 .52 4. 47 31/90-92 27. 65 8.74 4. 70 1, .69 0 .070 0 .498 2. .66 3. ,83 1. .59 0. .062 1 .02 4. 22 31/100-102 26. 43 8.91 5. 47 2. .10 0 .089 0 .558 3. .06 3. ,77 1. .59 0. .087 0 .84 3. 99 31/103-105 26. 26 8.96 4. 68 1, .67 0 .038 0 .575 1. .75 2. ,39 2. .65 0, .054 0 .40 9. 21 31/110-112 25. 93 8.95 5. 69 2. ,18 0 .087 0 .569 3. .20 3. ,70 1. ,67 0. .077 0 .92 4. 54 31/120-122 26. 62 8.72 5. 13 1. .93 0 .090 0 .506 3. .36 3. ,67 1. ,57 0. .068 0 .44 4. 25 31/130-132 25. 37 8.67 5. 34 2. .04 0 .081 0 .548 3. .15 4. ,05 1. ,65 0, .086 0 .58 4. 96 31/140-142 26. 72 8.87 5. 22 1. .92 0 .084 0 .524 2. .94 3. ,62 1. .74 0. .078 0 .49 4. 44 31/150-152 25. 37 8.66 5. 47 2. .10 0 .099 0 .541 3. .11 3. ,39 1. .72 0. .087 0 .31 4. 88 31/160-162 25. 31 8.66 4. 91 1. .92 0 .061 0 .548 2. .17 4. ,51 1. .97 0. .079 0 .61 7. 77 CORE 79-06-31: MAJOR ELEMENT RATIOS TO ALUMINUM (SALTFREE) SAMPLE Si/Al Fe/AI Mg/AI Mn/AI Ti/Al Na/AI Ca/AI K/AI P/AI 31/0-2 3.296 0.610 0. 207 0.009 0 .060 0. 374 0 .361 0.169 0.006 31/5-7 3.012 0.632 0. 243 0.009 0 .064 0. 304 0 .453 0.193 0.009 31/10-12 2.806 0.611 0. 235 0.009 0 .064 0. 356 0 .394 0.197 0.010 31/20-22 2.880 0.638 0. 251 0.010 0 .064 0. 354 0 .391 0.202 0.008 31/30-32 2.844 0.625 0. 237 0.010 0 .063 0. 298 0 .469 0.207 0.009 31/40-42 2.988 0.639 0. 225 0.009 0 .063 0. 342 0 .335 0.230 0.009 31/50-52 3.020 0.652 0. 226 0.009 0 .062 0. 316 0 .369 0.214 0.010 31/60-62 2.966 0.636 0. 242 0.011 0 .062 0. 383 0 .533 0.210 0.007 31/65-67 2.934 0.582 0. 201 0.006 0 .066 0. 237 0 .499 0.240 0.007 31/70-72 3.006 0.592 0. 221 0.010 0 .059 0. 315 0 .463 0.209 0.009 31/80-82 3.052 0.593 0. 228 0.009 0 .060 0. 391 0 .435 0.186 0.008 31/90-92 3.164 0.538 0. 193 0.008 0 .057 0. 304 0 .438 0.182 0.007 31/100-102 2.966 0.614 0. 236 0.010 0 .063 0. 343 0 .423 0.178 0.010 31/103-105 2.931 0.522 0. 186 0.004 0 .064 0. 195 0 .267 • 0.296 0.006 31/110-112 2.897 0.636 0. 243 0.010 0 .064 0. 358 0 .413 0.187 0.009 31/120-122 3.053 0.588 0. 221 0.010 0 .058 0. 385 0 .421 0.180 0.008 31/130-132 2.926 0.616 0. 235 0.009 0 .063 0. 363 0 .467 0.190 0.010 31/140-142 3.012 0.589 0. 216 0.009 0 .059 0. 331 0 .408 0.196 0.009 31/150-152 2.930 0.632 o; 242 0.011 0 .062 0. 359 0 .391 0.199 0.010 31/160-162 2.923 0.567 0. 222 0.007 0 .063 0. 251 0 .521 0.227 0.009 EXPLORER DEEP BASALT: UNCORRECTED MAJOR ELEMENT DATA, WEIGHT PERCENT ELEMENT. SAMPLE Si Al Fe Mg Mn Ti Na Ca K P CI LOI Bg 23.38 8.17 7.88 4.84 0.165 1.039 1.45 ' 7.96 0.28 0 .072 <0.02 0.16 Bv 22.36 7.90 6.61 7.35 0.134 0.706 1.85 7.66 0.15 0 .036 <0.02 0.43 EXPLORER DEEP BASALT: UNCORRECTED MAJOR ELEMENT DATA, WEIGHT PERCENT OXIDE EQUIVALENT. SAMPLE S i 0 2 A1 2 0 3 F e 2 0 3 MgO MnO T i 0 2 Na 20 CaO K20 P2 o 5 CI LOI C1=0 TOTAL Bg 50.01 15.43 11.27 8.02 0.213 1.733 1.95 11.14 0.34 0. 165 <0.02 0.16 0.0 100.43 Bv 47.83 14.92 9.45 12.19 0.173 1.178 2.49 10.72 0.18 0. 082 <0.02 0.43 0.0 99.64 Bg=basalt from glassy ch i l l margin of pillow Bv=vesicular basalt TABLE C.3 MINOR ELEMENTAL COMPOSITION Data are expressed on an uncorrected basis, on a sa l t - f ree basis, and as element/aluminium rat ios (of saIt - f ree concentrations). Al l values are In parts-per-mlI I Ion (ppm). n.a. Is not analyzed * original sample Insufficient for analysis, and required re-sampling. ** value estimated to f a c i l i t a t e sa l t - f ree ca lcu lat ion . ySr Is matrix adsorption coef f ic ient , calculated at the SrK* radiation wavelength. Bg Is a sample of dense volcanic glass (of the c h i l l margin on a basalt pillow) In dredge haul PGC-79-06-32 from Explorer Deep. Bv Is a sample of scorlaceous volcanic glass (of the c h i l l margin on a basalt pillow) In dredge haul PGC-79-06-32 from Explorer Deep. - 2 6 0 -SURFACE SAMPLES: MINOR ELEMENT DATA (values in ppm)  SAMPLE pSr Co Cu Ni Zn Ba 1/0-2* 10.51 26 39 100 121 2250 2/0-2 9.98 15 35 109 138 2426 4/0-2 10.21 22 33 85 110 2192 6/0-2* 10.42 17 39 76 121 n.a. 7/0-2 10.46 21 38 91 126 1842 8/0-2* 10.48 18 38 104 127 2150 10/0-2 10.18 15 32 73 122 1961 21/0-2 10.29 14 39 85 127 2285 22/0-4* 10.04 18 27 65 84 1445 29/0-5 10.21 17 37 97 135 2429 30/0-2 10.18 16 38 103 132 2503 31/0-2 10.52 18 31 67 89 1255 SALT-FREE MINOR ELEMENT DATA (values in ppm, except CI in wt. ! SAMPLE Co Cu Ni Zn Ba CI 1/0-2* 27 41 106 128 2378 2.95 2/0-2 16 36 113 143 2511 1.87 4/0-2 23 34 88 114 2273 1.95 6/0-2* 18' 41 80 127 n.a. 2.50 7/0-2 21 39 93 129 1880 1.12 8/0-2* 19 41 111 136 2299 3.55 10/0-2 •16 34 77 129 2068 2.85 21/0-2 15 41 90 134 2407 2.78 22/0-4* 18 27 65 84 1452 0.28 29/0-5 18 39 102 142 2562' 2.85 30/0-2 16 39 106 136 2576 1.56 31/0-2 18 32 68 91 •1278 0.98 MINOR ELEMENT RATIOS TO ALUMINUM (SALT-FREE, Xio" •3 ) SAMPLE Al(ppm) Co/AI Cu/AI Ni/Al' Zn/AI Ba/AI 1/0-2* 71000 • 0. 380 0. 577 1. 493 1 .803 33.49 2/0-2 78600 0. 204 0. 458 1. 438 1 .819 31.95 4/0-2 73500 0. 313 0. 463 1. 197 1 .551 30.92 6/0-2* 73300 0. 245 0. 559 1. 091 1 .733 n.a. 7/0-2 78000 0. 269 0. 500 1. 192 1 .654 24.10 8/0-2* 73500 0. 258 0. 558 1. 510 1 .850 31.28 10/0-2 75400 0. 212 0. 451 1. 021 1 .711 27.43 21/0-2 75900 0. 198 0. 540 1. 186 1.765 31.71 22/0-4* 79700 0. 226 0. 339 0. 816 1 .054 18.22 29/0-5 72400 0. 249 0. 539 1. 409 1 .961 35.39 30/0-2 72600 0. 220 0. 537 1. 460 1 .873 35.48 31/0-2 81800 0. 220 0. 391 0. 831 1 .112 15.62 -261-MINOR ELEMENT DATA (values in ppm) SAMPLE ySr Co Cu Ni Zn Ba 6/0-2* 10.42 17 39 76 121 n.a. 6/4-8* 10.27 16 39 73 129 2383 6/10-12* 10.12 19 38 102 134 2206 6/15-17* 10.42 19 32 76 122 1822 6/20-22* 10.11 20 37 93 135 2359 6/20-24* 10.07 20 38 108 131 2063 6/30-32* 10.08 23 36 99 135 2212 6/40-42* 10.13 19 38 87 130 2031 6/50-52* 10.26 23 36 116 132 2033 6/60-62* 10.32 22 37 117 134 2002 6/70-72* 10.16 21 36 108 140 2106 6/80-82* 10.24 19 37 112 136 2127 6/90-92 10.29 20 39 86 147 1972 6/100-102 10.36 20 41 119 144 1970 6/110-112 10.42 20 38 103 149 1902 ~ 6/110-112b* 10.43 21 39 97 149 1890 6/120-122 10.91 21 46 97 156 1793 SALT-FREE MINOR ELEMENT DATA (values in ppm, except CI in wt. %) SAMPLE Co Cu Ni Zn Ba CI 6/0-2* 18 41 80 127 n.a. 2.50 6/4-8* 16 40 75 132 2441 1.30 6/10-12* 20 41 109 143 2353 3.44 6/15-17* 20 34 80 128 1910 2.50** 6/20-22* 21 . 39 97 141 2460 2.25 6/30-32* 24 37 103 140 2296 2.02 6/40-42* 20 39 90 135 2109 2.03 6/50-52* 24 37 120 136 2100 1.76 6/60-62* 23 38 121 138 2064 1.64 6/70-72* 22 37 112 145 2176 1.76 6/80-82* 19 38 114 139 2166 1.00 6/90-92 21 40 88 151 2024 1.40 6/100-102 21 43 124 150 2046 2.04 6/110-112 21 39 106 153 1953 1.44 6/120-122 22 47 99 160 1836 1.28 -262-MINOR ELEMENT RATIOS TO ALUMINUM (SALT-FREE, XIO ) SAMPLE AT(ppm) Co/AI Cu/AI Ni/Al Zn/AI Ba/AI 6/0-2* 73300 0.245 0.559 1.091 1.733 n.a. 6/4-8* 70700 0.226 0.566 1.061 1.867 34.53 6/10-12* 77800 0.257 0.527 1.401 1.838 30.24 6/15-17* n.a. 6/20-22* 75000 0.280 0.520 1.293 1.880 32.80 6/30-32* 71500 0.336 0.517 1.440 1.958 32.11 6/40-42* 72800 0.275 0.536 1.236 1.854 28.97 6/50-52* 74900 0.320 0.494 1.602 1.816 28.04 6/60-62* 77200 0.298 0.492 1.567 1.788 26.74 6/70-72* 76800 0.286 0.482 1.458 1.888 28.33 6/80-82* 77200 0.246 0.492 1.477 1.800 28.06 6/90-92 77500 0.271 0.516 1.135 1.948 26.12 6/100-102 80800 0.260 0.532 1.535 1.856 25.32 6/110-112 78700 0.267 0.496 1.347 1.944 24.82 6/120-122 79500 0.277 0.591 1.245 2.012 23.09 MINOR ELEMENT DATA, (values in ppm) SAMPLE ySr Co Cu Ni Zn Ba 8/0-2* 10.48 18 38 104 127 2150 8/5-7 10.16 17 36 100 140 2461 8/10-12 10.15 17 38 94 140 2448 8/20-22* 10.14 22 35 117 118 1928 8/30-32 10.23 20 36 95 141 2072 8/40-42* 10.41 19 39 91 133 2166 8/50-52 10.37 19 40 99 136 2220 8/60-62 10.49 25 39 103 145 1852 8/70-72 10.43 23 42 115 143 1802 8/80-82 10.42 22 36 110 148 1967 8/90-92 10.45 22 39 102 145 1650 8/100-102 10.51 26 37 101 130 1553 8/110-112 10.72 22 41 91 140 1788 8/120-122 10.62 23 39 101 138 1725 8/130-132 10.76 24 41 78 126 1527 8/140-142 10.93 23 41 91 112 1171 8/150-152 10.89 25 42 56 122 1147 -263-SALT-FREE MINOR ELEMENT DATA (values in ppm, except CI in wt. %) SAMPLE Co Cu Ni Zn Ba CI 8/0-2* 19 41 111 136 2299 3.55 8/5-7 18 37 103 144 2536 1.63 8/10-12 18 40 98 146 2554 2.28 8/20-22* 23 36 122 123 2003 2.06 8/30-32 20 37 97 144 2113 1.07 8/40-42* 20 41 95 139 2263 2.35 8/50-52 19 40 100 138 2246 0.63 8/60-62 26 40 105 148 1893 1.20 8/70-72 23 42 116 144 1816 0.43 8/80-82 22 37 112 151 2003 1.00 8/90-92 23 40 105 149 1695 1.46 8/100-102 27 38 105 135 1608 1.88 8/110-112 22 42 93 143 1828 1.20 8/120-122 24 40 104 143 1783 1.79 8/130-132 25 42 81 130 1578 1.78 8/140-142 23 42 93 114 1192 0.96 8/150-152 25 43 57 124 1169 1.05 MINOR ELEMENT RATIOS TO ALUMINUM (SALT-FREE, X10 ) SAMPLE Al(ppm) Co/Al Cu/Al Ni/Al Zn/Al . Ba/AI 8/0-2* 73500 0 .258 0 .558 1. 510 1 .850 31. 28 8/5-7 76000 • 0 .237 0 .487 1. 355 1 .895 33. 37 8/10-12 73500 0 .245 0 .544 1. 333 1 .986 34. 75 8/20-22* 66600 0 .345 0 .540 1. 832 1 .847 30. 08 8/30-32 73400 0 .272 0 .504 1. 322 1 .962 28. 79 8/40-42* 77800 0 .257 0 .527 1. 221 1 .787 29. 09 8/50-52 75200 0 .253 0 .532 1. 330 1 .835 29. 87 8/60-62 77900 0 .334 0 .513 1. 348 1 .900 24. 30 8/70-72 75600 0 .304 0 .556 1. 534 1 .905 24. 02 8/80-82 79100 0 .278 0 .468 1. 416 1 .909 25. 32 8/90-92 79600 0 .289 0 .503 1. 319 1 .872 21. 29 8/100-102 78900 0 .342 0 .482 1. 331 1 .711 20. 38 8/110-112 78700 0 .280 0 .534 1. 182 1 .817 23. 23 8/120-122 80700 0 .297 0 .496 1. 289 1 .772 22. 09 8/130-132 81500 0 .307 0 .515 0. 994 1 .595 19. 36 8/140-142 78100 0 .294 0 .538 1. 191 1 .460 15. 26 8/150-152 77500 0 .322 0 .555 0. 735 1 .600 , 15. ,08 -264-MINOR ELEMENT DATA (values in ppm) SAMPLE ySr Co Cu Ni Zn Ba 10/0-2 10.18 15 32 73 122 1961 10/5-7 10.11 17 32 91 118 2001 10/10-12 - 10.35 21 34 101 120 1777 10/15-17 10.40** 22 38 94 126 1889 10/20-22 10.51 20 35 81 118 1480 10/25-27 10.90 22 36 68 99 795 10/30-32 11.15 25 38 56 98 628 10/40-42 11.11 22 38 54 99 811 10/50-52 10.92 21 41 71 101 828 10/60-62 11.23 24 41 55 101 740 10/70-72 11.18 26 40 62 102 727 10/80-82 11.07 26 38 61 95 724 10/90-92 10.96 26 40 59 95 771 10/90-92b* 11.04 26 38 84 93 761 10/100-102 10.85 23 37 89 104 802 10/110-112 10.78 ' 24 38 55 95 802 10/120-122 10.72 25 38 58 102 808 10/130-132 10.97 26 42 73 100 795 SALT-FREE MINOR ELEMENT DATA (values in ppm, except CI in wt. %) SAMPLE Co Cu Ni Zn • Ba CI 10/0-2 16 34 77 129 2068 2.85 10/5-7 18 .33 94 122 2061 1.60 10/10-12 22 35 105 124 1842 1.94 10/15-17 23 39 96 129 1936 1.34 10/20-22 20 36 82 120 1504 0.87 10/25-27 23 37 70 102 826 1.44 10/30-32 25 38 56 98 631 0.24 10/40-42 22 39 55 101 828 1.15 10/50-52 21 42 72 103 845 1.08 10/60-62 24 41 56 102 748 0.62 10/70-72 26 40 62 103 732 0.38 10/80-82 26 39 62 96 734 0.72 10/90-92 26 41 60 97 784 0.89 10/100-102 23 38 90 105 813 0.77 10/110-112 24 38 56 96 812 0.69 10/120-122 25 39 59 104 821 0.87 10/130-132 26 43 74 102 808 0.86 -265-MINOR ELEMENT RATIOS TO ALUMINUM (SALT-FREE, X i o " 3 ) SAMPLE Al(ppm) Co/Al Cu/Al Ni/Al Zn/Al Ba/AI 10/0-2 75400 0 .212 0.451 1.021 1.711 27.43 10/5-7 74700 0 .241 0.442 1.258 1.633 27.59 10/10-12 76500 0 .288 0.458 1.372 1.621. 24.08 10/15-17 72800 0 .316 0.536 1.319 1.772 26.59 10/20-22 77800 0 .257 0.463 1.054 1.542 19.33 10/25-27 84000 0 .274 0.440 0.833 1.214 9.83 10/30-32 88000 0 .284 0.432 0.636 1.114 7.17 10/40-42 84000 0 .262 0.464 0.655 1.202 9.86 10/50-52 83600 0 .251 0.502 0.861 1.232 10.11 10/60-62 n.a. 10/70-72 86500 0 .300 0.462 0.717 1.191 8.46 10/80-82 89800 0 .290 0.434 0.690 1.069 8.17 10/90-92 87400 0 .297 0.469 0.686 1.110 8.97 10/100-102 84400 0 .272 0.450 1.066 1.244 9.63 10/110-112 85100 0 .282 0.446 0.658 1.128 9.54 10/120-122 86700 0 .288 0.450 0.680 1.200 9.47 10/130-132 87800 0, .296 0.490 0.843 1.162 9.20 MINOR ELEMENT DATA (values in ppm) SAMPLE ySr Co Cu Ni Zn Ba 22/0-4* . 10.04 18 27 65 84 1445 22/5-6* 10.05 18 27 62 87 1381 22/10-11* . 11.25 17 41 42 85 626 22/15-16* 10.69 16 30 51 75 595 22/20-21* 11.00 19 30 48 70 467 22/25-26* 10.79 20 33 26 80 601 22/30-31* 10.69 17 32 51 68 352 22/35-36* 10.65 18 33 61 85 573 22/40-41* 10.04 20 23 45 54 512 22/45-46* 10.40 18 31 52 68 608 22/45 - 4 6 D * 10.39 19 27 40 68 648 22/50-51* 10.90 19 34 34 76 585 22/50-5 lb* 11.01 19 37 47 74 n.a. 22/60-61* 10.76 20 32 31 77 621 -266-SALT-FREE MINOR ELEMENT DATA (values in ppm, except CI in wt. %) SAMPLE Co Cu Ni Zn Ba CI 22/0-4* 18 27 65 84 1452 0.28 22/5-6* 18 27 62 87 1389 0.30 22/10-11* 17 42 43. 86 636 0.85 22/15-16* 16 30 52 76 601 0.56 22/20-21* 19 30 48 71 471 0.49 22/25-26* 20 33 26 80 605 0.33 22/30-31* 17 32 51 68 354 0.35 22/35-36* 18 33 62 86 578 0.50 22/40-41* 20 23 45" 54 516 0.42 22/45-46* 18 31 52 68 612 0.40 22/50-51* 19 34 34 77 590 0.44 22/60-61* . 20 32 31 77 621 <0.02 MINOR ELEMENT RATIOS TO ALUMINUM (SALT-FREE, Xio" )  SAMPLE A1( ppm) Co/AI Cu/AI Ni/Al Zn/AI Ba/AI 22/0-4* 79700 0 .226 0. 339 0 .816 1 .054 18.22 22/5-6* 81100 0 .222 0. 333 0 .764 1 .073 17.13 22/10-11* 60800 0 .280 0. 691 0 .707 1 .414 10.46 22/15-16* 80400 0 .199 0. 373 0 .647 0 .945 7.48 22/20-21* 82800 0 .229 0. 362 0 .580 0 .857 5.69 22/25-26* 90400 0 .221 0. 365 0 .288 0 .885 6.69 22/30-31* 84300 0 .202 0. 380 0 .605 0 .807 4.20 22/35-36* 83500. 0 .216 0. 395 0 .742 1 .030 6.92 22/40-41* 79400 • 0 .252 0. 290 0 .567 0 .680 6.50 22/45-46* 82100 0 .219 0. 378 0 .633 0 .828 7.45 22/50-51* 82600 0 .230 0. 412 0 .412 0 .932 7.14 22/60-61* 85400 0 .234 0. 375 0 .363 0 .902 7.27 -267-MINOR ELEMENT DATA (values in ppm) SAMPLE uSr Co Cu Ni Zn Ba 31/0-2 10.52 18 31 67 89 1255 31/0-4* 10.57 19 30 50 88 1269 31/5-7 11.07 21 37 43 90 567 31/10-12 11.04 21 . 38 27 93 652 31/20-22 11.22 22 40 41 92 533 31/30-32 10.98 22 36 64 92 538 31/40-42 10.98 23 ' 34 47 94 625 31/50-52 11.04 20 38 39 90 600 31/60-62 11.01 24 38 53 87 613 31/65-67 10.69 18 35 46 84 649 31/70-72 10.76 20 31 47 85 608 31/80-82 10.85 21 32 43 79 604 31/90-92 10.44 21 27 39 70 607 31/100-102 11.01 22 39 32 83 549 31/103-105 10.23 15 25 44 71 521 31/110-112 11.13 20 38 . 35 86 550 31/120-122 11.01 19 71 29 88 530 31/130-132 10.93 20 38 44 88 682 31/140-142 10.95 21 34 31 83 543 31/150-152 11.12 21 35 19 91 562 31/160-162 10.76 19 36 53 - 86 656 SALT-FREE MINOR ELEMENT DATA (values in ppm, except CI in wt. %) SAMPLE Co Cu Ni Zn Ba CI 31/0-2 18 32 68 91 1278 0.98 31/5-7 21 38 44 92 580 1.20 31/10-12 21 39 28 95 664 1.03 31/20-22 22 40 42 93 540 0.69 31/30-32 23 37 66 94 551 1.29 31/40-42 23 34 48 95 634 0.78 31/50-52 .20 38 39 91 607 0.61 31/60-62 24 38 53 87 614 0.07 31/65-67 18 36 47 86 664 1.23 31/70-72 20 31 47 86 614 0.51 31/80-82 21 32 43 80 608 0.39 31/90-92 21 27 40 71 617 0.92 31/100-102 22 40 32 84 556 0.74 31/103-105 15 25 44 71 525 0.38 31/110-112 20 39 36 87 558 0.82 31/120-122 19 71 29 89 533 0.32 31/130-132 20 38 44 89 688 0.46 31/140-142 21 34 31 84 547 0.37 31/150-152 21 35 19 91 564 0.17 31/160-162 19 36 53 87 662 0.49 -268-MINOR ELEMENT RATIOS TO ALUMINIUM (SALT-FREE r X1Q" 5) SAMPLE Al(ppm) Co/Al Cu/Al NI/AI Zn/Al Ba/AI 31/0-2 81800 0.220 0.391 0.831 1.112 15.62 31/5-7 85600 0.245 0.444 0.514 1.075 6.78 31/10-12 90700 0.232 0.430 0.309 1.047 7.32 31/20-22 88200 0.249 0.454 0.476 1.054 6.12 31/30-32 85500 0.269 0.433 0.772 1.099 6.44 31/40-42 86500 0.266 0.393 0.555 1.098 7.33 31/50-52 85800 0.233 0.443 0.454 1.061 7.07 31/60-62 82500 0.291 0.461 0.642 1.054 7.44 31/65-67 86500 0.208 0.416 0.543 0.994 7.68 31/70-72 85600 0.234 0.362 0.549 1.005 7.17 31/80-82 86900 0.242 0.368 0.495 0.920 7.00 31/90-92 87400 0.240 0.309 0.458 0.812 7.06 31/100-102 89100 0.247 0.449 0.359 0.943 6.24 31/103-105 89600 0.167 0.279 0.491 0.792 5.86 31/110-112 89500 0.223 0.436 0.402 0.972 6.23 31/120-122 87200 0.218 0.814 0.333 1.021 6.11 31/130-132 86700. 0.231 0.438 0.507 1.026 7.94 31/140-142 88700 0.237 0.383 0.349 0.947 6.17 31/150-152 86600 0.242 0.404 0.219 1.051 6.51 31/160-162 86600 0.219 0.416 0.612 1.005 7.64 MINOR ELEMENT DATA (values In ppm) SAMPLE uSr Co Cu NI Zn Ba Bv 13.12 55 71 424 78 n.a. Bg 13.31 48 67 121 83 n . a . b I ank 1.15 0.1 0.0 10 0.0 0.0 SALT-FREE MINOR ELEMENT DATA (values In ppm. except CI In wt.{) SAMPLE Co Cu NI Zn Ba CI Bv 55 71 424 78 n.a. <0.02 Bg 48 67 121 83 n.a. <0.02 bl ank 0.1 0.0 10 0.0 0.0 <0.02 MINOR ELEMENT RATIOS TO ALUMINIUM (SALT-FREE X10' -3) SAMPLE Al(ppm) Co/Al Cu/Al NI/AI Zn/Al Ba/AI Bv 79000 0.696 0.899 5.367 0.987 n.a. Bg 81700 0.588 0.820 1.481 1.016 n.a. - 2 6 9 -APPENDIX D CONTINUOUS SEISMIC PROFILE DATA WITH INTERPRETATIONS Approximate locations of core and dredge stations are indicated on the l ine drawings, see Fig. 1.1 for l ine locations. Lines 79-06-06 and 79-06-06a were of very poor qual i ty , hence no l ine drawings were made, though the data where usable were incorporated for bathymetric control . The vertical scale is in two-way travel time, and V.E.=vertical exaggeration. The CSP lines and the interpreted l ine drawings were reduced separately for inclusion in this thesis , and the scales no longer match exactly. -270-NW V . E . = 12.5 : 1 1 1 1 1 —I r r-0 5 10 15 20 25 30 35 K I L O M E T R E S Fig. D.01 CSP l ine PGC 79-06-03 parallel to the str ike of Paul Revere Ridge, just north-east of the crest of Paul Revere Ridge. -27I -S0NO03S Fig. D-02 CSP l ine PGC 79-06-04 across northern end Explorer Deep. Core 79-06-21 location is projected. The poor quality of the l ine l ike ly due in part to close proximity to Paul Revere Ridge. -272-S0N0D3S g. D-03 CSP l ine PGC 79-06-05 across northern end Explorer Deep. Cores 79-06-02, 79-06-05, and 79-06-06 are located on the l ine . Note that core 79-06-05 contained no sample. -273-Fig. D.04 CSP l ine PGC 79-06-07 across north-central Explorer Deep. Locations of cores 79-06-07 and 79-06-10 are indicated. -274-SQN0D3S D.05 CSP l ine PGC 79-06-08 across central Explorer Deep. Locations of cores 79-06-04 and 79-06-09 are indicated. Note core 79-06-09 contained only a few rock fragments in core catcher. - 275 -ro cn Fig. D-06 CSP lines PGC 79-06-09 and PGC 79-06-10 across south-central Explorer Deep. Locations of cores 79-06-08, 79-06-11, 79-06-12 (projected), 79-06-31 and dredge 79-06-32 (projected) are indicated. Note core 79-06-11 contained a core catcher sample only, and core 79-06-12 was empty. Note data are missing in a section of l ine PGC 79-06-09 due to air-gun fa i lu re . ro -si a l l N W S E -I ^ 2 7 9 - 0 6 - 1 1 3 O u 10 2 0 V. E. =10.1 : 1 10 15 K I L O M E T R E S 20 mm S E 7 9 - 0 6 - 1 3 V . E.= 10.1 i 1 10 K I L O M E T R E S N W 10, 20 Q 15 Fig. D.07 CSP l ines PGC 79-06-11 and PGC 79-06-13 across south end Explorer Deep. Locations of cores 79-06-29 and 79-06-30 are indicated. Note data are missing in a section of l ine PGC 79-06-13. SQN003S CM n ^ « D.08 CSP lines PGC-79-06-15 and PGC-79-06-16 parallel to str ike of Explorer Deep long axis. Locations of cores 79-06-29 and 79-06-30 are indicated; dredge PZ-69- l ld (source of Explorer Deep metal-l i ferous sediment; G r i l l et a l . , 1981) is also indicated. - 2 7 8 -Fig. D.09 CSP l ines PGC 79-06-22 to -25 along escarpment forming the Paul Revere Ridge. Locations of cores 79-06-21 and 79-06-22 are indicated. i 3 SCJN003S o S O N 0 0 3 S Fig. D.10 CSP l ines PGC 79-06-26 and PGC 79-06-33 sub-parallel to strike of Explorer Deep long axis. Position of core station 79-06-23 indicated, although core 79-06-23 contained no sample. Note the different scales for the two l ines . -280-Fig. D. l l CSP l ine PGC 79-06-42 across south end Explorer Deep, and l ine PGC 79-06-43 paral lel to str ike of Explorer Deep long axis. Note the location of core 79-06-10 is projected. 

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0052436/manifest

Comment

Related Items