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Geology, geochemistry, and origins of the Mount Bisson alkaline rocks, Munroe Creek, British Columbia,… Halleran, Arthur Alvin Douglas 1991

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GEOLOGY, GEOCHEMISTRY, AND ORIGINS OF THEMOUNT BISSON ALKALINE ROCKS, MUNROE CREEK,BRITISH COLUMBIA, CANADABYARTHUR ALVIN DOUGLAS HALLERANB.Sc., The University of British Columbia, 1980A THESIS SUBMITTED IN PARTIAL FULFILLMENT OFTHE REQUIREMENTS FOR THE DEGREE OFMASTERS OF SCIENCEinTHE FACULTY OF GRADUATE STUDIESDEPARTMENT OF GEOLOGICAL SCIENCESWe accept this thesis as conformingto the required standardTHE UNIVERSITY OF BRITISH COLUMBIADecember 1991.© Arthur Alvin Douglas Halleran, 1991.In presenting this thesis in partial fulfilment of the requirements for an advanceddegree at the University of British Columbia, I agree that the Library shall make itfreely available for reference and study. I further agree that permission for extensivecopying of this thesis for scholarly purposes may be granted by the head of mydepartment or by his or her representatives. It is understood that copying orpublication of this thesis for financial gain shall not be allowed without my writtenpermission.(SignatureDepartment of  62e/op ersi The University of British ColumbiaVancouver, CanadaDate DE-6 (2/88)ABSTRACTIgneous and metasomatic rocks comprise a newly recognizedsuite of REE enriched alkalic and granitic rocks within theWolverine metamorphic complex at Mt. Bisson. The alkaline rocksinclude Tertiary alkalic dikes, allanite pegmatites, syenitepegmatites and fenites. The fenites are the products ofmetasomatism of Wolverine amphibolites by Na, Fe 34', Sr, Ba, REE,Y and F enriched solutions. The granitic rocks includeCretaceous plutons, quartz-allanite pegmatites, monazitepegmatites and Tertiary plutons and pegmatites. Many of thegranites have S-type granite characteristics representative ofupper crustal melts. The mineral chemistry within these rocksrequires that both closed and open chemical processes haveparticipated.LREE solid solution data on coexisting allanite, titaniteand apatite facilitate the recognition of closed and openchemical system processes in rocks. Closed chemical systems arerecognized by: i) decreasing core to rim LREE concentrations,ii) fine scale oscillatory zoning paralleling crystallographicorientations, iii) consistency between texturally inferredcrystallization sequence and the measured LREE contents ofcoexisting minerals, and iv) dimininshed LREE contents inphases which are inferred to crystallize after allanite. Openchemical system processes are suggested: i) where all of theabove criteria are absent or ii) where one of these criteria isreversed. Additionally, three new mineral compositions; two fortitanite and one for apatite occur at Mt. Bisson.iiTABLE OF CONTENTS ABSTRACT^ iiTABLE OF CONTENTS^ iiiLIST OF FIGURESLIST OF TABLES^ viiiACKNOWLEDGEMENTS ix1.02.0INTRODUCTION^1.1 PREVIOUS WORK^GEOLOGY^1332.1 REGIONAL GEOLOGY^ 32.2 FIELD OCCURRENCES OF ALKALINE ANDIGNEOUS ROCKS 82.2.1 Laura Map Area^ 82.2.2 Will No. 1 Map Area^ 142.2.3 Will No. 2 Map Area 142.2.4 Ursa Map Area^ 172.3 SUMMARY OF FIELD RELATIONS^ 183.0 DESCRIPTIVE PETROLOGY^ 213.1 ALKALIC DIKE ROCKS 213.2 PEGMATITES BARREN OF RARE EARTH ELEMENTS^ 233.3 PEGMATITES BEARING RARE EARTH ELEMENTS^ 243.4 LAURA AND WILL FENITES^ 263.5 MB GRANITES^ 284.0 GEOCHEMISTRY 294.1 MAJOR ELEMENTS^ 294.2 TRACE ELEMENTS 364.3 RARE EARTH ELEMENTS^ 414.4 DISCUSSION OF PETROGRAPHY AND GEOCHEMISTRY ^ 49iii4.5 PEARCE ELEMENT RATIOS^ 565.0 MICROPROBE ANALYSES OF MINERALS 575.1 PYROXENE^ 585.2 FELDSPAR 655.3 AMPHIBOLE^ 705.4 BIOTITE 785.5 APATITE^ 805.6 TITANITE 875.7 ALLANITE^ 956.0 LREE BUDGETS IN COEXISTING ALLANITE, TITANITE, ANDAPATITE 1026.1 CLOSED AND OPEN CHEMICAL SYSTEMS: Examples fromMt. Bisson^ 1167.0 CONCLUSION 125REFERENCES^ 128APPENDIX A - PREPARATION AND ANALYTICAL PROCEDURES FORDETERMINATION OF MAJOR, MINOR, TRACE AND RAREEARTH ELEMENT CONCENTRATIONS^ 135APPENDIX B - ANALYTICAL CONDITIONS FOR MICROPROBEANALYSES^ 144LIST OF FIGURES Figure 1.0 - General geology for Mt. Bisson Area ^ 4Figure 2.0 - Geologic map of Laura No.1 area^ 11Figure 2.1 - Geologic map of Laura No.2 area 12Figure 2.2 - Geologic map of Will No.1 area^ 15Figure 2.3 - Geologic map of Will No.2 area 16Figure 2.4 - Schematic diagram showing sequence ofalkalic and igneous events at Mt. Bisson^ 19Figure 4.0 - Harker diagrams showing major elementcompositions of representative rocks^ 31Figure 4.1 - Mt. Bisson igneous rocks plotted onAl203 vs Na20+K2O+Ca0^ 33Figure 4.2 - Mt. Bisson igneous rocks plotted onalkalis vs silica with superimposed SiO2classification^ 34Figure 4.3 - Trace elements (ppm) plotted againstSiO2 for whole rock compositions^ 38Figure 4.4 - Log Sr (ppm) vs Log Ba (ppm) for wholerock compositions^ 39Figure 4.5 - Total REE concentrations vs rock sample,sorted into units 43Figure 4.6 - Chondrite normalized REE abundancepatterns for alkalic dikes^ 45Figure 4.7 - Chondrite normalized REE abundancepatterns for pegmatites 46Figure 4.8 - Chondrite normalized REE abundancepatterns for fenites^ 48Figure 4.9 - Chondrite normalized REE abundancepatterns for MB granites 50Figure 5.0a- Fenite and alkalic dike pyroxenecompositions plotted as Cations Na vs Mg^ 63Figure 5.0b- Pegmatite and MB granite pyroxenecompositions plotted as Cations Na vs Mg^ 64Figure 5.1 - Pyroxene compositions plotted as CationsCa+Mg+Fe2 vs Na+Fe3^ 66vFigure 5.2 - Feldspar compositions plotted asmole % An, Or and Ab^ 71Figure 5.3 - Plagioclase compositions plotted asCations Ca vs Na 73Figure 5.4a- Fenite alkali feldspar compositionsplotted as Cations K vs Ba^ 74Figure 5.4b- REE pegmatite and MB granite alkalifeldspar compositions plotted asCations K vs Ba^ 75Figure 5.5 - Fenite and REE pegmatite alkali feldsparcompositions plotted as Cations K vs Sr^ 76Figure 5.6 - Biotite compositions plotted asCations Fe2+Fe3 vs Mg^ 81Figure 5.7 - Biotite compositions plotted asCations Si vs Al 82Figure 5.8 - Apatite compositions plotted as CationsLREE+Y vs Ca Cations x 10/Sum Ca site^ 84Figure 5.9 - Apatite compositions plotted as CationsLREE+Y+Sr vs Ca Cations x 10/Sum ofCa site^ 85Figure 5.10- Titanite compositions plotted as cationsLREE+Y vs Ca 91Figure 5.11- Titanite compositions, excluding fenite7910 titanites, plotted as CationsLREE+Y va Ca^ 92Figure 5.12- Titanite compositions plotted asCations Nb vs Ti 93Figure 5.13- Titanite compositions plotted asCations LREE+Y+Sr+Nb+FeT vs Ca+Ti^ 94Figure 5.14- Allanite and epidote compositionsplotted as Cations Ca vsLREE+Y+Na+Mn+Th+Sr^ 98Figure 5.15- Allanite and epidote compositionsplotted as Cations Ca+Fe3 vsLREE+Y+Fe2^ 99Figure 5.16- Allanite and epidote compositionsplotted as Cations Ca+Al+Fe3 vsLREE+Y+Fe2^ 100viFigure 6.0 - Schematic representation of mineralcore to rim chemical variationsexpected in closed magmatic systems^ 103Figure 6.1 - Chondrite normalized LREE abundancepatterns of allanites^ 105Figure 6.2 - Chondrite normalized LREE abundancepatterns of titanites 106Figure 6.3 - Chondrite normalized LREE abundancepatterns of apatites^ 107Figure 6.4 - Chondrite normalized REE abundancepatterns of aegirine augite dikes andtheir accompanying LREE containing phases ^ 109Figure 6.5 - Chondrite normalized REE abundancepatterns of allanite pegmatites and theiraccompanying LREE containing phases^ 110Figure 6.6 - Chondrite normalized REE abundancepatterns of fenitized granodiorite andaccompanying titanite^ 113Figure 6.7 - Chondrite normalized REE abundancepatterns of Will fenites and theiraccompanying LREE containing phases 114Figure 6.8 - Chondrite normalized REE abundancepatterns of TMB granites and theiraccompanying LREE containing phases 117Figure 6.9 - Schematic representation of observedmineral core to rim chemical variationsin TMB granites^ 118Figure 6.10- Chondrite normalized REE abundancepatterns of quartz-allanite pegmatitesand their accompanying LREE containingphases^ 120Figure 6.11- Schematic representation of observedmineral core to rim chemical variationsin fenites^ 122Figure 6.12- Chondrite normalized REE abundancepatterns of alkali-feldspar dikes andaccompanying LREE phases^ 123viiLIST OF TABLESTable 1 - Legend for geological maps^ 9Table 2 - List of representative samples 10Table 3 - Visually estimated mineral modal abundances...22Table 4 - Whole rock major element concentrations^ 30Table 5 - Whole rock trace element concentrations^ 37Table 6 - Whole rock REE element concentrations^ 42Table 7 - Whole rock REE fractionation indexes^ 44Table 8 - Electron microprobe analyses of pyroxenes  ^60Table 9 - Electron microprobe analyses of feldspars  ^67Table 10 - Electron microprobe analyses of amphiboles....77Table 11 - Electron microprobe analyses of biotites^ 79Table 12 - Electron microprobe analyses of apatites^ 83Table 13 - Electron microprobe analyses of titanites  ^88Table 14 - Electron microprobe analyses of allanites 96viiiACKNOWLEDGEMENTSThis study has been funded by grants from theCanada/British Columbia Mineral Development Agreement,logistical support for one trip was supplied by ChevronMinerals Ltd. I am grateful to Kelly Russell, my advisor, forunderstanding I would be a phantom graduate and for hisconstructive criticism and numerous edits of the manuscript.Also thanks to Kelly Russell for the opportunity to work onPearce Element Ratios of trace elements, the precursor to thisstudy. Additional thanks are required for the many discussionswe had, of which much form the basis of the thesis. StanyaHorsky provided untiring technical assistance for the wholerock analyses and John Knight assisted in the electronmicroprobe analysis of pyroxenes and feldspars. Chunpei Zhaoprovided electron microprobe analysis of allanite for twosamples and feldspar and epidote for one sample. Drafting ofmaps by D. Phillips. Reviews of Lee Groats, Cliff Stanley andDick Chase are greatly appreciated. I would also like toacknowledge the many discussions with my brother WilliamHalleran and father Derry Halleran over coffee. Finally, thanksto my family, who at times understood what I was doing; mydaughter Lisl who knew I was working on something called affesis.is1.0 INTRODUCTIONMount Bisson located in the Wolverine Mountain Range 64 Kmnorthwest of MacKenzie has only been mapped at reconnaissancescale as Wolverine metamorphic rocks. Mt. Bisson in fact hostsa suite of alkaline and granitic rocks; alkalic dikes, alkalinepegmatites, fenites, granite and granodiorite plutons, and avariety of granite pegmatites emplaced in the Wolverinemetamorphic rocks. Many of these rocks are are Earth Element(REE) enriched (e.g., fenites have up to 8000 ppm REE, allanitepegmatites have > 35,000 ppm REE, and REE dikes have > 40,000ppm REE).The purpose of this research is to further the scientificunderstanding of the origins of the REE enriched rocks at Mt.Bisson. This study involves, firstly, the description of thesepreviously unrecognized rocks. Secondly, their occurrenceprovides an exceptional opportunity to study the behavior ofLREEs' in coexisting mineral solid solutions allanite, titaniteand apatite.The data, available to constrain the origins of these rocktypes, include field relationships, whole rock geochemistry(major, minor, trace and rare earth elements), and electronmicroprobe analyses of major phases and the accessory phasesallanite, titanite and apatite. These data are used todelineate and contrast the chemical characteristics of themagmatic, metasomatic, closed or open processes that have led1to the formation of these anomalous Mt. Bisson rock types.The consequences of this research are that:1) the geology of the Mt. Bisson area is known in moredetail,2) both magmatic and metasomatic processes are required toexplain the origins of the diverse assemblage of rocks at Mt.Bisson,3) both closed and open chemical system processes areneeded to fully explain the chemical variation observed in theminerals within the magmatic and metasomatic rocks at Mt.Bisson,4) electron microprobe analyses of coexisting allanite,titanite and apatite have elucidated the behavior of the LREEs'in both closed and open chemical systems, and5) three new mineral compositions, two for titanite andone for apatite, are recognized at Mt. Bisson.21.1 PREVIOUS WORKMcConnell (1896) first described the Wolverine metamorphiccomplex and mapped a major fault, north of Manson Creek,between the Cache Creek Group and the older rocks on the east.Dolmage (1927) mapped the Finlay River district, north ofManson Creek, Armstrong (1949) provided the first petrologicaldata and age determinations from the Wolverine metamorphicsuite. Muller (1961) and Tipper et al., (1974) mapped thesouthernmost part of the Wolverine Complex, east of longitude124° and published additional age dates. More recently,geological mapping of the Manson Creek map-area by Ferri andMelville (1988) has refined the regional geology.2.0 GEOLOGY2.1 REGIONAL GEOLOGYThe Mount Bisson alkaline rocks (Figure 1) occur within anintensely metamorphosed and highly deformed part of the Ominecacrystalline belt termed the Wolverine Metamorphic complex(Ferri and Melville 1988). In the Mt. Bisson area the Wolverinecomplex includes, calc-silicate, amphibolitic and graniticgneiss of middle to upper amphibolite facies. The OminecaCrystalline belt comprises Late Proterozoic siliciclasticsediments with minor carbonate and mafic rocks. Mansy andGabrielse (1978) used the name Ingenika Group to define theserocks. The term Wolverine Metamorphic complex is used wherethese sediments are highly deformed, metamorphosed to such anextent that original lithology is obliterated and extensively500^0SCALE 1:50,000I 500 metresbk 69 *•^srN flfrr j4> NNNN\^L ^N\vbk 43LEGENDinferred geologicalboundaryt— 7:1 Mount Sisson,Middle I ngesitrim Micaceous orartziWelomneWolverine gneiss, °upon.gnawCok- silicate gneiss, MeterOlArtel gneiss.Detail map areasA sample location*I*69 Age 69 million yews,potassium-argon dating(Tipper etas., 1974)Local.lsAwf2, Monsen Creek3. let einem Canoe,0 Prince George<$05. &preens Ridge(72)m \ L\^Ursa \-^NmmmeLauraNiFIG. 1. General geology of Mount Bisson Area. Insertillustrates location of Mount Bisson and other proximal alkalinerocks and carbonatites. Belt 1A and 1B defined by Pell (1987).4intruded by late felsic intrusions and associated Cretaceouspegmatites (Parrish, 1976; Ferri and Melville, 1988, 1989;Tipper et al., 1974). To the west of the Wolverine Complex, inthe study area, relatively unmetamorphosed quartzite,argillaceous quartzite and schists of the Proterozoic MiddleIngenika Group (Ferri and Melville, 1988) lie in west-side downnormal fault contact (Ferri and Melville, 1988) with the LatePaleozoic Slide Mountain Group (Monger and Price, 1979).Potassium-argon geochronometry of Wolverine metamorphicrocks from the Mt. Bisson area gave 43 to 69 Ma (Tipper et al.,1974; Ferri and Melville, 1989), and north of Mt. Bisson atNina Lake gave 40 to 65 Ma (Gabrielse, 1974; Parrish, 1979;Ferri and Melville, 1989). Cretaceous intrusions into theWolverine complex are granite and granodiorite plutons andpegmatites that have been deformed together with themetasedimentary sequence during metamorphism to amphibolitefacies (Tipper et al., 1974; Parrish, 1976; Ferri and Melville,1989; Deville and Struik, 1990). Deville and Struik, (1990)ascribed the intrusion and metamorphism to deep burial of theWolverine rocks during Cretaceous crustal thickening. ATertiary period of granitic pluton and pegmatite igneousactivity within the Wolverine complex postdating theamphibolite facies metamorphism has been recognized in the mapsheets surrounding Mt. Bisson (Parrish, 1976; Ferri andMelville, 1989; Deville and Struik, 1990; Struik and Northcote,1991). These Tertiary granitic intrusions crosscut theamphibolite fabric (Deville and Struik, 1990). Eocene to5Miocene dike complexes consisting of microgranitic, rhyolite,dacite, olivine basalt dikes crosscutting the Wolverinemetasediments and granitic rocks occurs on Mt. MacKinnon,southeast of Mt. Bisson. More than one period of extensionaffected the Wolverine complex during the Tertiary (Struik,pers. comm. 1991). The Tertiary igneous activity occurredduring uplift and crustal extension of the Wolverine complex(Deville and Struik, 1990).Alkaline intrusive complexes in the region (Figure 1)include: the Lonnie (Halleran, 1980; Pell, 1987), Veril (Pell,1987), Aley carbonatite (Mader, 1986, 1987) and the Prince andGeorge carbonatites (Mader and Greenwood, 1988).Pell (1987) demonstrated that in British Columbia,alkaline rocks occur in three northwest-trending belts. Theeastern belt comprises subcircular to elliptical alkalineintrusions (predominantly Devono-Mississippian in age) emplacedwithin Middle Cambrian to Middle Devonian miogeoclinal rocks(Pell, 1987). These intrusions and their extensive fenites weresubjected to sub-greenschist facies metamorphism during theJurassic/Cretaceous Columbian orogeny (Pell, 1987). Fenites aredefined as metasomatized country rocks in contact withcarbonatites (Heinrich, 1966), ijolites, pyroxenites andnepheline syenites (Carmichael et al., 1974). Mineralogicallyfenites are aggregates of alkali feldspar (orthoclase and/oralbite) and aegirine (and/or sodic amphiboles)(Carmichael etal., 1974). Additionally fenite solutions are enriched in LREE(Wendlandt and Harrison, 1979).6The central belt comprises foliated alkaline sills of lateDevonian to Early Mississippian ages in Late Precambian toEarly Cambrian Omineca Crystalline Complex metasedimentaryrock. The alkaline intrusions and associated Na-pyroxene andamphibolite rich fenites have undergone deformation andmetamorphism to amphibolite facies (Pell, 1987).In the western belt, sills of alkaline rocks were deformedand metamorphosed to upper amphibolite facies during theColumbian orogeny.The Mt. Bisson alkaline complex and Lonnie carbonatitecomplex occur in the central belt (Figure 1; See lb). The Mt.Bisson igneous complex is emplaced in the Wolverineamphibolites, whereas the Lonnie Carbonatite (Late Devonian toEarly Mississippian age; Pell, 1987) is emplaced within theMiddle Ingenika.The Mount Bisson complex comprises a group of diverse rocktypes including: small granite granodiorite plutons, alkalicdikes (e.g. syenite), a variety of granitic and alkalinepegmatites (including numerous allanite and monazitepegmatites) and metamorphic rocks of the Wolverine suitecharacterized by a strong alkalic overprint consistent withfenitization. Numerous rocks are REE enriched.72.2 FIELD OCCURRENCES OF ALKALINE AND IGNEOUS ROCKS: Mt. BISSONAlkaline and igneous rocks at Mt. Bisson were sampled atfive localities over a strike length of 10 Km (Figure 1)(Table1). In addition representatives of fine-grained granites weresampled. There are at least four large plutons (3 Km 2 or morein area) and numerous smaller satellite bodies of these fine-grained granites. The samples (Table 2) form the basis of thisstudy.2.2.1 Laura Map AreaFigures 2 and 2.1 are geologic maps for the Laura No. 1and No. 2 localities. The Laura map area involves a series ofintrusions which cut the metamorphic rocks of the Wolverinecomplex. The Wolverine metamorphic rocks include coarse-grainedamphibolite, biotite schist and strongly foliatedquartzofeldspathic gneiss. Locally, metamorphic rocks arecharacterized by what appears to be a mappable, metasomatic,alkalic signature, here mapped as the Laura fenite.There are a variety of intrusive rock types which cross-cut the structure of the Wolverine metamorphic rocks. One tofour metre wide REE-rich allanite pegmatites are common andcrosscut the Wolverine metasediments and fenites with verysharp contacts. The allanite pegmatites have a minimum strikelength of over 30 metres and cause no discernible fenitizationof the Wolverine metasediments. Late quartz veins, 50millimetres wide, cut the allanite pegmatites. Quartz feldsparpegmatites, hornblende pegmatites and fine grained granite8Table 1. Legend for geologic maps.LITHOLOGYAlkaline rocks 1414+1 distinct and strong pattern 1) alkalic dikessingle dikes^2) barren syenite pegmatites31 allanite pegmatitesLaura feniteF7,77.1 will feniteGranitic rockspegmatites1 ' 1111%1• II N N plutons: Cretaceous and TertiaryWolverine metasedimentmetamorphic rocksSYMBOLSOutcropUG-7837^XRF sample locationGeological contact :observedinferredgradational65^Strike and dip of strata45Mineral fabricall^Allanitemag^Magnetitecp^Chalcopyritemal^Malachite• • • • II . • • • •• • • • IN Breccia9Table 2. List of representative samples.Sample#^Map Area^ Rock TypeAlkalic dikes38M^ Will No.2^REE dike7819 Will No.2 Alkali-feldspar syenite dike23^ Will No.1/2^Aegirine-augite dikePegmatites barren of REE7835^ Laura No.1^Hornblende pegmatite7844 Laura No.1 Quartz-feldspar pegmatite7808^ Will No.2^Quartz syenite pegmatitePegmatites bearing REE7842-52^ Laura No.1^Quartz-allanite pegmatite7826 Laura No.1 Allanite pegmatite7911^ Laura No.2^Allanite pegmatiteUG-1 Ursa^ Monazite pegmatiteFenites7834^ Laura No.1^Fenite7837 Laura No.1 Fenite7840^ Laura No.1^Fenite7910 Laura No.2 Fenite7823^ Will No.2^Fenite7809 Will No.2 Fenite38^ Will No.2^FeniteMB Granite Plutons (Cretaceous are CMB granites and Tertiary are TMB granites)7822^ Will No.2^TMB granite43 Mt. Bisson TMBdranite7856^ Will No.1^Tat graniteNH Laura No.1 TMB granite7803^ Will No.2^CMB granodiorite1 0suG-7826Scale 0^5^10^15 metresX XXXX XXX X XMX X X XX X X X XX X X X X X X.•X X X X x^x•x xxxx.xxx:: xXyX X X X xx•..xxx^x X Di•X XXX X^ X X 4Xx X X X XX1,IX.XX^X.X111X X•X•X11,DeltX DIX XX X XXXX X XX^X X XXX ^XX X X X X X X X X X X X XX X^X X^X^X^X^X•X.11•• it' • •X• • 'yoxxxxxxxxxx..1x x *X ^1. • .x,^• xX X x x X X X X X II X•XX ■ X X X X X•X KIDS. X X XX X X X X X•X••■■ X X XDIX X X X X X X X X X X X X•X X X X X X •^X X X X X XX X X X X X X• X It X X XX X X X X X X^X X X^X X X X X X^XX X X X X X11,:is4 X X X " X '  X^XX X XX X^X II X X •• X X^•UG- 7837uG- 7842-52FIG. 2. Geologic map of Laura No.1 area. Refer to Table 1 forlegend and Table 2 for list of samples.FIG. 2.1. Geologic map of Laura No.2 area. Refer to Table1 for legend and Table 2 for list of samples.12plutons intrude and crosscut both the Wolverine metasedimentsand the Laura fenite. Field relations between the graniticplutons and the pegmatites were not observed.The Laura fenite is a distinct lithology comprisingWolverine metamorphic rocks which have an alkaline characterexpressed by the presence of aegirine-augite and/or thepresence of titanite, allanite and alkali feldspar. The rock ismassive, fine to medium grained and retains a fabric related tothe original metamorphic fabric of the Wolverine suite.Specifically, the Laura fenite rocks are commonly banded on amillimetre to centimetre scale. Dark bands comprise aegirine-augite, hornblende, titanite and allanite, whereas more felsicbands are dominated by alkalic feldspar. The fenite isextensive occurring as two separate bodies 200 metres by 200metres and 110 metres by 60 metres (Figure 2 and 2.1). Thecontacts between the Laura fenite and the host Wolverinegneisses are gradational and some metamorphic lithologies(e.g., amphibolites) are more intensely metasomatized thanothers (e.g., quartzofeldspathic strata) and the replacementprocess commonly preserves the older regional structure. Theseobservations suggest that this alkalic unit represents apreferential replacement of amphibolite gneisses within theWolverine complex. A similar phenomenon was noted by Pell(1987) in the Perry River Carbonatite Complex, BritishColumbia, where the more calcareous layers of the host rockwere fenitized preferentially over the quartzofeldspathicunits.132.2.2 Will No. 1 Map AreaThe Will No. 1 map area is illustrated in Figure 2.2.There is little exposure and consequently the field relationsbetween rock types are uncertain. The geology involves twoseparate aegirine-augite syenite dikes (from here on calledaegirine-augite dikes) which crosscut Wolverine metasediments.Inaddition, there are several outcrops of a fine-grainedgranite.2.2.3 Will No.2 Map AreaThe geology of the the Will No.2 map area is shown inFigure 2.3. The main rock types include: fine-grained graniteintrusions, a sequence of fenites, (Will 2 fenite, includingfenitized Wolverine amphibolites, schists, gneisses and agranodiorite), pegmatites, and late cross-cutting alkalic dikes.The Will fenite varies from a fine-grained, light-coloredrock with a weakly developed mineral fabric to a darker,biotite-rich schist with millimetre to centimetre banding. TheWill fenite is distinguished from the surrounding Wolverinerocks by the presence of aegirine-augite and rare earth elementbearing minerals, an increase in alkali feldspar content and adecrease in quartz content. Original metamorphic banding hasbeen enhanced with increases in concentration of mafic and rareearth bearing minerals associated with metasomatic replacement.The Will fenite is cut by syenite dikes and barren (non-REE-bearing) pegmatites. No contact between the fine-grainedgranites and Will fenites were observed; however, rare angular14Scale-16440  N20 metres0^10- 16 3 80 N 8tih-^ h-i--r--\\45-16420 N.........^KNIC ■XXXXXXXXIIN*.\11Ts4146., VIA;;rs,A.UG-23 . X^■ X•1 • x ■•4• •^ UG-7856^\s >14.'\;,‘..Y^ •NI Nvv?..0.x. ■UG -7857o$^;•• °At.-16400NFIG. 2.2. Geologic map of Will No.1 area. Refer to Table 1 forlegend and Table 2 for list of samples.151^I^I^I^1O 0 0N N NN^ A^ MO 0 0m m rn100^ 0m rnI^I^I^I^I0 0 041 CM CAn)^ A^oM0 0 rn m m■ NKNXXXXXXO'NNIIX 1•K X X X ■EXX X 11X X XX 1111X X X X XXXX X XXX,i' N..N1. N ▪ XX X X X x p1 ■ ■^X X X X X11X X XX X XX XXXXX.A K111X X X X ' X ' X ' X ‘?"1 'X XXXXXXXX▪ XX X ▪ X 1. • X X 1, XI 1. X• fx,X X IC 1•XXx• • ...I,• • . = .%X^X 1-153 80N-15380 N-153 40N▪ A •• pi lg.:.u6-71303:11Scale 0^10^20 metresXX XX X XX XX11XX X X XX X XXXX XX X XXXX XX . X X I-153 20N- 153 OoN-152 8ONFIG. 2.3. Geologic map of Will No.2 area. Refer to Table 1 forlegend and Table 2 for list of samples.16xenoliths of metasomatized Wolverine rocks occur within thegranitic intrusions. The granodiorite is characterized by thepresence of apple green colored mafics and probably resultsfrom fenitization. The quartz-feldspar pegmatite also containsxenoliths of the Wolverine metmorphics.Syenite dikes comprise three mineralogically distinct rocktypes: an aegirine-augite rich (> 70 volume percent) dike(aegirine-augite dikes), a fine-grained equigranular alkalifeldspar (> 90 volume percent) dike (alkali-feldspar dikes),and a REE enriched dike. The alkali feldspar dike crosscuts theWill fenite, quartz-feldspar pegmatites and the hornblendepegmatites.2.2.4 Ursa Map AreaThe Ursa (see Figure 1.0 for location) is a mylonitizedgneissic monazite-bearing pegmatite 10 metres long and 1 to 2metres wide. Other similar but less exposed or developedmonazite pegmatites were observed in the study area. The rockcomprises potassium feldspar, quartz, albite, monazite andtraces of biotite and titanite. The biotite is partly alteredto chlorite. This unit occurs within fine-grained phlogopite-bearing calcsilicate gneisses of the Wolverine complex. To thewest, the pegmatite is truncated by a fine-grained, felsicintrusion.172.3 SUMMARY OF FIELD RELATIONSThe igneous and alkalic units on Mt. Bisson includecrosscutting alkalic dikes, alkalic and nonalkalic pegmatites,granitic intrusions and a secondary alkalic metasomaticreplacement (fenites) of Wolverine amphibolite gneiss; many ofthese units have anomalously to high modal amounts of REEbearing minerals. Based on the field evidence of this study andmapping in surrounding map sheets by Deville and Struik (1990),Struik and Northcote (1991) and Ferri and Melville (1989), themagmatic and metasomatic events at Mt. Bisson (Figure 2.4), canbe summarized as:1) Cretaceous age granodiorite plutons (7803, CMBgranodiorite) and pegmatites (UG-1 and 7842-52) intrude crust.2) Metamorphism and deformation of the metasedimentary andplutonic rocks.3) Fenitization of Wolverine metasediments (38, 7809,7823, 7834, 7837, 7840, 7910) and Cretaceous aged granodiorite(7803). Fenitization is related to alkaline magmatic activitywhich occurred during one of the Tertiary periods of extensionrecognized in the Wolverine complex by Struik (1991).4) Post-fenite Tertiary alkaline magmatic rocks includingallanite pegmatites (7826, 7911), alkaline dikes (23, 7819,38M) and alkaline pegmatites (7808).5) Tertiary granitic plutons (43, NH, 7822, 7856) andpegmatites (7835, 7844) are post Tertiary alkaline intrusion18OLDEST^YOUNGESTCretaceous^Tertiary AlkalisMagmasWolverineUnits 114GraniticMagmasitg.RELATIVE AGEFIG. 2.4. Schematic diagram showing sequence of alkalic andigneous events at Mt. Bisson.19except for the youngest mappable alkaline igneous events (7819)which crosscut the quartz-feldspar pegmatites.The extent of the fenitization was mapped on the basis ofincreasing modal aegirine-augite, titanite, allanite, apatiteand feldspar and decreasing quartz, hornblende and biotite.Tertiary magmatic rocks crosscut and intrude the fenitesand contain angular fenite fragments. The Tertiary igneousunits are unmetamorphosed. Rarely, there is a slight alignmentof biotite. Rotated Wolverine amphibolite xenoliths enclosed byTertiary granitic pegmatites indicate intrusion into solidcountry rock. The spatial relationship of the pegmatites, thediverse mineralogy, and varying concentration of REE containingminerals suggest the presence of more than one period ofintrusion. Numerous allanite pegmatites, distinguished by thepresence of coarse REE-bearing allanite, are spatiallyseparated but share strong chemical similarities.203.0 DESCRIPTIVE PETROLOGYTable 3 summarizes the modal abundance of minerals inrepresentative samples taken from the 120 thin sectionsstudied. The rocks investigated at Mt. Bisson were divided into5 groups: they are; 1) Alkalic Dikes, 2) Pegmatitesbarren or having low concentrations of REE, 3) REE-bearingpegmatites, 4) fenites and 5) Mt. Bisson Granitic Plutons (MBgranites). MB granites as a whole include the Cretaceousgranodiorite (CMB granodiorite) and Tertiary granites (TMBgranites). Descriptive petrology of the five groups are listedbelow. The rocks are classified according to the mineral modalclassification of Streckeisen (1975).3.1 ALKALIC DIKE ROCKSThree types of syenite dikes (refer to Table 2 for samplenumbers) occur on Mt. Bisson: alkali-feldspar dikes, aegirine-augite dikes and REE dikes.Alkali-feldspar dikes are fine grained, equigranular andcontain 90% plagioclase, trace microperthite orthoclase, tracetitanite, apatite and only 10% disseminated mafic minerals,principally aegirine-augite. The dike has a consistent width of16 cm.Aegirine-augite dikes are up to 0.5 metre wide, consist of40 to 60% 0.1 to 1.5 centimetres long aegirine-augite, 35%perthite orthoclase, 3% titanite, 1% apatite, minor plagioclaseand trace magnetite, chalcopyrite and malachite.21Table 3. Visually estimated modal abundances (vol. %) for representative rocks from the Mt. Bisson area.Sample Volume %Number Location Qtz^Plag^Ksp^Px^Hbl^All^Sph^Ap Bio Chl Zr OtherAlkalic Dike Rocks38M Will #2 -^2^8^80a^-^3^2^5 - - - Op7819 Will #2 2^88^tr^10a^-^-^tr^tr - - - -23 Will #1/2 -^tr^58^40a^-^tr^2^tr - - - tr mal, chat, magPegmatites Barren of Rare Earth Elements7835 Laura #1 2^75^2^-^20^tr^tr^tr - - - tr epidote7844 Laura #1 50^25^25^-^-^-^-^- tr tr tr tr monazite, mag7808 Will #2 3^87^-^10h^-^tr^tr^- tr - - tr epidotePegmatites Bearing Rare Earth Elements7842-52 Laura #1 28^33^31^2a^-^3^2^1 - - tr tr thorite7826 Laura #1 -^32^32^10a^-^15^5^2 tr - tr tr neph7911 Laura #2 tr^40^30^15a^-^10^tr^2 tr - tr tr Op1 Ursa 40^25^35^-^-^tr^tr^tr tr tr tr tr Op, monaziteFenites7823 Will #2 tr^79^tr^20a tr^0.5^0.5^tr - - tr tr Op,^il, mag, hem7910 Laura #2 -^tr^76^20a^2^tr^2^tr tr - - tr Op,^it7837 Laura #1 tr^-^90^9^tr^-^0.5 0.5 - - tr7840A Laura #1 tr^-^74^24^-^2^tr^tr - - -38 Will #2 -^-^90^8^-^0.5^1^tr - - -Mount Bisson Granitic Plutons7822 Will #2 65^5^20^-^-^-^-^tr 5 tr - tr Op43 Laura #1 30^20^48^-^-^tr^-^tr 2 tr tr tr Op, mag7803 Will #2 tr^89^-^10^-^-^1^tr - - trNH Laura #1 30^30^35^5^-^-^-^- 2 trQtz = quartz; plag = plagioclase; Ksp = potassium feldspar; Px = pyroxene; Hbl = hornblende; All = allanite;Sph = sphene; Ap = apatite; Bio = biotite; Chl = chlorite; Zr = zircon; Op = opaques; mal = malachite; chat= chalcopyrite; mag = magnetite; hem = hematite; it = ilmenite; neph = nepheline; a = aegirine-augite; h =hedenbergite; tr = trace;22The plagioclase occurs as large exsolutions in theperthite and as nucleated albite at grain boundaries. Theslight grey pleochroic, euhedral to subhedral titanite, 2.0 to0.5 millimetres in size, has apatite and opaque minerals asinclusions.The REE dikes consist of 80% intergrown, inclusion-filledaegirine-augite, 8% potassium feldspar, 5% apatite, 3%allanite, 2% titanite with trace calcite and biotite found asinclusions in aegirine-augite. Allanite occurs as intergrowthswith titanite and aegirine-augite.Mafic minerals parallel the fine scale mineral layering ofthe Will alkalic unit. The contact with the Will alkalic unitis sharp for the aegirine-augite but the potassium feldsparprevalent in the dike and proximal to the dike grades intoplagioclase in the Will alkalic unit.3.2 PEGMATITES BARREN OF RARE EARTH ELEMENTSThree types of pegmatites are found which do not haveanomalous REE concentrations: quartz feldspar pegmatite(granitic), quartz syenite pegmatite (syenitic) and thehornblende pegmatite (quartz monzodiorite). The contactrelations between these pegmatites are not known because whilethe rock types commonly outcrop together, no lithologiccontacts have been observed. Large xenoliths of Wolverineamphibolites commonly occur within the pegmatite bodies.Major constituents of the hornblende pegmatites are large1.5 cm plagioclase, hornblende, minor 2.0 mm size potassium23feldspar, quartz and trace euhedral titanite, apatite, verytrace allanite and epidote. The subhedral to anhedral allaniteis yellow brown to dark red pleochroic. Both the plagioclaseand hornblende display patchy undulatory extinction.The quartz-feldspar pegmatite consists of 5.0 to 10.0 mmpolycrystalline quartz, potassium feldspar, anhedral tosubhedral plagioclase and trace to minor magnetite, biotite,chlorite, zircon, trace euhedral zoned monazite and opaques.Perthite occurs in elongated masses with recrystallizedplagioclase at the boundaries and minor myrmekitic texture isalso present in places. The biotite is altered to chlorite andhas slight kink banding.The coarse grained quartz syenite pegmatite compriseszoned antiperthite (An 23), hedenbergite, minor perthiticpotassium feldspar, occasional elongate quartz crystals andlate fracture-filling epidote. Subhedral hedenbergite isinterstitial but larger grains include plagioclase (An 32),euhedral titanite, hornblende and biotite. Late stagerecrystallization of quartz and plagioclase occur alongfractures and boundaries.3.3 PEGMATITES BEARING RARE EARTH ELEMENTSThe three types of rare earth element bearing pegmatitesare: allanite pegmatite (syenite to monzonite),monazite pegmatite (granite) and a quartz allanite pegmatite(quartz syenite to granite). Differences include whether or not24nepheline or quartz is present and whether allanite or monaziteis the main REE-bearing mineral.The allanite pegmatite consists of perthite, up to 35%green to brown pleochroic allanite, 5% titanite, plagioclase,apatite, minor to trace aegirine-augite, zircon and opaques.Nepheline occurs in one sample. The large, euhedral tosubhedral aegirine-augite has patches of (edenitic) hornblende.The subhedral to euhedral allanite is 0.3 to 20 millimetres insize, optically zoned and occurs with titanite and euhedral,grey-pleochroic apatite. Anhedral titanite occurs asintergrowths with allanite and apatite, and euhedral titanitecrystals up to 1 centimetre long are found within the allanitemineralized zones. The amount of plagioclase can varysubstantially and exhibits myrmekitic textures. Locally, 0.5cmwide quartz veins crosscut the pegmatites.The monazite pegmatite consists of recrystallizedpotassium feldspar, quartz, and aligned, round albite grainswith slighly aligned monazite, trace biotite, chlorite,titanite, allanite and zircon. The biotite is irregularlyshaped anhedral separate crystals intergrown with allanite. Thebiotite appears to be partly replaced by allanite; Hickling etal., (1970) observed the same relationship in the Boulder CreekBatholith, Colorado where allanite porphyroblasts replacebiotite. In addition, monazite coexisting with allanite is rare(Parrish, 1990).The quartz-rich REE pegmatite is finer grained andmineralogically heterogeneous having clusters of mafic25minerals. Aegirine-augite, allanite, titanite, euhedralapatite, pink pleochroic zircon and thorite occurs intergrownin a groundmass of potassium feldspar, quartz and minorplagioclase. Anhedral polycrystalline quartz grains areelongate parallel to the mafic zones. Some titanite has abrown-pleochroism with allanite along fractures or asinclusions. Titanite is included by apatite but also includesapatite and occurs as inclusions in allanite. Allanite displaysoscillatory zoning in grain centers grading into more patchyzoning towards the grain margins.3.4 LAURA and WILL FENITESThese fenites are fine to medium-grained crystalline rockswith regular banding on a millimetre to centimetre scale,occurring both as a massive equigranular layered unit and astacked unit which is conformable with the Wolverinemetasediments. Commonly, the original Wolverine fabric is stillevident and in places the fenite appears to have preferentiallyreplaced the amphibole beds. The dark bands comprise aegirine-augite, titanite, allanite, zircon and apatite with minorhornblende and biotite. The Laura #2 fenites have only traceallanite intergrown with a brown pleochroic titanite while inthe other fenites, allanite is substantually more abundant thantitanite. Light bands are dominated by plagioclase orpotassium-feldspar.Fenites are characterized by subhedral to anhedral,altered, light-blue-green to green aegirine-augite and augite26containing small patchy zones of magnesio-hornblende (Laura #1)and subcalcic tremolite (Laura #2). Trace biotite is found askinked fresh blades with potassium rich magnesio-hastingsite.Most potassium feldspar is anhedral, perthitic andinclusion-filled with trace myrmekitic texture (An 30) butminor euhedral (0.5 to 5.0 mm) crystals are found in somerocks. In the Will fenites, plagioclase (An 26 - 28) occurs asanhedral to subhedral crystals that often display cataclastictextures and myrmekitic textures.Euhedral titanite in the Will fenites displays a slightbrown pleochroism while in the Laura #2 fenite it is dark brownpleochroic; due to high Fe3+ content (Deer et al., 1962).Titanite includes allanite, hornblende, aegirine-augite and hasinclusions of apatite and zircon, at times as aggregates in themafic bands.The subhedral to anhedral allanite has patchy, convolutedzoning.The aegirine-augite has inclusions of allanite, euhedraltitanite, perthite, opaques, rare biotite and in places a 8%blue-green to dark-green pleochroic amphibole.Adjacent to the Wolverine amphibolite euhedral tosubhedral hornblende dominates the mafic bands. Aegirine-augitereplaces hornblende which has inclusions of titanite, allaniteand biotite along fractures parallel to cleavage. The contactwith the alkalic rocks is very gradational and there areconcentrations of 60-80% oligoclase with 10-15% aegirine-augitein the amphibolite.273.5 MB GRANITESPredominantly all the granitic plutons evaluated weredeemed to be Tertiary in age (TMB granites) and only oneassumed Cretaceous age granodiorite pluton (CMB granodiorite)was observed.The TMB granites includes all fine-grained, light colored,massive, fresh-looking granitic plutons. The constituentminerals include quartz, plagioclase (An 22 to 24), potassium-feldspar, biotite, chlorite, traces of magnetite, allanite,apatite and zircon. Plagioclase occurs as cloudymicrophenocrysts (commonly broken) and as smaller grains whichexhibit undulatory extinction or myrmekite texture. Normal andrare normal oscillatory zoning is also evident. Allanite canshow euhedral oscillatory zoning, twinning and may exhibitundulatory extinction. Biotite is partly replaced by chloriteand in some places (e.g., Will No. 2) defines a weak foliation.The CMB granite (7803) appears to be fenitized and containsaugite with aegirine-augite rims and trace titanite. Thefeldspar is predominantly plagioclase.284.0 GEOCHEMISTRYTwenty-four samples and eight duplicates were analyzed byx-ray fluorescence (XRF) for major, minor, trace elements (XRFfor Nb, Zr, Y, Sr, Rb, Ba; Li, Ti, and Cs by other methods) andREE (INAA for Ce, Dy, Eu, Ho, La, Lu, Nd, Pr, Sc, Sm, Tb, Th, Uand Yb. FeO was measured volumetrically and loss of mass onignition (LOI) was determined (Appendix A). Unweathered sampleswere cleaned and crushed to -200 mesh. Analytical accuracy wascontrolled with twelve calibration standards for the majoroxides, sixteen calibration standards for the trace elementsand two standards for the REE (Appendix A). Analyticalprecision was estimated by monitoring the standards BCR-1 andAGV-1. Sample preparation and analytical precision were furtherevaluated by running eight duplicate unknowns for the major,trace and rare earth elements (Appendix A). Estimatedanalytical uncertainties are listed in each table of chemicaldata. Normative compositions were calculated for the igneousunits.4.1 Major Element CharacteristicsMajor element oxide concentrations for representativerocks are listed in Table 4.Figure 4 illustrates major element oxide variation plottedversus Si02 content. Generally, CaO, MgO, FeO, Fe203, TiO, andP205 all decrease with increasing Si02. The oxides Al203, K20and Na20 show little systematic variation against Si02. The29Table 4. Major element oxides of Mount Bisson rock samples determined by XRF analysis of pressed glasspowders. Also listed is 1S, the estimated analytical uncertainty.SampleNumber Si02 TiO2Weight percent oxidesAl203^*Fe0 Fe203^Mn0^MgO^Ca0 Na20 K20 P205 Total LOIAlkalic Dike Rocks38M 43.64 0.58 13.66 7.60 3.67 0.33 5.84 18.10 2.30 1.54 2.66 99.92 0.737819 67.23 0.31 15.66 1.55 0.64 0.07 0.69 2.31 5.19 5.82 0.12 99.58 0.297819d 67.30 0.30 15.61 1.60 0.58 0.07 0.73 2.32 5.21 5.79 0.12 99.63 0.3123 55.16 1.79 11.88 4.71 2.76 0.36 3.13 10.11 3.64 5.13 0.49 99.17 0.38Pegmatites Barren of Rare Earth Elements7835 64.34 0.19 17.91 3.07 0.47 0.08 1.41 5.31 5.73 1.28 0.13 99.91 0.627835d 64.46 0.19 17.40 3.07 0.91 0.08 1.34 5.22 5.64 1.28 0.13 99.82 0.677844 81.90 0.15 7.93 2.21 1.60 0.05 0.16 0.37 2.48 2.20 0.03 99.10 0.207808 68.56 0.03 15.50 1.68 0.60 0.14 0.77 2.53 5.65 4.09 0.03 99.58 0.35Pegmatites Bearing Rare Earth Elements7842-52 71.50 1.17 12.43 1.43 0.84 0.09 0.51 2.46 2.86 5.86 0.14 99.30 0.347842-52d 71.54 1.17 12.53 1.39 0.82 0.09 0.50 2.45 2.86 5.83 0.14 99.31 0.327826 50.44 2.96 19.92 4.78 2.45 0.18 1.29 10.22 2.97 4.75 0.67 100.61 0.567911 59.08 1.25 17.42 3.78 1.44 0.17 1.39 7.76 5.61 1.51 0.42 99.38 0.287911d 59.08 1.25 17.28 3.82 1.43 0.17 1.43 7.81 5.58 1.52 0.43 99.80 0.301 72.98 0.12 15.28 0.82 0.18 0.02 0.38 2.17 3.88 3.80 0.17 99.81 0.38Fenites7834 53.81 0.38 13.11 4.80 1.29 0.20 6.46 11.17 2.80 4.76 0.61 99.47 0.377834d 53.58 0.38 13.24 4.87 1.21 0.20 6.54 11.16 2.86 4.75 0.60 99.39 0.357823 55.72 0.43 14.88 4.73 1.47 0.19 3.90 10.85 5.13 1.92 0.33 99.53 0.387910 53.68 6.95 15.99 1.95 2.11 0.11 2.08 8.40 3.93 5.23 0.07 100.52 0.467910d 53.74 6.98 16.02 2.00 2.06 0.11 2.07 8.39 3.93 5.23 0.07 100.61 0.447837 62.25 0.29 15.66 2.41 0.51 0.11 1.43 4.67 2.33 9.59 0.29 99.55 0.417840A 59.97 0.54 18.70 1.91 0.58 0.08 1.39 4.58 2.83 9.16 0.42 100.17 0.4738 60.93 0.51 16.95 2.45 1.01 0.10 2.03 4.44 5.06 5.98 0.27 99.72 0.487809 56.46 0.69 16.49 5.14 1.12 0.14 4.10 6.68 5.90 2.47 0.39 99.49 0.53Mount Bisson Granitic Plutons7822 73.27 0.16 14.24 1.20 0.02 0.03 0.36 1.27 3.43 5.46 0.29 99.71 0.4043 71.59 0.20 14.64 1.27 1.00 0.04 0.40 1.47 3.34 5.59 0.07 99.60 0.417856 72.09 0.20 14.46 1.51 0.96 0.04 0.53 1.75 3.97 3.96 0.08 99.55 0.407803 64.05 0.38 16.45 2.54 1.40 0.16 1.52 4.14 8.36 0.31 0.15 99.46 0.36NH 71.69 0.19 14.75 1.67 0.34 0.05 0.66 2.55 3.54 4.07 0.08 99.59 0.76NHd 71.60 0.20 14.59 1.69 0.64 0.05 0.61 2.54 3.53 4.04 0.07 99.57 0.761S 0.16 0.02 0.18 0.05 0.09 0.06 0.04 0.04 0.06 0.03 0.011. Duplicate samples denoted "d", *Fe0 by titration.3000000 Alkalic Dikes***** Barren PegmatitesAAAAA REE Pegmatites00000 Laura Fenites••••• Will Fenites***It* MB Granites48-40050^60^70^80Si02Aao^AANO : o* oi*90108-0 6-4-2-0100 8-Ncd 6-4-22016-CD 12-cdC.) 8-4-080 6-"4-2-0000■A Hosr•• A * 0*■A a 00^0 *0A rialO A■000O ■A M 0*Ok0 4cf) 4- 0O -CM A 02 -W ■ e * *■ • *0* WFIG. 4. Harker diagrams showing major element compositions ofrepresentative rocks.31most Si02-rich rocks are the TMB granites which consistentlyplot together. Two quartz-rich REE pegmatites (Cretaceous, UG-1and 7842-52) also plot with the TMB granites. Fenites andallanite pegmatites (7826 and 7911) have the lowest SiO2concentration but have relatively higher CaO, MgO, FeO, Fe2O3and P2O5. The alkalic dikes span from 44 wt% to 67 wt% SiO2.The peraluminous barren pegmatites (Figure 4.1) aresubalkaline and intermediate to acidic (Figure 4.2).Normatively, the samples are oversaturated with respect to SiO2but only quartz feldspar pegmatites are corundum normative. AllREE pegmatites are peraluminous (Figure 4.1) but only theallanite pegmatites plots as alkaline. The REE pegmatitesdisplay quite a large range in Wt% SiO2 from 50.44 to 73 Wt%.Tertiary allanite pegmatites 7826 and 7911 are chemically verysimilar (as compared to the others); however, 7826 has lowerSiO2, Na2O, and higher TiO2, Al203, FeO, Fe2O3, CaO, K2O andP2O5 relative to 7911. Normatively they are silica saturated tosilica undersaturated: normative nepheline, olivine and highAn. The two Cretaceous REE pegmatites are silica oversaturatedwith normative corundum only in the monazite pegmatite.Figure 4 illustrates the chemical diversity of thefenites. 7910 has the highest TiO2 concentration (6.95 wt%)observed at Mount Bisson. Na2O, Al203 and Fe2O3 concentrationsin the fenites span over the entire range observed for MountBisson rocks as a whole and concentrations of CaO, MgO and FeOare among the highest observed at Mount Bisson. 7840A and 783732th,-•-; 24-0cuUs.a.)Pi 20 —iZ0as0 16-+0c■IZc6 8—0000000 Alkalic Dikes***** Barren PegmatitesAAAAA REE Pegmatites***** MB GranitesAPERALUMINOUSMETALUMINOUS*r^8^IIII12^16^i203Al203 Wt percentFIG. 4.1. Mt. Bisson igneous rocks plotted on Al203 vsNa20+K2O+Ca0.cv12—+^_3314I Basic^I InterI^II I1^I o /I I^.I^I *,/I I^,1 b1 1^Ali k *I^A :AI /^II^I^/^1I I^9`^* II^I^/^II / II^'I^III^// /I^II0 1  /^I I) SUB*LKALINE : ROCKS.^I I^I2^ /^II^I^I^I^I ^I I^.^I^i^I^i^i^i^i30 50 70Si02 Wt percentUltrabasicALKALINE' IROCKSAcid*90FIG. 4.2.silica withsubalkalineare definedMt. Bisson igneous rocks plotted on alkalis vssuperimposed Si02 classification. Alkaline andboundary from Macdonald and Katsura (1964). Symbolsin Figure 4.1.34have the highest K2O concentration (9.16 to 9.59 wt% K2O) andsome of the lowest Na2O concentration observed at Mount Bisson.Fenites are divided into the predominantly higher Na2O andlower K2O Will fenites and the lower Na2O and higher K2O Laurafenites; Will fenite 38 is the exception with a K2Oconcentration similar to the Laura fenites. The fenites havealkaline characteristics.The TMB granitic plutons are subalkaline (Figure 4.2)peraluminous (Figure 4.1), acidic, and have normative corundum.TMB granites have the lowest concentrations of CaO, MgO, FeO,Fe2O3 and P2O5 and show little major element chemicalvariation. The CMB granodiorite is peraluminous, intermediate,has an alkaline affinity and is normative silica saturated. CMBgranodiorite has the highest Na2O concentration of 8.36 wt% andlowest K2O concentration of 0.31 wt% observed at Mt. Bisson.The ultrabasic to acidic (Figure 4.2) alkalic dikes arealkaline and have a wide range of major element concentrations(Figure 4). The dikes also are metaluminous to peraluminous(Figure 4.1). Norm calculations indicates the alkali-feldspardike is silica oversaturated and the aegirine-augite dike andREE dike are silica undersaturated. Both have normativenepheline, plus the REE dike has normative olivine and leucite.Notable chemical characteristics are:1) REE dikes have the highest P2O5 (2.66 wt%), FeO, Fe2O3,CaO and MgO concentration.2) Aegirine-augite dikes have 1.79 wt% TiO2, three timeshigher compared to the other dikes.354.2 TRACE ELEMENT CHARACTERISTICSTable 5 lists the trace element concentrations ofrepresentative alkaline and igneous rocks from Mount Bisson andFigure 4.3 plots the trace elements versus wt% SiO2.The trace elements Ba and Sr are highly enriched in some ofthe Mt. Bisson samples and range in concentration from 59 to35,000 ppm and 230 to 7800 ppm respectively. Additionally, Nbconcentration varies considerably from 0 to 4681 ppm, Zr from 0to 740 ppm and Y from 9 ppm to 350 ppm whereas Rb varies from 0to 200 ppm. Li and Tl occur only in low concentrations of 3 ppmto 28 ppm and 0.1 ppm to 1.2 ppm, respectively. Cs waspredominantly below lower detection limit. None of the traceelements analyzed display a consistent variation trend relativeto wt% SiO2The alkalic dikes have a range in Ba and Sr concentrationof 2500 to 4200 ppm and 400 to 760 ppm respectively (Figure4.4). Rb concentration is 0 for REE dikes but 100 ppm for theother dikes and the concentration of Nb ranges from 22 to 294ppm. The REE dikes and aegirine-augite dikes have lowconcentrations of Zr, 92 to 94 ppm, but high Y concentrations,204 and 228 ppm, while the alkali-feldspar dikes have a high Zrconcentration of 300 ppm and a low Y concentration of 18.5 ppm;the Y concentration observed in the dikes are among the highestand lowest observed at Mt. Bisson.The REE barren pegmatites have Ba concentrations of 360 to800 ppm and Sr concentrations of 100 to 750 ppm (Figure 4.4).The REE barren pegmatites also have the lowest Rb concentrations36Table 5. Trace element concentrations (ppm) in Mount Bisson rock samples determined by XRF analysis ofpressed rock powder. Also listed is 1S, the estimated analytical uncertainty.Sample^Nb Zr Y Sr^Rb Ba Lia^Tla CsaAlkalic Dike Rocks38M^294.5 92 228 705 bd 4219 10 0.2 <7.07819^21.8 305 19 397 113 2481 5 0.4 <2.07819d^23.0 300 19 401 113 2559 5 0.5 <2.023^150.5 94 204 762 101 2943 24 0.4 2.0Pegmatites Barren of Rare Earth Elements7835^13.1 24 21 717 20 416 5 <0.1 <2.07835d^13.8 21 23 747 21 368 6 <0.1 <2.07844^29.7 736 14 100 42 493 5 0.2 <2.07808^9.0 86 16 388 85 797 4 0.4 <2.0Pegmatites Bearing Rare Earth Elements7842-52^554.6 245 138 1031 63 5291 3 0.2 3.07842-52d 548.3 234 134 1015 62 5290 3 0.3 <2.07826^358.4 bd 342 444 bd 1841 4 0.3 <2.07911^241.4 bd 157 474 bd 357 5 <0.1 <4.07911d^230.7 bd 153 469 bd 360 6 <0.1 <6.01^bd 517 16 455 83 3010 9 0.4 <2.0Fenites7834^76.0 151 23 4368 107 26573 26 0.4 4.07834d^82.5 115 25 4512 108 26511 24 0.3 3.07823^33.6 192 39 1148 41 3544 10 0.1 <2.07910^4681.4 144 78 7830 82 15777 10 0.1 <4.07910d^4671.2 151 80 7798 82 15916 10 0.1 <2.07837^35.5 98 29 1398 198 9725 6 0.6 <2.07840A^421.0 113 23 4849 158 35737 4 0.6 2.038^81.5 397 36 1195 101 11093 12 0.5 <2.07809^44.9 180 34 7955 111 2545 28 0.6 5.0Mount Bisson Granitic Plutons7822^12.5 157 14 232 166 1661 20 1.2 5.07822d^13.1 160 14 240 172 1680 20 1.2 4.043^6.1 218 14 458 133 58 9 0.6 <2.07856^3.0 195 7 356 127 1965 7 0.4 <2.07803^117.7 659 60 466 bd 325 6 <0.1 <2.0NH 8.4 162 9 509 104 1311 10 0.4 <2.0NHd^10.7 165 11 524 108 1263 12 0.3 <2.01S ppm^7 10 2 (2%) 2 35 1 0.1 1.0Duplicate samples denoted "d"; bd refers to below detection limit, Ha" denotes samples analyzed by Chemex -see appendix A.370 **A *•0^*,^A,^A05 1000,10010,Z0.110000 E ^Fa100E 10000a00■ ocl^A0^o•^*A^A * Chic lil*00 db 0 _A* W,1115 200-a1 -0800El 800:1:4 -C:4400-k 200-'0400vzoo ->"1•00* A A40^50^60^70^80Si02*1000 0 S DrU * Cich *a. I^till^I^I40^50^60^70^80Si02FIG. 4.3. Trace elements (ppm) plotted against SiO2 for wholerock compositions. Symbols as in Figure 4.381 000 0 ---- 0El 0^•■ a**^MO 0ItA *^A OA**100 7 *00000 Alkalic Dikes***** Barren Pegm.atitesAAAc.c, REE Pelm.atites0000^ Laura FenitesNow Will Fenites***** MB Granites 10 I^I III^I^I^I^111111^I^I^I^I^11111^I^I^I100 1000 10000Log Ba (ppm)FIG. 4.4. Log Sr (ppm) vs Log Ba (ppm) for whole rockcompositions (McCarthy and Hasty, 1976).39observed at Mt. Bisson (Table 5). The quartz-feldspar pegmatite(7844) has the highest Zr concentration (736 ppm) at Mt. Bisson.The REE pegmatites compared to the barren pegmatites have awider range of Ba concentration, from 350 to 5300 ppm, and asmaller range in Sr concentrations, from 450 to 1000 ppm.Tertiary allanite pegmatites have 357 to 1841 ppm Ba, whereasthe Cretaceous REE pegmatites have substantially higher Baconcentrations of 3000 to 5290 ppm. Zr and Rb are below thelower detection limit in the Tertiary allanite pegmatites butvary from 238 to 517 ppm Zr and 62 to 83 ppm Rb in theCretaceous REE pegmatites.Fenites have the largest variance and the highestconcentration of Ba (2500 to 35700 ppm) and Sr (800 to 7800 ppm)observed at Mt. Bisson (Figure 4.4). Generally, the fenites fromthe Laura locale are 5 times richer in Ba and Sr than the Willfenites. Rb concentration ranges from 41 to 198 ppm, Y from 23to 80 ppm and Zr varies from 98 to 397 ppm. Two Laura fenitesamples are enriched in Nb (421 to 4680 ppm) relative to theother fenites which contain 36 to 82 ppm Nb.The fenites can be divided into two groups: 1) lower Y (26ppm ± 3.0 ppm) and Zr (109 ppm) containing Laura fenites and 2)higher Y (36 ppm + 2.5 ppm) and Zr containing Will fenites.The TMB granites as a group have similar Ba concentrations(1260 to 1965ppm), and similar Sr concentrations (230 to 524ppm), excluding granite # 43 which has 58 ppm Ba. The TMBgranites have Rb concentrations from 104 to 172 ppm, Zrconcentrations from 159 to 218 ppm, Y concentration from 9.0 ppm40to 15 ppm (lowest observed at Mount Bisson), and Nbconcentration from 3.0 to 13 ppm.4.3 RARE EARTH ELEMENT CHARACTERISTICTable 6 lists REE, Sc, Th, and U concentrations ofrepresentative alkaline and igneous rocks from Mt. Bisson.Figure 4.6 illustrates the variation of whole rock REEconcentrations.The alkalic dikes have very diverse total REE concentration(Figure 4.5) and chondrite normalized REE abundance patterns(REEcnp) (Figure 4.6) with a 200 to 30,000 times chondrite valueincrease in LREEs. The REE dikes have the highest concentrationof total REE, one of the highest (La/Lu) cn fractionation index(Larry, 1984) (at least >800), and a LREE fractionation index(La/Sm) cn (Larry, 1984) of at least >25.8 (Table 7). The Sm andLa concentrations for REE dikes are above the upper detectionlimit. The aegirine-augite dikes have a REE concentration of1388 ppm, a very low (La/Lu) cn fractionation index of 11.69, andvirtually no Eu anomaly. The alkali-feldspar dikes have lowertotal REE of 234 ppm, low (La/Lu) cn index of 34, and no Euanomaly.REE pegmatites have high total REE concentrations rangingfrom 2782 to >35000 ppm (Figure 4.5), whereas the barrenpegmatites have much lower total REE concentrations of 76 to 558ppm. Figure 4.7 illustrates the REEcnp for all pegmatites fromwhich the following can be concluded:41Table 6. Rare earth element concentrations (ppm) of Mount Bisson rock samples determined by neutronactivation of rock powder. Also listed is the 1S relative analytical uncertainty.Sample Cea Dy Eu^Ho^Laa^Lu Nd Pr Sc Sma Tb Th U YbAlkalic Dike Rocks38M >20000 101.0 159.0^<20.0^>9000.0 1.10 7970 2600 95.60 >200.0 25.0 1310.0 36.0 19.07819 120 3.1 1.8^<1.0^66.9 0.19 39 <50 2.90 6.0 <1.0 19.0 6.6 1.27819b 120 3.2 1.6^<1.0^62.7 0.19 35 <50 2.90 5.8 <1.0 20.0 6.1 1.223 553 55.0 22.0^12.0^152.0 1.30 380 70 69.30 98.4 10.0 4.1 4.6 12.0Pegmatites Barren of Rare Earth Elements7835 290 4.7 1.6^<1.0^169.0 0.18 77 <50 24.90 11.0 <1.0 33.0 1.6 1.47835b 290 4.0 1.8^<1.0^175.0 0.19 78 <50 24.80 11.4 <1.0 33.0 1.5 1.47844 150 2.8 0.8^<1.0^81.8 0.31 35 <50 0.33 4.9 <1.0 58.4 10.0 1.87808 38 1.9 0.6^<1.0^19.0 0.26 13 <50 19.90 1.9 <1.0 5.2 3.5 1.5Pegmatites Bearing Rare Earth Elements784252^2440 33.0 18.0^3.7^1240.0 0.15 430 240 7.60 77.5 6.0 1910.0 93.0 1.7784252b 2530 34.0 18.0^5.6^1270.0 0.12 380 130 7.80 79.3 6.0 2020.0 105.0 1.57826 >20000 117.0 77.8^12.0^>9000.0 2.00 4190 1400 26.10 >200.0 24.0 3050.0 91.0 13.07911 16400 51.0 30.0^7.4^>9000.0 1.30 2630 750 28.70 >200.0 12.0 1090.0 25.0 8.47911b 16500 52.0 32.0^7.6^>9000.0 1.40 2660 920 29.10 >200.0 13.0 1110.0 25.0 10.01 1370 5.2 2.7^<1.0^751.0 <0.10 450 140 1.30 60.6 2.0 305.0 6.1 <0.5Fenites7834 1170 6.7 6.5^1.0^874.0 0.24 250 120 76.30 28.5 1.4 3.8 1.4 2.27834b 1190 6.6 6.6^1.1^873.0 0.33 260 72 77.90 28.4 1.3 4.2 2.8 2.17823 1700 8.2 11.0^1.5^865.0 0.46 490 190 38.30 53.7 2.1 45.0 3.4 3.37910 4130 26.0 30.0^3.9^2140.0 0.45 1230 340 20.10 139.0 6.0 225.0 32.0 4.27910b 4240 26.0 31.0^3.3^2120.0 0.46 1260 410 20.70 137.0 6.0 231.0 35.0 3.87837 1470 6.6 5.5^1.2^1210.0 0.19 270 98 22.60 25.3 1.0 131.0 5.8 1.87840A 909 6.6 5.6^1.0^633.0 0.15 210 55 7.40 23.2 1.6 4.8 5.3 2.038 300 9.1 4.9^3.0^137.0 0.35 110 <50 23.00 19.4 1.6 23.0 4.1 2.77809 130 8.3 3.6^1.5^59.7 0.35 63 <50 22.80 12.9 1.4 41.0 4.3 2.3Mount Bisson Granite Plutons7822 130 2.1 0.9^<1.0^72.2 <0.10 34 <50 2.40 5.6 <1.0 74.8 8.9 0.743 300 2.0 1.4^<1.0^185.0 <0.10 56 <50 2.80 7.8 <1.0 162.0 20.0 <0.57856 47 <1.0 0.7^<1.0^27.0 <0.10 13 <50 2.70 2.1 <1.0 17.0 3.0 <0.57803 889 14.0 12.0^2.5^359.0 0.63 330 83 57.00 53.7 3.0 94.6 5.8 4.2NH 66 1.2 0.8^<1.0^37.0 <0.10 22 <50 3.80 3.2 <1.0 13.0 1.5 0.6NHb 67 1.6 0.8^<1.0^36.0 <0.10 21 <50 3.70 3.1 <1.0 13.0 2.0 0.71 S^2% 5% 7%^14%^4% 17% 7% 52% 2% 3% 3% 5% 26% 10%Duplicate samples denoted "b".a Ce, La and Sm have upper detection limit of >20,000ppm, >9,000ppm and >200 ppm respectively.42I 10000 T.c:4Es^1000 —100100000 _^Mount Sisson Complet AROCK SAMPLEFIG. 4.5. Total REE concentrations vs rock sample, sorted intounits. Refer to Table 5 for samples that have elements aboveupper detection.43Table 7. REE fractionation index (La/Lu)cn, LREE fractionation index (La/Sm)cn, HREE fractionationindex (Tb/Yb)cn and europium anomaly Eu/Sm are listed for Mt. Bisson rock samples.Sample (La/Lu)cn (La/Sm)cn^(Tb/Yb)cn Eu/SmAlkalic Dike Rocks38M* 181.0 25.8^ 6.2 ---7819 34.1 6.3 3.9 0.2923 11.7 0.9^ 3.9 0.22Pegmatites Barren of Rare Earth Elements7835 93.0 8.8^ 3.3 0.157844 26.4 9.6 2.6 0.167808 7.3 5.7^ 3.1 0.32Pegmatites Bearing Rare Earth Elements7842-52 929.6 9.2^ 17.6 0.237826* 450.0 25.8 8.6 ---7911* 667.0 25.8^ 6.3 0.161 751.0 7.1 18.7 0.05Fenites7834 307.0 17.6^ 2.9 0.237823 188.0 9.2 3.0 0.207910 468.2 8.9^ 7.0 0.227837 636.6 27.4 2.6 0.227840A 422.0 15.7^ 3.7 0.2438 39.1 4.1 2.8 0.257809 17.1 2.7^ 2.9 0.28Mount Bisson Granitic Plutons7822 72.2 7.4^ 6.7 0.1643 185.0 13.6 9.4 0.187856 27.0 7.4^ 9.4 0.337803 57.0 3.8 3.4 0.22NH 36.5 6.7^ 7.2 0.25* denotes element concentration higher than the upper detection limit for the analytical method.44FIG. 4.6 Chondrite normalized REE abundance patterns foralkalic dikes. Refer to Table 5 for upper and lower detectionlimit.45FIG. 4.7. Chondrite normalized REE abundance patterns forpegmatites. Refer to Table 5 for upper and lower detectionlimit.461) All pegmatites, especially the allanite pegmatites, areenriched in REEs.2) The pegmatites are very strongly enriched in LREE (100to 30,000 times chondrite values).3) The HREE enrichment is up to 100 times chondritevalues.The REE pegmatites have high (La/Lu) cn fractionationindices of 450 to 930 (Table 7). The two Cretaceous REEpegmatites have higher HREE (Tb/Yb) cn (Larry, 1984), (La/Lu) cnfractionation indices and lower LREE (La/Sm) cn fractionationindices than the Tertiary allanite pegmatites (Table 7). Barrenpegmatites have substantially lower (La/Lu) cn fractionationindices ranging from 7.3 to 93 and (Tb/Yb) cn indices of 2.6 to3.4 (Table 7).The monazite and allanite-bearing pegmatite (UG-1 and 7911)have negative Eu anomalies (Eu/Sm) of 0.045 and 0.155respectively, while the barren quartz feldspar pegmatites (7844)and hornblende pegmatites (7835) have small to moderate negativeEu anomalies of 0.16 and 0.15, respectively. The syenitepegmatites (7808) have a slight positive Eu anomaly (Table 7).Figure 4.8 illustrates chondrite normalized REE abundancepatterns for fenites. Samples from the fenite exhibit a largerange in total REE concentrations (351 to 8524 ppm)(Figure 4.6),and greater LREE enrichment than HREE (Figure 4.8). The fenitescan be separated into two groups:1) The higher REE fractionated Laura fenites characterizedby higher total REE concentrations (Figure 4.5), higher47FIG. 4.8. Chondrite normalized REE abundance patterns forfenites.48(La/Lu) cn of 307 to 637, and higher (La/Sm) cn of 8 to 27 (Table7) .2) The less REE fractionated Will fenites characterized bylower total REE concentration, lower (La/Lu) cn of 17 to 188, andlower (La/Sm) cn of 2.6 to 9.0. The HREE (Tb/Yb) cn fractionationindex is virtually the same for samples of the fenite except for7910, suggesting that REE variations within the fenite suiteresults from LREE variation alone. The Laura fenites havesimilar and positive Eu/Sm values (Table 7).The TMB granites as a group have similar LREE cnp and areenriched to a greater extent in LREE than HREE (Figure 4.9). TheTMB granites Eu/Sm anomalies varies from negative to positive(Table 7). The CMB granodiorite display higher REEconcentrations and a marketly different REEcnp compare to theTMB granites.4.4 DISCUSSION ON PETROGRAPHY AND GEOCHEMISTRYAll rock types at Mt. Bisson are igneous except thefenites. Fenitized rocks derive from Wolverine amphibolite andCretaceous granodiorite. The fenitization process commonlypreserves older structures suggesting that the alkalimetasomatism represents a preferential replacement ofamphibolite gneissess within the Wolverine complex.The majority of the Mt. Bisson igneous events, excludingthe fenitized granodiorite, monazite-pegmatite and quartzallanite pegmatite, appear to have only slight vestiges of49FIG. 4.9. Chondrite normalized REE abundance patterns for MBgranites.50regional metamorphism and/or deformation. This would suggestthat the igneous events were emplaced into the Wolverinemetasediments after the peak of the last major metamorphic-deformational event and this is consistent with the proposedTertiary age based on field data.Tertiary allanite pegmatites have very similar major oxide,trace element and REE chemistry and appear to be geneticallyrelated to each other. Any chemical variation between them canbe explained by the loss or addition of the observed mineralphases.Tertiary granitic plutons (TMB granites) share modal andnormative mineralogy and are very similar in major oxide, traceelement and REE chemistry. Additionally, the two Tertiarygranitic pegmatites have like characteristics to the TMBgranites and could also share origins. The differences mostlikely illustrate the diverse and differing evolution historiesof these magmas. For example, granite pluton #43, with its lowBa and anomalously high LREE concentrations (compared to theother Tertiary granitic plutons), may indicate a residual magmathat at least experienced loss of potassium feldspar andplagioclase causing a depletion in Ba concentration, a negativeEu anomaly and an enrichment of LREE. Whereas TMB granite #7822has a similar Eu anomaly, lower (La/Lu) cn , lower total REEconcentration, and 30 times higher Ba concentration compared togranite #43. These observations suggest #7822 crystallized froma melt that experienced a loss, but to a lesser degree than #43,of plagioclase and potassium feldspar.51The Tertiary granite pegmatites are genetically unrelatedto the Tertiary and Cretaceous REE pegmatites, this observationis based on chemical and mineralogical data. The mineralogy andgeochemical characteristics are indicative of late formingpegmatites. The TMB granite plutons and pegmatites have S-typegranite characteristics (White and Chappel, 1977) suggesting thegranites were derived from local partial melting ofmetasedimentary rocks.Mt. Bisson fenites, based on mineralogy, major oxide, traceand rare earth elements, can be divided into two groups:1) The Laura fenites with modal potassium feldspar >> modalplagioclase, high K20, Ba, Sr and total REE (more fractionated,mainly LREE) concentrations and low Na20, Y and Zrconcentrations.2) The Will fenites with modal plagioclase >> modalpotassium feldspar, lower K20, Ba, Sr and total REE (lessfractionated, mainly LREE) concentrations and higherconcentrations of Na20, Y and Zr.The chemical variation observed in the fenites mayindicate that:1) Fenitization affected different protoliths; this isconsistent with field data.2) Chemical composition of the fenitization fluids varied;reflected in the two chemically distinct fenites.3) The more the rocks appeared fenitized the higher therocks' Na, Fe3+ , Ba, Sr and REE concentrations.52The high Ba and Sr concentrations seen in the Mt. Bissonfenites are not unique. This pattern is consistent with fenitesobserved by Pell (1987) and Currie (1976). The extreme K2O- richand Na2O- poor concentrations seen in fenite samples 7837 and7840A is a similar pattern recognized in feldspathic fenites andfenitized granitic basement at Toror Hills, Uganda (Sutherland,1965).Locally the Cretaceous granodiorite has been subjected tofenitization. This is apparent from the chemical composition of7803 which has anomalously high Na, Nb, Zr, Y and REEconcentrations. The similarity in REE concentration, REE cnp ,major oxide chemical signature and close proximity to the Willfenites clearly separates the CMB granodiorite from the TMBgranites.Cretaceous REE pegmatites are all deformed and have similarmajor oxide concentrations, and REE fractionation indices. Theyare mineralogically and chemically distinct from the Tertiaryallanite pegmatites. The relationship between the Cretaceous REEpegmatites, however is uncertain.The monazite bearing Cretaceous REE pegmatites have a largenegative Eu anomaly, normative corundum and are silicaoversaturated and REE enriched; predominantly LREE. Pegmatitesthat are enriched in LREE and relatively depleted in europiumcrystallize from upper crustal melts which were already enrichedin REE (Meuke and Moller, 1988). The plagioclase residue of thecrustal melts preferentially retains the europium. Additionally,monazite-bearing granitic pegmatites also are produced by53regional metamorphism in granulite-facies migmatitic terranes(Shearer et al., 1987). The Cretaceous pegmatites data suggestthe pegmatites crystallized from REE enriched upper crustalmelts which had a plagioclase rich residue.The relationship between the Tertiary alkalic dikes and theother rock types is uncertain. Based on petrography andgeochemistry the following assertions can be made:1) LREE-enriched aegirine-augite dikes representconcentrated residual melts.2) Alkali-feldspar dikes have quite dissimilar chemistrycompared to the aegirine-augite dikes and appear to begenetically unrelated.In conclusion, the Cretaceous REE pegmatites crystallizedfrom upper crustal melts already enriched in REE but relativelydepleted in Eu during the Cretaceous regional metamorphism.Tertiary-aged fenitization by more than one solution enriched invariable amounts of Na, Fe3+ , Ba, Sr, REE, Y and Nbpreferentially fenitized Wolverine amphibolite units andCretaceous intrusions in varying degrees. Post-fenite allanitepegmatites are cogenetic and any chemical variation observedbetween them can be explained by the addition or loss ofobserved mineral phases. The remaining Tertiary alkalic dikesmay represent early crystallization of melts with little REEfractionation. The Tertiary granites might not define acogenetic group but are all S-type granites and share mineraland chemical traits. Their differences derive from diverseevolution history54Rocks with anomalously high REE concentrations includeCretaceous monazite pegmatites (2780 ppm REE), Cretaceousquartz-allanite pegmatites (4,400 ppm REE), Tertiary allanitepegmatites (>35,000 ppm REE), REE dikes (>45,000 ppm REE) andfenites (up to 8000 ppm REE). From the previous discussionabove, the Cretaceous REE pegmatites are unrelated to theTertiary REE pegmatites; upper crustal melt versus a deep seatedmelt. The fenites are metasomatically REE enriched rocks. Thus,REE enriched rocks at Mt. Bisson represent REE enriched igneousmelts and REE enriched metasomatic solutions.The occurrence ofsuch a diverse suite of rocks, some totally unrelated to eachother, being enriched in REEs makes the Mt. Bisson area quiteunique.554.5 PEARCE ELEMENT RATIOSTrace elements formulated as Pearce Element Ratios (PER)(Russell and Halleran, 1990) are sensitive indicators of closedand open system processes (Halleran and Russell, 1990). Inaddition, cogenetic units can be recognized in suites of rocksby utilizing PER. The Mt. Bisson units were evaluated with thePER approach. Cs, Li and Ti are potentially conserved withinthe Mt. Bisson units' mineral assemblages. Cs, Li and Ti areexcluded from substitution into mineral phases untill the laststages of crystallization; except for T1 which can substitutein sulphides. However, the concentrations of Cs, Li and Tl inthe Mt. Bisson rocks were close to or below the lower detectionlimit of the analytical techniques used. Cs, Li and Ti arestill valid choices but more sensitive analytical techniquesare needed.565.0 ELECTRON MICROPROBE ANALYSES OF MINERALSINTRODUCTIONMineral microprobe analyses were performed with anautomated Cameca SX-50 electron microprobe using naturalmineral standards except in the case of the REEs and Y whereDrake REE glasses were used (Drake and Weill, 1972).Selection of calibration standards for analyses was basedon a thorough electron microprobe evaluation of pertinentstandards (Appendix B). Where possible, calibration standardswere chosen such that the mineral standard was the same speciesas the unknown and:1) The element of interest was in higher concentration inthe calibration standard than the unknown.2) The calibration standard was homogeneous for theelement of interest; any observed variation was belowanalytical error (Appendix B).3) The calibration standard must be able to accuratelypredict the element in other well documented standards.During standard evaluation a database of replicateanalyses was obtained, providing an estimate of precision.Accuracy was judged by comparison of analyses with acceptedpublished values. In addition, during the analysis of unknowns,calibration and test standards were periodically analyzed toevaluate precision and accuracy for individual runs (AppendixB). Also researched were individual problems, such as Na57mobility in feldspars, background and peak interferences on REEanalyses (Appendix B).The following section presents chemical data for minerals.Each table of mineral analyses reports the estimated analyticalerror, based on the evaluation outlined previously. Thereported analytical error is represented by error bars on allsubsequent graphs.The main phases pyroxene, feldspar, amphibole, and biotiteand important accessory minerals allanite, epidote, titanitesand apatite were systemically analyzed in representative Mt.Bisson rock samples. All mineral phases were investigated withEDS and WDS to identify all elements and ensure completeanalyses. Peaks and background positions were carefullyselected utilizing the calibration standards and the unknowns.All operating conditions for the analyses are listed inAppendix B. The raw oxide weight percent data was reducedthrough the U.B.C. Geological Science program FORM1 (Mader etal., 1988). Site occupancies for elements in each mineral wasbased on scientific literature.Cores and rims of minerals were analyzed to establishchemical variation within and between grains and betweensamples.5.1 PyroxeneRepresentative pyroxene microprobe analyses are listed inTable 8. Pyroxene structural formulae were calculated based on6 oxygens with Fe(2+):Fe(3+) ratio adjusted by charge balance.58The calculated structural formulae indicate high qualitypyroxene analyses (Table 8). Low totals for some analyses arethe result of ferric iron being present. For each sample eightto twelve grains were analyzed for core and rim compositions.The Mt. Bisson pyroxenes are within the aegirine-augitesolid solution series except for a single occurrence ofhedenbergite in a syenite pegmatite.Compositional variations within Mt. Bisson pyroxenes areas follows:1) Cationic Na content varies from 0.022 to 0.264. Fenitepyroxenes span the observed Na range with 0.022 in Laura #1,0.128 in Will #2 and up to 0.264 in Laura #2. In addition, thefenitized CMB granodiorite has augite with patchy aegirine-augite rim zones containing 0.202 Na. The alkalic dikepyroxenes are also relatively enriched in Na with 0.096 and0.228 Na in the alkali-feldspar dike and aegirine-augite dikerespectively.2) Ca varies from 0.710 to 0.952 and is inversely relatedto the Na content.3) Al is less than 0.038 except in Will #2 fenite and theREE dike pyroxene which have from 0.050 to 0.078 Al.4) Ti is generally below detection limit.5) Mn is generally less than 0.030 except in the syenitepegmatite (7808) (0.129 Mn), the aegirine-augite dike (0.064Mn) and the CMB granodiorite (0.096 Mn in patchy rim zones),6) Mg and FeT are inversely related to each other.59Table 8. Average and representative electron microprobe analyses of Mt. Sisson pyroxenes.Sample^7803(1)N=16Oxide^X^S**7803core7803rim7803Na7808N=8X S**7910N=12X S**23N=10X^S**23core23rim7837N=8X^S**ErrorSSi02^51.80(0.19) 51.92 51.37 50.97 47.95(0.30) 51.95(0.17) 51.65(0.25) 51.64 51.46 51.45(0.19) 0.18TiO2^0.01(0.02) 0.01 0.05 0.01 0.03(0.02) 0.10(0.03) 0.05(0.02) 0.07 0.03 0.05(0.03) 0.34Al203^0.20(0.05) 0.16 0.30 0.18 0.34(0.13) 0.45(0.06) 0.58(0.17) 0.72 0.76 0.43(0.01) 0.06Fe0^12.91(0.64) 11.90 13.88 16.57 26.65(0.74) 16.21(0.24) 16.77(0.39) 16.84 16.32 14.09(0.57) 0.21Mg0^10.14(0.45) 10.88 9.58 6.64 0.14(0.09) 8.30(0.17) 7.27(0.33) 7.36 7.24 9.74(0.29) 0.14Mn0^0.56(0.07) 0.49 0.66 2.90 2.34(0.61) 0.36(0.03) 1.02(0.49) 0.70 1.94 0.60(0.04) 0.28Ca0^22.99(0.24) 23.22 22.50 18.41 21.27(0.35) 17.26(0.29) 19.01(0.70) 18.63 18.83 22.35(0.31) 0.10Na20^0.48(0.05) 0.47 0.57 2.66 0.39(0.15) 3.55(0.18) 2.66(0.49) 3.03 2.43 0.32(0.03) 0.12Total 99.09 99.05 98.91 98.34 99.11 98.18 99.01 99.02 99.03 99.03Structural Formulae ( a )Si°.^1.992 1.987 1.987 1.993 1.990 1.995 1.994 1.985 1.992 1.990 0.013Al(IV) 0.008 0.004 0.004 0.000 0.010 0.005 0.006 0.000 0.000 0.010 0.003Sum^2.000 1.991 1.991 1.993 2.000 2.000 2.000 1.985 1.992 2.000 0.012Ca2+^0.948 0.952 0.933 0.771 0.946 0.710 0.786 0.767 0.781 0.927 0.006Mg2+^0.578 0.621 0.552 0.387 0.008 0.475 0.418 0.422 0.418 0.562 0.009Fe2+^0.376 0.329 0.397 0.335 0.892 0.273 0.359 0.320 0.366 0.435 0.007Al(VI) 0.001 0.003 0.009 0.008 0.007 0.016 0.020 0.033 0.035 0.010 0.003Mn2+^0.019 0.016 0.022 0.096 0.082 0.012 0.034 0.023 0.064 0.020 0.010Na+^0.035 0.035 0.043 0.202 0.032 0.264 0.199 0.228 0.182 0.024 0.010Ti 4+^0.001 0.000 0.002 0.000 0.001 0.003 0.002 0.002 0.001 0.001 0.010Fe3+^0.042 0.052 0.052 0.206 0.033 0.248 0.183 0.221 0.162 0.021 0.001Sum^2.000 2.009 2.009 2.007 2.000 2.000 2.000 2.015 2.009 2.000 0.022End member CompositionsEn^0.304 0.327 0.294 0.259 0.005 0.326 0.268 0.280 0.267 0.292 0.005Fs^0.198 0.173 0.211 0.225 0.483 0.187 0.229 0.212 0.234 0.226 0.005Dp^0.498 0.501 0.496 0.516 0.512 0.487 0.503 0.509 0.499 0.482 0.005Others 0.051 0.056 0.068 0.343 0.084 0.372 0.280 0.336 0.284 0.040 0.010(a) Fe(2+)Fe(3+) ration adjusted Oct(2)Tet(2)Oxy(6) Fixed anion sum.X = average, S** observed standard deviation of the data, S is the standard error expected fromanalytical error alone.(1) statistics on 7803 do not include the Na20 rich alteration rim zones.Core and rim analyses are the extremes found within each sample but not necessarily the same grain.End members are Mg2S1206 (En), Fe 2+2Si206 (Fs) and Ca(Mg,Fe)Si206 (Dp)Others = Mn,Fe,Ti,Al,Na60Sample#Oxide7837core7837rim38N=15X^S**38core38rim7823N=13X^S**7911N=9X^S**7819N=12X^S**7819rim7819coreSi02 51.12 51.47 52.23(0.34) 51.84 52.53 51.02(0.28) 50.88(0.24) 50.62(0.54) 51.44 49.50TiO2 0.07 0.07 0.06(0.04) 0.11 0.01 0.08(0.04) 0.07(0.03) 0.05(0.03) 0.01 0.06Al203 0.39 0.53 0.63(0.43) 1.10 0.46 1.09(0.27) 0.83(0.31) 0.34(0.34) 0.17 0.30Fe0 14.73 13.57 12.71(1.05) 14.47 11.03 14.78(0.51) 14.08(0.35) 17.69(2.07) 14.54 20.60Mg0 9.50 10.21 10.32(0.58) 9.10 11.23 8.44(0.28) 9.63(0.27) 7.38(1.12) 9.34 5.92Mn0 0.62 0.53 0.53(0.08) 0.41 0.46 0.53(0.05) 0.75(0.05) 0.34(0.05) 0.31 0.39Ca0 22.02 22.31 22.09(0.71) 20.68 22.87 22.07(0.27) 21.53(0.40) 20.80(0.72) 22.15 19.41Na20 0.30 0.30 1.04(0.37) 1.73 0.66 0.93(0.10) 0.83(0.18) 1.08(0.45) 0.73 1.23Total 98.75 98.99 99.61 99.45 99.26 98.94 98.60 98.30 98.30 97.40Structural Formulae ( a )Si t°. 1.989 1.986 1.987 1.980 1.997 1.977 1.970 1.995 1.995 1.991Al(IV) 0.007 0.010 0.013 0.002 0.000 0.023 0.030 0.005 0.000 0.000Sum 1.996 1.996 2.000 1.982 1.997 2.000 2.000 2.000 1.995 1.991Ca2+ 0.918 0.923 0.900 0.846 0.932 0.917 0.893 0.879 0.921 0.837Mg2+ 0.551 0.587 0.585 0.518 0.637 0.488 0.556 0.439 0.540 0.355Fe2+ 0.456 0.416 0.333 0.349 0.316 0.418 0.376 0.505 0.415 0.597Al(VI) 0.011 0.140 0.015 0.048 0.021 0.027 0.008 0.011 0.008 0.014Mn2+ 0.020 0.017 0.017 0.013 0.015 0.017 0.025 0.011 0.010 0.013Na+ 0.023 0.022 0.076 0.128 0.050 0.070 0.061 0.081 0.055 0.096Ti 4+ 0.002 0.002 0.002 0.003 0.000 0.002 0.002 0.001 0.000 0.002Fe3l' 0.023 0.022 0.071 0.113 0.034 0.061 0.080 0.072 0.057 0.096Sun 2.004 2.004 2.000 2.019 2.003 2.000 2.000 2.000 2.005 2.009End member CompositionEn 0.286 0.305 0.322 0.302 0.338 0.268 0.305 0.241 0.288 0.198Fs 0.237 0.216 0.183 0.204 0.178 0.229 0.206 0.277 0.221 0.334Dp 0.477 0.479 0.495 0.494 0.494 0.503 0.489 0.482 0.491 0.468Other 0.041 0.040 0.100 0.179 0.063 0.098 0.096 0.097 0.069 0.124Table 8 continued61The hedenbergite from syenite pegmatites is chemicallyhomogeneous except for the substitution of Mn for Fe 2+ ; Mn doesnot partition strongly into the early formed ferromagnesianminerals but substitutes for Fe 2+ in Ca-poor pyroxene (Campbellabd Borley, 1974).Figure 5.Oa and 5.0b illustrates pyroxene compositionsplotted on Na vs Mg (Ca vs Fe[Total] has an inverserelationship to Na vs Mg). The following observations can bemade:1) Mt. Bisson pyroxene compositions vary widely incationic Na, Ca, Mg, and FeT.2) The pyroxene data from the fenites form three separateddistinct clusters on Figure 5.Oa.3) Pyroxenes from the alkali-feldspar dikes and REE dikesshow core to rim zoning of Na, Fe-rich (mainly Fe 3+ in the REEdike) and Ca, Mg-poor cores. In addition, pyroxenes from REEdikes have higher Al rims relative to cores.4) The patchy aegirine-augite on the rims of the augitefrom the CMB granodiorite have high Na content compared to theunaltered core to rim data.With the exception of the hedenbergite, the chemicalvariance of cationic Na, Fe2+ , Fe3+ , Mg and Ca observed in theMt. Bisson pyroxenes is consistent with the aegirine-augitesolid solution exchange ofNaFe3+ '^"- CaMgFe2+6200000 Fenites00000 Alkalic DikesI^1^I^I^I^I^I^I^I^I^I0.2 0.4 0.6Mg Cations (P.F.U.)FIG. 5.0a. Fenite and alkalic dike pyroxene compositionsplotted as Cations Na vs Mg. Arrows connect select core to rimcompositions.630.3 - Mount Bisson Pyroxenes2S00.1 - ***** Barren PegmatitesAA AAA REE Pegmatites***** MB Granites0.0 ^0.0 0.2^0.4^0.6^0.8Mg Cations (P.F.U.)FIG. 5.0b. Pegmatite and MB granite pyroxene compositionsplotted as Cations Na vs Mg.64(Figure 5.1). The pyroxenes from the Laura #2 fenite have thehighest aegirine component.The Mn-rich hedenbergite suggests late stagecrystallization (Campbell and Borley, 1974), in part supportedby its interstitial anhedral texture. The low Ti contentobserved in the Mt. Bisson pyroxenes may be caused by the earlyappearance of titanite depleting the magmas of TiO2 (Gibb,1973; Tracy and Robinson, 1977). Pyroxene compositions in thedifferent fenites varies significantly in aegirine componentand illustrates the diverse chemical nature of the fenites. Na-rich aegirine-augite patchy zones on the otherwise homogeneousaugite in the CMB granodiorite is supportive evidence for post-emplacement fenitization. Similar chemical zoning as found inthe alkalic dikes was observed in the Monteregian dikes fromthe Monteregian alkaline province of southern Quebec (Bedard etal., 1988). One of the explanations given by Bedard et al.(1988) is that of incompletely crystallized magma mixed with anew pulse of magma; open system process.5.2 FeldsparsRepresentative feldspar microprobe analyses are listed inTable 9. Feldspar structural formulae were calculated based oneight oxygens. For each sample, grains were analyzed for coreto rim compositions, exsolution feldspar were also analyzed.The Wt% oxide totals and consistent calculated structuralformulae indicate high quality microprobe analyses.65***** Barren PegmatitesAAAAA REE Pegmatites*Or*** MB Granites0000^ Fenites00000 Alkalic DikesFIG. 5 1. Pyroxene compositions plotted as Cations Ca+Mg+Fe 2+vs Na+Fe1+ ; aegirine-augite solid solution.66Table 9. Average and representative electron microprobe analyses of Mt. Bisson feldsparsSampleOxide7819NagX S**7819K-sparX^S**23^23Plag^K-sparX^S**^X^S**7835PlagX S**7835K-sparX^S**7844PlagX S**7844K-sparX^S**Si02 68.52(0.33) 64.27(0.15) 69.12(0.33) 64.48(0.19) 62.61(0.68) 64.20(0.30) 66.78(0.46) 64.80(0.23)Al203 18.95(0.14) 17.75(0.11) 19.19(0.20) 17.97(0.10) 22.65(0.38) 18.15(0.09) 20.35(0.22) 18.22(0.06)Fe0 0.25(0.07) 0.26(0.05) 0.24(0.06)^0.24(0.05) 0.13(0.04) 0.05(0.03) 0.10(0.03) 0.05(0.03)Mg0 0.00(0.00) 0.00(0.00) 0.00(0.00)^0.00(0.00) 0.00(0.00) 0.00(0.00) 0.00(0.00) 0.00(0.00)Na20 11.38(0.10) 0.71(0.04) 11.42(0.10)^0.74(0.17) 8.71(0.32) 1.03(0.11) 10.40(0.31) 1.27(0.15)Ca0 0.09(0.11) 0.00(0.00) 0.11(0.05)^0.00(0.00) 4.43(0.45) 0.03(0.08) 1.55(0.27) 0.04(0.03)K20 0.13(0.03) 15.39(0.13) 0.14(0.03)^15.52(0.30) 0.36(0.12) 15.05(0.19) 0.47(0.35) 14.76(0.23)Ba0 0.01(0.01) 0.33(0.08) 0.01(0.01)^0.38(0.06) 0.00(0.00) 0.30(0.08) 0.00(0.00) 0.23(0.03)Sr0 0.01(0.01) 0.00(0.00) 0.06(0.05)^0.04(0.03) 0.07(0.09) 0.03(0.05) 0.01(0.01) 0.00(0.00)Total 99.34 98.71 100.29^99.38 98.96 98.84 99.65 99.38Structural formulae(a)Si 4°. 3.013 3.011 3.010^3.004 2.801 2.998 2.940 3.003A13+ 0.982 0.980 0.985^0.987 1.194 0.999 1.056 0.995Sum 3.995 3.991 3.995^3.991 3.995 3.997 3.996 3.998K+ 0.008 0.920 0.0080.923 0.021 0.897 0.026 0.873Na+ 0.970 0.065 0.964^0.067 0.756 0.094 0.888 0.114Ca2+ 0.004 0.000 0.0050.000 0.212 0.002 0.073 0.002Ba2+ 0.000 0.006 0.000^0.007 0.000 0.006 0.000 0.004mg2+ 0.000 0.000 0.000^0.000 0.000 0.000 0.000 0.000Fe2+ 0.009 0.010 0.009^0.010 0.005 0.002 0.004 0.002Sr2+ 0.000 0.000 0.002^0.001 0.002 0.001 0.001 0.000Sum 0.991 1.001 0.988^1.007 0.995 1.000 0.993 0.995End member CompositionsK 0.008 0.920 0.008^0.923 0.021 0.897 0.026 0.873Na 0.970 0.065 0.964^0.067 0.756 0.094 0.888 0.114Ca 0.004 0.000 0.005^0.000 0.212 0.002 0.073 0.002Ba 0.000 0.006 0.000^0.007 0.000 0.006 0.000 0.004Others 0.010 0.011 0.010^0.011 0.007 0.003 0.005 0.002N=18 N=4 N=9^N=7 N=15 N=16 N=12 N=9(a) Structural formulae based on Oct(1)Tet(4)Oxy(8). X = average, S** observed standard deviation of thedata, S is the standard error expected from analytical error alone. N = number of analyses for average.Core and rim analyses within each sample are on the same grain.End members are KAlSi308 (K), NaAlSi308 (Na), CaAl2Si208 (Ca) and BaAl2Si0208 (Ba). Others = Mg, Fe, Sr.67Table 9 continuedSample^7808Plag7808K-spar7842-52Plag7842-52K-spar7911Plag7911K-sparUG-1PlagUG-1K-sparOxide X^S** X^S** core rim X^S** core rim X^S** X^S**Si02 67.92(0.57) 64.95 67.47(0.36) 63.05 64.38 65.38(0.32) 65.05 64.76 62.95(1.38) 64.95(0.16)Al203 19.70(0.21) 18.07 19.91(0.18) 18.95 18.16 21.02(0.16) 18.22 18.01 22.94(0.86) 18.21(0.09)Fe0 0.12(0.04) 0.05 0.12(0.04) 0.13 0.11 0.12(0.02) 0.06 0.11 0.05(0.03) 0.04(0.03)Mg0 0.00(0.00) 0.00 0.00(0.04) 0.00 0.00 0.00(0.00) 0.00 0.00 0.00(0.00) 0.00(0.00)Na20 11.08(0.25) 0.58 10.98(0.12) 2.97 1.47 9.78(0.22) 2.36 0.96 8.79(0.66) 1.15(0.20)Ca0 0.74(0.33) 0.01 0.78(0.14) 0.02 0.00 2.56(0.12) 0.07 0.00 4.53(1.06) 0.03(0.02)K20 0.18(0.07) 15.89 0.15(0.04) 11.38 14.01 0.38(0.17) 13.30 15.32 0.37(0.13) 14.92(0.33)BaO 0.01(0.02) 0.16 0.03(0.02) 1.55 0.69 0.02(0.02) 0.18 0.15 0.02(0.01) 0.27(0.12)Sr0 0.01(0.02) 0.00 0.36(0.14) 0.78 0.34 0.04(0.04) 0.06 0.02 0.01(0.01) 0.01(0.02)Total 99.77 99.71 99.79 98.83 99.16 99.28 99.30 99.33 99.66 99.57Structural formulae(a)Si 4+ 2.978 3.009 2.965 2.951 2.998 2.897 3.003 3.008 2.796 3.005AO+ 1.018 0.987 1.031 1.045 0.997 1.098 0.991 0.986 1.201 0.993Sum 3.997 3.996 3.996 3.996 3.995 3.995 3.994 3.994 3.997 3.998K+ 0.010 0.939 0.008 0.679 0.832 0.022 0.783 0.908 0.021 0.880Na+ 0.942 0.052 0.936 0.270 0.133 0.841 0.211 0.087 0.757 0.103Ca2+ 0.035 0.001 0.037 0.001 0.000 0.122 0.004 0.000 0.216 0.001Ba2+ 0.000 0.003 0.001 0.028 0.013 0.000 0.003 0.003 0.003 0.005Mg2+ 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000Fe2+ 0.004 0.002 0.004 0.005 0.004 0.004 0.002 0.004 0.002 0.002Sr2+ 0.000 0.000 0.009 0.021 0.009 0.001 0.002 0.001 0.000 0.000Sun 0.992 0.997 0.995 1.005 0.991 0.989 1.005 1.002 0.996 0.992End member CompositionsK 0.010 0.939 0.008 0.679 0.832 0.022 0.783 0.908 0.021 0.880Na 0.942 0.052 0.936 0.270 0.133 0.841 0.211 0.087 0.757 0.103Ca 0.035 0.001 0.037 0.001 0.000 0.122 0.004 0.000 0.216 0.001Ba 0.000 0.003 0.001 0.028 0.014 0.003 0.003 0.003 0.000 0.005Other 0.002 0.005 0.014 0.026 0.014 0.006 0.004 0.005 0.002 0.002N=9 N=1 N=11 N=7 N=14 N=468Table 9 continuedSampleOxide7823PlagX S**7823K-sparcore^rim7837K-sparcore^rim7910(1)^7910 (1)Plag^K-spar43Plagcore rim43K-sparcore^rim7803^ErrorPlagX^S**^SSi02 64.08(0.20) 63.40 62.12 64.78 62.94 68.23 62.97 63.27 61.46 63.33 63.86 64.02 68.33(0.24) (0.22)Al203 21.89(0.14) 18.82 18.84 18.38 18.42 18.94 18.30 19.23 24.04 22.53 18.81 18.38 19.44(0.17)^(0.15)Fe0 0.11(0.04) 0.10 0.27 0.13 0.13 0.29 0.27 0.21 0.06 0.05 0.04 0.05 0.19(0.04) (0.21)MgO 0.00(0.00) 0.00 0.00 0.00 0.00 0.00 0.02 0.01 0.00 0.00 0.00 0.00 0.00(0.00) (0.14)Na20 9.30(0.11) 2.51 1.36 2.63 1.68 11.39 1.33 5.90 8.01 9.23 1.68 0.99 11.23(0.11)^(0.10)Ca0 3.31(0.15) 0.09 0.05 0.05 0.03 0.01 0.00 0.03 5.88 4.17 0.17 0.02 0.44(0.11)^(0.10)K20 0.44(0.07) 12.02 13.51 12.31 13.33 0.13 14.02 6.27 0.41 0.20 13.71 15.00 0.20(0.06) (0.22)BaO 0.10(0.03) 1.84 2.28 0.70 1.75 0.00 1.46 2.19 0.01 0.02 1.10 0.63 0.02(0.02) (0.26)Sr0 0.19(0.05) 0.09 0.07 0.14 0.16 0.01 0.61 1.36 0.13 0.00 0.04 0.02 0.01(0.01)^(0.30)Total 99.42 98.87 98.50 99.12 98.44 99.00 99.02 98.47 100.00 99.53 99.41 99.11 99.86Structural formulae(a)Si 4+ 2.849 2.964 2.946 2.996 2.971 3.010 2.968 2.941 2.733 2.813 2.970 2.988 2.992^(0.015)A13+ 1.147 1.037 1.053 1.002 1.025 0.985 1.017 1.053 1.260 1.180 1.031 1.011 1.003^(0.009)Sum 3.996 4.001 3.999 3.998 3.995 3.995 3.985 3.994 3.994 3.993 4.001 3.999 3.995^(0.018)K+ 0.025 0.717 0.817 0.726 0.803 0.007 0.845 0.372 0.023 0.011 0.813 0.893 0.011^(0.014)Na+ 0.802 0.228 0.125 0.236 0.154 0.974 0.121 0.532 0.691 0.795 0.152 0.090 0.954^(0.009)Ca2+ 0.158 0.005 0.003 0.003 0.002 0.000 0.000 0.001 0.280 0.199 0.009 0.001 0.021^(0.005)Ba2+ 0.002 0.034 0.042 0.013 0.032 0.000 0.027 0.040 0.000 0.000 0.020 0.012 0.001^(0.005)Mg2+ 0.000 0.000 0.000 0.000 0.000 0.000 0.001 0.001 0.000 0.000 0.000 0.000 0.000^(0.010)Fe2+ 0.004 0.004 0.011 0.005 0.005 0.101 0.011 0.008 0.002 0.002 0.002 0.002 0.007^(0.008)Sr2+ 0.005 0.002 0.002 0.004 0.004 0.000 0.017 0.037 0.003 0.000 0.001 0.001 0.001^(0.008)Sum 0.995 0.989 1.000 0.986 1.000 0.993 1.023 0.990 1.000 1.007 0.996 0.998 0.994^(0.024)End member CompositionsK 0.025 0.717 0.817 0.726 0.803 0.007 0.845 0.372 0.023 0.011 0.813 0.893 0.011^(0.014)Na 0.802 0.228 0.125 0.236 0.154 0.974 0.121 0.532 0.691 0.795 0.152 0.090 0.954^(0.009)Ca 0.158 0.005 0.003 0.003 0.002 0.000 0.000 0.001 0.280 0.199 0.009 0.001 0.021^(0.005)Ba 0.002 0.034 0.042 0.013 0.032 0.000 0.027 0.040 0.000 0.000 0.020 0.012 0.001^(0.005)Other 0.009 0.006 0.013 0.009 0.010 0.011 0.029 0.045 0.006 0.002 0.003 0.003 0.008^(0.015)N=20 N=26(1) Analyzed by Zhou (1991)69Plagioclase composition (Figure 5.2) varies from An0 toAn30 and the K-feldspar is orthoclase. Figure 5.3 illustratesthe extent of plagioclase solid solution.Feldspars were analyzed for Ba and Sr. The feniteorthoclase has the highest Ba content of up to 0.049 (Figure5.4a and 5.4b) and Sr up to 0.038 (Figure 5.5) while thequartz-allanite pegmatites also have high Ba of 0.028. The Baand Sr content are confined to the alkali-feldspar solidsolution series.Potassium feldspar in TMB granite #43 have cores enrichedin Ba and Ca but depleted in Na and K relative to the rims(Figure 5.4b). Quartz-allanite pegmatites (7842) and allanitepegmatites (7911) have potassium feldspar with cores enrichedin Na but depleted in K relative to rims, in addition, 7842have cores enriched in Ba (Figure 5.4b) and Sr (Figure 5.4a).Cores of potassium feldspars in fenites are depleted in Ba andK but enriched in Na relative to rims (Figure 5.4a). TMBgranite 43 has plagioclase with Al and Ca enriched but Nadepleted cores relative to rims.5.3 AmphiboleRepresentative microprobe analyses are listed in Table 10.Amphibole structural formulae were calculated based on 24anions (0,0H,F,C1) with cations partitioned after Dorais(1990). Amphiboles from Mt. Bisson are calcic: (Ca+Na)B > 1.34;Nag < 0.67 (Leake, 1978)(Table 10). Amphiboles are classifiedafter Hawthorne (1983). The hornblende pegmatites have both70FIG. 5.2. Feldspar compositions plotted as mole % An, Or andAb.71FIG. 5.2 continued7200000 Alkalic Dikes***** Barren PegmatitesAzsa6.6. REE Pegmatites0000^ Fenites***** MB GranitesFIG. 5.3. Plagioclase compositions plotted as Cations Ca vsNa.730.05 0002S+on0.04 -^00MD• 0o^ ^^ qb^ ^ El-rb00.00^^ i^1^1^I^1^1^i^1^0.0 0.2 0.4 0.6 0.8^1.0K Cations (P.F.U.)0FIG. 5.4a. Fenite alkali feldspar compositions plotted asCations K vs Ba. Dashed line is lower limit of detection andshaded squares are select core compositions.741^Ii ii0.4^0.6^0.8K Cations (P.F.U.)FIG. 5.4b. REE pegmatite and MB granite alkali feldsparcompositions plotted as Cations K vs Ba. Dashed line is lowerlimit of detection and shaded symbols are select corecompositions. Symbols as in Figure 5.3.75K Cations (P.F.U.)FIG. 5.5. Fenite and REE pegmatite alkali feldsparcompositions plotted as Cations K vs Sr. Dashed line is lowerlimit of detection and shaded symbols are select corecompositions. Arrow connects core to rim compositions. Symbolsas in Figure 5.3.76Table 10. Representative electron microprobe analyses of Mt. Bisson amphiboles.Sample 7835 7835 7835^7911 7823 7910 7837 Error# N=5Oxide X SSi02 46.97 44.14 42.36^45.43 39.41 52.80 44.83 (0.18)TiO2 0.57 0.96 1.10^0.73 1.19 0.32 1.00 (0.34)Al203 5.39 8.17 9.56^6.93 11.76 1.48 7.12 (0.06)Fe0 20.31 20.66 19.80^19.85 20.43 15.16 20.81 (0.21)Mn0 0.52 0.46 0.44^0.59 0.38 0.38 0.58 (0.28)Mg0 9.89 8.66 8.97^10.00 8.29 14.07 9.07 (0.14)Ca0 11.95 11.85 12.00^11.75 11.71 8.53 11.85 (0.10)Na20 1.01 1.41 1.67^1.67 2.44 3.32 1.32 (0.12)K20 0.61 1.04 1.18^0.82 1.76 0.75 0.83 (0.12)F 0.40 0.32 0.48^0.50 0.79 1.18 0.50 (0.12)Cl 0.06 0.14 0.12^0.03 0.09 0.01 0.06 (0.12)Total 97.68 97.81 97.68^98.30 98.25 98.00 97.970-F,Cl 97.50 97.65 97.45^98.08 97.90 97.50 97.75Structural Formulae ( a )Si 4+ 7.107 6.746 6.497^6.855 6.088 7.740 6.825 (0.049)A1 3+ 0.893 1.254 1.503^1.145 1.912 0.256 1.175 (0.010)Fe3+ - - - - 0.004 (0.025)Sum 8.000 8.000 8.000^8.000 8.000 8.000 8.000A1 3+ 0.068 0.217 0.225^0.087 0.240 0.000 0.103 (0.005)Ti 4+ 0.065 0.110 0.127^0.083 0.139 0.035 0.115 (0.039)Fe3l' 2.200 2.125 2.088^2.199 2.004 1.855 2.170 (0.028)mg2+ 2.230 1.973  2.051^2.249 1.918 3.074 2.058 (0.034)Fe2+ 0.370 0.516 0.452^0.306 0.649 0.000 0.480 (0.007)Mn2+ 0.067 0.060 0.057^0.075 0.050 0.036 0.075 (0.010)Sum 5.000 5.001 5.000^4.999 5.000 5.000 5.000Mn2+ - -^- 0.011 - (0.010)Ca2+ 1.937 1.940 1.972^1.900 1.948 1.340 1.933 (0.020)Na+ 0.063 0.060 0.028^0.100 0.052 0.649 0.067 (0.010)Sum 2.000 2.000 2.000^2.000 2.000 2.000 2.000Na+ 0.234 0.358 0.469^0.380 0.684 0.295 0.323 (0.036)K+ 0.118 0.203 0.231^0.158 0.349 0.140 0.161 (0.024)Sum 0.352 0.561 0.700^0.538 1.033 0.435 0.484F" 0.191 0.155 0.233^0.239 0.386 0.547 0.241 (0.058)Cl" 0.015 0.036 0.031^0.008 0.023 0.003 0.016 (0.031)(a) Fe(2+)Fe(3+) ratio adjusted Sodic-Calcic A(1)B(2)C(5)T(8) (0,011,F,Cl)(24) Fixed anion sum, formulaecorrected for F and Cl. X = average, S is the standard error expected from analytical error alone, N =number of analyses for average.77magnesio-hornblende and edenitic hornblende while the allanitepegmatites have edenitic hornblende included by augite. Feniteshave potassium rich magnesio-hastingsiteinclusions in augite (Will #2 fenite), patchy inclusions ofmagnesio-hornblende in augite (Laura #1 fenite) and patchyzones of subcalcic tremolite in aegirine-augite (Laura #2fenite).Compositional variations within Mt. Bisson amphiboles areas follows:1) Cation Ca content is 1.90 to 1.97, except in amphibolesfor the Laura #2 fenite where it is only 1.34.2) Na is over 0.170 with highs of 0.736 and 0.944 inamphiboles from the Will #2 and Laura #2 fenites respectively.3) Highest F ,0.547, occurs in the Laura #2 feniteamphiboles.5.4 BiotiteRepresentative microprobe analyses of Mt. Bisson biotitesare listed in Table 11. Biotite structural formulae werecalculated based on 24 anions (0, OH, F C1), with Fe 3+ :Fe2+calculated assuming Fe 2+ substitutes for Mg and Fe 3+substitutes for Al and Mg (Cornelius and Cornelis, 1977).Biotite from TMB granites have the highest cationic Al, Feand lowest Mg and K, with cores enriched in Si and Al anddepleted in Fe and K. Fenite biotites have the lowest Ti andhighest F content and are chemically homogeneous except for Fenriched cores.78Table 11. Representative electron microprobe analyses of Mt. Bisson biotites.Sample UG-1 UG-1b 7823 7823 43 43 ErrorOxide core rim core rimSi02 37.14 28.43 36.24 36.55 36.06 35.25 (0.18)Al203 13.63 15.63 13.03 12.96 14.61 13.88 (0.06)Mg0 10.30 12.45 12.00 12.08 8.78 8.49 (0.14)Fe0 20.81 23.52 20.93 20.83 23.39 24.26 (0.21)TiO 4.67 3.79 2.23 2.18 3.81 3.86 (0.34)Mn0 0.09 0.09 0.26 0.25 0.31 0.42 (0.28)K20 9.67 0.05 9.31 9.35 8.83 9.35 (0.12)Na20 0.00 0.00 0.00 0.00 0.00 0.00 (0.12)Ca0 0.00 4.02 0.03 0.00 0.05 0.02 (0.10)F 0.41 0.38 1.21 0.89 0.46 0.51 (0.12)Cl 0.30 0.00 0.03 0.07 0.14 0.19 (0.12)Total 97.02 - 95.27 95.16 96.44 96.230-F,Cl 96.78 94.75 94.77 96.22 95.98Structural Formulae ( a )Si 4+ 5.807 5.755 5.807 5.669 5.620 (0.045)A13+ 2.193 2.245 2.193 2.331 2.380 (0.014)8.000 8.000 8.000 8.000 8.000A1 3+ 0.319 0.193 0.234 0.376 0.228 (0.006)mg2+ 2.400 2.840 2.861 2.057 2.018 (0.035)Fe2+ 0.154 0.000 0.000 0.074 0.226 (0.002)Ti 4+ 0.549 0.266 0.260 0.450 0.463 (0.040)Mn2+ 0.012 0.035 0.034 0.041 0.057 (0.037)Fell' 2.567 2.780 2.768 3.001 3.009 (0.034)6.001 6.114 6.157 5.999 6.0011.929 1.886 1.895 1.771 1.902 (0.027)0.000 0.000 0.000 0.000 0.000ca2+ 0.000 0.005 0.000 0.008 0.003 (0.017)F" 0.203 0.608 0.447 0.229 0.257 (0.060)Cl" 0.080 0.008 0.019 0.037 0.051 (0.032)(a) Fe(2+)Fe(3+) ratio adjusted Tri-Octahedral Biotite, Int(2) Oct(6) Tet(8) (oxy, OH, F, Cl,)(24),formulae corrected for F and Cl. S is the average standard error expected from analytical error alone. bbiotite alteration product.79Mt. Bisson biotite compositions plotted on Mg vs Fe 2+ +Fe3+ (Figure 5.6) form three distinct groups. TMB granitebiotites compositions form a group with high Al but low Si onAl vs Si (Figure 5.7).5.5 ApatiteRepresentative electron microprobe analyses of Mt. Bissonapatites are listed in Table 12. Apatite structural formulaewere calculated based on 25 anions (0,0H,F,C1,) and the cationswere partitioned after Deer et al., (1962).Compositional variations within Mt. Bisson apatites are asfollows:1) Cationic LREE and Sr content varies from 0.01 to 0.095and 0.003 to 0.094 respectively with extremes of > 0.297 REEand > 0.593 Sr observed in apatites from the Laura #2 fenite.2) Ca varies from 9.221 to 10.065 and is inversely relatedto the (LREE + Sr) content.3) F varies from 1.421 to 1.976.REE and Sr replaces Ca in the apatite structure (Deer etal., 1962) (Figure 5.8 and 5.9). The high REE and Sr contentobserved in some fenite apatites are unique. Examples fromliterature for comparison include > 9.00 wt% rare earth oxidesin apatite from the Kangerdlugssuaq alkaline intrusion, EastGreenland (Henderson, 1980) and 11 wt% SrO inapatite from the Khibina tundra Kola Peninsula nepheline rocks(Deer et al., 1962). Apatite with greater than 5.0 wt% SrO are80Mount Sisson biotites3.0 -2SA***** MB Granites (43)AAAAA REE Pegmatite (UG-1)0^^^^ Fenite (7823)** *1.8 1^I^I^1^1^1^1^i^12.4 2.9 3.4Fe2 + Fe3 Cations (P.F.U.)C7-:a'—'2.6 -2.2+.,csUX 2.2 -oFIG. 5.6. Biotite compositions plotted as Cations Fe 2++Fe3+ vsMg.81..-,r7-a.rn2.7 -Mount Bisson biotites2S1^*004-) 2L).p.5 -cd^•0Aoo^nn714 0 II]***** MB Granites (43)AAAAA REE Pegmatite (UG-1)00000 Fenite (7823)2.3 I^I^I5.4^5.6 5.8^6.0Si Cations (P.F.U.)FIG. 5.7. Biotite compositions plotted as Cations Si vs Al.82Table 12. Average and representative electron microprobe analyses of Mt. Bisson apatites.Sample 7819 23 7835 7842 7911 7911 7823 7837 7910 43 ErrorOxide X N=3 S** X N=4 S** rim core X N=3 S**P205 41.88 41.52(0.36) 41.87(0.27) 40.47 41.50 41.01 41.57(0.10) 41.58 38.45 40.71 (0.47)Na20 0.12 0.15(0.03) 0.04(0.01) 0.04 0.05 0.07 0.03(0.01) 0.07 0.36 0.08 (0.12)Ca0 53.05 53.64(0.06) 54.81(0.28) 53.89 54.62 54.28 54.97(0.43) 55.18 47.23 54.33 (0.21)Sr0 0.37 0.95(0.11) 0.03(0.02) 0.56 0.10 0.06 0.10(0.02) 0.23 5.63 0.05 (0.30)La203 0.38 0.30(0.04) 0.03(0.01) 0.20 0.06 0.14 0.08(0.02) 0.08 0.97 0.11 (0.04)Ce203 0.35 0.66(0.03) 0.11(0.03) 0.49 0.17 0.35 0.25(0.07) 0.08 2.09 0.29 (0.07)Pr203 nd 0.07(0.04) 0.05(0.05) nd nd 0.12 0.07(0.09) nd 0.20 nd (0.08)Nd203 0.05 0.37(0.08) 0.07(0.06) 0.29 0.16 0.08 . 0.18(0.07) nd 1.08 0.22 (0.19)Sm203 nd nd 0.03(0.05) nd 0.04 0.10 0.02(0.03) 0.01 0.16 0.16 (0.03)Y203 0.03 0.10(0.01) 0.10(0.05) 0.26 0.11 0.16 0.08(0.03) 0.02 nd 0.63 (0.04)F 2.61 3.07(0.18) 3.69(0.34) 2.89 3.12 3.05 3.68(0.23) 3.24 3.11 3.48 (0.14)Cl 0.04 0.02(0.01) 0.04(0.02) 0.03 0.06 0.08 0.02(0.01) 0.10 0.03 0.09 (0.07)Total 98.97 100.90 101.00 99.36 100.12 99.67 101.09 100.71 99.35 100.400-F,Cl 97.86 99.61 99.45 98.14 98.78 98.37 99.54 99.34 98.04 98.92Structural formulae ( a )P5+ 6.101 6.020 6.000 5.968 6.013 5.991 5.980 5.992 5.918 5.926 (0.089)Fe2+ 0.004 0.003 0.006 0.022 0.007 0.007 0.001 0.010 0.003 0.020 (0.038)Mn2+ 0.008 0.005 0.010 0.014 0.012 0.014 0.003 0.007 0.003 0.014 (0.043)mg2+ - - - - - 0.004 0.001 - (0.038)0.002Na+ 0.040 0.048 0.014 0.012 0.024 0.022 0.013 0.022 0.127 0.027 (0.042)Ca2+ 9.884 9.843 9.930 10.054 10.016 10.039 10.002 10.065 9.221 10.009 (0.089)Sr2+ 0.037 0.094 0.003 0.056 0.010 0.006 0.010 0.022 0.593 0.005 (0.032)La3+ 0.024 0.019 0.002 0.013 0.003 0.008 0.005 0.004 0.066 0.006 (0.003)Ce3+ 0.022 0.040 0.007 0.031 0.011 0.022 0.015 0.004 0.138 0.019 (0.005)Pr3+ - 0.005 0.003 - 0.008 0.005 0.013 nd (0.005)Nd3+ 0.003 0.023 0.004 0.019 0.010 0.005 0.012 0.070 0.014 (0.012)Sm3+ - - 0.002 - 0.002 0.006 0.001 0.010 0.010 (0.002)Y3+ 0.003 0.008 0.009 0.023 0.010 0.014 0.005 0.002 nd 0.058 (0.014)Sum 10.075 10.088 10.006 10.244 10.105 10.155 10.073 10.136 10.244 10.184 (0.119)F - 1.421 1.660 1.976 1.591 1.689 1.665 1.971 1.747 1.788 1.893 (0.082)Cl - 0.011 0.006 0.012 0.008 0.017 0.023 0.005 0.028 0.009 0.023 (0.022)( a ) structural formulae based on 26(O,OH,F,CL) fixed anion sum. Nb205 measured but not detected. X =average, S** observed standard deviation of the data, S is the standard error expected from analyticalerror alone. Fe, Mn and Mg analyzed for but below detection level.830-00000 Alkalic Dikes***** Barren PegmatitesREE Pegmatites0000^ Fenites***** MB Granites0•r4os10.09.89.6rn9.40os9.2 -4.)os9.08.80.0^0.1^0.2^0.3LREE + Y Cations (P.F.U.)Mount Bisson Apatites2S-FIG. 5.8. Apatite compositions plotted as Cations LREE+Y vs CaCations x 10/Sum Ca site; normalized Ca Cations. Dashed line islower limit of detection.841^I^1^I^l^I^1^I L40.2 0.4 0.6 0.8^1.0LREE + Y + Sr Cations (P.F.U.)FIG. 5.9. Apatite compositions plotted as Cations LREE+Y+Sr vsCa Cations x 10/Sum of Ca site; normalized Ca Cations. Dashedline is lower limit of detection.85named saamite. The apatites at Mt. Bisson are F-apatites withone occurrence of saamite.Apatites in the allanite pegmatites have cores slightlyenriched in LREE relative to the rims.Based on LREE content, apatites at Mt. Bisson form twogroups:1) Apatites coexisting with allanite and have low REEcontent.2) Apatites with no allanite association and haverelatively high REE content.Exceptions are apatites from the TMB granites and Laura #2fenites (7910). The TMB granites have high total REE;predominantly Y, content and coexists with allanite. Apatitesfrom 7910 are extremely LREE rich and coexists with allanite;allanite occurs as trace intergrowths with titanite. Timing ofapatite crystallization with respect to allanite and/ortitanite crystallization is an important control in theconcentrations of REE in apatites (Henderson, 1980; Burt,1989).865.6 TitanitesRepresentative electron microprobe analyses of Mt. Bissontitanites are listed in Table 13. Structural formulae werecalculated based on 5 anions (0, OH, F) (Exley, 1980), withcalculated Fe3+/Fe2+ . Fe3+ substitutes for Ti to balance REEsubstitution in the Ca site (Deer et al., 1962). Ca in thetitanite structure is replaced by Sr, Ba, REE, Na and Mn whichis balanced by Fe3+ + Al substitution for Ti while Ti isreplaced by Sn, Nb, Ta, and Fe (Deer et al., 1962; Groat etal., 1985; Burt, 1989). For each sample, two to six grains wereanalyzed for core and rim compositions. Calculated structuralformulae indicate the analyses are stoichiometric, however, itis likely HREE are present in some titanites. As well,calculated structural formulae for titanite from 7910 indicateunidentified element/elements substituting for Ca.Compositional variations within Mt. Bisson titanites areas follows:1) Red brown pleochroic titanites from the Laura #2 fenitehave up to 0.688 total REE cations while the remainingtitanites have from below the lower limit of detection to 0.048REE.2) Ca content decreased with increased REE content.3) The highest Nb (0.084) and SrO (0.111) are found intitanites from the quartz-allanite pegmatites (7842) and Laura#2 fenites (7910) respectively. All other Mt. Bissontitanites have Nb <0.014 and Sr below detection level. Ticontent decreases with increasing Nb content.87Table 13. Average and representative electron microprobe analyses of Mt. Bisson titanites.SampleOxide23N=4X^S**7819core7819rim7835^7835rim(1) core7835rim7842^7842rim(1) core7842rim7911 7911Si02 29.42(0.12) 29.71 29.24 30.15 29.86 29.97 28.88 28.68 29.09 28.84 29.50Al203 1.13(0.06) 0.32 0.85 2.04 1.74 2.16 1.36 0.74 1.31 1.40 1.45TiO2 35.38(0.33) 37.73 36.49 35.32 35.40 35.05 30.64 33.43 31.89 34.67 35.11Fe0 1.72(0.08) 1.23 1.48 1.30 1.11 1.14 2.73 2.65 2.46 1.96 1.51Mg0 0.01(0.01) 0.00 0.01 0.01 0.00 0.02 nd nd nd 0.01 0.01Nb205 0.50(0.09) 0.13 0.16 0.16 0.36 0.44 5.38 2.31 3.78 0.70 0.59Mn0 0.09(0.03) 0.05 0.05 0.04 0.11 0.06 0.15 0.11 0.18 0.13 0.12Ca0 26.18(0.16) 26.93 26.77 27.66 27.19 27.08 26.39 25.73 25.77 26.49 26.51Na20 0.17(0.01) 0.11 0.07 0.01 0.02 0.02 0.14 0.10 0.12 0.11 0.04Sr0 0.04(0.03) nd nd nd nd nd nd 0.06 nd nd ndLa203 0.21(0.04) 0.27 0.36 nd 0.06 nd nd 0.27 0.10 0.04 0.03Ce203 1.21(0.15) 0.62 1.14 0.13 0.37 0.25 0.40 1.43 0.66 0.59 0.52Pr203 0.25(0.19) 0.11 0.11 nd 0.38 0.37 0.05 0.14 0.05 0.19 0.39Nd203 0.86(0.24) 0.16 0.21 0.01 0.73 0.22 0.23 0.88 0.50 0.55 0.40Sm203 0.12(0.03) 0.05 0.06 0.05 0.05 0.02 0.07 0.05 0.16 0.15 0.03Y203 0.30(0.05) 0.06 0.09 0.30 0.20 0.60 0.34 0.38 0.78 0.60 0.66F 0.29(0.03) 0.15 0.24 0.45 0.42 0.45 nd 0.05 0.03 0.40 0.33Total (2) 97.76 97.57 97.23 97.44 97.82 97.67 96.76 97.00 96.87 96.65 97.06Structural formulae ( a )Si 4+ 0.999 1.001 0.993 1.018 1.004 1.005 0.996 0.992 1.002 0.987 1.001AO+ 0.001 - 0.007 - - 0.004 0.008 - 0.013Ti 4+ -AO+ 0.044 0.013 0.025 0.080 0.069 0.085 0.051 0.022 0.053 0.044 0.058Ti 4+ 0.904 0.956 0.932 0.889 0.895 0.883 0.795 0.869 0.826 0.893 0.896Fe2+ 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000mg2+ 0.001 0.000 0.001 0.000 0.000 0.001 nd nd nd 0.000 0.000Fe3l' 0.049 0.035 0.042 0.036 0.031 0.032 0.079 0.077 0.071 0.056 0.043NO+ 0.008 0.002 0.003 0.002 0.005 0.007 0.084 0.036 0.059 0.011 0.009Sun 1.006 1.006 1.003 1.007 1.000 1.008 1.020 1.004 1.009 1.004 1.010Mn2+ 0.003 0.001 0.001 0.001 0.003 0.002 0.004 0.003 0.005 0.004 0.003Ca2+ 0.953 0.972 0.974 0.991 0.979 0.972 0.974 0.953 0.951 0.970 0.964Na+ 0.011 0.007 0.005 0.001 0.001 0.001 0.009 0.007 0.008 0.007 0.002Sr2+ 0.001 nd nd nd nd nd nd 0.001 nd nd ndLa3+ 0.003 0.003 0.004 nd 0.001 nd nd 0.003 0.001 0.000 0.000Ce3+ 0.015 0.008 0.014 0.002 0.005 0.003 0.005 0.018 0.008 0.007 0.006Pr3+ 0.003 0.001 0.001 nd 0.005 0.004 0.001 0.002 0.001 0.002 0.005Nd3+ 0.010 0.002 0.002 nd 0.009 0.003 0.003 0.011 0.006 0.007 0.005Sm"1- 0.001 0.000 0.001 0.000 0.000 nd 0.001 0.000 0.002 0.002 0.000Y3+ 0.005 0.001 0.002 0.004 0.004 0.011 0.006 0.007 0.014 0.011 0.012Sum 1.005 0.995 1.004 1.001 1.008 0.996 1.007 1.007 0.996 1.010 0.998F - 0.031 0.016 0.026 0.048 0.045 0.049 nd 0.005 0.003 0.044 0.03588Table 13 continuedSample 7823 7910 7837 7837 7803 7803 ErrorOxide X N=4 S** X N=6 S** rim core rim coreSi02 29.63(0.24) 18.93(0.45) 29.26 28.94 29.18 28.78 (0.18)Al203 2.03(0.07) 0.75(0.11) 1.46 1.41 0.97 0.84 (0.06)TiO2 35.43(0.24) 18.43(0.32) 35.48 35.68 34.85 36.04 (0.34)Fe0 1.07(0.07) 9.78(0.08) 1.26 1.46 1.74 1.57 (0.21)MgO 0.01(0.01) 0.51(0.03) nd nd nd nd (0.14)Nb205 0.41(0.15) 0.64(0.06) 0.70 0.68 1.46 0.92 (0.10)Mn0 0.08(0.02) 0.18(0.02) 0.10 0.05 0.12 0.16 (0.28)Ca0 27.03(0.16) 2.90(0.10) 27.37 27.11 25.36 25.54 (0.10)Na20 0.04(0.03) nd 0.01 0.04 0.26 0.23 (0.12)Sr0 0.07(0.09) 4.10(0.49) nd nd nd nd (0.20)La203 nd 14.73(0.37) nd 0.10 0.20 0.31 (0.04)Ce203 0.32(0.04) 19.70(0.30) 0.29 0.57 1.42 1.65 (0.04)Pr203 0.06(0.05) 1.27(0.07) 0.12 0.08 0.14 0.31 (0.22)Nd203 0.42(0.08) 3.52(0.25) 0.15 0.41 1.00 1.04 (0.21)Sm203 0.15(0.10) 0.14(0.05) 0.05 0.12 0.23 0.22 (0.05)Y203 0.34(0.05) nd 0.25 0.06 0.37 0.20 (0.10)F 0.15(0.10) 0.01 0.28 0.16 0.15 0.04 (0.12)Total 2 97.18 95.59 96.66 96.80 97.38 97.83Structural formulae ( a )Si 4+ 1.000 0.883 0.994 0.986 0.999 0.985 (0.009)A1 3+ 0.041 0.006 0.014 0.001 0.015 (0.001)Ti 4+ 0.076A1 3+ 0.081 0.000 0.052 0.043 0.038 0.019 (0.002)Ti 4+ 0.900 0.570 0.906 0.914 0.898 0.927 (0.010)Fe24" 0.000 0.063 0.000 0.000 0.000 0.000 (0.002)Mg2+ 0.000 0.035 nd nd nd nd (0.007)Fe3+ 0.030 0.318 0.036 0.042 0.050 0.045 (0.006)Nb5+ 0.006 0.014 0.011 0.010 0.023 0.014 (0.002)Sum 1.017 1.000 1.005 1.009 1.009 1.005 (0.013)Mn2+ 0.002 0.007 0.003 0.001 0.004 0.005 (0.001)Ca2+ 0.978 0.145 0.996 0.990 0.930 0.936 (0.007)Na+ 0.003 nd 0.001 0.003 0.017 0.015 (0.008)Sr2+ 0.001 0.111 nd nd nd nd (0.004)La3+ nd 0.253 nd 0.001 0.002 0.004 (0.001)Cell' 0.004 0.336 0.004 0.007 0.018 0.021 (0.001)Pr3+ 0.001 0.022 0.001 0.001 0.002 0.004 (0.003)NO+ 0.005 0.059 0.002 0.005 0.012 0.013 (0.003)Sill + 0.002 0.002 0.001 0.001 0.003 0.002 (0.001)0+ 0.006 nd 0.004 0.001 0.007 0.004 (0.002)Sum 1.002 0.935 1.012 1.010 0.995 1.004 (0.012)F - 0.016 nd 0.030 0.017 0.016 0.004 (0.013)(a) structural formulae based on 5(O,OH,F); Fe(2+)Fe(3+) ratio adjusted. X = average, S** observedstandard deviation of the data, S is the standard error expected from analytical error alone. (1) rimsin contact with allanite; core and rim points within each sample are the same grain. (2) totals afterdeducting 0-F89Figure 5.10 illustrates that virtually all of the Ca isreplaced by REE in titanites from the Laura #2 fenites (7910).Exley (1980) reported similar high REE in red brown pleochroictitanite from the Skye Granite but titanites from 7910 have Sr(REE-Sr titanite). Mt. Bisson titanites compositions, excluding7910 titanites, plotted on Ca vs REE (Figure 5.11) illustratesthat, rims of titanite grains from quartz-allanite pegmatitesand hornblende pegmatites are depleted in LREE and enriched inCa relative to cores. Titanite compositions plotted on Nb vs Ti(Figure 5.12) illustrates titanites from quartz-allanitepegmatites have anomalous Nb content and Nb enriched, Tidepleted rims relative to cores. In this figure titanites from7910 have low cationic Ti; Fe3+ replaces Ti to balance REEsubstitution in the Ca site (Deer et al., 1962). This Nd-REEtitanite could be the first reported in British Columbia. Paulet al., (1981) and Groat et a/., (1985) described titanitesfrom Manitoba that contain Nb but, unlike the Mt. Bisson Nb-REEtitanite, they contain Ta and lack REE.The majority of the chemical variation observed for Mt.Bisson titanites is explained byCa+Ti-REE+Sr+Nb+Fe (Figure 5.13).Based on REE content, titanites at Mt. Bisson form twogroups:1) Titanites with relatively low REE content coexistingwith allanite.2)Titanites with relatively high REE content and noallanite association.901.2Mount Bisson Titanites0.8a.;crfi 0.60os0.4osFig. 5.111.00.2CCCCO Alkalic DikesLA.6.6.6. BEE Pegmatites***** Barren Pegmatites• • • • • Fenites.teeeer MB Granites79101,30.00.0 1.00.2^0.4^0.6^0.8LREE + Y Cations (P.F.U.)FIG. 5.10. Titanite compositions plotted as cations LREE+Y vsCa. Analytical error is too small to plot.911.05Moult Bisson Titanites2S0.850.00I ^0 000000 Alkalic DikesAAAAA REE Pegmatites***** Barren Pegmatites0000^ Fenites***** MB GranitesI^1^I^1^i0.02 0.04 0.06LREE + Y Cations (P.F.U.)A* *00.081.00 -1.:SCx":10L42 0.95 -0mUmC...) 0.90 -FIG. 5.11. Titanite compositions, excluding fenite 7910titanites, plotted as Cations LREE+Y va Ca. Dashed line is lowerlimit of detection. Arrows connect select core to rimcompositions.927910II?1.0Mount Bisson Titanites0.50.002S+CCCCO Alkalic Dikes6.6666. REE Pegmatites***** Barren Pegmatites• • • Ill • Fenites1Werertr MB Granites0.04^0.08I Nb Cations (P.F.U.)0.12FIG. 5.12. Titanite compositions plotted as Cations Nb vs Ti.Arrows connect select core to rim compositions.93..Mount Bisson Titanites2.01* 5 —a.,ong0.4.; 1.0 —os0•p-iE-4+c 0.5 -U0.00.0....... .^7910JP, ,CCCOO Alkalic Dikes66.666. REE Pegmatites***** Barren Pegmatites•• • • • Fenites1Wt*** MB Granites1^1^1^1^1^1^1^1^10.4 0.8 1.2 1.6 2.0LREE+Y+Sr+Nb+FeT Cations (P.F.U.)FIG. 5.13. Titanite compositions plotted as CationsLREE+Y+Sr+Nb+FeT vs Ca+Ti. Dashed line has slope of 1.00.94However, Titanites from 7910 fenite do not fit into the twogroups; the REE rich titanite is intergrown with traceallanite. The timing of titanite crystallization with respectto allanite crystallization is an important control in theconcentration of LREE in titanite.5.7 AllaniteRepresentative electron microprobe analyses of Mt. Bissonallanites are listed in Table 14. Allanite structuralformulae were calculated by normalizing to 25 anions (0, OH, F)and 16 cations which resulted in an estimate of the Fe 2+/Fe3+ratio (Deer et al., 1962; Exley, 1980; Chesner and Ettlinger,1989). For each sample, two to six grains were analyzed forcore and rim compositions.Analyses totals range from 86.47 to 95.00 wt% oxides;allanite with the lowest totals have the highest Th02 content.Low analyses totals for allanite could be due to water content;allanite has up to 3.80 wt% H2O (Deer et al., 1966; Hickling,1970), other volatiles, ferric iron, incorrect absorptionfactors for REE, hydration by Th, and Th absorption of majorelement radiation (Gromet and Silver, 1983). SiO2 analyses ofMt. Bisson allanites (average SiO2 is 29.53 + 0.58 wt%) areslightly lower than 32 published allanites with similar REEconcentration (SiO2 wt% average of 31.42 + 0.93) (Exley, 1989;Gromet and Silver, 1983; Hickling et al., 1970; Michael, 1984;Chesner and Ettlinger, 1989; Deer et al., 1962). The allanitecalculated structural formulae also gave slightly low Si but95Table 14. Representative electron microprobe analyses of Mt. Bisson allanitesSampleOxide38 7835 7842 7911 UG-1 UG- 1core7823 1 7823 1 7837rim7910 1 43core43rim7823 1^7823 1^Errorepidote epidote^SSi02 30.71 29.92 29.74 29.37 29.76 29.68 31.62 32.92 29.22 32.24 28.77 26.94 37.65 35.39 (0.38)AL203 14.36 13.14 10.97 11.67 14.09 14.28 14.67 14.95 10.41 10.60 15.52 14.98 21.05 19.92 (0.20)TiO 0.84 1.27 0.97 1.32 1.93 2.14 0.36 0.93 1.95 1.95 1.25 1.56 0.05 0.03 (0.20)Fe0 14.01 15.74 18.58 16.53 12.43 12.18 13.43 13.91 17.52 18.77 14.44 12.99 16.24 16.27 (0.27)Mg0 0.92 0.81 0.44 0.90 1.07 0.91 0.74 0.78 0.81 0.31 0.66 0.41 0.00 0.01 (0.14)MnO 0.24 0.39 0.30 0.35 0.09 0.17 0.21 0.19 0.31 0.47 0.28 0.39 0.07 0.06 (0.30)Na20 0.04 0.00 0.00 0.04 0.00 0.35 0.07 0.05 0.02 0.02 0.19 0.24 0.00 0.01 (0.02)CaO 12.11 11.89 11.28 10.91 10.03 10.98 9.79 12.02 9.83 10.80 8.51 7.09 22.56 20.56 (0.10)Sr0 0.00 0.08 0.28 0.02 0.00 0.00 0.00 0.01 0.02 4.28 0.00 0.00 0.47 0.31 (0.11)La203 6.03 5.74 7.42 7.77 6.94 6.14 8.00 5.53 8.30 5.98 6.02 4.68 0.02 1.20 (0.04)Ce203 11.11 9.89 10.63 11.09 12.48 10.98 14.92 11.65 12.67 9.29 9.24 7.85 0.07 2.19 (0.02)Pr203 0.94 0.87 0.74 0.77 1.19 1.09 0.98 0.98 0.92 0.54 0.68 0.57 0.00 0.15 (0.15)Nd203 2.96 2.74 1.91 2.11 4.45 3.83 3.10 3.45 2.37 2.15 1.90 1.69 0.02 0.62 (0.04)Sm203 0.20 0.23 0.10 0.13 0.45 0.43 0.08 0.18 0.05 0.11 0.17 0.19 0.00 0.16 (0.02)Y203 0.02 0.09 0.00 0.08 0.03 0.06 0.00 0.03 0.00 0.00 0.08 0.05 0.00 0.00 (0.04)Th02 0.48 1.51 1.38 0.85 0.00 0.00 0.00 0.32 0.32 0.12 2.52 6.28 0.02 0.05 (1.23)F 0.00 0.00 0.02 0.00 0.03 0.00 nn nm 0.08 nm 0.42 0.97 0.00 0.00 (0.04)Total 94.97 94.31 94.76 93.91 94.97 93.22 97.97 97.90 94.80 98.61 90.65 86.87 98.22 96.960-F 94.97 94.31 94.76 93.91 94.96 93.22 97.97 97.90 94.77 98.61 90.47 86.47 98.22 96.96Structural formulae ( a )Si 4+ 6.006 5.913 5.988 5.945 5.971 5.969 6.168 6.169 5.962 6.179 5.654 5.785 5.975 5.856 (0.098)Al(IV) 0.000 0.087 0.012 0.055 0.020 0.031 0.000 0.000 0.038 0.000 0.346 0.352 0.025 0.144 (0.002)Al(VI) 3.310 2.972 2.591 2.729 3.303 3.354 3.373 3.302 2.465 2.394 3.249 3.349 3.912 3.741 (0.054)Fe2+ 1.679 1.561 1.911 1.795 1.916 1.702 1.991 1.526 1.990 1.592 0.016 0.489 0.000 0.020 (0.039)-4+Ti 0.124 0.189 0.147 0.201 0.291 0.324 0.053 0.131 0.299 0.281 0.185 0.246 0.006 0.004 (0.031)Mg2+ 0.268 0.238 0.132 0.271 0.320 0.273 0.215 0.218 0.246 0.089 0.193 0.128 0.000 0.002 (0.043)Fe3+ 0.613 1.040 1.217 1.003 0.170 0.346 0.200 0.654 0.999 1.416 2.357 1.789 2.155 2.231 (0.017)Sum 5.993 6.000 5.998 5.999 6.000 5.999 5.832 5.831 5.999 5.772 6.000 6.001 6.073 5.998 (0.087)Ca2+ 2.538 2.517 2.433 2.366 2.156 2.260 2.046 2.413 2.149 2.218 1.792 1.592 3.836 3.645 (0.030)Na 0.015 0.000 0.000 0.016 0.000 0.136 0.026 0.018 0.008 0.007 0.072 0.098 0.000 0.003 (0.008)CO+ 0.795 0.715 0.784 0.822 0.917 0.808 1.066 0.799 0.946 0.652 0.665 0.602 0.004 0.133 (0.009)La3+ 0.435 0.418 0.551 0.581 0.514 0.455 0.576 0.382 0.625 0.423 0.436 0.362 0.001 0.073 (0.007)Pr3+ 0.067 0.063 0.054 0.057 0.087 0.080 0.070 0.067 0.068 0.038 0.049 0.043 0.000 0.009 (0.011)NO+ 0.207 0.193 0.137 0.153 0.319 0.275 0.216 0.231 0.173 0.147 0.133 0.126 0.001 0.037 (0.003)Sm + 0.014 0.016 0.007 0.009 0.031 0.030 0.005 0.012 0.003 0.007 0.011 0.014 0.000 0.009 (0.001)Sr2+ 0.000 0.010 0.032 0.002 0.000 0.000 0.000 0.001 0.002 0.476 0.000 0.000 0.043 0.030 (0.013)0.002 0.009 0.000 0.009 0.003 0.006 0.000 0.003 0.000 0.000 0.008 0.006 0.000 0.000 (0.004)Th4+ 0.021 0.034 0.063 0.040 0.000 0.000 0.000 0.014 0.015 0.005 0.113 0.300 0.001 0.002 (0.057)Mn2+ 0.040 0.068 0.051 0.060 0.015 0.029 0.035 0.030 0.054 0.076 0.047 0.069 0.009 0.008 (0.052)Sum 4.134 4.074 4.114 4.114 4.042 4.079 4.040 3.970 4.043 4.049 3.327 3.212 3.896 3.949 (0.086)F - 0.000 0.000 0.010 0.000 0.009 0.000 nn run 0.052 nn 0.261 0.643 nn nn^(0.026)(1) analyzed by Zhou (1991). run = not measured( a ) structural formulae based on 25(0,0H,F,Cl) fixed anion sum, Fe(2+)Fe(3+) calculated by normalizing to25 anions and 16 cations. S is the standard error expected from analytical error alone.96overall the results are good with the exception of the high Thcontaining TMB granite #43.Compostional variations within Mt. Bisson allanite are asfollows:1) Cationic REE + Y varies from 1.153 to 1.933 with the Cacontent inversely related to REE + Y content.2) Fe3+ varies from 0.200 to 2.357 and Fe 2+ varies from0.016 to 1.991.3) Highest Th, 0.300, and F, 0.643, occurs in the TMBgranites.4) Allanite from the fenites (7910) have up to 0.476 Sr.Fenites have REE enriched epidote with up to 0.261 REE.Figure 5.14 illustrates the exchangeCa -'-REE+Na+Mn+Th+Sr(Deer et al., 1962). Mt. Bisson allanites, with the exceptionof TMB granite allanite, form a trend with a slope of onetowards the epidote analyses. Exley, (1980) states allanite isrelated to epidote by the coupled substitutionCaFe3+-1' REEFe2+(Figure 5.15), while Sorensen (1990) feels thatCa(AlFe3+ ) --"-REEFe2+(Figure 5.16) better explains the exchange.Allanites from monazite pegmatites and the TMB granite #43have REE enriched cores relative to rims. In addition, #43 hasTh and Ca depleted cores relative to rims. Substitution of Caand Th in allanite indicates that it is going towards a Ca andTh allanite endmember rather then an epidote endmember (Gromet973.1512.5Ca (P.F.U.)Mount Bisson Allanites2S00000 Alkalic Dikes* * * * * Barren PegmatitesAAAAA REE Pegmatites**It** MB Granites00000 Fenites• • • • • Epidote (7823)•01.5FIG. 5.14. Allanite and epidote compositions plotted asCations Ca vs LREE+Y+Na+Mn+Th+Sr.985Mount Bisson Allanites1-01.50 a 0 o^2SA^ -I-0 AA *tttl^A A0B* * **•r -2.5^3.5^4.5^5.5^6.5Ca + Fe3 (P.F.U.)FIG. 5.15. 411anite and epOote compositions plotted asCations Ca+Fe + vs LREE+Y+Fe 4+ . Symbols as in Figure 5.14.995Mount Bisson Allanites2S0 A4.1,06 Li 4111,*** *lc*Ailf•0516^7^8^i^9Ca + Al + Fe3 (P.F.U.)10FIG. 5.16. Allanite and epidqe compositions plotted asCations Ca+Al+Fe3+ vs LREE+Y+Fe4+ . Symbols as in Figure 5.14.1 00and Silver, 1983). Allanites in fenites have centres that aredepleted in REE relative to margins.1016.0 LREE BUDGETS IN COEXISTING ALLANITE, TITANITE, AND APATITEElectron microprobe analyses of LREE in allanite,titanite, and apatite, provide insight into the origins of Mt.Bisson igneous and alkaline rocks. Specifically, the mineralchemistry and associated chemical zoning in minerals provideconstraints on whether the processes are open or closed andmagmatic or metasomatic. The nature of chemical zoning in theseminerals can be used to separate open versus closed chemicalsystems. In addition, the mineral compositional data are usedto establish an empirical estimation of the effects ofcrystallization order on REE concentration in allanite,titanite, and apatite.LREEs usually occur as trace amounts in silicate melts andare rarely accommodated in substantial amounts in naturallyoccurring crystalline phases (McKay, 1989; Hanson, 1989).Allanite can accommodate a large proportion of a whole rocks'LREE and thus provides a mechanism of fractionating the LREE.Titanite and apatite also accommodate substantial amounts ofLREE (Exley, 1980; Gromet and Silver, 1983; Michael, 1985);thus the LREE concentration of these phases largely reflectsthe composition of the melt at the time of theircrystallization (Burt, 1989). Allanite, titanite, and apatitewith chemical zoning that displays core to rim decreases inLREE concentrations (Figure 6.0) are consistent with formationin a closed chemical system with a finite LREE budget (Exley,1980; Gromet and Silver, 1983; Michael, 1984; 1985).102FIG. 6.0. Schematic representation of mineral core to rimchemical variations expected in closed magmatic systems (Exley,1980; Gromet and Silver, 1983; Michael, 1984, 1985; Bedard,1988).103The result of decreasing LREE concentration in the melt iseuhedral oscillatory zoning in allanite with core to rimdecreases in LREE (Gromet and Silver, 1983). As allanite isable to fractionate the melt of LREE; removes substantuallymore La than Nd, the decreasing LREE concentration in the meltwill also be shadowed by a fractionation ratio change; La/Nd(Michael, 1985). This changing La/Nd ratio in the melt causesallanite to have higher La/Nd ratios in cores relative to rims(Michael, 1985). Additionally, previous studies suggest that:1) titanite preferentially incorporates MREE and HREE overLREE (Gromet and Silver, 1983; Michael, 1985),2) titanite can deplete but not fractionate MREE and HREE(Gromet and Silver, 1983; Michael, 1985),3) titanite, relative to apatite, can better accommodateHREE (Henderson, 1980; Burt, 1989), and4) apatite preferentially accommodates LREE relative totitanite (Henderson, 1980).Figures 6.1 to 6.3 are LREE chondrite normalizedabundance patterns, (LREEcnp), of representative Mt. Bissonallanites, titanites and apatites. Relative to chondrites,allanite is strongly enriched in LREE and have fractionatedLREE patterns. Titanite and apatite are less enriched in LREEwith respect to chondrite and tend to have flat patternsconsistent with little REE fractionation.104FIG. 6.1. Chondrite normalized LREE abundance patterns ofallanites.105FIG. 6.2. Chondrite normalized LREE abundance patterns oftitanites.106FIG. 6.3. Chondrite normalized LREE abundance patterns ofapatites.107In essence allanite, titanite and apatite compete for thesame REEs throughout crystallization. Characteristic REE ratiosof igneous melts and metasomatic fluids are recorded in thecompositions and crystal zoning of early- and latecrystallizing allanite, titanite and apatite (Michael, 1985).Specifically the chemical zonation in these minerals canconstrain the relative sequence of crystallization, the mineralparagenesis throughout crystallization and whether the systembehaved as a closed or open chemical system.Comparison of whole rock LREEcnp to corresponding electronmicroprobe measured mineral compositions quantify's themineralogical contribution to the general LREEcnp of the wholerock (Hanson, 1989). This is important in identifing the phaseor phases which influenced the LREE content of the melt themost. LREEcnp of whole rocks and minerals also record theextent of fractionation or enrichment of LREE relative tochondrite.In Figure 6.4 the whole rock LREEcnp of the aegirine-augite dike, with 5 to 10 vol% titanite and trace apatite, issimilar to the LREEcnp of the associated titanite. The highmodal abundance of titanite essures that it is the maincontributor to the whole rock LREEcnp ; titanite contains mostof the LREE found in the whole rock.The whole rock LREEcnp of the allanite pegmatite issimilar to the LREEcnp of the associated allanite (Figure 6.5).The modal abundance of allanite (up to 17 vol%) issubstantually higher than titanite and apatite. Titanite and108Aegirine—Augite Dikes100000 7PAE-4Ix 10000AZ^--CD=UCxl^1000KAt:4 -100eeeee Whole RockBEIBBEI Titanite)14-4"14-44-* Apatite1 0 IIIIIIIIIIIIIIIILa Ce Pr Nd^Sin Eu^Tb Dy Ho^YbLuFIG. 6.4. Chondrite normalized REE abundance patterns ofaegirine augite dikes and their accompanying LREE containingphases.109oeeee Whole RockAllanite00000 Titanite*404** ApatiteFIG. 6.5. Chondrite normalized REE abundance patterns ofallanite pegmatites and their accompanying LREE containingphases.110apatite have less LREEcnp than the whole rock LREE cnp . Theallanite pegmatites' LREEcnp reflects the LREEcnp of allanite;allanite contains most of the LREE.All Mt. Bisson rocks' whole rock LREE cnp reflect theLREEcnp of the major LREE containing phases. Allanite is thedominant LREE containing phase in the allanite pegmatite, Willfenites, REE-dike, and TMB granites. Titanite is the dominantLREE containing phase in the CMB granodiorite, alkali-feldspardikes, aegirine-augite dikes, and Laura #2 fenites. Allaniteand titanite both are important in the quartz-allanitepegmatites.Gromet and Silver (1983) observed allanite with core torim decreases in LREE and increases in Ca+Th. Minerals (e.g.,feldspar) which crystallized after allanite, were observed tohave anomalously low REE concentrations. They concluded:1) the allanite formed in a chemically closed system anddepleted the melt of LREE,2) the LREE zoning in allanite reflected changes in themelts' LREE concentration.,3) the core to rim increase of Ca+Th in allanite was takenas evidence against kinetic zoning, and4) finally, the low REE concentrations in late formedminerals suggested formation in a melt already depleted of LREEby earlier crystallizing allanite.Gromet and Silver (1983) observations on this chemically closedsystem provide insights into the behavior of all systems thathave a finite LREE budget.111At Mt. Bisson the LREE data from titanites and apatitestests the hypothesis, formation of allanite depletes liquids ofLREE. Titanite and apatite record in their LREE concentrationchanges in the melt LREE compositions because they accommodatethe REEs that are available.Four samples are used below as examples to demonstrate theeffects of allanite crystallization on LREE behavior in melts.The examples include, aegirine-augite dikes, CMB granodiorite,allanite pegmatites and fenites.Aegirine-augite dikes (Figure 6.4) contain titanite andapatite whereas, the CMB granodiorite (Figure 6.6) containsonly titanite. The LREE concentration of titanite varies from2.65 to 3.40 wt% rare earth oxides (REO) while the apatite has1.40 wt% REO.Allanite pegmatites (Figure 6.5) and Will fenites (Figure6.7) contain allanite, titanite and apatite. Textural evidencesuggests that titanite and apatite formed after the formationof allanite. LREE concentrations of titanite vary from 0.95 to1.37 wt% REO. Apatite concentrations range from 0.43 to 0.60wt% REO.Data from these four examples show that titanite andapatite in allanite-absent rocks have 2 to 3 times the LREEconcentrations of titanite and apatite in allanite-bearingrocks. This pattern holds for all Mt. Bisson rocks, suggestingsthat early-crystallized allanite depletes liquids of LREE. Inaddition, order of crystallization and the presence or absenceof allanite is an important factor in determining LREE112La Cc Pr NA^Sm Eu Tb Dy HI)^Yb LuFenitized Granodiorite(CMB Granite)cra—s_.,0IIIIIIIIIIIIIIII1 00000100 a.1000000 Whole Rock00000 TitaniteFIG. 6.6. Chondrite normalized REE abundance patterns offenitized granodiorite and accompanying titanite.113ceeee Whole RockAces62!riA AllaniteEIBBEIO Titanite****-* ApatiteFIG. 6.7. Chondrite normalized REE abundance patterns of Willfenites and their accompanying LREE containing phases.114concentration in titanite and apatite. This will permitchemical data to be used to constrain timing ofcrystallization.Thus in a chemically closed system (e.g., with a finiteLREE budget) we expect the melt to be come depleted in LREE bythe early crystallization of allanite and later crystallizationof titanite and apatite with lower LREE content. It isinteresting to note that the Will fenites have patternsconsistent with the closed chemical system model.In summary, past research (e.g., Exley, 1980; Gromet andSilver, 1983; Michael, 1985) and data for these 4 examples fromMt. Bisson suggests that allanite derived from a chemicallyclosed system will display:1) core to rim decreases in LREE,2) higher La/Nd ratios in cores relative to rims, and3) euhedral, oscillatory zoning.In contrast in a open chemical system allanite will display:1) centers to margin increase in LREE, or at least veryinconsistent LREE variation,2) no systematic variation of La/Nd ratios, and3) convoluted and patchy zoning.Titanite and apatite will have the same characteristics asallanite, except in titanite La/Nd ratios will not vary fromrim to core.1156.1 CLOSED AND OPEN CHEMICAL SYSTEMS; Examples from Mt. SissonThe TMB granites have allanite and apatite but lacktitanite (Figure 6.8). Evenly distributed, oscillatory zoned,euhedral allanite have core to rim decreases in LREE andincreases in Ca+Th (Figure 6.9). In addition, cores of allanitehave higher La/Nd ratios relative to rims (3.28 to 2.87). Theapatites have low La to Nd concentrations, anomalously high Smand Y concentrations, and have low La/Nd ratios (0.43). Theallanite zoning indicates early crystallization of the allanitefrom a chemically closed melt (Gromet and Silver, 1983;Michael, 1985). LREE content and especially high Sm and Yconcentrations in apatite are consistent with post-allanitecrystallization and reflect the absence of titanite.The systematic and sympathetic REE variation within bothallanite and apatite from TMB granites is consistent with afinite REE budget. Core to rim chemical variation of additionalphases (e.g., Ba variation in potassium feldspar) from the TMBgranites are illustrated in Figure 6.9. It is concluded thatmineral data from the TMB granites are consistent withchemically closed magmatic system.Allanite pegmatites (Figure 6.5) display fine oscillatoryzoning in euhedral allanites and contains euhedral titanite andapatite. Apatites have core to rim decreases in LREE whereasthe allanite zoning is below detection by the electronmicroprobe. Both titanite and apatite have low La/Nd ratios(0.15 and 1.50) and low LREE concentrations (1.37 and 0.43 wt%RE oxides). These observations suggest allanite crystallized116oeeee Whole RockAllanite CoreAllanite Rim***** ApatiteFIG. 6.8. Chondrite normalized REE abundance patterns of TMBgranites and their accompanying LREE containing phases.117FIG. 6.9. Schematic representation of observed mineral core torim chemical variations in TMB granites. The core to rimvariation is consistent with a closed system, refer to Figure6.0.118before titanite and apatite. The low LREE concentration and lowLa/Nd suggest titanite and apatite crystallized in a LREEdepleted and LREE fractionated melt. These chemical data areconsistent with a chemically closed magmatic system.Quartz-allanite pegmatites (Figure 6.10) illustrate theimportance of mineral zoning interpretations in differentiatingbetween chemically open or closed systems. Core to rimdecreases in LREE of titanite, core to rim decreases in Ba ofpotassium feldspars, and depletion of LREE in the melt byallanite and titanite crystallization is consistent with havingbeen formed in a closed chemical system. However, allanites'core to rim chemical variation is inconsistent with a closedchemical system. Allanite display patchy zoning: crystalscomprise fragmented sections with euhedral crystal faces,strong oscillatory zoning and surrounded by convoluted zoningor large sections of non-zoned allanite. More anhedralallanites show less oscillatory zoning and tent to be moreunzoned. Sorensen (1990) suggested an origin involvingdestabilization, partial dissolution and redeposition forCalifornia allanites with similar textures. The mineral datafrom the quartz-allanite pegmatite suggest that the rock formedin a chemically closed system. After the rock formed theallanite experienced dissolution and redeposition; LREE inallanite can be very mobile (Exley, 1980; Gromet and Silver,1983).The core to rim chemical zonation in assemblages withinthe fenite rocks are inconsistent with behavior expected in a119eeeee Whole Rock,61AtuN6 Allanite***** Titanite CoreBBBEHEI Titanite Rim***** ApatiteFIG. 6.10. Chondrite normalized REE abundance patterns ofQuartz-allanite pegmatites and their accompanying LREEcontaining phases.120closed chemical system. In particular, allanite, potassiumfeldspar and pyroxene (Figure 6.11) have chemical zoning whichinclude: LREE increases from core to rim in allanite, Baincreases but Na decreases for core to rim in plagioclase, andFe decreases but Mg increases from core to rim in pyroxene.Patchy-zoned anhedral allanite in the fenites show core tomargin enrichment of LREE and are similar to metasomatizedallanites described by Sorensen (1990). Sorensen (1990)proposed an open system, external source process caused bysubsolidus hydrothermal remobilization of LREE and subsequentfractionation of the LREE. Thus, the fenites are inferred toderive from chemically open metasomatic process.Alkali-feldspar syenite dikes (Figure 6.12) have titaniteand apatite which display core to rim increases of LREE, highLREE concentration (1.88 wt% RE oxides in titanite and 0.78 wt%RE oxides in apatite) high La/Nd ratios (3.11 for titanite and14.00 for apatite). The La/Nd ratio does not change from coreto rim in titanite. The high RE oxide concentration and La/Ndratio in titanite and apatite are consistent with the absenceof allanites. The constant core to rim La/Nd for titanite andapatites is consistent with their LREE properties. The core torim increases of LREE in titanite are consistent with behaviorexpected in an open chemical system.Utilizing the LREE analyses data of allanite, titanite andapatite in conjunction with other mineral chemical data Mt.Bisson units separate into the following two groups:121FIG. 6.11. Schematic representation of observed mineral core torim chemical variations in fenites. The core to rim variation isinconsistent with a closed system, refer to Figure 6.0.1220eee0 Whole Rock00EI0E1 Titanite Core***** Titanite Rim***** ApatiteFIG. 6.12. Chondrite normalized REE abundance patterns ofalkali-feldspar dikes and accompanying LREE phases.1231) units that represent a closed chemical system;aegirine-augite dikes, hornblende pegmatites, allanitepegmatites, monazite pegmatites and TMB granites.2) units that represent an open chemical system; fenitesand alkali-feldspar dikes.The syenite pegmatites and quartz pegmatites could not beplaced in any groups as they have no allanite, titanite andapatite and display no zoning in other minerals.1247.0 CONCLUSIONThis research increased the understanding of the geology atMt. Bisson and recognized that magmatic, metasomatic, chemicallyclosed and open system processes were important contributors tothe formation of Mt. Bisson rocks. These conclusions were basedon field relationships, whole rock geochemistry (major, minor,trace and rare earth elements), and electron microprobe analysesof the major phases as well as the accessories allanite, titaniteand apatite.Igneous and metasomatic rocks comprise Mt. Bisson alkalineunits. The alkaline igneous units include allanite pegmatites,syenite pegmatites and alkalic dikes whereas the metasomaticalkaline units consist only of fenites. The fenites areamphibolites that were preferentially metasomatized by solutionsenriched in varing concentrations of Na, Fe3+, Sr, Ba, REE, Y andF; in addition, quartzofeldspathic and igneous rocks were alsofenitized. Non alkaline igneous units include Cretaceous andTertiary age granite plutons and pegmatites.To further quantify the origins of Mt. Bisson igneous andmetasomatic rocks both chemically closed and open systemprocesses are required. Chemically closed system processes arerecognized in the following igneous units, aegirine-augite dikes,hornblende pegmatites, allanite pegmatites, monazite pegmatitesand TMB granites. The alkali-feldspar dikes are inconsistent witha chemically closed system and suggest chemically open igneoussystem processes. Chemically open metasomatic system processes125are apparent in the fenites including the fenitized CMBgranodiorite.REE enriched rocks are included in the igneous rocks,(alkaline; allanite pegmatites, REE dikes, and granitic;quartz-allanite pegmatites and monazite pegmatites), andmetasomatic rocks, (fenites).Additionally, recognized at Mt. Bisson are three newmineral compositions, two for titanite and one for apatite.They are:1) REE-Nb titaniteCa0.974Na0.009LREE0.014Tio . 795Hbo. 084 Fe3+0.079A10.055 S 10.996052) REE-Sr titanite, andCa0.145Sr0.111LREE0.672Ti0.646Hbo.014Fe 2+0-063Fe3+0.318Hg0.035A 10.041Sio.883053) Sr-REE apatiteCa0,221Sr0.593Na0.127LREE0.297F5.913024 ( Fl . 788C 10.0090Hx )As a consequence of classifying Mt. Bisson rocks asmagmatic or metasomatic and chemically closed or open moreglobal significant results are derived for the recognitionof chemically closed system processes in rocks. 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The feldspar minerals 2: Chemical andtextural properties, Springer-Verlag, Heidelberg, Germany,690p.Smith, J.V. 1983. Some chemical properties of feldspar.Chapt.12, Reviews in Mineralogy; Mineralogical Society ofAmerica, Feldspar Mineralogy Volume 12, pp. 281-296.Sorensen, H. (ed.). 1974. The Alkaline Rocks. New York:John Wiley and Sons, 622p.Sorensen, S.S. 1991. Petrogenetic significance of zonedallanite in garnet amphibolites from a paleo-subductionzone: Cataline Schist, southern California. AmericanMineralogist, 76: 589-601.Staatz, M.H., Conkline, N.M., and Brownfield, I.K. 1977.Rare earhts, thorium, and other minor elements in sphenefrom some plutonic rocks in west-central Alaska. JournalResearch U.S. Geological Survey, Vol 5, No.5, pp. 623-628.Stanley, C., and Sinclar, A.J. 1986. Relative erroranalysis of replicate geochemical data: Advantages andapplications. Exploration in the Northern Cordillera,Association of Exploration Geochemist's regional meeting,Vancouver B.C. May 1986, Programs with abstract,Geochemical Expo 86.Streckeisen, A. 1975. To each plutonic rock its propername. Earth Science Review, 12: 1-33.Struik, L.C. 1991. Tertiary plate boundaries in theNorthern American Cordillera. Unpublished notes.Struik, L.C., and Northcote, B.K. 1991. Pine Pass map area,southwest of the Northern Rocky Mountain Trench, BritishColumbia. Geological Survey of Canada, Current Research,Part A, Paper 91-1A, pp. 285-291.Struik, L.C. 1991. pers communication.Sutherland, D.S. 1965. Potash-trachytes and ultra-potssic133rocks associated with the carbonatite complex of TororHills, Uganda. Mineralogical Magazine 35: 363-378Thompson, M., and Howarth, R.J. 1978. A new approach to theestimate of analytical precision. Journal of GeochemicalExploration, 9: 23-30.Tipper, H.W., Campbell, R.B., Taylor, G.C, and Stott, D.F.1974. Parsnip River, British Columbia. Geological Surveyof Canada, Map 142A, Sheet 93.Tracy, R.J., and Robinson, P. 1977. Zoned titanian augitein alkalic olivine basalt from Tahiti and the nature oftitanium substitutions in augite. American Mineralogist,62: 634-645.Wendlandt, R.F., and Harrison, W.J. 1979. Rare earthpartitioning between immiscible carbonate and silicateliquids and CO2 vapor: Results and implications for theformation of light rare earth-enriched rocks.Contributions to Mineralogy and Petrology, 69: 409-419.White, A.J.R., and Chappell, B.W. 1977. Ultrametamorphismand granitoid genesis. Tectonophysics, 43: 2-22.134APPENDIX APREPARATION AND ANALYTICAL PROCEDURES FOR DETERMINATION OF MAJOR,MINOR, TRACE AND RARE EARTH ELEMENT CONCENTRATIONSA.1 POWDER PREPARATIONClean, unweathered samples, about eight centimetres roundwere crushed to less than 0.5 centimetres in a jaw crusher. Thesamples were then hand sorted to ensure no weathered, fracturesurfaces remained and the finest material discarded to preventcross contamination. Unmineralized samples were crushed firstprogressing to heavily rare earth element mineralized sampleseliminating the possibility of contamination of the rock powders.The samples were pulverized to -200 mesh in a shatterbox using aminimal amount of time to prevent the oxidation of iron. The rockpowders were then passed through a -200 mesh screen to ensure auniform grain size.A.2 MAJOR AND MINOR ELEMENTSThe University of British Columbia Geological SciencePhillips Model 1410 X-ray flourescence was used for the analysisof twenty-four samples, eight duplicates and twelve standardswith one standard (BCR-1) run as a monitor, for the followingelements: Si, Ti, Al, Fe, Mn, Mg, Ca, Na, K, and P. In additionFe0 was determined volumetrically.XRF pellet preparation procedure, is from Russell et al.,(1989) and listed below;(1) Perform LOI on 2-3 grams of -200 mesh sample powder.(2) Weigh 1.000g of devolatilized powdered rock and 2.000 glithium tetraborate. Mix together in a graphitecrucible.(3) Place the graphite crucible in a muffle furnace at1,000°C for 10 miniuts. Remove the crucible and allowit to cool.(4) The cool fused rock buttons are crushed in ringcups(upto 6 at a time) on the small ring grinder. The crusherhead must be protected from contamination.(5) Pellet preparation: Prepare a 2% PVA (Polyvinylalcohol)solution, heat it to boiling and stir it frequently.(6) Thoroughly clean the inner cylinder, the plunger and thepolished pellet of the evacuable die as well as themetal funnel parts.(7) Put the polished pellet in the cylinder with the bestsurface up. Place the metal funnel into the cylinder.(8) Mix the sample with 3 drops of PVA solution gently inthe paper cup. Put it through the funnel on top of thepolished pellet. Make the surface even with the funnelplunger.(9) Remove gently both funnel parts. Add a spoon of boric135acid and smooth the surface.(10)Add the steel plunger (the flat side of the plungertowards the pellet). Center the assembly on the pumpplatform and center the plunger under the press.(11)Gradually apply pressure to the die assembly up toapproximately 20 tons pressure. Maintain this pressurefor one minute and then release it.(12)The pellet is removed from the assembly on the redplatform press. Place an 0-ring over the plunger andput the assemble upside down against the pressplatform. Apply pressure until the plunger movesthrough the bore. Be very careful not to drop thepolished pellet when taking the assembly apart.(13)The pellet is air-dried for at least 12 hours or atleast 2 hours in the dessicator before use in the XRF.Table A.1 The major and minor element WtX oxides, mean and standard deviation the BCR-1 treated as anunknown. Also listed is the accepted value (BV).Monitor BCR-1Si02 TiO2 Al203 Fe203 Mn0 Mg0 Ca0 Na20 K20 P205 Total1 54.56 2.30 14.28 13.34 0.16 3.41 6.79 3.53 1.63 0.37 100.372 54.44 2.30 14.26 13.53 0.16 3.41 6.81 3.49 1.63 0.37 100.403 54.44 2.31 14.30 13.51 0.16 3.43 6.82 3.44 1.64 0.37 100.424 54.33 2.32 14.28 13.51 0.16 3.40 6.83 3.57 1.64 0.36 100.405 54.34 2.32 14.32 13.53 0.16 3.36 6.84 3.54 1.64 0.35 100.406 54.37 2.35 13.91 13.71 0.17 3.42 6.90 3.56 1.65 0.36 100.407 54.38 2.33 14.28 13.55 0.16 3.38 6.86 3.50 1.62 0.36 100.428 54.29 2.31 14.28 13.59 0.16 3.38 6.87 3.53 1.63 0.36 100.409 54.40 2.33 13.93 13.71 0.17 3.42 6.89 3.53 1.63 0.36 100.3710 54.44 2.30 14.26 13.53 0.16 3.39 6.86 3.48 1.61 0.37 100.4011 54.26 2.32 14.28 13.58 0.16 3.41 6.89 3.54 1.62 0.36 100.4212 54.36 2.30 14.21 13.62 0.16 3.39 6.87 3.51 1.62 0.37 100.4113 54.22 2.31 14.30 13.62 0.17 3.40 6.89 3.53 1.63 0.36 100.4314 54.33 2.30 14.26 13.61 0.16 3.43 6.85 3.49 1.61 0.36 100.4015 54.34 2.29 14.31 13.59 0.16 3.38 6.85 3.52 1.61 0.36 100.41X 54.38 2.31 14.20 13.56 0.16 3.41 6.86 3.50 1.63 0.36 100.37S^0.09 0.02 0.18 0.09 0.01 0.03 0.04 0.06 0.02 0.01BV 54.53 2.26 13.72 13.42 0.18 3.48 6.97 3.30 1.70 0.36 99.92The raw XRF count data were reduced using the U.B.C.Geological Science mainframe computer program "BEAR".Analytical precision and accuracy was evaluated by analyzingthe standard BCR-1 as a monitor, comparing the measured value ofthe standards with their known value, and by comparing eightduplicate analyses. The monitor, BCR-1, defines the machineanalytical precision of the analysis run including any machinedrift. Table A.1 indicates the precision.136Table A.2 The measured (M) and recommended (R) Wt% oxide values of major and minor elements for thecalibration standards.Standard Si02 Al203 Fe203 Mg° Ca0 Na0 K20 TiO2 Mn0 P205 Total8CR-1 54.38 14.20 13.56 3.41 6.86 3.50 1.63 2.31 0.16 0.36 100.37 M54.53 13.72 13.42 3.48 6.97 3.30 1.70 2.26 0.18 0.36 99.92 RAGV1 60.59 16.64 6.75 1.53 5.06 4.23 2.90 0.97 0.09 0.51 99.28 M59.61 17.19 6.81 1.52 4.95 4.32 2.92 1.06 0.10 0.51 98.99 RNIMN 52.47 16.31 9.08 7.45 11.60 2.74 0.26 0.14 0.17 0.04 100.26 M52.64 16.50 8.90 7.50 11.50 2.46 0.25 0.20 0.18 0.03 100.16 RW1 51.81 15.36 11.08 6.56 10.91 2.46 0.58 0.95 0.16 0.14 100.01 M52.72 15.02 11.09 6.63 10.98 2.15 0.64 1.07 0.17 0.14 100.61 RGSP1 68.07 14.62 4.16 0.98 2.03 2.79 5.49 0.56 0.03 0.27 99.00 M67.32 15.28 4.28 0.97 2.03 2.81 5.51 0.66 0.04 0.28 99.18 RGA 70.24 14.20 2.88 0.93 2.42 3.40 4.05 0.30 0.14 0.12 98.69 M69.95 14.51 2.83 0.95 2.45 3.55 4.03 0.38 0.09 0.12 98.86 RJB1 52.01 15.18 8.88 7.87 9.34 2.96 1.33 1.19 0.14 0.24 99.14 M52.60 14.62 9.04 7.76 9.35 2.79 1.42 1.34 0.15 0.26 99.33 RJG1 71.07 14.27 2.43 0.98 2.35 3.44 4.16 0.20 0.06 0.11 99.07 M72.35 14.20 2.17 0.76 2.17 3.39 3.96 0.27 0.06 0.09 99.42 RG2 70.22 14.70 2.69 0.73 1.94 3.84 4.48 0.38 0.03 0.13 99.15 M69.22 15.40 2.67 0.75 1.96 4.06 4.46 0.48 0.03 0.13 99.16 RNIML 53.58 14.93 9.90 0.46 3.19 8.41 5.32 0.39 0.77 0.07 97.02 M52.40 13.64 9.99 0.28 3.22 8.37 5.51 0.48 0.77 0.06 94.72 RNIMG 75.88 11.80 2.06 0.24 0.80 3.09 4.90 0.06 0.02 0.02 98.86 M75.70 12.08 2.04 0.06 0.78 3.36 4.99 0.09 0.02 0.01 99.13 RGH 74.90 12.50 1.33 0.02 0.70 3.67 4.95 0.77 0.08 0.01 98.92 M75.85 12.51 1.34 0.03 0.69 3.85 4.76 0.08 0.05 0.01 99.17 RA set of twelve standards were analyzed for calibrationpurposes. The standards also gave an estimate of the accuracy ofthe analysis. By comparing the standard's measured oxides withthe known published values a degree of accuracy can be obtained(Table A.2).The analysis of eight duplicate samples represents the errorexpected from sample preparation; predominantly pelletpreparation (duplicates originated from the same rock powder)involving the weighing of the lithium tetraborate and rock powder(Table A.3). Comparing Table A.3 with Table A.1 it is clear thatthe majority of the observed differences between duplicateanalyses is very similar to the analytical precision defined byBCR-1. However in some cases it is worse. When evaluating thechemical variation between rock units the experimental analyticalerror, if worse than machine precision, is the prefered error touse rather than the machine precision.137Table A.3 The major and minor element wt% oxides, mean and standard deviation for duplicates. Alsolisted is the average difference (AVE). Duplicate 7822 was spilt during pellet making and was included toillustrate how sensitive the pellet making was.7835 7842-52 7911 NH 7822 7834 7910 7819 (AVE)Si02^1 64.34 71.50 59.08 71.69 73.27 53.81 53.68 67.232 64.46 71.54 59.08 71.60 73.10 53.58 53.74 67.30(X1-X2) 0.12 0.04 0.00 0.09 0.17 0.23 0.06 0.13 0.09TiO2^1 0.19 1.17 1.25 0.19 0.16 0.38 6.95 0.312 0.19 1.17 1.25 0.20 0.16 0.38 6.98 0.32(X1-X2) 0.00 0.00 0.00 0.01 0.00 0.00 0.03 0.01 0.01Al203 1 17.91 12.43 17.42 14.75 14.24 13.11 15.99 15.662 17.40 12.53 17.28 14.59 13.87 13.24 16.02 15.61(X1-X2) 0.51 0.10 0.14 0.16 0.37 0.13 0.03 0.05 0.16Fe203 1 3.88 2.43 5.64 2.20 1.22 6.61 4.37 2.392 4.32 2.37 5.68 2.51 2.08 6.63 4.28 2.33(X1-X2) 0.44 0.06 0.04 0.31 0.86 0.02 0.09 0.06 0.14MnO^1 0.08 0.09 0.17 0.05 0.03 0.20 0.11 0.072 0.08 0.09 0.17 0.05 0.04 0.20 0.11 0.07(X1-X2) 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.01MgO^1 1.41 0.51 1.39 0.66 0.36 6.46 2.08 0.692 1.34 0.50 1.43 0.61 0.39 6.54 2.07 0.73(X1-X2) 0.07 0.01 0.04 0.05 0.03 0.08 0.01 0.04 0.04Ca0^1 5.31 2.46 7.76 2.55 1.27 11.17 8.40 2.312 5.22 2.45 7.81 2.54 1.28 11.16 8.39 2.32(X1 - X2) 0.09 0.01 0.05 0.01 0.01 0.01 0.01 0.01 0.02Na20^1 5.73 2.86 5.61 3.54 3.43 2.80 3.93 5.192 5.64 2.86 5.58 3.53 3.31 2.86 3.93 5.21(X1-X2) 0.09 0.00 0.03 0.01 0.12 0.06 0.00 0.02 0.04K20^1 1.28 5.86 1.51 4.07 5.46 4.76 5.23 5.822 1.28 5.83 1.52 4.04 5.37 4.75 5.23 5.79(X1-X2) 0.00 0.03 0.01 0.03 0.09 0.01 0.00 0.03 0.03P205^1 0.13 0.14 0.42 0.08 0.29 0.61 0.07 0.122 0.13 0.14 0.43 0.07 0.07 0.60 0.07 0.12(X1-X2) 0.00 0.00 0.01 0.01 0.22 0.01 0.00 0.00 0.01Volumetric Analysis of FeOThe samples already have anthem which will give an estimatethe sample. The amount of NH4VO3NH4VO3 for 1.0 grams of FeO. TheXRF Fe203 wt% calculated forof maximum FeO wt% possible inis estimated by 0.01 grams ofNH4VO3 is measured to 5 place138Table A.4 Fe0 titration wt% and also listed (X1 -X2).7835 7842-52 7911 NH 7822 7834 7910 7819 (AVE)Fe0^1 3.07 1.43 3.78 1.67 1.20 4.80 1.95 1.552 3.07 1.39 3.82 1.69 1.22 4.87 2.00 1.60(X1-X2) 0.00 0.04 0.04 0.02 0.02 0.07 0.05 0.05 0.04Fe203 1 0.47 0.84 1.44 0.65 -0.12 1.29 2.11 0.642 0.91 0.82 1.43 0.64 0.72 1.21 2.06 0.58(X1-X2) 0.44 0.02 0.01 0.01 0.84 0.08 0.05 0.06 0.09decimal. Measure 0.500 grams of -200 mesh rock powder anddissolve the sample in HF acid. The sample is titrated until anapple green tint first appears. The wt% FeO in the sample iscalculated by:FeO wt% = 61.42 (V-v'T)R^tv' = wt of NH4VO3 in standardt = titrant of standardR = wt of sampleV = wt of NH4VO3 with sampleT = titrant of sampleFe2O3 in sample is calculated from:Fe2O3 = Fe203(Total) - FeO*where FeO* = Fe2O3 equivalent FeO. 8 duplicates were run forprecision (Table A.4).A.3 TRACE ELEMENTSTwenty-four samples and eight duplicates were analyzed by anautomated Phillips 1400 X-ray Fluorescence at the University ofBritish Columbia Department of Oceanography for the followingelements Nb, Zr, Y, Sr, Rb, and Ba. Pressed powder pelletpreparation is as follows:(1) Measure 3 grams of -200 mesh rock powder using Polyvinylalcohol (PVA) as a binding agent and boric acid asbacking. Continue from step #6 under pellet preparationsection A.2 for and major and minor elements.(2) Sixteen standards were run for calibration purposes, toevaluate accuracy and as monitors (AGV-1) to estimateanalytical error.(3) The raw counts per second were reduced using the programTRACE version 1.0 (Russell and Thirugnanam, 1989).139Table A.5 Trace element concentrations (ppm) measured (M) in the standards and compared to the acceptedpublished values, with the difference between the two indicated (D). R = rejected results. The calculatedaverage difference + is also listed.Nb Zr Y Sr RbMBaDAGV-1 14.2 -0.78 248 23 19.5 -1.5 663 3 68 1 1203 -16G-2 11.1 -1.90 322 22 14.1 2.7 469 -9 168 -2 1839 -41GSP-1 22.7 -3.3 521 -9 32 2.9 235 1 260 6 1280 -31PCC-1 1.9 0.9 2 -6 0.9 0.9 -1 -1 -1 -1 -37 -38BHVO-1 20.0 1.1 188 8 26 -0.6 411 -9 6 -4 228 93SY-1 R R 280 0.4 135 4.7 253 -22 R R 426 -34MRG-1 21.0 0.9 114 9 12 -4.4 287 27 7 -0.6 211 161NIM-D 1.4 1.4 2 -18 2.3 2.3 1.3 -1.7 -0.8 -0.8 -38 -48NIM-G 56.0 3.1 283 -17 139 -4.1 8 -2 325 4.6 74 -46NIM-N 1.8 -0.2 15 -8 5.2 -1.8 264 4 3 -3 64 -36NIM-S 0.5 -3.5 23 -10 16.6 -3.4 60 -2 524 -6 2483 83GA 13.2 3.2 157 7 25 4.0 314 4 182 7 794 -56W-2 8.7 1.9 97 3 22 -1.3 197 5 18 -3 187 13DRN 8.0 2.0 R R 26 -3.8 417 17 74 4 414 29G-2 12.9 -0.1 326 26 14 2.9 470 -9 171 1 1862 -18GSP-1 21.3 -4.7 506 24 29 0.2 230 -4 251 -3 1295 -15Ave. 2.2 13 2.6 7.5 3 45Comparing the calibration standard's measured concentrationof trace elements to their accepted published values (Table A.5)gives an estimate of accuracy.The precision for the analytical run will be based on therepeated AGV-1 analysis and the average calculated error in TableA.6 (in ppm) except for Sr which will be 2.0 relative percent.A.4 Li, Tl, and CsTwenty-four samples and eight duplicates of -200 mesh rockpowder were sent to Chemex Labs Ltd for Li, Tl, and Cs analysis.Two standards were sent to evaluate accuracy and precision. Themethod used for the analyses is listed in Table A.7.Based on the duplicates analyses the precision is 1.0 ppmfor Li, 0.1 ppm Tl, and 1 ppm for Cs.140Table A.6 Duplicate analyses for trace elements in ppm. Also listed is the average calculated (X1-X2).7835 7842-42 7911DuplicatesNH^7822 7834 7910 7819 (X1-X2)AveNb 1^13.05 554.60 241.43 8.36 12.53 75.96 4681.39 21.762^13.81 548.28 230.69 10.69 13.06 82.45 4671.18 23.02(X1-X2)^0.76 6.32 10.74 2.33 0.53 6.49 10.21 1.26 6.75Zr 1^23.64 244.70 bd 161.68 157.34 151.38 143.99 305.742^21.05 233.56 bd 165.47 160.27 115.06 151.05 299.93(X1-X2)^2.59 11.14 3.79 2.93 36.32 7.06 5.81 9.95Y^1^21.08 137.97 157.12 9.26 14.31 23.13 78.21 18.562^23.43 134.08 153.28 11.38 14.49 24.88 79.93 18.56(X1-X2)^2.35 3.89 3.84 2.12 0.18 1.75 1.72 0.00 1.98Sr 1^717.32 1031.23 473.89 508.63 231.91 4367.56 7830.16 396.802^747.19 1014.54 468.56 524.02 239.90 4512.44 7797.78 400.55(X1-X2) 29.87 16.69 5.33 15.39 7.99 144.88 32.38 3.75 32.03Rb 1^19.90 63.26 bd 104.31 165.84 106.87 81.77 113.282^21.11 61.77 bd 108.03 171.65 107.83 81.51 113.19(X1-X2)^1.21 1.49 3.72 5.81 0.96 0.26 0.09 1.93Ba 1^416.25 5291.58 357.14 1311.51 1661.94 26573.62 15777.45 2480.892^368.29 5290.32 360.57 1263.79 1680.31 26511.44 15916.69 2558.65(X1-X2) 47.96 1.26 3.43 47.72 18.37 62.18 139.24 77.76 47.74Table A.7 Analysis method for Li, 11, and Cs and detection limit indicated.Element^Method^DetectionLi^HC104-HNO3-HF digestion^AAS 1.0 ppm11 HC104-HNO3-HF dig-ext AAS-BKGD Corr^0.1 ppmCs NAA^0.5 ppmA.5 RARE EARTH ELEMENTSTwenty-four samples, eight duplicates and the standards P1and WP1, all -200 mesh rock powder, were sent to Bondar-Clegg forneutron activation for the following elements; Ce, Dy, Er, Eu,Gd, Ho, La, Lu, Nd, Pr, Sc, Sm, Tb, Th, Tm, U, and Yb.WP-1 and P-1 (U.B.C. standards) were analyzed and calibratedwith numerous standards (Erdman 1985). Comparing the Erdman(1985) results with the Bonder-Clegg analyses for this studyprovides some indication of accuracy and precision.141Table A.8 Rare earth analyses mean and 1 standard deviation of error from repetitive analyses for WP-1and P-1 (Erdman 1985) compered to the Bonder-Clegg analysis, for this study.Element WP-1* WP-1- P-1* P-1- DetectionLimitEu 0.7+0.12 0.9 0.6+0.06 0.7 0.5La 12.8+0.43 13.0 12.0+0.28 12.0 0.2Lu 0.2+0.00 0.17 0.3+0.00 0.29 0.05Sc 9.2+0.20 10.00 10.4+0.41 10.80 0.05Sm 3.1+0.09 3.1 2.7+0.15 2.9 0.05Tb 0.5+0.34 <1.0 nd <1.0 1.00Th 2.2+0.27 2.1 3.7+0.18 3.5 0.20Yb 1.5+0.13 1.2 2.1+0.12 1.9 0.20*Analysis by Erdman (1985) WP-1 repeated 12 times, P-1 repeated 8 times. Standards for calibration were SY2,MIN-L, NIM-G, NIM-S, SY3, RGM-1, QL0-1, BHVO-1, GSP-1, STM-1, BCR-1 and ARCHO-1. WP-1- and P-1- analysis byBonder-Clegg INAA for this study.Table A.9 Precision (relative %) of Rare Earth analysis (INAA), detection limit also listed.Element R% detection (ppm)Th 5.0 0.2Ce 2.0 2.0La 3.8 0.2Sm 3.4 0.05Dy 5.4 0.5Eu 7.0 0.5Nd 7.4 0.5Pr 52.5 25.0Yb 10.0 0.2Lu 17.4 0.05Sc 1.6 0.0526.5 0.5R% = estimated relative precision based on WD-1, P-1 and (X1-X2) of duplicates.The calculate precision for the rare earths is in the form ofrelative % because of the very large variation of the rareelement concentration from sample to sample. The accuracy of therare earth analyses seem to be quite good as is indicated byTable A.8.A.6 CONCLUSIONThe Table A.10 lists the best estimates of analyticaluncertainty for each element analyzed. These estimateduncertainties are used when testing hypotheses or in errorpropagation.142Table A.10 Summary of analytical error of analyzed elements.Average Absolute Error (Wt%)Si020.16TiO20.02Al2030.18Fe00.05Fe203^Mn0^MgO^Ca0^Na200.09^0.01^0.04^0.04^0.06K200.03P2050.01Average Absolute Error (ppm)Nb7.0Zr10.0Y2.0Rb^Ba^Li^Tl1.9 35 1.0^0.1Cs1.0Average Relative Error (%)Sr2.0Eu7.0La3.8Lu^Sc17.4^1.6Sm3.4Tb^Th^Yb^Ho^Ce^Dy^Nd3.0^5.0^10.0^14.2^2.0^5.4^7.4Pr^U52.5^26.5Elements below detection limits include Er, Gd, and Tm.143APPENDIX BMICROPROBE ANALYSESMICROPROBE EVALUATION OF STANDARDSThe pyroxene electron microprobe standards wereevaluated for homogeneity, precision, accuracy and toprovide estimates of analytical uncertainty associated withmicroprobe analyses. Operating conditions for the analysisof pyroxenes are listed in Table Bl.Table B1: Operating conditions used in Camexa SX-50 microprobe analysis of pyroxenes include: 15KV accelerating potential, beam current of 20 na, beam diameter of 2 microns and bias of 70.Counting time was initially 30 seconds and was reduced to 20 seconds with no appreciable changein precision and accuracy. Background counting time was half the peak counting time.El Line Standard Std# Spec Xtal +Bkg -Bkg Int countSi Ka Diopside S379 4 TAP 700 700 I 30/20Al Ka Garnet S007 2 TAP 800 800 I 30/20Ti Ka Rutile S013 3 PET 600 600 I 30/20Fe Ka Aegirine-Augite S246 1 LIF 450 450 I 30/20Mg Ka Diopside S379 2 TAP 1500 1500 I 30/20Mn Ka Pyromangite 5245 1 LIF 580 580 I 30/20Cr Ka Chromite S222 1 LIF 700 700 I 30/20Na Ka Aegirine-Augite S246 4 TAP 700 700 I 30/20Ca Ka Diopside S379 3 PET 750 750 I 30/20Ba Lb Barite S016 3 PET 400 400 I 30/20Ni Ka Ni-olivine S241 1 LIF 600 600 I 30/20Sr Lb Strontianite S274 3 PET 650 650 I 30/20Evaluation of Standards for HomogeneityIn order to have the highest confidence in analysisquality, the calibration standards must be homogeneous inthe oxide that the standard is calibrated for. The procedurefor evaluating homogeneity is a follows:1) Analyze 15 random points on each standard using theassumed "best" standard for calibration; the primaryobjective is to estimate precision as it is a measure notonly of the error for the analytical method but also of thehomogeneity of the standard.2) Calculate the average oxide concentration andassociated standard deviation for each standard (Table B2).Ideally the standard deviation of the data should not belarger than expected from machine analytical error. This144Table B2: Analyses of standards used for oxide calibration for pyroxene analyses. N=15 is numberof random points analyzed on each standard. BOOK = published values listed if exist, NM = notmeasured, Sd = standard deviation of data (absolute error) and %ERR = relative precision error.Sample Si02 Al203 1102 FeO MgO Mn0 Na20 Ca0 Total379 N=15 55.44 0.05 0.06 0.06 18.89 0.04 0.00 25.76 100.30Sd 0.18 0.01 0.02 0.02 0.14 0.02 0.00 0.10%ERR 0.32 -- -- 0.72 -- -- 0.39BOOK 55.37 NM 0.09 NM 18.87 NM 0.03 25.73 100.09246 N=15 51.71 0.17 2.50 27.28 0.07 1.23 13.40 0.17 96.53Sd 0.13 0.01 0.05 0.21 0.01 0.07 0.11 0.01%ERR 0.27 8.42 2.08 0.78 -- 5.52 0.86 8.44BOOK 52.62 0.20 2.20 27.19 0.08 1.03 13.32 0.10 96.74245 N=15 46.98 0.01 0.02 4.62 4.42 41.57 0.01 1.00 98.63Sd 0.28 0.01 0.01 0.11 0.04 0.28 0.01 0.03%ERR 0.58 -- -- 2.41 0.93 0.68 -- 3.41BOOK 47.96 0.02 NM 4.74 4.44 41.40 NM 1.00 99.56007 N=15 39.09 21.34 0.41 0.06 0.55 0.66 bd 35.53Sd 0.13 0.06 0.03 0.02 0.02 0.04 0.24%ERR 0.35 0.27 7.52 -- 3.30 5.61 0.69BOOK 38.70 20.90 0.25 0.05 0.50 0.75 NM 35.10381 N=15 50.58 6.42 0.52 14.83 25.82 0.24 0.11 1.58 100.10Sd 0.23 0.07 0.02 0.12 0.21 0.03 0.01 0.03%ERR 0.46 1.12 4.49 0.80 0.80 12.14 11.40 2.12BOOK 49.80 7.90 0.51 14.37 25.50 0.21 0.12 1.50 99.91025 N=15 53.73 0.67 0.24 2.92 17.16 0.07 0.22 24.46 99.47Sd 0.21 0.05 0.03 0.11 0.09 0.03 0.06 0.14%ERR 0.40 7.88 14.04 3.63 0.55 -- 29.77 0.58BOOK 53.94 0.66 0.23 2.93 16.93 0.01 0.24 24.55 99.49122 N=15 53.68 0.63 0.25 2.94 17.17 0.07 0.22 24.47 99.43Sd 0.21 0.04 0.02 0.21 0.22 0.04 0.05 0.17%ERR 0.40 6.19 8.57 7.17 1.30 -- 21.76 0.70BOOK 53.94 0.66 0.26 2.93 16.73 0.07 0.24 24.55 99.38279 N=15 55.16 0.19 0.02 0.23 18.50 0.03 0.15 25.55 99.83Sd 0.30 0.19 0.01 0.06 0.19 0.02 0.09 0.27%ERR 0.55 -- -- 28.76 1.01 -- -- 1.05BOOK 54.87 0.11 0.00 0.24 18.30 0.04 0.34 25.63 99.53420 N=15 54.87 0.17 0.10 0.03 18.71 0.04 0.05 25.37 99.34Sd 0.21 0.02 0.02 0.02 0.09 0.02 0.01 0.20%ERR 0.39 9.58 19.61 -- 0.48 -- 0.78BOOK 55.36 0.09 0.09 0.05 18.63 0.05 0.02 25.73 100.02145Table B2 continued019 14=7 54.95 10.14 0.11 5.67 8.24 0.03 6.05 14.62 99.81Sd 0.34 0.80 0.02 0.51 0.40 0.02 0.47 0.69%ERR 0.63 7.90 22.64 8.95 4.83 -- 7.75 4.75234 14=10 55.60 8.75 0.35 4.43 11.65 0.07 5.25 13.64 99.74Sd 0.31 0.08 0.02 0.09 0.12 0.02 0.07 0.07%ERR 0.56 0.96 4.55 2.12 1.00 -- 1.35 0.54159 14=15 59.09 25.13 0.03 0.38 0.36 0.02 15.08 0.50 100.59Sd 0.29 1.10 0.05 0.62 0.46 0.02 0.41 0.62%ERR 0.50 4.39 -- -- 2.76 124.10392 14=10 51.23 0.01 0.01 31.73 17.39 0.02 0.01 0.01 100.41Sd 0.19 -- -- 0.28 0.20 -%ERR 0.37 -- -- 0.89 1.15 --378 N=15 49.43 8.88 0.82 6.20 15.63 0.14 1.08 17.47 99.65Sd 0.29 0.09 0.03 0.09 0.17 0.02 0.03 0.10%ERR 0.58 1.02 3.40 1.39 1.07 -- 2.40 0.56BOOK 49.57 8.74 0.82 6.05 15.66 0.15 1.02 17.90 99.91230 14=15 52.91 0.92 0.09 14.06 26.67 0.45 0.01 1.19 96.30Sd 0.27 0.02 0.02 0.25 0.17 0.03 0.01 0.02%ERR 0.51 2.28 22.22 1.78 0.64 6.67 -- 1.68BOOK 54.09 1.23 0.16 15.22 26.79 0.00 0.00 1.50 98.99391 14=15 48.15 0.00 0.00 29.17 0.02 0.01 0.01 21.96 99.32Sd 0.21 0.01 0.01 0.23 0.01 0.02 0.01 0.18%ERR 0.44 -- -- 0.80 -- -- 0.84031^14=15 53.30 0.76 0.01 6.59 14.16 0.12 0.32 24.45 99.71Sd 0.18 0.05 0.01 0.12 0.10 0.03 0.02 0.15%ERR 0.33 7.15 -- 1.87 0.71 -- 4.98 0.61114 14=15 55.21 0.04 0.01 0.06 18.72 0.03 0.02 25.68 99.76Sd 0.22 0.02 0.02 0.05 0.10 0.03 0.01 0.12%ERR 0.40 -- -- 0.56 -- -- 0.47BOOK 55.36 0.00 0.10 0.09 18.77 0.01 0.02 25.75094 14=15 55.55 0.01 0.00 0.02 18.38 0.01 0.03 26.08 100.08Sd 0.20 0.01 0.01 0.02 0.68 0.01 0.01 0.72%ERR 0.37 -- 3.68 -- 2.76041 14=15 59.16 24.99 0.02 0.34 0.55 0.01 14.88 0.80 100.75Sd 0.24 0.77 0.01 0.19 0.43 0.02 0.46 0.61%ERR 0.38 3.08BOOK 59.51 24.31 0.00 0.31 0.58 0.01 14.37 0.77 99.86146might not always be the case in natural standards which haveextensive cationic substitution. Plotting the data onelement ratio plots (Figure Bl, B2, B3) a quick visualjudgement on homogeneity (precision) can be made on thestandard. With some understanding of the possiblestoichiometric substitutions the axis can be picked toreflect mineral stoichiometry. If the standard ishomogeneous the variation of the data must be less than orequal to analytical error (machine error). Figure B1 and B2illustrate homogeneous standards while Figure B3 illustratesa nonhomogeneous, non-stoichiometric diopside glass.3) Now pick the final calibration standards for theoxides that are to be analyzed for; they should have thebest precision for that oxide as well as a concentrationhigher than the unknown and reliable published values.Accuracy Evaluation of the StandardsThe ability of the calibration standards to reproducethe published analyses of the remaining standards is thesole test of accuracy for the calibration standards. Therecommended procedure is:1) Calibrate on the best calibration standards (TableB3) based on homogeneity and analyze 15 points on eachstandard (calibration and others).2) The analytical precision of the run is estimated bycomputing the average and associated standard deviation ofeach oxide. The computed standard deviation in the datashould be equal or close to analytical error; analyticalerror is based on the precision of the calibration standardsfrom the homogeneous test; no matter how precise the machineis, the analytical error is only as good as the precision ofthe calibration standard.3) If the precision is acceptable, the accuracy isevaluated by comparing the average measured concentration ofeach oxide against published values (see Table B2 forexample). The accepted way to test accuracy is to plot theaverage measured wt% oxide against the published bookvalues; Figure B4 and B5 are examples for CaO and Al203. Thedata should form a trend with a slope of one (withinanalytical error). It should be noted that some standardswith very bad precision can still have average measured wt%oxide totals equal to published values.1470.60Pyroxene StandardDiopside S3790.55 -2.0 Std.Dev.Error Bounds0.45 -00000 Microprobe Analysis• • • •• Published Value0.400.40 0.45^0.6^10I^.  Ca/Si0.55 0.60FIG. Bl. 15 analyses of pyroxene standard 5379 plotted asCations Ca/Si vs Mg/Si to test for homogeneity. S379 was used ascalibration standard for Si, Ca and Mg. Also plotted is thepublished analysis of S379.1480.60Pyroxene StandardDiopside S4200.55 -2.0 Std.Dev.Error Bounds0.45 -00000 Microprobe Analysis• • • • • Published Value0.400.40 0.45I^.0.50Ca/Si0.55 0.60FIG. B2. 16 analyses of pyroxene standard S420 plotted asCations Ca/Si vs Mg/Si to test for homogeneity. Also plotted isthe published analysis of S420. S420 is homogeneous andtherefore the data plot as a tight cluster.1490 0oo °0 0 0 00.45 -0.60Pyroxene StandardDiopside S0940.55 -2.0 Std.Dev.Error Bounds--I-0.400.401^i^1^1^i0.45^0.50 0.55 0.60Ca/SiFIG. B3. 15 analyses of pyroxene standard S094 plotted asCations Ca/Si vs Mg/Si to test for homogeneity. The data plot asa group that is larger than expected from analytical errorindicating that S094, a synethetic diopside glass, isnonhomogeneous.15040PYROXENE STANDARDSACCURACY DIAGRAMSW30-a• •• • • Calibration StandardsA.6.6.6.6. Standards run as Unknowns110^20^30I^I I^1Ca0 Measured00 40FIG. B4. Accuracy of measured CaO in standards is defined byplotting published analysis against the measured oxide analysis.1513 0PYROXENE STANDARDSACCURACY DIAGRAMS• • • • • Calibration Standards&mum. Standards run as UnknownsI^1^i10 20Al203 Measured0 300FIG. B5. Accuracy of measured Al203 in standards defined byplotting published analysis against the measured oxide analysis.152Table B3: A summary of the statistics for calibration standards and the chosen calibrationoxides.Std # mineral oxide N X S X DL(WT%)379 diopside Si02 15 55.44 0.18 0.32 0.20007 garnet Al203 15 21.34 0.06 0.27 0.10013 rutile TiO2 15 99.85 0.34 0.34 0.12246 aegirine-augite Fe0 15 27.28 0.21 0.77 0.18379 diopside Mg0 15 18.89 0.14 0.72 0.06245 pyroxmangite Mn0 15 41.57 0.28 0.68 0.14379 diopside Ca0 15 25.76 0.10 0.39 0.04246 aegirine-augite Na20 15 13.40 0.11 0.86 0.10N is the number of analyses, X is the average oxides wt% of the 15 analyses, S is the standarddeviation of the data, % is the relative % error and DL is the detection limit.Analytical Error ControlDuring the homogeneity and accuracy evaluation of thestandards a good estimate of analytical error is obtainedwhich can be used as a bench mark. It is still imperativethat the analytical error is defined for each analytical runof unknowns. This is done by:1) analyzing the calibration standards completely atthe beginning of the run, after a chosen number of analysesof unknown, depending on operator, in the middle of the runand at the end of the run. The mean and standard deviationof the calibrated oxide is computed. The data can be plottedand checked on graphs such as Figure Bl, B2, B3, B4, B5 thatstill have the preceding homogeneity test data on them.2) Analyze check standards of the same mineral groupwhich has good published data but for some reason was notchosen as a calibration standard; e.g., apatite 5421 hasthorough published analyses which include REE. The REEcontent in S421 is too low to be a calibration standard butcan be used to see if the analytical run can predict the REEwt% (accuracy) and supplies a measure of precision for alower concentration.3) During the analytical run, analyze a mineral whichis known not to have the oxide/oxides of interest. This wasuseful in the REE analyses as sometimes picking the peakenergy of Lb at low Kv was difficult, e.g., analyses ofquartz during analytical runs of titanites would give 0.00wt% REO except in one run where Pr203 was observed to beconsistently above 0.00 wt%; usually >0.20 wt%. This wasrecognized as an operating error and Pr203 was recalibratedfor and the run reanalyzed.It is important to remember that the experimental errordefined during the analytical run is the error used to153define the 2 standard deviation for that data.Predominantly, the relative experimental error definedduring the analysis is the same as the relative analyticalerror obtained during the calibration standard evaluationtests.Thompson and Howarth (1976) have shown that theabsolute and relative errors in analytical analyses can varysignificantly over a wide range in concentration; thestandard deviation of the calibration standard does notadequately represent the analytical precision. Often thecalibration standards have substantially higherconcentrations of an oxide than the unknowns to be analyzed.Using the pyroxene standard database as an example (TableB2) it was noted that the absolute precision of oxideanalyses for homogeneous standards improves as the weightpercent of the oxide decreased in the standard, e.g., MgOwt% in S379 is 18.87 ± 0.14; S245 is 4.42 + 0.04 and in S007is 0.55 ± 0.02. Therefore, it is unwarranted to use theprecision of an oxide occurring in high concentrations in acalibration standard to define precision of that oxideocurring in substantially lower concentrations in unknowns.At best, in this case, the calibration standard provides theworst scenario of analytical error for the analyzed oxide inthe form of relative % error. The significance of this isapparent when analyzing for trace elements such as Ba andREE occurring in low concentrations in mineral phases. TheBa calibration standard has 51.69 + 0.26 wt% BaO whereas theobserved consistent core to rim BaO variation in anunknown's potassium feldspar is 1.00 to 0.50 wt%; within 2standard deviation of absolute analytical error based on thecalibration standard. The relative % error defined by theBaO calibration standards might not be valid for the lowconcentration observed in the unknows.A better estimate of analytical precision for theanalyses of trace elements in low concentrations in unknownsis defined by the repeated analyses of a set of goodstandards with a wide range of concentrations for the oxideof interest. Stanley and Sinclair (1986) graphically displayreplicate geochemical data representative of a wide range ofconcentration to define a more definitive relative error.Figure B6 illustrates the Stanley and Sinclair (1986) typegraph with plotted CaO electron microprobe analyses ofhomogeneous pyroxene standards. This precision plot definesthe detection limit at zero concentration as 2So (Stanleyand Sinclair, 1986). There is a lack of good standards witha wide range of low concentrations of trace elements thatcan be used to construct such a graph.The next best method is to repeatedly analyze a checkstandard with low trace element concentrations during theanalyses run of the unknowns (see titantites and apatites).154PYROXENE STANDARDSMicroprobe AnalysisFIG. B6. Pyroxene standard's measured CaO vs 2Sn, each datapoint is average of 15 replicate analyses. 2Sn = 2 timesstandard deviation of n data points, 2So = detection limit ofanalysis (Stanley and Sinlair 1986).155Table B4: Pyroxene standard evaluation. X* indicates standard recommended for calibration, Xindicates standard is good, - indicates standard is no good.STD # Label Si02 Al203 TiO2 Fe0 Mg0 Mn0 Na20 Ca0379 Diopside X* X* X*246 Aegirine-Augite X X* X*245 Pyromangite X*007 Garnet X*381 Orthopyroxene025 Diopside122 Diopside279 Diopside -420 Diopside X*019 Omphacite234 Omphacite X X X159 Jadeite392 Enstatite378 Augite230 Hyperthene391 Hedenbergite031 Diopside -114 Diopside X X094 Diopside -041 Jadeite -013 Rutile X*A check standard in this predisposition cannot be used as acalibration standard as the oxide concentration is too lowcompared to the wide range expected in the unknowns. Theresult of these analyses is a more realistic appraisal ofanalytical precision for small variations of trace elementsin unknowns with low concentrations of the trace element.These methods were used in the microprobe section toevaluate consistent small core to rim chemical variationsand define precision and the detection limits.Table B4 lists a summary of the pyroxene standardevaluation.MICROPROBE ANALYSES OF MINERAL PHASESTo ensure a complete analysis, energy-dispersive (ED)analysis was performed. Wavelength dispersive scan wasinvaluable in the defining of measurable peaks andbackground count areas for elements, especially for REEs, inthe mineral phase of interest. After the WDS of thecalibration standards and a few representative unknowns themeasurable peaks and backgrounds for the elements for thespecific mineral phase were picked.156FeldsparOperating conditions for the microprobe analysis offeldspars using the Cameca SX-50 microprobe are listed inTable B5. Evaluating the feldspar calibration standards withthe same procedures used on the pyroxene standards indicate:1) the feldspar calibration standards are homogeneous forthe oxides of interest, 2) internal accuracy was very goodand 3) the precision was also very good. Average oxideconcentrations and calculated standard deviation are listedin Table B6 while analytical error expected from using thefeldspar calibration standards are listed in Table B7.Table B5: Operating conditions for microprobe analysis of feldspars, include 15KV acceleratingpotential, beam current of 20 na, beam diameter of 5 microns and bias of 80. Counting times usedwere 20 secs on peak and 10 secs background.El line Standard Std# Spec Xtal +Bkg -Bkg Int countNa Ka Albite 5020 4 TAP 700 -700 I 20/10Si Ka Orthoclase S028 4 TAP 700 -700 I 20/10Al Ka Anorthite S427 2 TAP 800 -800 I 20/10Fe Ka Aegirine-augite S246 1 LIF 450 -450 I 20/10Mg Ka Diopside 5379 2 TAP 1500 -1500 I 20/10K Ka Orthoclase S028 3 PET 550 -550 I 20/10Ca Ka Anorthite 5101 3 PET 750 -750 I 20/10Ba La Barite S016 3 PET 650 -650 I 20/10Sr La Strontianite 5274 3 PET 650 -650 I 20/10A major concern in obtaining good stoichiometicanalyses of feldspars is the mobility of Na20 due to heatfrom the analysis beam, especially when using a small beamsize of 5 microns. Two albite standards (S020 and S105) wereanalyzed with a 5 micron and a 10 micron beam diameter. Thefollowing was concluded:1) No loss of Na20 was observed for either the 5 or 10micron beam for 13 different analyses on S020 and S105 witha counting time of 20 seconds.2) When analyzing the same spot, Na20 is more mobileusing the 5 micron beam than the 10 micron beam.3) The Na20 is more stable in the albite standard S020than the S105 standard. That more than 360 seconds of a 5micron beam on the same spot on 5020 is needed before Na20starts to move (Figure B7).The albite S020 was the preferred Na20 calibrationstandard because of its stability. During analysis ofunknowns, 5020 was analyzed at the start, middle and end ofeach run. Each analysis included 9 elements and 360 seconds157AAAAA Albite Standard S02000000 Albite Standard S105FIG. B7. The albite standards S020 and S105 were analyzed witha 5 micron beam for a total of 720 seconds to test how mobilethe Na content is. Also plotted is 2 standard deviation due toanalytical error.158of continuous beam on the same spot. To ensure continuingaccurate calibration of Na2O, the analysis of S020 wasrestricted to 1/4 of the standard leaving the remaining 3/4for only 30 second spot Na2O calibration analyses. Thisrestricts the destructive burning of the standard.Two Na-plagioclase feldspars in two Mount Bisson unitswere evaluated with the 5 micron size analyzing beam forNa2O mobility. It was found that the Na2O was extremelymobile (Figure B8). The implications are that if for someTable B6: Average oxides and calculated standard deviation of microprobe analyses of thefeldspar standards used for calibration. Also listed are two quartz microprobe analyses.oxide 5028 5020 S427 5101 QtzNa20 1.05(0.02) 11.73(0.10) 4.32(0.02) 0.02(0.01) 0.00Si02 64.26(0.22) 68.95(0.35) 52.90(0.14) 42.77(0.22) 100.50(0.55)Al203 18.18(0.11) 19.04(0.10) 28.70(0.15) 35.76(0.08) 0.02(0.01)Fe0 0.00 0.00 0.43(0.03) 0.03(0.01) 0.16(0.07)Mg0 0.00 0.00 0.09(0.01) 0.00 0.07(0.09)K20 14.87(0.22) 0.02(0.01) 0.36(0.02) 0.00 0.00(0.00)Ca0 0.00 0.01 12.09(0.07) 20.26(0.10) 0.05(0.01)BaO 0.62(0.03) 0.01 0.02(0.01) 0.00 0.03(0.01)Sr0 0.00 0.01 0.10(0.06) 0.00 0.00(0.00)N 12 12 12 12 2Table B7: A summary of the statistics of the calibration standards for the Microprobe analysesof feldspars.Std# mineral oxide N X S %ERR DL(wt%)S020 albite Na20 12 11.73 0.10 0.85 0.10S028 orthoclase Si02 12 64.26 0.22 0.34 0.20S427 anorthite Al203 12 28.70 0.15 0.50 0.10S246 aegirine-augite Fe0 15 13.38 0.21 0.77 0.18S379 diopside Mg0 15 25.80 0.28 0.68 0.06S028 orthoclase K20 12 14.87 0.22 1.48 0.065101 anorthite Ca0 12 20.26 0.10 0.50 0.04S016 barite Ba0 4 51.69 0.26 0.50 0.105274 strontianite Sr0 4 69.70 0.30 0.50 0.10N is the number of analyses, X is the average oxides wt%, S is the standard deviation, %ERR is therelative % error and DL is the detection limit.mechanical or calibration reason an automative run isaborted any points in the XYZ SIT file analyzed before theabort must be repicked to prevent incorrect Na2Oconcentrations. Rerunning the same XYZ SIT file to save timewill result in poor analyses.1591^1^1^1^1^1^1^1^1^1^1^1^1^1^1^1^1^1^135-Na—Plag unknownsMount Bisson Complex11-0 180 360 540 720TIMEFIG. B8. Two Na-plagioclase unknowns were analyzed with a 5micron beam for 2 to 3 total analyses of 9 elements (360 to 720secs) to test mobility of Na. Also plotted is 2 standarddeviation due to analytical error.160AmphiboleOperating Conditions for the analysis of amphiboleusing the Cameca SX-50 microprobe are listed in Table B8.Analytical error expected from using the amphibolecalibration standards are listed in Table B9.Table 88. Operating conditions for the microprobe analysis of Mt. Sisson Complex amphibolesinclude: accelerating voltage of 15 Kv, beam current of 20 na and a 10 micron beam size.El Line Standard Std# Spec Xtal +Bkg -Bkg I CountNa Ka Hornblende 5229 2 TAP 700 -700 1 15/7.5F Ka F-richterite S024 2 TAP 770 -770 I 15/7.5Cl Ka Sylvte S286 3 PET 650 -650 I 10/5K Ka F-phlogopite S024 3 PET 550 -550 I 10/5Si Ka Diopside S379 2 TAP 700 -700 I 10/5Al Ka Hornblende S229 2 TAP 800 -800 I 10/5Ti Ka Rutile 5013 3 PET 600 -600 I 10/5Fe Ka Aegirine-augite S246 1 LIF 450 -450 I 15/7.5Mg Ka Diopside S379 2 TAP 1500 -1500 I 10/5Mn Ka Spessartite S015 1 LIF 580 -580 I 10Ca Ka Hornblende 5229 3 PET 750 -750 I 10Table 89. A summary of the statistics of the calibration standards for the microprobe analysisof amphiboles.Std # Mineral Oxide N X S %ERR DL(wtX)S229 Hornblende Na20 3 2.61 0.02 0.77 0.10$229 Hornblende Al203 3 14.92 0.02 0.13 0.10S229 Hornblende Ca0 3 10.47 0.00 0.00 0.04S024 F-phlogopite K20 3 11.16 0.22 1.97 0.06S024 F-phlogopite F 3 8.70 0.03 0.34S379 Diopside Si02 3 55.37 0.18 0.32 0.10S379 Diopside MgO 3 18.50 0.20 1.08 0.06S246 Aegirine-augite Fe0 3 27.41 0.12 0.44 0.18S015 Spessartite Mn0 3 35.87 0.33 0.92 0.14S013 Rutle TiO2 3 99.85 0.34 0.34 0.12N is the number of analyses, X is the average oxide wt%, S is the standard deviation, % ERR is therelative % error and DL is the detection limit.161Table B10. Operating conditions for the microprobe analysis of Mt. Bisson biotites include,accelerating voltage of 15 KV, current of 20 na and beam size of 10 microns.EL Line Standard Std# Spec Xtal +Bkg -Bkg I countNa Ka Hornblende S229 2 TAP 700 -700 1 15/7.5K Ka F-phlogopite S024 3 PET 550 -550 I 10/5F Ka F-phlogopite S024 2 TAP 770 -770 1 15/7.5Cl Ka Sylvite S286 3 PET 650 -650 I 10/5Si Ka Muscovite 5164 2 TAP 700 -700 1 10/5Al Ka Muscovite S164 2 TAP 800 -800 1 10/5Fe Ka Biotite S082 1 LIF 450 -450 1 25/12.5Mg Ka F-phlogopite S024 2 TAP 1500 -1500 1 10/5Mn Ka Spessertine S015 I LIF 580 -580 I 10/5Ti Ka Rutile S013 3 PET 600 -600 1 10/5Ca Ka Hornblende S229 3 PET 750 -750 1 10/5BiotiteOperating conditions for the analysis of biotite usingthe Cameca SX-50 microprobe are listed in Table B10.ApatiteOperating conditions for the analysis of apatites usingthe Cameca SX-50 microprobe are listed in Table B11. Averageoxides and calculated standard deviation of microprobeanalyses of the calibration standard 5421, a check standard5126 and the Drake REE glasses are listed in Table B12.It is apparent that the accuracy and precision of theapatite analytical run is very good. The calibrationstandards for the REE have very good precision and accuracyand they predicted the correct amount in the check standardS126 (apatite) and in the calibration standard S421(apatite) even at low concentrations. In addition, instandards where specific REEs are not present, 0.00 wt% wasproperly predicted. The precision of Y203 is good but theaccuracy was not as the predicted concentrations in thestandards were a bit low.Analytical error expected from using the apatitecalibration standards are listed in Table B13.162Table B11. Operating conditions for microprobe analysis of Mt. Bisson apatites include 15 Kvaccelerating potential, beam current of 30 na, beam diameter of 10 microns and bias of 70.EL line Standard Std# Spec Xtal +Bkg -Bkg Int countF Ka F-apatite 5421 4 TAP 260 -200 I 20/10Na Ka Aegirine-augite S246 4 TAP 700 -700 I 10/15Cl Ka NaCl S285 3 PET 650 -650 I 20/10Ca Ka F-apatite $421 3 PET 750 -750 I 20/10P Ka F-apatite S421 3 PET 700 -700 1 20/10Fe Ka Fayalite S104 1 LIF 450 -450 I 20/10Mg Ka Foresterite S022 4 TAP 1500 -1500 I 20/10Mn Ka Pyroxmangite S245 1 LIF 580 -580 1 20/10Sr La Strontianite 5274 3 PET 650 -650 I 20/10La La Drake Glass S261 3 PET 500 -500 1 40/20Ce La Drake Glass 5261 3 PET 550 -225 I 40/20Pr Lb Drake Glass S261 3 PET 160 -250 I 40/20Nd Lb Drake Glass S260 1 LIF 450 -275 1 40/20Sm Lb Drake Glass S260 1 LIF 400 -400 I 40/20Y La Drake Glass S261 4 TAP 400 -400 I 40/20Nb La Microlite S115 3 PET 670 -670 I 40/20Table B12. Average oxides and calculated standard deviation of microprobe analyses of some ofthe standards used for the calibration of apatite. Also listed are the calculated oxide Wt% REEin some standards where they are known not to exist.Std # S421 S421* S126 S126* S260 S260* 5261 S261*Oxide N=7 N=4 N=2 N=3F 3.57(0.14) 3.50 3.96(0.18)Cl 0.37(0.07) 0.41Ca0 53.95(0.21) 54.02 54.28(0.43) 54.31P205 40.79(0.47) 40.88 40.79(0.50) 40.95Sr0 0.00 0.00 0.40(0.06) 0.23 0.00 0.00 0.00 0.00La203 0.46(0.03) 0.45 0.11(0.03) 0.13 0.04(0.01) 0.00 4.09(0.04) 4.28Ce203 0.61(0.02) 0.52 0.28(0.03) 0.29 0.00 0.00 3.85(0.07) 4.00Pr203 0.04(0.03) 0.12 0.04(0.07) 0.00 0.00 4.27(0.08) 4.44Nd203 0.19(0.08) 0.26 0.19(0.03) 0.12 4.33(0.14) 4.26 0.00 0.00Sm203 0.03(0.03) - 0.02(0.04) 4.24(0.03) 4.26 0.00 0.00Y203 0.09(0.01) 0.09 0.02(0.01) 0.04 0.00 0.00 3.59(0.04) 4.08Nb203 0.00 0.00 0.00 0.00 0.00 0.00Standard deviation in ( ), * represents published values, N = number of analyses163Table B13. A summary of the statistics of the calibration standards for the microprobe analysisof apatites.Std# Mineral Oxide N X S %ERR DL(wt%)S421 F-apatite F 7 3.57 0.14 3.90S246 Aegirine-augite Na20 3 13.40 0.12 0.89 0.10S421 F-apatite Ca0 7 53.95 0.21 0.39 0.04S421 F-apatite P205 7 40.79 0.47 1.15S104 Fayalite Fe0 3 69.81 0.25 0.36 0.18S022 Foresterite Mg0 3. 57.17 0.14 0.24 0.06S245 Pyroxmangite Mn0 3 41.55 0.28 0.67 0.14S274 Stontianite Sr0 4 69.80 0.30 0.43 0.10S260 Drake Glass Nd203 3 4.33 0.14 3.23 0.16S260 Drake Glass Sm203 3 4.24 0.03 0.70 0.06S261 Drake Glass La203 3 4.09 0.04 0.98 0.06S261 Drake Glass Ce203 3 3.85 0.07 1.82 0.05S261 Drake Glass Pr203 3 4.27 0.08 1.87 0.14S261 Drake Glass Y203 3 3.59 0.04 1.11 0.08S115 Microlite Nb205 3 4.63 0.19 4.00N is the number of analyses, X is the average wt%, S is the standard deviation and %ERR is therelative % error.TitanitesOperating conditions for the analysis of titanitesusing the Cameca SX-50 microprobe are listed in Table B14.The REE analyses have a high degree of precision andaccuracy as is illustrated in the analyses of S421 and crosschecked in the standard that are known not to contain theREEs (Table B15). The oxide Pr203 does have a high standarddeviation of 0.22 wt% and is consistently calculated to behigher in its calibration standard (Table B16). The peak wasincorrectly defined and this problem was corrected. Thestandard deviation for new oxides were calculated using thenew calibration standards while the standard deviation ofoxides analyzed for before in other microprobe analyses wereonly checked for precision and accuracy. The standard S379was used for the Si02 and had good precision and accuracybut consistently predicted low (>1.00 wt%) Si02 in the Drakeglasses. This could be the result of different molecularstructure or absorbtion by REEs; irregardless, the titaniteformula calculations indicate the analyses of the unknowntitanites are good. In addition low REE content in thecalibration standards make the high REE analyses of thetitanites in fenite 7910 more prone to higher analyticalerror.164Table B14. Operating conditions for microprobe analysis of titanites include 15 KV acceleratingpotential, beam current of 30 na, beam diameter of 10 microns and bias of 70.El Line Standard Std# Spec Xtal +Bkg -Bkg Int countNa Ka Aegirine-augite S246 4 TAP 700 -700 1 20/10F Ka F-apatite S421 4 TAP 770 -770 I 20/10Si Ka Diopside 5379 4 TAP 700 -700 1 20/10At Ka Garnet S007 4 TAP 800 -800 I 20/10Ti Ka Rutile S013 3 PET 600 -600 I 20/10Fe Ka Fayalite S104 1 LIF 450 -450 1 20/10Mg Ka Foresterite S022 4 TAP 1500 -1500 I 20/10Mn Ka Pyroxmangite S245 1 LIF 580 -580 I 20/10Ca Ka Diopside S379 3 PET 750 -750 I 20/10Sr La Strontianite S274 3 PET 650 -650 I 20/10La La Drake glass S261 3 PET 500 -500 I 40/20Ce La Drake glass S261 3 PET 550 -225 I 40/20Pr Lb Drake glass S261 3 PET 160 -250 1 40/20Nd Lb Drake glass S260 1 LIF 450 -275 I 40/20Sm Lb Drake glass S260 1 LIF 450 -450 I 40/20Y La Drake glass 5261 4 TAP 400 -400 1 40/20Nb La Microlite S115 3 PET 670 -670 I 40/20Note Spec #2 was not functional at this time.Table B15. Average oxides and calculated standard deviation of microprobe analyses of some ofthe standards used for the calibration of the titanites. Also listed are the calculated oxidewt% REEs in some standards where they are known not to exist.OxideS260N=2S260* S261N=6S261* S379N=2S421N=5S421* S007N=2Sr0 0 0 0.01 0 0.00 0.00 0 0.01La203 0.02 0 4.26(0.04) 4.28 0.00 0.48(0.02) 0.45 0.01Ce203 0.00 0 3.97(0.04) 4.00 0.00 0.64(0.03) 0.52 0.00Pr203 0.10 0 4.68(0.22) 4.44 0.17 0.12 0.45Nd203 4.83(0.21) 4.26 0.06 0 0.02 0.20(0.07) 0.26 0.03Sm203 4.31(0.05) 4.26 0.01 0 0.00 0.04Y203 0.00 0 3.87(0.10) 0 0.00 0.10(0.03) 0.09 0.00Nb203 0.00 0 0.00 0 0.01 0.01Standard deviation in ( ),^represents published values,^N = number of analyses165Table B16. A summary of the statistics of the calibration standards for the microprobe analysisof titanites.Std# Mineral Oxide N X S %ERR DL(wt%)S246 Aegirine-augite Na20 4 13.32 0.10 0.75 0.10S421 F-apatite F 6 3.08 0.22 7.14S379 Diopside si02 4 55.20 0.40 0.72 0.20S007 Garnet Al203 4 21.00 0.40 1.90 0.10$013 Rutile TiO2 4 99.84 0.32 0.13 0.12S104 Fayalite Fe0 2 69.54 0.27 0.39 0.18S022 Foresterite Mg0 3 57.17 0.14 0.24 0.06S245 Pyroxmangite Mn0 4 41.60 0.30 0.72 0.14S379 Diopside Ca0 4 25.73 0.04 0.16 0.04S274 Strontianite Sr0 4 69.80 0.11 0.16 0.10S261 Drake Glass La203 6 4.26 0.04 0.94 0.06S261 Drake Glass Ce203 6 3.97 0.04 1.00 0.06S261 Drake Glass Pr203 6 4.68 0.22 4.70 0.14S260 Drake Glass Nd203 2 4.83 0.21 4.35 0.17S260 Drake Glass Sm203 2 4.31 0.05 1.16 0.10S261 Drake Glass Y203 6 3.87 0.10 2.58 0.08S115 Microlite Nb205 3 4.63 0.19 4.10N is the number of analyses, X is the average wt%, S is the standard deviation, % ERR is therelative % error and DL is dection limit.AllaniteOperating conditions for the analysis of allanitesusing the Cameca SX-50 microprobe are listed in Table B17.Analytical error expected from using the allanitecalibration standards are listed in Table B18.166Table B17. Operating conditions for microprobe analysis of allanites, include 25 Kv acceleratingpotential. beam current of 30 na, beam diameter of 10 microns and bias of 70.El line Standard Std# Spec Xtal +Bkg -Bkg Int countNa Ka Aegirine-augite S246 4 TAP 700 -700 I 20/10F Ka F-apatite S421 4 TAP 240 -200 1 20/10Si Ka Diopside S379 4 TAP 700 -700 I 20/10Al Ka Garnet S007 4 TAP 800 -800 1 20/10Ti Ka Rutile S013 3 PET 600 -600 1 20/10Fe Ka Fayalite S104 1 LIF 450 -450 1 20/10Mg Ka Foresterite S022 4 TAP 1500 -1500 I 20/10Mn Ka Pyroxmangite S245 1 LIF 580 -580 1 20/10Ca Ka Diopside S379 3 PET 750 -750 I 20/10Sr Lb Strontianite S274 3 PET 650 -650 I 20/10La La Drake Glass S261 3 PET 500 -500 1 40/20Ce La Drake Glass S261 3 PET 550 -225 1 40/20Pr Lb Drake Glass S261 3 PET 160 -250 1 40/20Nd Lb Drake Glass S260 1 LIF 450 -275 1 40/20Sm Lb Drake Glass S260 1 LIF 450 -450 I 40/20Y La Drake Glass S261 4 TAP 400 -400 I 40/20Th La Metal 5343 1 LIF 500 -500 1 40/20Nb La Microlite S115 3 PET 670 -670 1 40/20Table B18. A summary of the statistiacs of the calibration standards for the microprobe analysisof allanites.Std# Mineral Oxide N X S %ERR DL(wt%)S246 Aegiringe-augite Na20 3 13.30 0.02 0.15 0.10S421 F-apatite F 4 3.77 0.04 1.06S379 Diopside Si02 5 55.10 0.38 0.69 0.20S007 Garnet Al203 3 20.96 0.20 0.95 0.10S013 Rutile TiO2 2 100.50 0.20 0.20 0.12S104 Fayalite Fe0 3 69.54 0.27 0.39 0.18S022 Foresterite Mg0 3 57.17 0.14 0.24 0.06S245 Pyroxmangite Mn0 4 41.60 0.30 0.72 0.14S379 Diopside Ca0 6 25.61 0.10 0.39 0.04S274 Strontianite Sr0 4 69.80 0.11 0.16 0.10S261 Drake Glass La203 6 4.28 0.04 0.93 0.06S261 Drake Glass Ce203 6 3.99 0.02 0.50 0.06S261 Drake Glass Pr203 6 4.31 0.15 3.48 0.14S260 Drake Glass Nd203 4 4.30 0.04 0.93 0.16S260 Drake Glass Sm203 4 4.29 0.02 0.47 0.06S261 Drake Glass Y203 6 4.05 0.04 1.06 0.08S343 Metal Th02 3 115.64 1.23 1.06S115 Microlite Nb205 3 4.63 0.19 4.10N is the number of analyses, X is the average wt%, S is the standard deviation, % ERR is therelative X error and DL is the detection limit.167

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