UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Wall-rock alteration at Zeballos, B. C. Allen, Alfred Roy 1941

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

Item Metadata

Download

Media
831-UBC_1941_A7 A4 W2.pdf [ 10.81MB ]
Metadata
JSON: 831-1.0053063.json
JSON-LD: 831-1.0053063-ld.json
RDF/XML (Pretty): 831-1.0053063-rdf.xml
RDF/JSON: 831-1.0053063-rdf.json
Turtle: 831-1.0053063-turtle.txt
N-Triples: 831-1.0053063-rdf-ntriples.txt
Original Record: 831-1.0053063-source.json
Full Text
831-1.0053063-fulltext.txt
Citation
831-1.0053063.ris

Full Text

WALL—ROCK ALTERATION AT ZEBALLOS, B. G. by Alfred. Roy A l l e n A Thesis submitted In P a r t i a l Ed. I f i l m e n t of The. Requirements f o r the Degree of The U n i v e r s i t y of B r i t i s h Columbia. MASTER OF APPLIED SCIElfCE in- the Department of GEOLOGY A p r i l j 1941. fall-Rock. A l t e r a t i o n at Zeballos. B. G. coraaras A. .. Introd.ucti.on.; B. General. Geo logy: C. Wall-Rock A l t e r a t i o n : (a) Spud. V a l l e y Vein. "1. General Geology. 2.. The i'resh Wall-rock. 3* The A l t e r e d Wall—rock. 4. D e s c r i p t i o n of S l i d e s . 5. Summary and Conclusions ;: (t>) P r i d e n t Vein. 1. General Geology. 2 i. The ITresh Wall-rock. 3. The A l t e r e d Wall-rock. 4. D e s c r i p t l o t i of Slides.. 51 Summary and Conclusions .:• (c.) The Mount Zeballos. Vein. 1. General Geology. 2. The i'resh Wall-rock. 3V The Altered.. Wall-rock.. 4. Description"- of. S l i d e s . 5. Summary and Conclusions. : (d) The White Star Vein. li General Geology. 2. The Fresh ?/all-rock. 3.. The A l t e r e d Wall-rock. 4. D e s c r i p t i o n of Slides.. 5. Summary and Conclusions. (e) The P r i v a t e e r Veins. .1.. General. Geology. 2... The J?resh wall-rock. 3.. The A l t e r e d Wall-rock. 4. D e s c r i p t i o n of Slides.. 5. Summary and Conclusions. D. Summary and Conclusions; (a) C l a s s i f i c a t i o n , of the Ore Deposits. (b) The Ore S o l u t i o n - - i t s o r i g i n and composition. . (c) The E f f e c t of the Wall-rock on A l t e r a t i o n . G E O L O G Y OP T H E Z E B A L L O S A R E A 7 " M i n e s - J, S. Steve-nson.. A. Introduction.: Zeballos, the newest mining camp i n B r i t i s h Columbia, i s located on the west coast of Vancouver Is l a n d , 200 miles northwest, of V i c t o r i a . The. f i v e mines included i n t h i s report occur close to the southwest contact of the Zeballos b a t h o l i t h i n the area drained by Spud and Goldvalley creeks. The area drained by the Zeballos r i v e r i s very rugged* and. much of i t i s covered w i t h a luxurious growth of timber. The annual r a i n f a l l i s about 200 inches per year. Gold was f i r s t found i n the gravels of the Zeballos r i v e r . Intensive prospecting was spurred to a "rush" a f t e r s e v e r a l small high-grade lode-veins were discovered. The P r i v a t e e r and Spud v a l l e y mines s t a r t e d m i l l i n g ore i n the ea r l y winter of 1938* the Mount Zeballos in. August,. 1939,. and the C e n t r a l Zeballos i n January, 1940. Today these four pro-ducing mines form the nucleus of an a c t i v e and progressive new mining community. B... General Geology; The rocks underlying the Zeballos mining area, are l a t e T r i a s s i c to early. J u r a s s i c sediments and volc a n i c s i n -truded by an igneous assemblage ranging from quartz gabbro to quartz, monzonite and f e l s i t e . The sedimentary and v o l c a n i c rocks, named the Van-couver group, are d i v i d e d i n t o the Karmutsen v o l c a n i c s , Q,uat-sino limestone, and Bonanza groups. -2-*Tiie Karmutsen volcanics^ consist of dark green to black a n d e s l t i c and b a s a l t i c flows with p i l l o w and amygdaloidal s t r u c t u r e . The flow rocks contain zones of green, grey, and reddish v o l c a n i c breccias and t u f f s , and a few l e n t i c u l a r beds of white to dark grey limestone» The contact between the Kar-mutsen vo l c a n i c s and Q,uatsi.no formation i s w e l l defined, and along i t there i s some evidence of f a u l t i n g . The Q,uatsino formation consists, of at l e a s t s e v e r a l hundred feet of f i n e - g r a i n e d to coarsely c r y s t a l l i n e dark grey to white limestone.. Through the limestone, p a r t i c u l a r l y near the top there, are green v o l c a n i c flows,, and grey, green, and brown t u f f s -Lying conformably upon the Quatsino formation the Bonanza group c o n s i s t s -6f"^liiir-toebg- of thin-bedded limestone, a r g i l l i t e , and q u a r t z i t e . Overlying the sediments there i s a heterogeneous assemblage of green or grey, f i n e - g r a i n e d , ande-s l t i c a c i d flows, i n t e r l a y e r e d w i t h green, purple, red or. grey b r e c c i a s , and f i n e - g r a i n e d t u f f s . Some of the coarse-grained flows are p o r p h y r i t i c , and a few of. the c r y s t a l l i n e t u f f s r e-semble p o r p h y r i e s i The Zeballos b a t h o l i t h cuts the vol c a n i c and s e d i -mentary-rocks. The igneous rocks range from quartz gabbro and d i o r i t e to quartz monzonite and pegmatite, the a c i d types being most abundant i n the southwest. An i n t r i c a t e network of dykes, stocks, and i r r e g u l a r bodies occur around the periphery of the b a t h o l i t h . A l l of the producing mines are located near the MICRO-PHOTOGRAPH Crossed E i c o l s M a g n i f i c a t i o n 80 Diam. A Thi n - s e c t i o n of The Zeballos B a t h o l i t h ^ u a r t z - d i o r i t e . Note the f e l t of s e r i c i t e r e p l a c i n g a l l but the outer zone of f e l d s p a r c r y s t a l s . P l a t e y c h l o r i t e , i n e x t i n c t i o n , i s c l o s e l y associated with the s i r i c i t e . MXCROPHOTOGRAPH Ma g n i f i c a t i o n Approximately 160 Diameters. A Thin- s e c t i o n of The A l t e r e d Wall-rock Adjacent To The Spud V a l l e y Vein. R A f e l t of t i n y r u t i l e c r y s t a l s . A Apatite c r y s t a l s . f Feldspar almost wholly replaced by s e r i c i t e and c h l o r i t e . Q, Uuartz. MICROPHOTQGRAPH Ma g n i f i c a t i o n Approximately 160 Diameters. A Th i n - s e c t i o n of The A l t e r e d Vsall-rock Adjacent To The Spud V a l l e y Vein. Py A g r a i n of p y r i t e . S A c o l l o r l e s s , f i b r o u s aggregate of rather coarse s e r i c i t e scales,developed around and penetrating the p y r i t e . R Innumerable very small a c i c u l a r c r y s t a l s of r u t i l e i n the s e r i c i t e . Groundmass Feldspar a l t e r e d to s e r i c i t e , carbonate, and probably some k a o l i n . southwest'cbntact of the Zeballos b a t h o l i t h w i t h the Bonanza group, some i n the igneous rock, and others i n the vol c a n i c and sedimentary rocks. 0. Wall-Rock A l t e r a t i o n s .(a) Spud V a l l e y Vein. 1. General Geology-The main v e i n l i e s i n the quartz d i o r i t e of the Zeballos b a t h o l i t h , 150G feet to 3000 feet northeast of- the southwest contact. The s t r i k e i s north 60° to 85° northwest. 2. Fresh Wall-rock--The f r e s h rock i s a l i g h t grey medium-grained quartz d i o r i t e . Brown b i o t i t e and dark green hornblende occur i n about equal amounts along with glassy quartz and shiney, well-formed f e l d s p a r s . 5. A l t e r e d Wall-rock-Kext to the vein the rock i s a l i g h t to greenish grey s medium-grained, f r i a b l e aggregate of s e r i c i t e , a l b i t e , and c h l o r i t e . The b i o t i t e and hornblende have been converted to c h l o r i t e , s e r i c i t e , and probably some magnetite. The r u t i l e and t i t an I t e have been p a r t i a l l y a l t e r e d to leucoxene. There Is l i t t l e sulphide m i n e r a l i z a t i o n i n the a l t e r e d w a l l - r o c k . Thin bands of brown weathering carbonate l i e p a r a l l e l to the v e i n . 4. D e s c r i p t i o n of S l i d e s -i . Slide_SJL_VJLj£l. S l i g h t l y A l t e r e d Wall-rock'. -4-" ' Mlnea?al Composition: P l a g i o c l a s e fLabradoxite Ab f e QAn 5 0 36^ feldspar f M n 4 G ' J . V-Oligoclase Ab 8 0An 2o 5<g • • \ Quartz' 16% B l o t I t e 14$ Hornblende 1Q#: S e r i c i t e 4$ • • C h l o r i t e 4$ Accessories 2%~ P l a g i o c laseffeIdspara.. Medium to large c r y s t a l s of zoned fe l d s p a r are the c h i e f constituent of the s l i d e . The inner zone i s l a b r a d o r i t e with maximum e x t i n c t i o n to the a l b i t e twin laminae, at 28°. The second zone i s andesine, and the outer zone o l i g o c l a s e , w i t h reversed e x t i n c t i o n on the albite-twinning lamenae from. -10° to +-70. S e r i c i t e replaces c h i e f l y the l a b r a -d o r i t e , but also the andesine-oligoclase to a l e s s e r degree, p a r t i c u l a r l y along small f r a c t u r e s . Some feld s p a r c r y s t a l s are almost completely a l t e r e d to s e r i c i t e , and others are unaltered. Q.uartz. Quartz occurs as an i n t e r s t i t i a l f i l l i n g between the f e l d s p a r c r y s t a l s . B i o t i t e . Elongated plates, of dark brown b i o t i t e occur between feld s p a r c r y s t a l s and quartz. C h l o r i t e and magnetite replace the b i o t i t e . The r e p l a c i n g minerals occur together, the magne-t i t e i n small i r r e g u l a r g r a i n s , t i n y a c i c u l a r needles, or l a r g e r shapeless g r a i n s , and the c h l o r i t e penetrating the b i o -t i t e i n long sharply defined tongues. Hornblende« Dark green hornblende, pleochroic from straw yellow to dark o l i v e green, i s p a r t i a l l y a l t e r e d to c h l o r i t e and. magnetite. S e r i c i t e . Tiny blades and fan-shaped aggregates of s e r i c i t e replace tlie> f e l d s p a r . The replacement Is most Intense i n the l a b r a d o r i t e , but i t also occurs along cracks In the andeslne and o l i g o c l a s e . Some of t h i s white mica may be paragonite, but by the spectrograph i t i s i d e n t i c a l to muscovite and i s therefore c h i e f l y a p o t a s s i c mica* Accessoriesi Apatite;. - Numerous c r y s t a l s of a p a t i t e occur embedded In the f e l d s p a r , b i o t i t e , and quartz. The c r y s t a l s range from almost sub-microscopics to one m i l l i m e t e r long. Small i n c l u s i o n s of. an unknown composition are common i n the a p a t i t e c r y s t a l s . Magnetite. Sub-angular to cubic and octahedral gra i n s , small a c i c u l a r c r y s t a l s and shapeless masses, of magnetite l i e i n the c h l o r i t e , hornblende and b i o t i t e . i i . S l i d e S. V. #2. A l t e r e d Quartz D i o r i t e . M i n e r a l Composition: ^ n .. ' f L a b r a d o r i t e AbR 0Anfr n 36^ P l a g i o c l a s e j A r i d e s i n e A b ^ A n ^ 6% - E e l d s » a r l o i l g o c l a s e Ab|gAn|g 4 • Quartz 28$ B i o t i t e 10% Hornblende 3% S e r i c i t e 10% Ch l o r i t e . 4% Accessories "6% Sulphides 2% Feldspars• Much of the s l i d e c o n s i s t s of well-formed c r y s t a l s of f e l d s p a r up to two'millimeters.: long. The zoning, l i k e i n Section S. V. #1, rangesfrom l a b r a d o r i t e , AbsoAn^Q, i n the center to andesine, AbgQAn^Q, and oligoclase,Ab^QAn^Q, at the outer surface. The a l t e r a t i o n of fel d s p a r to s e r i c i t e has i n sev e r a l c r y s t a l s progressed to the o l i g o c l a s e zone and stopped. C h l o r i t e i s c l o s e l y intergrown w i t h s e r i c i t e and a l i t t l e c a l c i t e replaces f e l d s p a r , but some b i o t i t e penetrates the fe l d s p a r c r y s t a l s , and the c h l o r i t e and c a l c i t e may be an. a l t e r a t i o n of the b i o t i t e r ather than the f e l d s p a r . Quartz. I r r e g u l a r grains of quartz l i e between the feldspar crystals.. The quartz, in. a minor way r appears to replace the f e l d s p a r * The quartz i s more abundant, i n s l i d e S. V. #2. than i n s l i d e S. V. #1, but i t . i s s i m i l a r i n hab i t and occurrence, and i s not a secondary generation. B i o t i t e . Dark brown p l a t e s of b i o t i t e occur developed between fe l d s p a r c r y s t a l s . The b i o t i t e . Is. c l o s e l y associated with. i hornblende... C h l o r i t e and magnetite ^ occur In the b i o t i t e . Small grains^ of magnetite have b e e n ' p a r t i a l l y altered, to rut l i e and. t i t a n i t e . and the t i t a n i t e has been a l t e r e d -to ..leucoxine (?) . . Fornblende.. Dark green hornblende, c l o s e l y associated w i t h b i o t i t e is. p a r t i a l l y converted to c h l o r i t e and a l i t t l e c a l c i t e . S e r i c i t e • S e r i c i t e , i n a compact, f e l t of very small f a n - l i k e f l a k e s replaces, f e i d s p a r . C h l o r i t e . O l i v e green c h l o r i t e replaces b i o t i t e and hornblende. The l a r g e i r r e g u l a r f l a k e s show anomolous blue, black, and purple b i r e f r i n g e n c e , and p a r a l l e l e x t i n c t i o n . Magnetite, r u t l i e , and t i t a n i t e are c l o s e l y associated with. the. c h l o r i t e . Accessories % Rutlle. and. T i t a n i t e . B i o t i t e . and magnetite appear to be p a r t i a l l y a l t e r e d to r u t i l e and t i t a n i t e * One p l a t e of b i o t i t e i s almost completely a l t e r e d to an: extremely f i n e f e l t of r u t i l e needles. The t l t a n i t e occurs as. l a r g e r stubby c r y s t a l s showing s y m e t r i c a l e x t i n c t i o n . A p a t i t e • numerous c r y s t a l s of a p a t i t e occur through the s e c t i o n . Sulphides. P y r i t e appears to replace- hornblende . i i i . S l i d e S. V. #3. A l t e r e d Quartz D i o r i t e . M i n e r a l Composition: P l a g i o c l a s e / O l i g o c l a s e Ab£oAn20 12% Feldspar \ A l b i t e A b g 5 A n 5 20% Quartz 18% S e r i c i t e 18% C h l o r i t e 16% Carbonate 5% R u t i l e , T l t a n i t e and Leucoxene 7% Accessories 1% ; Sulphides 3% P l a g i o c l a s e Feldspars. The c l o s e l y packed feldspar c r y s t a l s are. p a r t l y a l t e r e d to s e r i c i t e ( c h l o r i t e and c a l c i t e . The com-p o s i t i o n of most of the c r y s t a l s i s albite,Abg5An5, but i t ranges to o l i g o c l a s e ,Abg0An.20. I n t e r s t i t i a l quartz appears to have, replaced the fe l d s p a r , and. a l b i t e may have replaced o l i g o -c l a s e . The index of. r e f r a c t i o n of the a l b i t e . i s l e s s than balsam. Quartz. Granules of quartz l i e between, the. f e l d s p a r g r a i n s , r e p l a c i n g them to a minor degree. The: quartz i n most of the s l i d e i s as abundant as. i n S l i d e S. V. #1 •, but a s c a r c i t y of quartz on the one side of the s l i d e brings, the t o t a l content down to 18%. S e r i c i t e . "A very f i n e f e l t of s e r i c i t e replaces feldspar. S e v e r a l large: p i a t e y grains of s e r i c i t e are c l o s e l y associated w i t h , and most probably a l t e r e d t o , r u t i l e , t i t a n i t e , and c h l o r i t e * C h l o r i t e . The c h l o r i t e i s s i m i l a r i n occurrence to the sericite. The very f i n e c h l o r i t e Is c o l o r l e s s with b i r e f r i n g e n c e to pale orange, and the. green coarser v a r i e t y shows anomolous blue and dark purple b i r e f r i n g e n c e . Carbonate• i r r e g u l a r patches of carbonate occur i n t i m a t e l y associated, with, the s e r i c i t e , e v i d e n t l y r e p l a c i n g the p l a g l o -clase f e l d s p a r . The mineral l i e s In narrow bands and weathers brown. I t i s probably c a l c i t e containing a. l i t t l e i r o n * R u t i l e and T i t a n i t e . Brown a c i c u l a r crystals, of. r u t i l e replace c h l o r i t e , s e r i c i t e and probably c a l c i t e . The c r y s t a l s are i n r a d i a t i n g groups i n masses, I n some p l a c e s , o r i e n t e d along cleavage planes. Under refl e c t e d ! l i g h t they appear, light. ;. yellow w i t h a resinous l u s t e r . The t i t a n i t e occurs as stubby t e t r a g o n a l c r y s t a l s , but. few. are diamond-shaped. The t i t a n i t e a n d r u t i l e are p a r t i a l l y a l t e r e d to white leucoxene. Accessory Minerals.. A p a t i t e occurs i n about the same quantity and a s s o c i a t i o n s as i n the previous s l i d e s . Sulphides. P y r i t e In aggregates of small rounded and i r r e g u l a r grains occurs w i t h the c h l o r i t e , c a l c i t e and t i t a n i t e . i v . S l i d e S. ¥. #4. ' A l t e r e d Wall-rock. Mine r a l G omp os i t i o n ; Plagiocia.se COllgo clase 1Q% [Feldspar 1 A l b i t e 54% — 9 - '' ' ' S e r i c i t e 9% C h l o r i t e 1% Carbonate 11$%' •  ' . R u t i l e and T l t a n i t e 4% Accessories: 1% P l a g i o c l a s e Feldspar. There are two generations of feldspar i n the h i g h l y a l t e r e d quartz: d i o r i t e . A l b i t e replaces o l i g o -c l a s e . Small, or i e n t e d , corroded remnants of oligoclase. occur i n the a l b i t e . The contacts, are uneven and tongues of a l b i t e p r o j e c t i n t o the o l i g o c l a s e . Maximum e x t i n c t i o n in. the a l b i t e twinning i n the a l b i t e i s 18°, and i n the o l i g o c l a s e , 7;°* The Index of r e f r a c t i o n of the a l b i t e i s l e s s than that of balsam, and .the o l i g o c l a s e almost equal to* or greater than that of balsam. S e r i c i t e . S e r i c i t e occurs, as f a i r l y large f l a x e s , c l o s e l y as-s o c i a t e d w i t h r u t i l e , c h l o r i t e and c a l c i t e , or as small f a n -shaped scales-, matted w i t h c h l o r i t e and replacing, f e l d s p a r . Some of this, mineral may be t a l c , since a chemical t e s t on small, g r a i n s which look l i k e t a l c , was p o s i t i v e f o r magnesium and negative f o r aluminium. C h l o r i t e . L i g h t green f l a k e s of c h l o r i t e are Intergrown with s e r i c i t e , c a l c i t e , r u t i l e and t l t a n i t e , and t i n y c o l o r l e s s scales are a s s o c i a t e d w i t h s e r i c i t e . C a l c i t e . .Irregular masses of c a l c i t e are associated w i t h serir./ c i t e , c h l o r i t e , ' r u t i l e and t l t a n i t e . The c a l c i t e . appears to r e -place f e l d s p a r , but there are i n d i c a t i o n s that the c a l c i t e replaces s e r i c i t e . a n d c h l o r i t e , which had. p r e v i o u s l y replaced the f e l d s p a r . R u t i l e and T l t a n i t e . Brown a c l c u l a r c r y s t a l s of r u t i l e , -10-replace s e r i c i t e ( ? ) In,long, roughly p a r a l l e l bands, re -s u l t i n g in. a f i b r o u s matted appearance. The pseudo-fibres are bent around other crystals: such as p y r i t e , f e l d s p a r , and c a l c i t e , i n d i c a t i n g that the r u t i l e i s a l a t e product. A few l a r g e r stubby c r y s t a l s of" t i t a n i t e occur throughout the mass of r u t i l e but none of these are large enough to give an i n t e r -ference f i g u r e under crossed n l c o l s . Rhombic sec t i o n s , however, show symetrical e x t i n c t i o n , under r e f l e c t e d l i g h t the mineral has a l i g h t straw yellow c o l o r and a resinous, l u s t e r . The most common a s s o c i a t i o n i s with s e r i c i t e , r u t i l e and p y r i t e Accessories. A p a t i t e i s abundant i n the s e c t i o n . Sulphides«- Pyrite,; i n the form, of .skeleton c r y s t a l s , and rounded g r a i n s , i s associated w i t h the , t i t a n i t e . and r u t i l e . v. S l i d e S. V. #5. A l t e r e d Q u a r t z , D i o r i t e . Kine r a l Gomp o s i t i o n. t A l b i t e Abg5An5 -1% Quartz 36% S e r i c i t e 50% C h l o r i t e 20fo T i t a n i t e 5% Accessories 3% ^ Sulphides 1% A l b i t e . A l l the f e l d s p a r except a few small grains i s a l t e r e d to s e r i c i t e , c h l o r i t e and c a l c i t e . The unaltered f e l d s p a r i s a l b i t e . Quartz. Large angular quartz grains are f r e s h and unaltered, but some show s t r a i n shadows. S e r i c i t e and C h l o r i t e . The f e l d s p a r c r y s t a l s are wholly re-placed by a f i n e f e l t of s e r i c i t e flakes: throughout, which are -11-ir r e g u l a r : patches of l i g h t green to c o l o r l e s s c h l o r i t e . R u t i l e and T l t a n i t e . Tiny a c i c u l a r r u t i l e needles matted i n t o f i b r o u s brown masses occur associated with s e r i c i t e . Stubby, brown to c o l o r l e s s , t i t a n i t e c r y s t a l s are disseminated through-out the s e r i c i t e and e h l o x i t e * The . fel d s p a r c r y s t a l s which are not completely a l t e r e d to s e r i c i t e are clouded by innumerable a c i c u l a r r u t i l e c r y s t a l s . The r u t i l e and t i t a n i t e i s p a r t i a l l y a l t e r e d to leucoxene* Accessories and Sulphides. A p a t i t e occurs through the s e c t i o n , p y r i t e occurs c l o s e l y associated with r u t i l e and t i t a n i t e . S e v e r a l small grains of magnetite occur close to the r u t i l e and t i t a n i t e . v i S l i d e S. V. #6:. . A l t e r e d Quartz" D i o r i t e . M i n e r a l Composition.:: A l b i t e A b 9 5 A n 5 60% Quartz 8.8% S e r i c i t e 14% C h l o r i t e 3% T i t a n i t e 10% Accessories 2% Sulphides 2% A l b i t e . Large c r y s t a l s of a l b i t e Include a few f l a k e s and • needles of s e r i c i t e , c h l o r i t e and r u t i l e . Quartz. Grains of quartz showing s t r a i n shadows l i e between the fe l d s p a r c r y s t a l s . Aggregates of small unoriented quartz grains appear t o be secondary. S e r i c i t e and C h l o r i t e . S e r i c i t e , and a l i t t l e c h l o r i t e , i n a f i n e f e l t , r e p l a c e f e l d s p a r ^ Much, of the mineral which appears l i k e s e r i c i t e may be t a l c . -12-• a o N EH H CQ O I o o EH o h e Sulphides Accessories Titanium Minerals c r y s t a l s i s associated with s e r i c i t e . Many well-formed crystals of transparent to brown t i t a n i t e occur i n swarms through the se c t i o n . These are p a r t i a l l y a l t e r e d to leucoxene. Accessory M i n e r a l s . A p a t i t e is. abundant i n the s e c t i o n i n large c r y s t a l s . Sulphides. P y r i t e i s abundant. Y;»- Summary and Conclusions-C r y s t a l l o b l a s t i c a l b i t e , t i t a n i u m minerals i n f e l t e d masses, and s e r i c i t e pseudomorphic a f t e r feldspar c h a r a c t e r i z e the a l t e r a t i o n , of w a l l rock i n the Spud v a l l e y v e i n . S l i d e s . S. Y. #5 and. S.V. #6 are each composed of h i g h l y a l t e r e d wall-rock, one a l b i t i z e d and the other s i l i c i f i e d , suggesting that the two processes were a l t e r n a t e l y i n force. The presence of ti t a n i u m minerals was checked by a spectro-graph! c analysis.. Because they occur as n e e d l e - l i k e c r y s t a l s , g eniculated twins, and appear quite d i f f e r e n t from the c r y s t a l s known to be t i t a n i t e , the very small c r y s t a l s are c a l l e d r u t i l e . The absence of c a l c i t e and abundance of s e r i c i t e i n the h i g h l y a l t e r e d w a l l-rack i s noteworthy. Away from the vein i n the outer zone of a l t e r a t i o n c h l o r i t e i s scarce, i t i s abundant i n the c e n t r a l zone of a l t e r a t i o n , and again scarce in. the h i g h l y a l t e r e d w a l l - r o c k . A l b i t e , quartz, c a l c i t e and c h l o r i t e occur i n zones or bands i n the wa l l - r o c k p a r a l l e l to the v e i n . This suggests three a l t e r n a t i v e s ; 1., that the aqueous s o l u t i o n was flowing along the vein-channels i n a " p u l s a t i n g " fashion, 2.., that the. s o l u t i o n reacted on the w a l l - r o c k u n t i l chemical e q u i l i b r i u m was reached, and r e -ac t i o n ' subsided u n t i l the wall-rock was redharged w i t h f r e s h s o l u t i o n ; or •• . 3., that the composition of the s o l u t i o n was changing w i t h respect to some constituents and not others* (b) P r i d e n t V e i n . I * General D e s c r l p t l o n -The P r i d e n t veins l i e . i n the quartz d i o r i t e of the Zeballos b a t h o l i t h about 1000 f e e t east of the west contact, and about 1200 feet north of the White Star mine. Two v e i n s , one s t r i k i n g northeast and the other east, i n t e r s e c t i n the mine workings. The veins l i k e l y belong to the same age of m i n e r a l i z a t i o n . The mine i s operated by the P r i v a t e e r mining company, and the ore i s concentrated i n the p r i v a t e e r m i l l . 2. Fresh Wall-rock-The f r e s h w a l l - r o c k i s a l i g h t grey, medium-grained quartz d i o r i t e . I t i s b r i t t l e , w i t h a conchoidal f r a c t u r e . 3. A l t e r e d \falI-rock-The a l t e r e d w a l l - r o c k is. d u l l grey to li g h t , buff, f i n e - g r a i n e d and carbonaceous. I t i s s o f t e r than the fresh, rock and has an i r r e g u l a r f r a c t u r e . The quartz content i s s l i g h t l y higher than that of the f r e s h rock, and the f e l d s p a r , b i o t i t e and hornblende are converted to s e r i c i t e , c a l c i t e and -15-chc$>i$e«' Hear the. v e i n c h l o r i t e i a abundant, but i n the v e i n i t . i s absent. Tiny, roughly p a r a l l e l , I n t e r l a c i n g v e i n l e t s , weathering brown, cut the a l t e r e d rock, p a r a l l e l to the v e i n . 4. D e s c r i p t i o n of S l i d e s -The. f i v e t h i n - s e c t i o n s include rocks adjacent t o , and i n , the Priden t v e i n . i . S l i d e P r . ^ 1. Fresh quartz d i o r i t e . M i n e r a l composition; l a b r a d o r i t e AbsoAngQ^ Average, Andesine A b ? 0 A n 3 A Andes ine 56^" Oli g o c l a s e AbqnAn-, n( • u ^ B i o t i t e 5% Hornblende 2% S e r i c i t e 5% C a l c i t e 3% C h l o r i t e 2% Accessories 1.5% Sulphides. 0*5% Quartz. The quartz i s i n l a r g e i r r e g u l a r grains disseminated r e g u l a r l y through the s e c t i o n . No s t r a i n shadows are evident and i n c l u s i o n s are not abundant. Feldspar. Large, zoned c r y s t a l s of f e l d s p a r c o n s t i t u t e more than, h a l f the s l i d e . The inner zone i s l a b r a d o r i t e w i t h compo-s i t i o n , Ab g 0An 5Q. S e r i c i t e i s developed throughout the l a b r a d o r i t e . The c e n t r a l zone i s andesine, with composition Ab ? 0An 3Q. This, zone i s almost v o i d of s e r i c i t e . The outer zone is. o l i g o c l a s e , composition AbgoAn^Q- Most of the c r y s t a l boundaries are. w e l l - d e f i n e d , but a. few are i r r e g u l a r . S e r i c i t e , c h l o r i t e , b i o t i t e , and hornblende penetrate the outer zone. I n t e r p e n e t r a t i o n twins are common. A p a t i t e , the chief acces-sory mineral occurs i n many f e l d s p a r c r y s t a l s . The abrupt change in * composition "between the zones i s apparent without crossed n i c o l s - - t h e d i f f e r e n c e i n Indices of r e f r a c t i o n clearly-showing the zone boundaries . The a lb i t e-twinning on the outer zone v a r i e s from a negative to a zero, and p o s i t i v e angle of e x t i n c t i o n . B i o t i t e . Large 5 f l a k e s of dark brown b i o t i t e , p a r t i a l l y c h l o r i -t i z e d , occur throughout the slide.. Hornblende. The dark green hornblende i s p a r t i a l l y c h l o r i -t i z e d , and. ple o c h r o i c from green to brown. Sericite.. Blades and f l a k e s occur abundantly throughout the la b r a d o r i t e zone of the f e l d s p a r s , and sp a r i n g l y throughout the outer zones. Some of t h i s white, mica may be paragonite, but a spectrographic analysis, proves i t i d e n t i c a l to a known sample of muscovite, hence i t i s a l l r e f e r r e d to as s e r i c i t e . C a i e l t e . Small i r r e g u l a r patches of c a l c i t e occur i n the se c t i o n . There are often c l o s e l y associated with the c h l o r i t e . C h l o r i t e . L i g h t apple green and c o l o r l e s s f l a k e s of c h l o r i t e occur throughout the s l i d e . They show, anomalous blue to grey maximum i n t e r f e r e n c e c o l o r s , and e x t i n c t i o n i s p a r a l l e l to the cleavage. The v a r i e t y i s b e l i e v e d to be pen n l n i t e . I t i s as-sociated w i t h the b i o t i t e , hornblende and c a l c i t e . A ccessories. C o l o r l e s s a p a t i t e i n elongated c r y s t a l s with small, rounded i n c l u s i o n s i s common, along with brown, t i n y a c i c u l a r c r y s t a l s and black S k e l e t a l c r y s t a l s of. magnetite imbedded i n the c h l o r i t e and c a l c i t e . Sulphides:. A small amount of p y r i t e occurs, i n the s e c t i o n . -17-' i i S l i d e Br." #2. S l i g h t l y A l t e r e d Quartz. D i o r i t e . M i n e r a l Composition: Labradorite A b 5 0 A n 5 0 2 5 $ ) A v Andesine A W n ^ f\ Andesine 32$ Oligo c l a s e Ab9 0An 1 0 5%) ' Quartz 20$ S e r i c i t e 18$ C h l o r i t e 12$" C a l c i t e 12$; B i o t i t e 3$ • Magnetite 2$~ Accessories 2$ Quartz. Quartz i n f i n e r grains, than i n the unaltered rock i s evenly disseminated throughout the s e c t i o n . Feldspar. Most of the feld s p a r c r y s t a l s are a l t e r e d t o f i n e -grained masses of s e r i c i t e , c h l o r i t e and. c a l c i t e . The a l t e r a -tion, appears to have s t a r t e d i n the center of the c r y s t a l s and migrated outwards. The remaining f r e s h feldspar comprises about 32$ of the s e c t i o n , and the zones from the center to the edges of the se c t i o n s are l a b r a d o r i t e , andesine and oligoclase, r e s p e c t i v l e y . The p r o p o r t i o n and composition of each i s e s t i -mated as f o l l o w s : Labradorite 80$ AbgQAn^ Ande sine 10$" Ab7QAn3Q Oligoclase 10$ AbgQAnio B i o t i t e . A small quantity of b i o t i t e , but no hornblende, occurs i n the s e c t i o n . The b i o t i t e f l a k e s are p a r t i a l l y re-placed by c h l o r i t e and c a l c i t e . C a l c i t e . The c a l c i t e occurs i n i r r e g u l a r patches through the. s e c t i o n . C a l c i t e i s present i n small q u a n t i t i e s i n the r e -placed feldspar c r y s t a l s and b i o t i t e f l a k e s . Small v e i n l e t s cut p a r a l l e l ? across the se c t i o n . -18-C h l o r i t e . ' Light green or c o l o r l e s s c h l o r i t e occurs i n the re-placed feldspar and b i o t i t e , as w e l l as throughout the i n t e r -s t i t i a l f i l l i n g . Mast of the f l a k e s are very.-small and the colorless. Is more abundant than the green v a r i e t y . The green f l a k e s carry numerous brown, r u t i l e c r y s t a l s . . Accessory M i n e r a l s . A p a t i t e , r u t i l e and t i t a n i t e occur throughout the quartz, f e l d s p a r , s e r i c i t e , c a l c i t e and c h l o r i t e . Magnetite. Magnetite, i n very f i n e g r a i n s , occurs throughout the s e c t i o n . i l l . S l i d e #3. A l t e r e d Quartz D i o r i t e . ' M i n e r a l Composition; Quartz; .  ' 23%~ • Andesine Abgo-^40 ~) Average, O l i g o c l a s e Ab^QAn-jA Oligoclase 11% ^ Bio'tite 0.5%' S e r i c i t e 38% C a l c i t e 20%: C h l o r i t e 4% Accessories 3% Sulphides•. 0.5% Q.uartz. Quartz occurs i n an aggregate of f i n e grains cut by a second generation in. small veInlets.. Feldspar. Most of the f e l d s p a r c r y s t a l s are completely r e -placed by s e r i c i t e , c h l o r i t e and c a l c i t e , but the c r y s t a l shapes are preserved. Other f e l d s p a r c r y s t a l s are replaced ex-cept f o r a narrow zone aound the outer edge. The a l b i t e twinning and index of r e f r a c t i o n on the unreplaced zone i n d i -cate that i t i s o l i g o c l a s e . The remaining feldspar c r y s t a l s are p a r t i a l l y replaced along cracks and cleavage planes. Enough of the c r y s t a l i s preserved to measure the e x t i n c t i o n on -19-the a l b i t e twinning, and these c r y s t a l s , l i k e those i n the fresh rock show an. increase, i n the sodic constituent toward the outer zone. Bio t i t e .. A. few I r r e g u l a r flakes^o'f. b i o t i t e , l a r g e l y replaced by c h l o r i t e and c a l c i t e occur as a very minor constituent of the rock. S e r i c i t e . The replaced feldspar c r y s t a l s are mostly s e r i c i t e , with minor amounts of c h l o r i t e and c a l c i t e . Much of the i n t e r -s t i t i a l m a t e r i a l i s a very f i n e f e l t of s e r i c i t e and c a l c i t e w i t h a minor amount of. c h l o r i t e . S e r i c i t e f l a k e s and plume-shaped c r y s t a l s penetrate every mineral i n the s e c t i o n except the sulphides* Calcite« Small veins of c a l c i t e traverse the s e c t i o n . I r r e g u l a r patches of c a l c i t e occur haphazardly arranged through the rock. Very f i n e grains of c a l c i t e occur associated with the s e r i c i t e and c h l o r i t e . C h l o r i t e . Light..apple-green colored f l a k e s of c h l o r i t e occur i n the s e c t i o n . Several of these are large enough to produce an i n t e r f e r e n c e f i g u r e . The mineral i s pleochroic from straw-yellow to l i g h t apple-green. A .finer, c o l o r l e s s v a r i e t y of c h l o r i t e i s sparsely disseminated throughout the s e r i c i t e and c a l c i t e . Accessory Minerals.. A c i c u l a r c r y s t a l s of a p a t i t e are abundant throughout the quartz, f e l d s p a r , and s e r i c i t e - c a l c i t e aggregate. I r r e g u l a r g r a i n s , a c i c u l a r needles i n r a d i a t i n g masses of r u t i l e , and. short, well-formed c r y s t a l s , of t i t a n i t e occur c l o s e l y as-sociated w i t h the c h l o r i t e and c a l c i t e . I r r e g u l a r grains of -20-magnetite* aire s p a r s e l y scattered through.' the section.. Sulphide M i n e r a l s . Several small grains, of p y r i t e occur- i n the section:. i v . S l i d e #4.: A l t e r e d w a l l - r o c k adjacent to v e i n . M i n e r a l 0Qmpo.sltl.oji: quartz. 30$ Andes ine S e r i c i t e 25$ C a l c i t e 23$ C h l o r i t e 8$' Accessories 3$ Sulphides 8$ Quartz. Quartz occurs i n medium s i z e d i r r e g u l a r grains evenly d i s t r i b u t e d throughout the rock.. Feldspar.. Several small, i r r e g u l a r zones of f e l d s p a r remain unreplaced by s e r i c i t e , c a l c i t e and c h l o r i t e . . Many weJL-defined areas of f i n e --grained mica and carbonate are recognize— able a s completely replaced f e l d s p a r crystals..,. S e r i c i t e , C a l c i t e and C h l o r i t e . These three minerals con-s t i t u t e over h a l f the r©ck. The: s e r i c i t e i s the most abundant mineral In the a l t e r e d f e l d s p a r s . C a l c i t e occurs i n .-several small veins, probably a l a t e r generation. C h l o r i t e , i n very f i n e f l a k e s and bundles, occurs c l o s e l y intergrown with sericite and c a l c i t e . Some of the mineral which appears to be s e r i c i t e may be t a l c , since a chemical t e s t on several grains r e s u l t e d i n a p o s i t i v e r e a c t i o n f o r magnesium. Accessories. A p a t i t e i n small a c i c u l a r c r y s t a l s , r u t i l e In a c i c u l a r aggregates, t i t a n i t e i n stubby c r y s t a l s , and magnetite, or i l m e n i t e , i n skeleton c r y s t a l s c o n s t i t u t e the accessory -21-minerals. Sulphides . P y r i t e i n cubes, and grains occurs along with a few grains of s p h a l e r i t e . Quartz. Quartz, i n i r r e g u l a r , medium-sized g r a i n s , ,:vs,-evenly d i s t r i b u t e d throughout the s e c t i o n . S e r i c i t e . S e r i c i t e occurs i n f i n e - g r a i n e d c l o s e l y packed C a l c i t e . Many p a r a l l e l bands of c a l c i t e t raverse the s e c t i o n . A minor amount of c a l c i t e i s intergrown w i t h the s e r i c i t e . The t i n y veins are p a r a l l e l to the main v e i n , and appear to be a l a t e r generation than the disseminated type of c a l c i t e . Accessory M i n e r a l s . A p a t i t e , r u t i l e and t i t a n i t e c r y s t a l s are disseminated throughout the s e c t i o n . Sulphide M i n e r a l s . Several cubic p y r i t e c r y s t a l s and shapeless g r a i n s occur i n the s e c t i o n . 5 • Summary and Con.cluslo.ns-A l t e r a t i o n of the w a l l rock i s intense, but i t does not penetrate f a r from the v e i n . The amounts of quartz, accessory minerals, and sulphides, do not change appreciably from f r e s h to a l t e r e d w a l l -rock. v. S l i d e #5. Vein m a t e r i a l , with i n c l u s i o n s of wall-rock Ml ne r a l C omp o s i t i o n : Quartz S e r i c i t e C a l c i t e Accessories Sulphides 28% 25% 42% 3% Oof - 2 2 -A' uniform- Increase i n the. carbonate constituent of the rock, occurs, with i n t e n s i f i c a t i o n of a l t e r a t i o n . The p l a g i o c l a s e feldspar, i s replaced c h i e f l y by s e r i c i t e , and to a minor degree by c a l c i t e and c h l o r i t e . The ferromagnesian minerals, b i o t i t e and horne-blende, are a l t e r e d to c h l o r i t e , c a l c i t e and magnetite. The development of c h l o r i t e has been r e s t r i c t e d to the outer zone of a l t e r a t i o n , or the c h l o r i t e next to the v e i n has been a l t e r e d to s e r i c i t e . SUMMARY OE THE. PRIDENT SLIDES tsi -p CS CO a) <D 43 •H •P O •H d -H l <D O O 0 W , CO 0) •p •H O H O -P •RL fH o H i d o CQ 0) •H U o CQ 02 d3 o o CQ CD •rl XI P( H CO Pr. 1. 24 > f 56" \ ! i t 5 3 '1' • " ' 1 5 3 2 1.5 0 . 5 P r . 2. 20 f l " * 32 ? 3 0 18 i J.; .. . 12 12 " ' 2. 2 Pr .- 3 . 23 : 1 1 • 0.5 0 | ! 28 1 20 3 • 2 2 . 5 P r . 30 i 1 • 2 1 r 0 0 1 25 ; ™ 23 s ;.8 3 8 P r . < 5. ! 28 k !: i 0 0 0 I 25 i 40 | 0 3 4 -23-(c) the Mount Zeballos Vein, -k • General Geology-The f i s s u r e — v e i n l i e s i n metamorphosed v o l -. canic rocks of the Bonanza formation. The northeast end of the v e i n i s about 600 feet southwest of the contact between the Bonanza formation and the Zeballos b a t h o l i t h . 2. Fresh Wall-rock-The rock i s a dark green to black compact f i n e -grained andesite, containing small phenocrysts of glassy feldspar, and sparsely disseminated grains of i r o n sulphide. I t i s hard and breaks.with a. concholdal f r a c t u r e . 3* A l t e r e d l a l l - r o c k -The a l t e r e d wall-rock is. buff-grey and fine-grained, w i t h an earthy t e x t u r e . When breathed upon i t gives a strong aluminous, or clayey odor. The f e l d s p a r has. been a l t e r e d to s e r i c i t e , c h l o r i t e and c a l c i t e . The hornblende and b i o t i t e have been con-verted to c h l o r i t e , r u t i l e and magnetite. S i l i c a i s only abundant i n the v e i n s . C a l c i t e i s abundant i n the altered 1zone and a l a t e r generation i s a minor constituent of the s i l i c e o u s v e i n m a t e r i a l . The presence of a small, amount of vesuvianite indicates, high-temperature a l t e r a t i o n , probably pre-vein con-t a c t metamo.rphism by the underlying q u a r t z — d i o r i t e b a t h o l i t h . 4• D e s c r i p t i o n of Thin Sections-Five t h i n sections represent f r e s h rock, a l t e r e d rock and v e i n m a t e r i a l . -24-i * - . S l i d e M. Z. #1. P a r t i a l l y a l t e r e d andesite 3" from the v e i n . M i n e r a l Composition; Andesine-oligoclase Abr^An, Hornblende Light brown b i o t i t e R u t i l e and t i t a n i t e C a l c i t e S e r i c i t e Accessories 2% 1% 1% Feldspar. Large phenocrysts of untwinned and weakly-zoned feldspar occur embedded i n a groundmass of small lath-shaped f e l d s p a r s . The l a r g e f e l d s p a r s are p a r t i a l l y replaced by horn-blende... b i o t i t e and s e r i c i t e , p r i n c i p a l l y along f r a c t u r e s and grained v a r i e t y shows a suggestion of p a r a l l e l o r i e n t a t i o n . I t s composition i s s i m i l a r to that ...of the phenocrysts. Hornblende. L i g h t green, lath—shaped crystals- of hornblende are evenly disseminated throughout the s l i d e . The pleochroism colors, are straw-yellow to blue-green and t h i s along with other s i m i l a r c h a r a c t e r i s t i c s suggests that i t i s i d e n t i c a l with the amphibole i n the p u r e e l s i l l s described by R i e e . 1 * Magnetite i s c l o s e l y associated w i t h the hornblende. B i o t i t e . L i g h t brown to c o l o r l e s s b i o t i t e occurs i n bunchy aggregates. I t i s associated with no " p a r t i c u l a r m i n e r a l . C a l c i t e . A small v e i n l e t of. c a l c i t e traverses the s e c t i o n . L i t t l e or no c a l c i t e i s disseminated through the f e l d s p a r or ferromagn.esian minerals.. S e r i c i t e . The Large f e l d s p a r s are hosts, f o r a small quantity the outer edges. Tfeie composition i s about Ah^.0AnSQ *. The. f i n e -1* R i c e , ;H.. M. A.., American M i n e r a l o g i s t , Ybl» 20,. Ho.. 4. -25-of s e r i c i t e . Acce:ssory M i n e r a l s . Vesuvianite occurs i n one group of elongate! c r y s t a l s . Ilmenite or magnetite, p y r r h o t l t e } a n d p y r i t e i n very f i n e g r a i n s occur i n long v e i n l e t s and disseminated grains c l o s e l y associated with the hornblende. i i . S l i d e M. Z. #2. A l t e r e d andesite l-g-"- from the main v e i n , and cut by a s m a l l quartz v e i n . M i n e r a l Composition; Andesine-oligoclase 2$ Quartz i n v e i n l e t 10$ S e r i c i t e 30$ C a l c i t e .. . 30$ C h l o r i t e 24$ ' R u t i l e and T i t a n i t e 4$ Pyrite. 2$ Feldspar. One large f e l d s p a r phenocrysts, and many small i r -r e g ular species remain only p a r t i a l l y a l t e r e d to s e r i c i t e , c h l o r i t e and c a l c i t e . quartz. A. c l e a r - c u t v e i n l e t of quartz traverses the s e c t i o n . the -fiVs-V A smaller one, p a r a l l e l s :1A:., and contains, some c a l c i t e . S e r i c i t e , C a l c i t e and C h l o r i t e . Most of the se c t i o n Is a f e l t e d mass of very f i n e scaley aggregates of. s e r i c i t e , c a l c i t e and c h l o r i t e . The r e l a t i v e amounts present are a rough e s t i -mation. Titanite.. Minute, elongated c r y s t a l s of t i t a n i t e are scattered throughout the s e c t i o n . Several small c l u s t e r s of c r y s t a l s appear to be an a l t e r a t i o n from, hornblende or b i o t i t e since, they form a s o l i d , network around, but not penetrating feldspar d r y s t a l s . -26-p y r l t e . P y r i t e , In i r r e g u l a r grains and isometric c r y s t a l s occurs i n the quartz and q u a r t z - c a l c i t e v e i n l e t s , and i n the wall-rock, close to the mineral v e i n . i i i . S l i d e M. Z. #5. Highly a l t e r e d andesite -g-" from the v e i n . M i n e r a l Composition; quartz 4$" Andesine-oligoclase AboQAn,,, 7$ C a l c i t e 37% C h l o r i t e 23$" S e r i c i t e 20% Vesuvianite 4$ T i t a n i t e 5% Q.uartz. One i r r e g u l a r v e i n l e t of quartz; cuts the section.-Ee I d spar > Small remnants, of h i g h l y altered, f e l d s p a r c r y s t a l s are evenly d i s t r i b u t e d throughout the s e c t i o n . C a l c i t e , C h l o r i t e and S e r i c i t e . These three minerals irake up a f i n e f e l t e d mass. The c h l o r i t e and s e r i c i t e are i n sealey aggregates and the c a l c i t e i n i r r e g u l a r masses. Vesuvianite. Vesuvianite i n patches of c l o s e l y intergrown elongated c o l o r l e s s c r y s t a l s w i t h h i g h r e l i e f and low b i r e f r i n -gence occur i n the rock. The v e s u v i a n i t e shows no apparent a s s o c i a t i o n w i t h other minerals... I t i s a pre-vein. product from the high-temperature, contact metamorphic e f f e c t of the Zeballos batholith-. T i t a n i t e . Minute-, rounded i r r e g u l a r and elongated, dark brown grains occur evenly d i s t r i b u t e d through the s e c t i o n . In ad-d i t i o n , there are s e v e r a l c l u s t e r s of elongated, poorly deve-loped c r y s t a l s . The mineral .is. dark, brown to black under transmitted l i g h t , but w i t h r e f l e c t e d l i g h t i t i s y e l l o w i s h --27-brown: with* a resinous l u s t e r . iv.. Slide. M. : Z> #4 • Yein. m a t e r i a l , with small i n c l u s i o n s of the wall-rock. M i n e r a l C omp as i t i o n ; Quartz Sulphides: C a l c i t e S e r i c i t e C h l o r i t e Quartz. Elongated c r y s t a l s of quartz are set perpendicular to the vein: w a l l s . C a l c i t e . Small q u a n t i t i e s of c a l c i t e are present i n the v e i n . Sulphides. The sulphides-minerals i n the v e i n are p y r i t e , s p h a l e r i t e , arsenopyrite, p y r r h o t i t e and galena. S e r i c i t e and C h l o r i t e . The w a l l - r o c k adjacent t o , and included i n the v e i n , i s composed of s e r i c i t e , c h l o r i t e and c a l c i t e , with l i t t l e or no: sulphide m i n e r a l i z a t i o n . v. S l i d e M. Z. #5. , Vein m a t e r i a l with included, wall-rack.; M i n e r a l Composition; . Quartz Sulphides C a l c i t e S e r i c i t e C h l o r i t e Quartz. Most of the s l i d e i s composed of elongated c r y s t a l s and i r r e g u l a r quartz: grains w i t h some c l o s e l y associated c a l c i t e . Sulphides. P y r i t e , arsenopyrite, and s p h a l e r i t e . C a l c i t e , S e r i c i t e and C h l o r i t e . The included fragments of w a l l -28-rock. are composed of an aggregate of minute f l a k e s and grains of c a l c i t e , s e r i c i t e and c h l o r i t e . 6 • Summary and Gonclusions-The w a l l - r o c k a l t e r a t i o n i s much the same as i n the quartz die-rite.- i t does not extend f a r from the mineral v e i n , and the feldspar, hornblende and b i o t i t e have been con-verted to s e r i c i t e : calcite-. c h l o r i t e - magnetite and t i t a n i t e . One notable d i f f e r e n c e , however, i s the absence of e i t h e r s i l i c i f i c a t i o n or a l b i t i z a t i o n . The presence of vesuvianite i s i n d i c a t i v e of pre-vein contact me tamo r p h i sm by the Zeballos b a t h o l i t h . The mineral i s not a l t e r e d by the a c t i o n of the vein-forming s o l u -t i o n , hence the temperature i n the w a l l - r o c k during vein de-p o s i t i o n was lower than during, igneous i n t r u s i o n . SUMMARY OW THE MOUHT ZEBALLOS SLIDES M. Z. 1. M. Z. 2 . Z. • 3» Z. 4. Z. O « M. 0) i o5 a a •H o ta so 0 -rl | ° 37 -P H 0 10 • r-i .a O K 34' pre-" , "* * sent s CD P -p •P •H •r-i •H O •P O •H O H W 'r-i cd <D 0 CO 18 1 1 30 I 30 ipres. I --— J . 1 p •H Jh O H o 24 cd a) •r-t CD u <P 0 •H tn fl as cd a) -P 0 •H q H 7~~" 1 4 2 -29-(&) The White St a r Vein.. 1* General Geology-The White Star -workings are. about 2500 feet southeast of the P r i v a t e e r mine, and. i n the quartz d i o r i t e of the Zeballos b a t h o l i t h about 600 feet east of the west contact. The m i n e r a l i z a t i o n i s i n two f i s s u r e veins i n the quartz d i o r i t e * The veins cut pale g r e y , f e l s i t i c dykes. 2. The Fresh Dyke-rock-The rock i s a very f i n e - g r a i n e d , greenish~grey d a c i t e , with glassy f e l d s p a r phenocrysts up to f i v e milimeters long, scattered specks of a black m e t a l l i c , m i n e r a l , and a. few grains of black to brown hornblende.: I t Is. hard and breaks w i t h a clean conchoidal f r a c t u r e * 3 * The A l t e r e d Dyke-rock-The altered, rock i s whiter and s o f t e r than the f r e s h v a r i e t y s but b r i t t l e , with, an angular f r a c t u r e . The f e l d s p a r phenocrysts. and groundmass have been, completely r e -placed by s e r i c i t e . c a l c i t e and c h l o r i t e * The hornblende has been converted to t i t a n i t e and r u t i l e . 4. D e s c r i p t i o n of Sections-i * S e c t i o n W* S .. 3 * Fresh f e l s i t i c dyke-rock. Mineral. Composition; -30-Feldspar. Large^ zoned fe l d s p a r c r y s t a l s are set i n a ground-mass l a r g e l y composed of tiny, if^Ms^par /lath-shaped^.crystals . Some of the phenocrysts are p a r t i a l l y replaced and others are wholly replaced by s e r i c i t e , c a l c i t e and c h l o r i t e . The center zone i s andesine with e x t i n c t i o n angles on the a l b i t e twins up to 30°, and on the outer zones, o l i g o c l a s e , w i t h e x t i n c t i o n , at a maximum of 10°. The- t i n y , lath-shaped feldspars i n the m a t r i x are zoned and twinned. The composition i s o l i g o c l a s e with maximum e x t i n c t i o n of 10°. The fineness of grain,and the intimate association, of the feldspar w i t h the s e r i c i t e j f c a l c i t e and chlorite^make an estimate of the composition i m p r a c t i c a l . Quartz. Minute, quartz, grains i n l e n t i c u l a r aggregates about two milimeters long occur sparsely disseminated through the s e c t i o n . The t o t a l amount of quartz present i s believed l e s s than 5%. Hornblende.. Several, very small patches of brown hornblende occur c l o s e l y a s s ociated w i t h c h l o r i t e * B i o t i t e . One elongated f i b r o u s mass of brown b i o t i t e occurs i n the s e c t i o n . S e r i c i t e , C h l o r i t e and C a l c i t e . The three minerals s e r i c i t e , c h l o r i t e and calcite«,form f e l t e d masses approximating the shape of f e l d s p a r p h e n o c r y s t s — a p p a r e n t l y having a l l r e s u l t e d from the a l t e r a t i o n s of the f e l d s p a r * Some recognizable f e l d s p a r c r y s t a l s are p a r t i a l l y a l t e r e d to s e r i c i t e alone, others to c a l c i t e and c h l o r i t e , and some to s e r i c i t e and c a l c i t e . T i t a n i t e and R u t i l e * Minor amounts, of t i t a n i t e and r u t i l e occur associated, w i t h the c h l o r i t e and c a l c i t e . Pyrite.: Several cubic c r y s t a l s and grains of p y r i t e are em-bedded. I n the rock. • i i . S l i d e s W. S. 2 & 1. A l t e r e d Dyke-rock. M i n e r a l Compositions Feldspar (Andeslne-oligocILase) Quartz. S e r i c i t e C h l o r i t e C a l c i t e R u t i l e and T i t a n i t e Feldspar.; The p l a g i o c l a s e phenocrysts are completely a l t e r e d to s e r i c i t e , c a l c i t e and c h l o r i t e . The f i n e - g r a i n e d groundmass has been p a r t i a l l y , replaced, but some p l a g i o c l a s e grains r e -main unaltered..:. Q.uartz, The fine 5. l e n t i c u l a r aggregates .of t i n y quartz grains are not a l t e r e d . S e r i c i t e , C h l o r i t e and Calcite.- The feldspar phenocrysts are completely a l t e r e d , but t h e i r shape i s retained by the f e l t e d mass of s e r i c i t e and c h l o r i t e w i t h a minor amount of c a l c i t e . These minerals, also; developed i n i r r e g u l a r areas throughout the groundmass.. Small c a l c i t e . s e r i c i t e and c h l o r i t e veins cut the s e c t i o n , and one c a l c i t e v e i n l e t i s l a t e r than the cubic p y r i t e . Several elongated aggregates of s e r i c i t e f l a k e s appear about, the s i z e and shape of the hornblende and b i o t i t e plates, i n the f r e s h rock, and. may be. pseudomorphic a f t e r these minerals* R u t i l e . R u t i l e i s developed i n patches of very small ac i c u l a r crystals.. One angular area appears to be. the shape and; s i z e -32-of a f e l d s p a r phenocryst, but I t is. c a l c i t e with numerous brown, a c i c u l a r c r y s t a l s of" r u t i l e , developed along the cleav-age planes. The sequence of a l t e r a t i o n has been, therefore, p l a g i o c l a s e a l t e r e d to. c a l c i t e , and c a l c i t e to r u t i l e . i 1 i . g l i d e W. S. #1. H i g h l y a l t e r e d dyke-rock. Mineral. Composition;; Feldspar Quartz S e r i c i t e C a l c i t e C h l o r i t e H u t i l e and T i t a n i t e This section, i s p r a c t i c a l l y i d e n t i c a l with S l i d e W.. S. #2. 5 c Summary and: Conclusions-The f i n e - g r a i n e d rock i s close to a d a c i t e i n composition. Uearly 90$ of the f r e s h rock i s f e l d s p a r and quartz with f e l d s p a r the most abundant. The small l e n t i c u l a r zones of unaltered quartz grains Indicate a sedimentary o r i g i n but no. other supporting c r i t e r i a are evident. The f e l d s p a r phenocrysts are recognizable a f t e r complete a l t e r a t i o n . S e r i -c i t e i s the maj or a l t e r a t i o n , w i t h c h l o r i t e , c a l c i t e and r u t i l e as minor products. The a l t e r a t i o n s f o l l o w a course p a r a l l e l , to that of the s i m i l a r i ; but coarser-grained rocks, the quartz dio.ri.te from the Spud v a l l e y and Prident veins. (®) The P r i v a t e e r Veins. 1... General Geology-The Privateer, mine Is located i n the 'Bonanza. formation, a f:ew hundred, f e e t west of the west contact of the Zeballos batholith... Veins s t r i k i n g east-west cut sediments, volcanic b r e c c i a s , t u f f s and l a v a s , and I n t r u s i v e sheets of quartz d i o r i t e . The veins, terminate before reaching a pronounced f a u l t zone s t r i k i n g , east of north and dipping •65° west'. 2* Fresh Wall-rock-a . The f r e s h •rack, i s * l i g h t grey, fi.ne.-grained,. hard and b r i t t l e , a s i l i c i f i e d B » ^ U . Small i r r e g u l a r patches: of t i n y p y r i t e g r a i n s , i n c r e a s i n g i n abundance close to the veins, c o n s t i t u t e the o n l y structure in. the rock. M i c r o s c o p i c a l l y the rock i s . composed, of" an extremely fin e - g r a i n e d aggregate, of lath-shaped labradorite, : diopslde.., w o . l l a s t o n i t e v e s u v i a n i t e , apatite,and garnet c r y s t a l s disseminated through a groundmass of. a l b i t e and quartz.. 3. A l t e r e d Wa.ll-rock-Qlose to the v e i n the rock i s bleached l i g h t grey to white, but i t i s as hard, and b r i t t l e as the fresh, rock. P y r i t e , i n I r r e g u l a r patches,and. very f i n e - g r a i n e d , increases i n abundance close to the v e i n . Small, white and grey s i l i c e o u s . v e i n l e t s traverse the a l t e r e d rock. Micros.copically, the c h i e f c h a r a c t e r i s t i c s of the a l t e r e d rock are: (1) The abundance, of r e l a t i v e l y coarse c l i h o z o i s i t e . .-34-(2) A tendency toward porphyrinic structure with comparitively large phenocrysts of a l b i t e and quartz developed i n the f i n e groundmass. (3) P r a c t i c a l l y complete removal of the small, lath-shaped l a b r a d o r i t e c r y s t a l s . (4) The presence of large bladed w o l l a s t o n i t e c r y s t a l s . 4. D e s c r i p t i o n of S l i d e s -i . S l i d e p r . 37 #1. Contact Metamorphic rock. M i n e r a l Composition.: A l b i t e ..Labradorite Ab5QAn5Q Quartz. Diopside Wollastonite. Vesuvianite Garnet (?) , A p a t i t e p y r i t e A l b i t e . E q u l - s i z e d grains of untwinned a l b i t e c o n s t i t u t e a large p r o p o r t i o n of the groundmass.. A rough estimate of the amount, i s 50$ of the s e c t i o n . L a b r a d o r i t e . Small, lath-shaped c r y s t a l s of. twinned feldspar occur rather sparsely disseminated through the section... Quartz. A ffe» gra i n s of quartz, occur c l o s e l y intergrown w i t h the f e l d s p a r . Diopside. I r r e g u l a r bunches of grains and c r y s t a l s of diopside occur through the s e c t i o n . The index of the grains was deter-mined by o i l immersion to be close to 1.70. W o l l a s t o n i t e . Bladed c r y s t a l s of w o l l a s t o n i t e with t i n y i n -c l u s i o n s of. an unknown, mineral occur s p a r i n g l y through the s e c t i o n . Vesuvianitev Elongated c r y s t a l s of vesuvianite occur spari n g l y i n the s e c t i o n . The index of r e f r a c t i o n , tested with immersion o i l s , I s 1 ..7+ . A p a t i t e . Abundant, well-formed a p a t i t e c r y s t a l s occur l o c a l l y through the s e c t i o n . Garnet ( ? ) . Swarms, of t i n y , dark red garnet (?) i s the most conspicuous gangue m i n e r a l . Pyrite.. Small grains of p y r i t e occur sparsely d i s t r i b u t e d through the rock. 11. S l i d e p, 5.7 #&. Contact metamorphic rock near the v e i n . M i n e r a l C omp o s i t i o n ; A l b i t e Quartz Diopside YCollastonlte Vesuvianite Clin.oz.oi s i t e C a l c i t e A p a t i t e Garnet P y r i t e A l b i t e . The fine--grained groundmass of angular, c l o s e l y packed and untwinned a l b i t e grains i s unchanged i n the altered.rock. Secondary a l b i t e grains i n comparatively large,, untwinned pheno-cr y s t s have been developed, and the small lath-shaped l a b r a -d o r i t e c r y s t a l s have been almost wholly removed. Quartz.. Comparatively l a r g e grains of quartz have been I n t r o -duced, apparently along with the a l b i t e . Diopside. Tabular c r y s t a l s of diopside are abundant i n the a l t e r e d rock. -36-W a l l a s t o h i t e . Large bladed c r y s t a l s containing small t. dark i n c l u s i o n s of an unknown mineral are abundant in, the se c t i o n . The Index of r e f r a c t i o n , by o i l immersion, i s 1.62+-. The long bladed c r y s t a l s do not appear to be oriented i n any one d i r e c -tion-.-Vesuviahlte. Elongated c r y s t a l s i n bunches occur sp a r i n g l y through the section.. Clinozoisite-.. .One of the s t r i k i n g , differences, between the a l t e r e d and. the unaltered rock under the microscope i s the presence of c l i n o z o i s i t e . Abundant sub-angular c r y s t a l s and i r r e g u l a r grains of c l i n o z o i s i t e showing low and v a r i a b l e b i -r efringence, p a r a l l e l extinction., and high index of. retfraction^ l i e uniformly d i s t r i b u t e d throughout the f i n e groundmass of. quartz., feldspar,, diopside and w.ollastonite. This mineral is: not an a l t e r a t i o n from the v e i n s o l u t i o n but a contact— metamorphic product formed during the. I n t r u s i o n of the Zeballos b a t h o l i t h . A p a t i t e . Well-formed c r y s t a l s , of a p a t i t e are d i s t r i b u t e d through, the a l t e r e d rock., along w i t h some, l a r g e r , p a r t i a l l y eorroded crystals,., C a l c i t e . C a l c i t e , i n small i r r e g u l a r patches, constitutes: a minor part of the s l i g h t l y a l t e r e d wall-rock. Garnet ( ? ) . Small, dark redlsh-black grains are sparsely d i s -seminated through, the rock and appear to. be garnets. p y r i t e . Small cubic c r y s t a l s and large i r r e g u l a r grains of p y r i t e are a, minor constituent of the a l t e r e d w a l l rock. .. -37-' 5. Summary and Conclusions-Albite,, e l l n o z o i s i t e and quartz are developed In the a l t e r e d rock, and u n l i k e the a l t e r a t i o n , of the quartz-d i o r i t e c dacite or andesite, s e r i c i t e , c h l o r i t e and t i t a n i t e are absent. The secondary a l b i t e and quartz, are coarser-grained than the primary minerals. The freshest specimen of wall-rock.represented by S l i d e #1? contains, metamorphie minerals and has apparently been a l t e r e d by the i n t r u s i o n of the quartz: d i o r i t e p r i o r to the formation of the mineral v e i n . The development of large • c r y s t a l s . o f a l b i t e and quartz i n d i c a t e s that the ve i n solution was r i c h in -sodium and s i l i c a ; The f a c t that the e l l n o z o i s i t e i s not pcesent i n both s e c t i o n s , and that s e r i c i t e and c h l o r i t e are absent from both 5suggests that the a l t e r a t i o n of the o r i g i n a l rock was "^spotty" , and probably governed by now-obliterated l o c a l con-d i t i o n s . D. Summary and Conclusionsi (a) C i a s s i . f i cat i o n of the Zeballos ore deposits. The deposits are mi n e r a l i z e d f i s s u r e - v e i n s of.the mesothermal c l a s s . Data herewith compiled: p e r t a i n i n g to the wall-rock a l t e r a t i o n ^ a l o n g w i t h evidence regarding v e i n - s t r u c t u r e and m i n e r a l i z a t i o n , make p o s s i b l e t h i s d e f i n i t e c l a s s i f i c a t i o n of the Zeballos ore deposits. The f o l l o w i n g comparison i s con-c l u s i v e evidence that the deposits are p r a c t i c a l l y i d e n t i c a l w ith Lindgren's type megothermal deposit.. ; 2. Lindgren 1* . . , M i n e r a l J)eJosits., 1928, pp. -6:02-604... M * •H £ • HI cd M o •H £ • d a o CD 02 P Si d u H-> •P 0 O CQ ,d d CQ •H -p d o CD 02 fH O o 0 Cd Q. X* U CQ cd i CD te. o d ^! fn o o -P EJ • » o O CQ fH ;3 •i-i -p: d 6 p •H o ,d o ciS 02 •r-i CQ o d P> CD CD •i-i ft cd U si CH CD U •P •<H n CD CQ n -p ca CQ H CD o cd cd a H •H d o CD -P o i> CD •r-i CQ •rH Ei +3 CQ d cd d CQ fn CD CD CD fH -P X$ -P EiO d H d fx] CTJ d d ~ •H CD Hi d Si o " H —-: a -38-CQ O H H cd CD ts3 -P ciJ ; d o •H •-P cd fn CD -P H <! o o •i r-f H I-CQ 0 d •r-l CQ O H H cd ,Q CD KT ! 0 XI -p d •H d o •H P cd H CD -P H| cd M o o fn I H< H d fl-•H fl-d ea CQ o xS cd •H H) 4-5 CD CQ cd 02 -P (4 o CD P d -P d d H H> o c cd CQ cd ft -P *M CD •H o CD 02 o d O te, CD ft -P CD H CD »H Si H) d -P -p. cd d d P CD cd o 02 fn d p . te. d & S4 +3 -p o cd CD fn > CD te, CD d H ft -P CD CD cd CD CQ . CD H 02 ; fH . +> CD d cd +> fH CD o Xj -P o CD d iH •H d Xl P te, H) CD f-1 CD fl ,—* CD •H o > te, CO CD > CQ 02 cd s CD -d H1-H •d CD CD 02 1 P HI P fH CD d ^ tp H2 02 csS CD d Si CM •H O o 02 CD d d t> •H -d CD •H cd CD 02 fH H1 CD O - bQ HJ -d O cd o d -P o cd d cd •P cd 02 02 d Si •H CD CD +3 O cd CD O H fH o r-H XJ G . fH cd •d CD d CD oi CD •H cd CD u «W d CD CD cd >> •P fH H) fH d ^P cd CD •H CD d a> > CQ CD £}• ft &H o d •H d CD t> CD Hi cd fH 0 •d •H d o o' fH 0 <H =H •H cd 02 O d d o w ft 0 d •H 02 CD Si -P !>5 Si xS 0 •rH fH 0 -p O cd . fH ! o 02 d •H 0 !> H cd 0 si HJ O CQ CD & d i CQ >i d ( fH o o d cd o o ft 0 fH fH o 02 H| cd xf d ft i>> o >> H •rH H fH 0 a ;rH •P d 0 fH CQ d •H fH O d cd 0 •d o XI fH a •i, d o O •H d cd •H -P H •H 0 fH d ( 0 xJ Si s> cd i> H H-3 >> d O Hi o CQ •qQ 0 H cd te CQ cd 0 •P d •H x5 • ip 0 •rH 02 fH d d fH fH d !>> cd 0 >> ft CQ Si ft 02 CD fQ Si O •rt d 02 cd +J d d cd l>>' •H 0 CQ cd H l>>' H 02 H o H fH H tf o 02 6D cd cd 0 H si d d H P O p o •i-t fH H •rH W) fH ' d o CD o CO o H HJ •H Xi •H 02 -P fH o CD PH «M 0 0 d 02 X* o CQ .a 'H d N-•H -p H1 O -P X3 02 o fH ft +i d cd H Hi 0 vt i—. 0 a* d CD HJ cd fH a* CQ d cd p-cd sen 0 d •r-l i fH -P -o 02 HJ cd cd i d 02 P o d CD 02 H-i 0 o 0 M d cd H-i Q Si d o fH o •H Si o O -p td o a te. td fH a d d cd d X! • H cd i cd o <3 d d o 0 fH HI d •ri •rH •rH cd •H fH cd H o •P +3 . 0 M cd ft cd •H O •r-l > fH 02 H fH cd CQ CD 02 d cd O d -P •H -P H fH > . o H •H d 0 o •rH a O fH 02 0 D tiD i>5 H 02 xj cd O tiD ft H 0 d -p a 0 O cd 0 a 'rH o H 0 d H" -P: •rH 0 a 02 cd fH 0 •rH rH s> o cd d <w CQ 0 fH i u -P •H fH XJ >i' id CQ 0 !o0 cd P ft d o J8 a •rH fH d 0 Xl O X* o 02 H H o 0 o H d •P d cd o si H cd cd XS ,Q fH EH 0 •rH P d 0 XS X! 02 H 0 « cd XS •p 1 0 CD •p d CD N XJ d •rH H 0 0 fH H cd >> -P •r-i O o CQ -d CD H cd X3 fH Si M •H cd p -P o cd lPo fH H H •H XJ • d. o 0 Si O d cd -P d CD H o a1 d CQ fH 02 UG ho 0 H o 0 >5 a -p -p •d O fH HI 0 fH cD a fH d EH ;H fH 1 E-i - Hi P -P 02 O 0 +> HI ft d cd d CQ d H ,—» ft d d •H . s . 0 O o cd to •rH o o cd U -— d • o H 02' o Si . P •—' ft a d •ri d CD •ri si Si o rH -P -d •H H CD rH cd rf -P •H G rl CD O •H CD P CD P t=-•rl Pi cd £3 rl 03 ri o O CD 0) -p o hi - «i H p o a cd 03 o <W ri <! lii <W •r-1 <! o O 0 O CD CD CO a 03 rl rH d u o3 •ri -p 3 O -p o 03 <ri 0 o H a a5 CD GO ri QD GO r) CD ri •ri « cd cd a •3 H CD a •r) a -P •rl a a •ri CD ri a •H •Q s> o • cd H «, cd N CD ta CD -P Si 0 a -p rl P 0 a •H 03 a5 tiO . . o H d . cd •rl Cd i S-H • ft u H i < 6 0 © •n u 03 , .. rl 03 •H 6 CD d . u p' a >s i. d H cd •rt H P cd d cd o cd ri •ri cd CD P +3 CD 03 d H a H d cd CD cd ri i U < M CD H o N> a r-i o H •H cd ri a a i •H H cd CD H -p a .3 cd u •H P CD a O rl <H -P o o a , P <ri cd 03 1 a -p O a o u a •r) •rl o CD P Pi cd S> cd ri 03 CD CD •ri .d -P a P H cd 'd cd a o w cd -p CD •ri si r-1 d p CD o5 CD -P u P a •H CD cd r> a H -—-H •H CD cd ri ri CD P cd cd a •H ri d d si o 'ri si <d CD g o <H o CQ H cd 03 •r! a o ri •ri -39 i cd H i d CD o •ri M d r-1 P CD H O CD a p CD p 3 d cd rl a W 03 cd CD cd CD a H S\ f-i 'ri 3 EH 03 ElD cd a 00 rl cd O cd tiO rl cd CD rl d CD P o CD si •ri p p O r-i •H CD 03 « ri o <ri CD CD r-1 d p 03 cd t>> cd CD H i> H O d CD a Pi P CD a •ri a a •H o •ri d CD cd p xi p cd •rl 03 CD p o -H -p cd d rH rl a cd -P. CD a cd o a s» CD CD a si d o p CQ a CD o CD cd O CD a cd cq ri cd CD r-1 •ri cd r-1 p Pi Pi •ri CD CD 03 O ri E50 u CD •H cd cd ri CD -p Pi cd CD ,3 03 03 03 P i cd CD a CD ri a .a o P o o p o •ri o a 0 ri CD rl •rl -P rl P a ^4 O a •H a> •rt •H o H O <ri d d a o o CD •H rl d a ri < o rl < ri 0 ^! CD cd H d H {> p 4^ 03 H a H a cd cd td' CD 03 O CD S •d is td' d a •P p a 03 •ri - -rl •ri cd d a ri CD a o 0 •r! P-i > CD cd CD ri cd U -p a P 0 p 03 CD •rl o •rl P a O •P -P •ri O H o CD rH H rH cd o rH H cd -d a a cd H cd -d a H o !>> a cd CD cd O H •rl f> CD ri a •d ^! 0 NJ cd CD •ri a > d p cd •rl 3 p o3 •ri a .a !>> Pi a H o cd CD .a 0 CO 3 cd H p 0 r-1 o u cd a •rl H 0 CD o o p cd si a CD •rl !> p -d •H f> ri a a CD 0 H d o cd a -p P 03 ri d p a •rl a cd Pi cd rl CD 03 H CO +3 ri •r-i o nci a •rl ci cd 03 H •rl •ri a 0 CD -p 0 ri cd •rl si d &Q a o PH p CO p d 0 !> rl 0 03 0 H Pi 0 cd 0 rl a p i 0 rl t>> H P a 0 •d •rl 0 03 •ri P H 0 P •rl u o rH o "ri o p . a d o 0 d a 0 i—i a H o d a 0 p •ri P O •ri 03 H cd M 0 a •rl a cd •ri 03 0 a w cd a o rl ri 0 r^i 0 £-i 0 P •ri d rH cd o o d a cd 0 P •rl a -ri ri 0 03 >S •d 0 o cd S>> 0 H M 0 cd a •ri 03 'ri H cd cd p 03 i>> >> ^3 ri o 03 d ri ri cd cd Pi ? 03 p d d rH o 0 <ri ri 0 0 P r4 a EH 0 o d 0 •rl d a p 03 0 p o ri d 0 ri 0 p H cd >s H 0 P 0 H Pi O O TCJ o a cd 03 rH 03 cd -^1 03 0 a cd rH Pi 0 oD cd i> cd 0 rH Pi ri 0 a •ri a p 03 ri •rl >d 0 0 P o cd 0 p ri P cd cd o cd ri o tiD a o H cd d 0 u 0 03 0 ri Pi 03 •ri 0 ri a p 0 P 0 tJ a 0 ri o O cd N cd H r-i a a Pi a o 0 cd cd ri ri 0 d m a a < •rl cd < 0 P •ri O rH cd o d a cd 0 -p •ri O •ri ri 0 CQ <ri o 0 P cd 0 ri 5)0 aO cd d 0 P H 0 •ri •i— -40-d o CD El •ri O a o o ri •ri P •ri -P oj cd CD •d. cd CD P 'ri 0 p a 'H p -p CD H •ri a a Q •ri P cd M 0 P H o3 P CQ •ri cd 0 ri CQ M o o ri 0 H 'ri p> a ri •d H 0 >> 0 P •ri r-J 0 •ri +3 d o o cd a o CQ •ri a ,p P •ri cd cd •d ri a 0 P 0 •ri a ri a 0 ct3 o P) a CO a o 0 o o ' CQ o cd o >> o cd ,p p CQ d CQ •ri a o a cd a a o a a •ri a •ri -P •ri cd ri <d o 0 CQ a P a H <ri = a cd o 'ri 0 .d £-1 a •<-i .a O cd 0 rri •r-i CQ CQ cd p o Pi rri <4 p a cd -P CQ a o o 03 •P 0 i 03 -—» SX a •r-1 01 0-0 EH CO 0 0 ri itP •p a 03 a >> •ri o 0 r=> •ri ,p o a •d cd a <d o ri •ri 0 03 03 ri •r-i a 03 -d • a •d •ri d 0 cd a cd o oi a cd a 0 •ri a-0 a 0 3 ri p> o o 3 •ri •ri o o 'ri a a cd 03 03 0 cd 0 03 0 a p <—i CQ cd 03 p •ri •A -P cd p d d o <ri a a Pi p> o 0 cd o p> H •ri 03 © •ri i—-P O O •P .a cd a •ri -—' ri a P 0 0 o a • cd H -p •ri •ri Pi a 'ri i—i p cd o •ri p a cd ra i 0 P cd ri © -p a EH P cd .d a a •> a EH • ri d^ EH © p 0 r-1 o a a ,—» • P 0 ,—. a cd CD r-i 'ri o H cd P cd 'ri *—' o H cd CQ The Structure of the F i s s u r e - v e i n s : Lindgren's d e s c i p t i o n * of the structure of .me so thermal f i s s u r e veins i s an. almost perfect d e s c r i p t i o n of the s t r u c t u r e of the Zeballos f i s s u r e - v e i n s i 1. The ( i n d i v i d u a l ) f i s s u r e s are f a i r l y regular i n s t r i k e and d i p . 2. They have ne i t h e r the near-surface, extremely brecciated structure nor the l e n t i c u l a r , massive form of the deep-seated deposits. 3* "Smooth w a l l s and s l i c k e n s i d e s are abundant." 4. - "A coarsely c r y s t a l l i n e massive texture i s most common; combs, and rough banding by depo s i t i o n are by no means unknown, e s p e c i a l l y where the deposits contain c a l c i t e or b a r i t e . " 5. "As the f i s s u r e s were opened i n zones of f r a c t u r e , open spaces are present i n many deposits, though, the w a l l s u s u a l l y come together within, short i n t e r v a l s * ' 1 6. "The sulphides are coarsely c r y s t a l l i n e and roughly banded,, p a r a l l e l to the walls.** Regarding drusy openings, Lindgren s t a t e s ; " I f replacement Is promoted by r a p i d moving s o l u t i o n s , s o l u t i o n may be more a c t i v e than, d e p o s i t i o n , and drusy structure may r e -s u l t by l o c a l , d e f i c i e n c y of p r e c i p i t a t i n g substances i n the s o l u t i o n . " ^' This explains the p o s s i b i l i t y of drusy s t r u c t u r e at moderate pressure and depth, since, the c o n t r o l l i n g f a c t o r s are the speed, of. movement and chemistry of the s o l u t i o n . , The one f a c t that does not f i t w i t h the evidence 3. Lindgren W., M i n e r a l Deposits^ 1928, pp. 191-193 & p. 599. 4., Lindgren F. «, The nature of Replacement, Economic Geology, -42-pointing' to. me so thermal o r i g i n i s the c r u s t i f i c a t i o n In the veins p a r a l l e l to the w a l l s * The c r u s t i f I c a t i o n produces a f r i a b l e type of ore common to epithermal d e p o s i t i o n * The w r i t e r suggest that Lindgren's explanation, of drusy structure may be a p p l i e d w i t h equal success to c r u s t i f i c a t i o n . I f l o c a l conditions were such that, a rapid-moving s o l u t i o n alternated between s o l u t i o n and depositions I . can see no reason why c r u s t i f i c a t i o n may not occur at mesothermal pressure. The f a c t cannot be denied, however, that c r u s t i f i c a t i o n i s c h a r a c t e r i s t i c of low pressure d e p o s i t i o n , and that the fissure-veins,may have been formed at a pressure lower than that common i n mesothermal de p o s i t i o n , i n other words, at mesothermal temperature and epithermal pressure* The. M i n e r a l i z a t i o n : , In a comprehensive study of pol i s h e d sections. from the P r i v a t e e r v e i n Mr* E. J . W. I r i s h l i s t e d the m e t a l l i c 5. minerals i n order of abundance as i o l l o w s : 1. p y r i t e 2. Arsenopyrite 3* Galena. 4. S p h a l e r i t e 5. Chalcopyrite 6. P y r r h o t i t e 7. Gold 8* Unknown p y r i t e , arsenopyrite, s p h a l e r i t e and p y r r h o t i t e were observed in. the thin, s e c t i o n s * A l l of these minerals ex-cept p y r r h o t i t e arer-found i n mesothermal mineral deposits. P y r r h o t i t e i s commonly found i n deposits formed at higher temperature, ahd may suggest that the Zeballos veins were 5. I r i s h . E. J. T h e J ^ e r a ^ g v _ o f _spiae of the Gold Mines of B r i t i s h , Columbia, M.'A* Thesis, U.B.C., 1940. . -43-" formed under high-temperature mesGthermalL c o n d i t i o n s , (h) The Ore .So l u t l o n ~ - i t s O r i g i n and Composition. Since the f i s s u r e veins cut the upper s h e l l of the Zeballos b a t h o l i t h and pen e t r a t e t i n t o the o v e r l y i n g roof-rocks the n a t u r a l conelusion i s that the ore-bearing s o l u t i o n was derived from within-.the b a t h o l i t h , and was emitted sometime a f t e r the outer zone of igneous rock was s o l i d enough to f r a c -ture i n a smooth break. The ore s o l u t i o n presumably bears a. gehetie r e l a t i o n s h i p to the. b a t h o l i t h , and was probably derived by d i f f e r e n t i a t i o n , w i t h i n that igneous magma. How the ore-bearing; f l u i d was freed from, the magma, chamber, transported upT^ardand deposited i n the present, f i s s u r e - v e i n s Is a matter of conjecture., s i n c e the nature of the f l u i d and the one'—., m a t e r i a l before t a k i n g t h e i r present form i s unknown and cannot be reproduced i n the laboratoryV Any one, or a combination 9 of. the three following: t h e o r i e s might explain, the process. 6. BoweJXf and h i s supporters, suppose that, thei mineral constituents concentrate i n the magma chamber (as a residue from: f r a c t i o n a l c r y s t a l l i z a t i o n ) i n the form of an a l k a l i n e aqueous s o l u t i o n which may b o i l i f i t reaches a zone of moder-atei. The escaping gas penetrates cracks and f i s s u r e s and may be d i s t i l l e d . The d i s t i l l a t e - from the b o i l i n g s o l u t i o n s i s an acid.; aqueous solutions, which carries, the ore-forming m a t e r i a l oh-its^ upward ascent, through i n t e r s t i c e s i n the rock. The s o l u t i o n reacts with, the w a l l - r o c k depositing much of i t s load, i n c l u d i n g ore minerals, and r e p l a c i n g wall-rock-mlnerals:, to become chemically n e u t r a l and f i n a l l y a l k a l i n e . ; The ascending -44-s o l u t i a n 1'inall.y reaches the surface where i t is. transported to the sea.. Secondly> Penner, " and h i s supporters, advocate boiling.--In the magma chamber, and the gas condensing near.the source as an acid,aqueous s o l u t i o n . The s o l u t i o n , forced up-ward through i n t e r s t i c e s i n the roof-rock,, by gas pressure from below, deposits.,, i t s load, reacts w i t h the wall-rocks,, interchanging c o n s t i t u e n t s , becoming neutrals or b a s i c , and " f i n a l l y passe.s;| to the surface and the sea. a. L a s t l y , Sraton, and. h i s associates point out that the o r i g i n a l m a t e r i a l may be i n the form of an. a l k a l i n e s o l u -tion, which passes: upward" through the cracks and J o i n t s i n the rocks, deposits i t s load, reacts on the wall-rock, i n t e r -changing m a t e r i a l , and f i n a l l y reaches, the surface of the earth and flows to the sea. > . Whether the s o l u t i o n was a c i d or a l k a l i n e , and b o i l e d e a r l y or l a t e , i s not known, but the. mineral changes i n the ....... a l t e r e d wall-rock, i n d i c a t e that the s o l u t i o n was aqueous and c a r r i e d K, Ga, Ma, S i . Mg,,. 3?e, pb, Zn, As., Cu, Au, S, GGg, .'and"]S% That the s o l u t i o n was aqueous i s evidenced by the a d d i t i o n of water to the wall-rock, i n the form of the f o l i o w i n g hydrous m i n e r a l s - - s e r i c i t e , c h l o r i t e , and t a l c . Potassium may have been supplied by the b i o t i t e pre-sent i n the o r i g i n a l rock, but potassium must have been i n t r o -duced wi t h the m i n e r a l i z i n g s o l u t i o n to account f o r the amount o i s e r i c i t e formed.. The presence of s e r i c i t e i s an i n d i c a t i o n -45-$hat the: hydrous s o l u t i o n may have been a l k a l i n e , but 9 . 0. C. Schmedeman says; * " S e r i c i t e as a mineral i s not I n d i -c a t i v e of e i t h e r a l k a l i n e or a c i d attack, but i t probably forms (-where potash i s added) only from, a l k a l i n e or weak a c i d s o l u - . t i o n s . " Calcium was probably.a constituent of the s o l u t i o n since most of the secondary minerals formed are c a l c i c , i n -cluding cal c i t e , . Calcium would be derived from the a l t e r a t i o n of the f e l d s p a r s and much would probably be d i s s o l v e d from any limestone beds i n the sedimentary formations cut by the f i s -sures. The r e l a t i v e q u a n t i t i e s of calcium added and leached from the wall-rock i s not a c c u r a t e l y known, but there Is sus-pected to have been an. addition, from t h s , hydrous s o l u t i o n . Sodium was most l i k e l y an. important constituent of the hydrous s o l u t i o n , because although some was supplied by the primary feldspars:, a large amount was added In the form of a l b i t e . The term " a l b i t i z a t i o n " Is commonly associated with gold deposits.. A f t e r a study of numerous mines where a l b i t i -z a t i o n is. an e s t a b l i s h e d f a c t , Gallaher suggests; 1 0* 1. "Where gold i s the only valuable mineral, and other m e t a l l i c minerals are not abundant, the g e n e t i c a l l y r e l a t e d igneous, rocks are commonly high in. a l b i t e . " 2-* "where s i l v e r is, more abundant the lime content of the f e l d s p a r of the associated rocks is. higher."-9~T Schmedeman, G. C., Botes, on the Chemistry of Ore S o l u t i o n s . Economic Geology, V o l . 33, D e c , 1918, p.. 803. 10. David Gallaher, A l b i t e and Gold, Economic Geology, Sept.-Oct., 1940, V o l . 35. :3- "Where the s i l v e r i s i n considerable excess over gold, as: gold is: subordinate to the other metals, or where the m e t a l l i c minerals are very abundant, soda feldspars are general-l y , l a c k i n g , and not. uncommonly the g e n e t i c a l l y r e l a t e d igneous rocks are notably potassic.:" Ah apparent genetic a s s o c i a t i o n between a l b i t e and gold deposits i s w e l l known throughout Canada and B r i t i s h Colum-b i a , i n the Skeena Eiver D i s t r i c t , Kerr 1 1 * noted that "-the i n t r u s i v e s t h a t are v a r i a b l e i n character due to d i f f e r e n t i a t i o n , e s p e c i a l l y those high In a c i d p l a g i o c l a s e , are by f a r the most Important producers of mineral deposits. Those hig h i n a l b i t e p l a g i o c l a s e commonly have associated mineral deposits, and these g e n e r a l l y have a high gold content. The uniform i n t r u s i v e s , e s p e c i a l l y some f a i r l y high In orthoclase and Intermediate p l a g i o e l a s e , have not producedmuch important m i n e r a l i z a t i o n . " : i n the M a l a r t i c area, Gunning ^* observed a probable genetic r e l a t i o n , between a l b i t e - r i c h I n t r u s i v e rocks and gold d e p o s i t s , the a l b i t e being an important component of the pre-mine r a l - v e i n i n t r u s i v e s , and a constituent of the ore s o l u t i o n s . The w r i t e r suggests t h a t , rather than the soda-rich f e l d s p a r having some a f f i n i t y f o r gold or some chemical c o n t r o l over i t s concentration or p r e c i p i t a t i o n , the gold and a l b i t e are cen. simply products r e s u l t i n g firom continued c o n t r a t i o n i n a, l a r g e , n e c e s s a r i l y h i g h l y - d i f f e r e n t i a t e d body of magma, and since both u s u a l l y are freed near the end-point i n the d i f f e r e n t i a t i o n pro-cess, they commonly occur ;together^ __ • I T T K e r r ]?. A., BeonomIc"Geology, June-July, .1938, p.- 432. 12.. Gunning E. C., Canadian G e o l o g i c a l Survey, Mem. 206, pp. 42-44 i'lfi-e argument that gold and other metals: may be .-carried"'-In ..solution with double sodium-potassium sulphides, as suggested by Eoxace Freeman, * and J . E. Spurr.M.; has a d i r e c t bearing upon the problem, of. the: close a s s o c i a t i o n of gold:. w i t h albite,, since, the s o l u t i o n s ; forming a l b i t e and s e r i -c i t e .were, n e c e s s a r i l y r i c h i n §-I^ 4.ti«a5,Whether the a l k a l i e s were i n the sulphide form or not i s unknown, but i f they were, there seems to be no doubt that the heavy metals could be taken i n t o aqueous, s o l u t i o n as double sulphides and transported as such. S i l i c a has been an important constituent of the s o l u -t i o n since most of the v e i n m a t e r i a l i s quartz. Considerable s i l i c a i s released, by the fe l d s p a r when i t i s a l t e r e d to s e r i -c i t e . and t h i s may be removed to the vein i n s o l u t i o n and there p r e c i p i t a t e d , but since the v e i n i s often s e v e r a l times greater i n volume; than the volume of altered w a l l - r o c k , s i l i c a must have been added by v e i n - f i l l i n g s o l u t i o n . The secondary quartz i s a l l c r y s t a l l i n e suggesting a confining pressure higher than that of the epithermal or xenothermal. zones. Magnesium may have been a rather important constituent of the. s o l u t i o n , f&ere the vein cut the sedimentary and v o l -c a n i c rocks, o$ course. magnesium could have been taken Into s o l u t i o n from, magnesium carbonate minerals. The b i o t i t e and hornblende i n the o r i g i n a l , unaltered,;, igneous wa l l - r o c k may s supply a s m a l l quantity of magnesium.:, but hardly enough f o r 13:i. Horace, Freeman, Engineering and f i n i n g Journal-Press, Vol... 120, lo.. 2.5.,, pp.. 97.3-975: V o l . 121, Ho. 1.4, pp. 571, 5 Vol.. 122, Eo.... 9, pp. 340-341. 1.4.. Spurr J . E., Engineering and Mining Journal-Press, V o l . 120, No. 25, pp.. 975-977. •-48-the format lean of so much c h l o r i t e , i:t..:was noted, however, that the c h l o r i t e seldom occurs i n the v e i n *>r a c t u a l l y adjacent to i t , hut u s u a l l y along a- zone i n the •wall-rock ao short distance from the f i s s u r e . Apparently the c h l o r i t e , i f ever formed i n and adjacent to the v e i n , was l a t e r replaced by non-magnesium m a t e r i a l , whi.ch suggests that i f not during the e n t i r e p e r i o d of vein-formation, at l e a s t during the l a s t stages, the s o l u t i o n was. magnesium-poor.. ' The presence of the elements. Je, Pb, Zn, As, Cu, Au and, S i n the hydrous, s o l u t i o n i s evidenced by the gold and the m e t a l l i c minerals i n the veins. The presence of COg i n the s o l u t i o n is. quite p o s s i b l e since the abundant c a l c i t e may have been, formed by the a c t i o n of GOg on calcium—bearing m i n e r a l s , or calcium i n the hydrous s o l u -tion.. Titanium was probably i n the s o l u t i o n i n the form of TiC^. Other elements, such as H£ as HgS, and 01 as HC1, were quite probably present i n the solution., but d e f i n i t e evidence i s l a c k i n g . (c) The E f f e c t of the Wall-Rock on the Alteration.. The veins cut four types of wall-rock, namely, quartz d i o r i t e , andeslte, dyke-rock resembling d a c i t e , and a s i l i c i f i e d contact metamorphlc rock. The quartz d i o r i t e , andesite and dacite are quite s i m i l a r In m l n e r a l o g i c a l composition and the a l t e r a t i o n i n each i s p r a c t i c a l l y i d e n t i c a l . The s i l i c i f i e d rock, however, i s p r a c t i c a l l y unaltered. The a l t e r a t i o n of the p l a g i o c l a s e feldspars to s e r i --49-cite- could "be accompli shed by a s o l u t i o n r i c h i n H 20, K2O and COrj r e a c t i n g at moderate temperature as f o l l o w s : 1. iNa20 • GaO . 3/2 A l 2 0 3 . 5Si 02-hH20f C© 2^K 20ssH 20 - i l ^ O . 3 / 2 A l 2 0 3 . 3 S i 0 2 11 Labradorite S S e r i c i t e tCaC03+3/2Si02ff¥a2Si03. 2. 3 (3Ma 20. 4CaO . 7 A l 2 0 3 .26Si0 2) -M4H20-l-12G02-f7K20--30 Andesine 14(H 20-iK 20.3/2Al 20 3.3Si0 2}+12CaC0 3*27Si0 24-9Na 2Si0 3. 14 S e r i c i t e 3 . 3 (9/2]\Fa20 - GaO . , l l / 2 A l 2 0 3 . 2 9 S i 0 2J +llH20t3G02^H/2K 20= 30 O l i g o c l a s e 11 (H2G »iK20 -3/2Al20 3 • 3Si 0 2) f 3CaG03+-27/2H"a£Si.03-+8l/2Si02, 11 S e r i c i t e The s o l u t i o n would be charged with GaC0 3, S i 0 2 and N a 2 S i 0 3 , which could be c a r r i e d along the f i s s u r e , react with other constituents i n the s o l u t i o n or wall-rock, or be deposi-ted i n the wall-rock or f i s s u r e . Probably a combination of the above three a l t e r n a t i v e s occurred i n the Zeballos deposits, the. CaC0 3 and S i 0 2 depositing i n open f i s s u r e s , and the M'a 2Si0 3 r e a c t i n g , under favorable conditions, producing a l b i t e . The same rea c t i o n s , without the K 20, would give paragonite as an a l t e r a t i o n product i n place of s e r i c i t e . 1. iHa20.-Ca0.3/2Al203.5Sl02fH20-4.G02= -Labradorite H 20.tNa20.3/2Al 20 3.3Si0 2*CaC0 3*2Si0 2 • P a r a ^ n i t e ' . 2... 3 (3^20'.4Caav.7Al263:-26-SiQ2$+14H2©+l£GQg':= 30 Andesine 14 (H 20 .#Ha2G .3/2Al203•..3Si02:.i"1t.l2Ca;ae3f3:4Si02+-2¥a2Si03. 14 Paragonite 3. 3(9/2Ma20.Ca0.1l/2Al203.29Si0 2)4-llH20+3G02= 30 Oligoclase: •llOlgOj^ • 11 paragonite , Since i t i s impossible to t e l l paragonite from s e r i -c i t e i n thin, s e c t i o n some of the s o - c a l l e d s e r i c i t e , may be paragonite, although spectrographic a n a l y s i s has established the mica to be c h i e f l y p o t a s s i c rather than sodic. The b i o t i t e a l t e r i n g to c h l o r i t e frees some potassium carbonate, and although there, i s an addition, of potassium to the s o l u t i o n , i t . i s u n l i k e l y that t h i s i s s u f f i c e n t to account f o r the volume of s e r i c i t e formed. B i o t i t e C h l o r i t e The presence of. diopside, "wollastonite, vesuvianite and c l i n o - e n s t a t i t e i n the wall-rock of the p r i v a t e e r mine suggests that the rock, i s a. product from the high-temperature a l t e r a t i o n o f a calcareous, t u f f or sediment.. These minerals are not a f f e c t e d by n e u t r a l , weak a c i d or a l k a l i n e hydrous sol u -t i o n , at. mesothermal temperature. I t i s . d i f f i c u l a t , however, to ex p l a i n why the feld s p a r was not converted to s e r i c i t e by the -51-s o l u t i o n , unless the i n s o l u b l e minerals made the wall-rock impervious, and the s o l u t i o n could not accumulate i n s u f f i c i e n t concentration to attack the f e l d s p a r s . E. Acknowledgements. The. w r i t e r is. deeply g r a t e f u l to Dr. H. C. Gunning f o r h i s u n t i r i n g guidance i n the laboratory, and h i s c a r e f u l c r i t i c i s m of the i n t e r p r e t a t i o n of r e s u l t s , as w e l l as f o r supplying the hand-specimens and t h i n sections upon which t h i s study i s based. Mr. W i l l i a m H• Mathews a s s i s t e d the w r i t e r g r e a t l y by making, spectrographic analyses of several minerals. 

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.831.1-0053063/manifest

Comment

Related Items