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CanadianMineralogist Vol. 3 I, pp. 137-146 (1993)

SIGNIFICANCEOF DUMORTIERITE IN AN ALUMINOSILICATE.RICHALTERATION ZONE, LOUVICOURT,OUEBEC

MEHMETF. TANER BP Resources Canala Limited, lzs Mines Selbaie' Case Postale j70, Joutel, Qulbec JOY IN0

ROBERTF.MARTIN Departmentof Eanhand Planetary Sciences, McGill Universiry' 3450University Street, Montr,1al, Qutbec H3A 2A7

ABSTRACI

A dumortierite-bearing,aluminosilicate-rich zone of hydrothermalalteration has been found in the northeasternsector of Louvicourt Township, in-the Abitibi greenstonebelt, Val d'Or area Quebec.The affected schists(metavolcanic rocks of &e Malartic Group) are andalusite-bearing;they are located near the southerncontact of^the Bevcon pluton. The presenceof dumonieritemakes the rocks pinkish. Its a andb cell parameters,I 1.822(5) nd20.251(7) A, arelarger than usually reported, and mayreflect the presence of vlMg andlvAI. Thec diminsionis 4.698(I ) A. Theaverage chemical composition of thedumortierite in two samplesdiffers slightly: (A16.sA4g0.r2Ti0.mFeo.oootro.zs)x.0rB(Si2.8lAl0.r4Po.oa)>z.seorz.0e(oH)q.q.l (surfaceexposure) and (A16.62Mg6'67Ti6.orF"o.orio.r)*.ril$ir-A1o*i,o.oJo-6"-(OH)1.16 (subsurface).The dumortieritereplaces andalusite, whi;ii:fodA diiring iii6 miitari

Souuens

Nousd6crivons une zone d'altdration riche en aluminosilicateet contenantde la dumorti6ritedans le secteurnord-est du canton de Louvicourt, ceinturedes roches vertes de l'Abitibi, r6gion de Val d'Or, Qudbec.ks schistesaffectds, d l'origine desroches m(tavolcaniquesdu Groupede Malartic, contiennentde I'andalousite;ils sont situdsprds du contactavec le pluton de Bevcon- l,a or6sencede dumorti6ritedonne aux rochesune teinte rose violac6e.ks dimensionsa et b de la maille de la dumortidrite' ll.3226) et20.251 (D A, sontsup6rieures i celle-squi sontdocumentdes dans la littdrature,et seraientI'expression de la pr6sence de uMg'et IvAl. La'dimensionc est 4.698(l)A.'La compositionchimique de la dumorti6ritediffbre l6gbrementdans deux dchantillns: (A16.56Mge.12Ti6.s?Fe6.006tr6.25)x.0tB(Si2.81A10.14P0.04)r2.eeor7.0e(OH)0.er(6chantillon de surface) et (Al6.62Mg6.s7Ti6.*F.o.ooirjo."l;.qrstSirLAt';po.orlooooroBotoqf'ltcarotte). l,a dumorti6riteremplace l'andalousite, qui s'6ff;fdil; p;-reds:riini'atiori'inetamorphiriueOiiibatres m6tavolcaniques lessivdes et ddform6es.L'introduction du boreserait donc tardive.i,a pr6sencede la dumortidriie,signal6e pour la premidrefois dansla ceinturede rochesvertes de l'Abitibi, aurait une significatioti co1n-" indice de cibles d'exploration I cause du lien entre les roches alt6r6eshyperalumineuses et la min6ralisationen Cu et Au. Mots-cl6s: dumortifrite, dimensionsde la maille, donn6esi la microsondedlectronique, andalousite, zones d'alt6ration, Louvicourt, campminier de Val-d'Or, ceinturede I'Abitibi, Qu6bec.

INTRODUCTION LouvicourtTownship, Val d'Or area Quebec(Fig. l). The occunenceofdumortierite sheds light on the locally A dumortierite-bearing,aluminosilicate-rich zone of intense hydrothermal transformations that affected hydrothermally altered rocks has been found in the meta-igneousrocks in partsof this belt. Our objectives Abitibi greenstonebelt, in the northeasternsector of in this paperare l) to characterizethe dumortierite,frst 138 TIIE CANADIAN MINERALOGIST

Ftc. l. Simplified geologicalmap of the Val d'or mining district, showinglocation of the dumonierite-bearingzone and of the areacovered by Figure 2. The mapis modifiedfrom a compilationof the Ministbrede l'Energie et desRessources du Qu6bec, andImreh (1984).

notedin a fine-grainedassemblage ofalteration products Sharpe(1968), Dimroth et al. (1982,1983),and H6bert byTaner(1984),2)to examineitsrelationship with other et al. (1991). aluminosilicatephases, and 3) to exploreis possible associationwith Au- and Cu-bearingfluids responsible llcer Gsorocv for mineralizationin this part of the Abitibi belt. Severalgeological units can be recognizednear t}re Gsot-ocrcnt.Snrmrc dumortierite-bearingzone (Fig. 2); undifferentiated mafic to felsic rocks of the CentralPyroclastic Belt of The dumortierite-bearingzone is located in the Sharpe(1968) are the most widespread.These rocks extremesoutheastern part ofthe Abitibi greenstonebelt, consistof l) a complexsequence ofdiorites, which host in the SuperiorProvince of CanadianShield, about 28 the dumortierite-bearingaluminosilicate-rich assem- km eastof Val d'Or, nearthe junction of Highways1 17 blage,a largesericite-enriched zone (Fig. 2), anda facies and 113 (Figs. 1, 2). The affectedrocks are considered containing "opalescent" ooeyes",such as recog- ultimately to havebeen volcanic in origin. nized in the Dumagami mine area by Marquis er aL The geologyof the Val d'Or miningdistrict (Fig. l) (1990),2) undifferentiatedmalic to felsicvolcanic rocks is dominated by suites of fuchean mafic to felsic of the Malartic Group, 3) a horizon of mafic volcanic volcanicrocks, including pyroclastic facies; the major rocks containing disseminatedmagnetite, 4) horn- cyclesof volcanicactivity were separated by periodsof blende-rich diorite porphyry, similar to the diorite clastic sedimentation.The volcanic sequenceswere porphyry of the Annamaqueshowing (Fig. 1), and 5) a intrudedby severalintermediate to felsic syntectonic horizon of chloritoid-bearingmetavolcanic rocks. and late-tectonicplutons of trondhjemitic to tonalitic The Bevcon pluton consists of tonalite and character, of which the Bevcon pluton @g. 2) is trondhjemite,typical of the intrusive complexesin the consideredtypical. All volcanic and sedimentaryrocks Val d'Orminingdistrict.It is stronglyaltered andlocally havebeen metamorphosed, generally to the greenschist deformed;silicification and albitizationhave led to the facies,and locally deformedalong numerouszones of developmentof a micrographicintergrowth of quartz mylonitization. Further information on the geological and albite (Ianer 1990).The pluton hoststwo gold setting of igneousactivity in the area is provided by deposits(Bevcon and Buffadisson, both former produc- DUMORTIERITE IN AN ALUMINOSILICAIE-RICH ALTERATION ZONE 139 0 q

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Frc. 2. Schematiclocal geology,from field observationsand interpreted from aeromagnetic survey(Taner 1990). ers) near its highly shearednofihem border (Sauv6 distributed ovet abotrt2}Eoof the area.The intensityof 198s). the color varieswith the proportionof dumortierite.The To the south of the dumortierite-bearingzone, the regionally developedschistosity strikes roughly east- Vicourgabbroicsill, whichhoststhe Sigma-2 goldmine, w6st anddips steeplyto the north. The axial plane of has local granophyricsegregations (Hdben et al. 1988' minor foldJ parallels the schistosity.Deformation af- 1991).This sill andthe map-unitsmentioned above are fecteda dumortierite-bearingfelsic dyke whosestrike is cut by relatively undeformeddiabase dykes. perpendicular- to the schistositY The dumortierite-bearingschist consistsof alternat- ing grey andalusite-richand white quartz-rich bands THa DuMonrnnrrE-BEARn{cZol.IE (Fig. ). The grainsof andalusite,0.5to 0.8mm across' locally containeuhedral inclusions of dumortierite,with The dumortierite-bearingrock, an andalusite- du- rare rutile. Where enrichedin dumortierite,the rock is mortierite- rutile quartziticschist, with localkyanite and pinkish and generallycontains 607o qiwu, up to 20Vo pyrophyllite, is unevenly developedover an area of andalusite,up to 207o dumortierite, with 2Vo ruttle' about 180x 300 m to the southof the pluton. The same sericite and rare epidote.Zircon and apatiteare acces- lithological unit wasencountered in drill coreat a depth sory phases.Kyanite occursexclusively associated with of.2i75m; on this basis,the map-unitis inferredto dip quartzin veins. Pyrophyllite is found in the samearea, 40o to the north (Fig. 2), and seemsto have a roughly in dumortierite-freerocks. constantthickness. The outcropsare mottled (Fig. 3)' The pinkish schist is presentas "knots" that range with the strikingly pinkish dumortierite-bearingrocks from l0 to 40 cm in diameter(Fig. 3)' andas conform- r40 THE CANADIAN MINERALOGIST

Flc. 3. Main dumortierite-richourcrop. The purplishpink color variesin intensity with abundanceof dumortierite.

Ftc. 4. Andalusite(An) phenoblastwith inclusionsofthe euhedral,rectangular dumortierite @u) and rutile (Ru) grains (opaque).We interpret this as rextural evidenceof the replacementof andalusiteby dumortierite. DUMORTIERITE IN AN ALI]MINOSILICATE.RICH ALTERATION ZONE t4l ablelayers up to onecm thick. Thepresence of deformed (estimated),y 1.686(2). These values are somewhat paramorphsafter p-quartz, with the amoeboidshape lowerthanthose given by Alexatderet al. (1986).Rutile 6pical of phenocrystsin felsic volcanicrocks, suggests invariablylies closeto the dumortieritegrains (Fig.4). that the impure quafiite may have developedat the Powder-diffractionmaxima from the polycrystalline expenseof sucha rock type.A quartzofeldspathicschist dumortierite t andalusitemixture were correctedand containingsericite - chlorite- rutile I andalusite,found indexedaccording PDF 7-:71arrd 13-122. On thebasis within the andalusite- dumortieritezone. also contains of ten corrected and indexed peaks, the Louvicourt parameters: bipyramidal cx,-quartzparamorphic after B-quartzphe- dumortieritehas the following unit-Ce[ a n@rysts,still visible in spite of tlrc deformation.This 11.822(5),b 20251(7),c 4.698(l) A. Whereasthe c rock thus alsois ofprobable felsic volcanicorigin. dimension matches the values reported for twelve natural specimensby Alexander et al. (1986) and seventeenexamples of dumortieritesynthesized at low MINERALOGY pressure(Werding & Schreyer1990), both flte a andb dimensions of our sample exceed significantly the The dumortieriteand andalusitewere first identified rangesin c andD encoqntered by them(l 1.781- I 1.802 using optical properties,and their presencelater was and 20.177- 20.222A, respectively: Alexanderet al. confirmedby X-ray diffraction (powder method),first 1986;11.790- 1l.8ll and20.2l8-20.243A, respec- with a Gandolficamera (diameter: I 14.6mm), thenwith tively: Werding & Schreyer1990). The larger unit-cell a Guinier-Hiigg focusing camera (CuKcr, radiation, volumethat results01,24.8 A3 comparedto 1115.4* syntheticspinel added as internal standard). 1122.2A\ is consistentwith the incorporationof a Dumortierite, an aluminum borosilicate. consists larger cation in a tetrahedrallyor octahedrallycoordi- mostly of acicular (Ftg. 5) 100-200 pm in natedposition that affectsthe X-Y plane of this orthor- length,generally radially disposedin andalusite@g. 6) hombic mineral (seeDiscussion). Interestingly, the cell and fibrous in quartz grains (Fig. 7). It also occursas dimensionsreported by Moore & Amki (1978) for the rectangulareuhedra 100 pm acrossin andalusite(e.9., from Saharina() that they selected Fig. 5). It is characterizedby a distinct pleochroic for structureanalysis, a 11.828(l), b 20|243(3),c scheme:Xpink to purple,I=Zcolorless, with a parallel 4.7001(5)A, resembleours closely; unfortunately, they extinction in the longifidinal section and a negative did not characterizeits chemicalcomposition. elongation,which distinguishesit fromfibrous silliman- The unit-cell dimensionsof the andalusite"based on ite. Dumortieriteis biaxial negative;its 27is about40o 22indexedpeaks, are: a7.7967(15), D 7.8988(16),c with strongdispersion (r> u).Indices ofrefraction were 5.5529(ll) L, V 341.97(UA3. The observeda andb measuredat room temperature:a 1.670(2),F = 1.68a values are within 1o of those found for reference

Ftc. 5. Typical sheafof radially disposedeuhedral dumonierite (Du) crysals; thesecrystals likely did not ariseby replacement,but arean overgrowthat the borderof an andalusite (An) graln. t42 TIIE CANADIAN MINERALOGIST

Flc. 6. Detail of replacementof andalusite(An) by dumortierite(Du).

Ftc. 7. Typical occurrenceof fibrous dumortierite(Du) within a quwtz-ich zone(Qz). andalusitefrom MinasGerais, (PDF 13-122):its lusiteschist were studied, one from a surfaceexposure c dimensionis 5.5580A. Theunit-cell dimensions of the andone from a sectionof drill core(Table 1). We used kyanite,based on 42 indexedpeaks, are: a 7.1193(8), b usinga CamscaCAMEBAX electronmicroprobe oper- 7.8453(8),c 5.5696(10)A, o 89.973(15),B atedat 15kV, 7 nA anda countingtime of 30 seconds. (Al, I 0 l. I 35(1 ), 1 I 06.004(I 3)", V 292.936) 43.These cell Thefollowing standards were used: orthoclase Si in parametersare very closeto thoseofreference kyanite a fust session),kyanite (Al, Si in a secondsession), (PDF I l-46). diopside @Ig), andradite(Fe), manganiferousilmenite (Mn, Ti), apatite(P) andLiF (D. Thedatawere corrected usinga ZAF progtam.The presence of boronas a major CoMPosmoN oFTT{E DuMoRTrERrrE elementwas confirmedin an energy-dispersionspec- trum; no elementother than thosereported in Table I is Two different samplesof dumortierite-bearinganda- presentin significantamounts. The low analyticaltotals DUMORTIERITE IN AN ALI.]MINOSILICAIE-RICH ALTERATION ZONE 143

TABI.A 1. COMPOSITION OF DIJMOBTIMITE EBOM I]OI'NCOT'BT reportedby Alexanderet al. (1986),and Fe contens are aslow asin their mostiron-poor specimen. Our dataand 2 compositionsquoted by Willner & Schreyer(1991) showthat phosphorusis an importantminor constituent gio2rt.t 8.2A 20.81 27.& 2?.S5 91.85 loz 0.89 o,92 0.87 0.68 of dumortierite;it shouldbe routinely soughtin future \ot 69.13 80.28 61.61 62.62 60.81 studieson this species. F@ 0.0? 0.08 0.04 0.04 A minor extentof OH-for-O substitutionis required ![gO 0.81 0.83 0.5t 0.69 P2O5 0.52 0.53 0.30 0.30 in theLouvicourt materialto insureelectrostatic neutral- ity. The importance of OH-for-O substitution was BeO" 0.14 8.74 0.16 establishedby Moore & &aki (1978). Nexatder et al. uror 7.4 t,74 I to (1986) reportedresults of an infrared absorption(IR) 90.0? 100.00 s0.48 1@.(p 100.00 study of three of their twelve samples,which reveals "small OH absorptionbands of similar intensities";they tnt.Vo CoElDBldoE dstsmlnsd by slsoircn daFpmba (6 tegt fo assumedthese bands to be indicaiive of 0.6 H2O, @ldliloE d ealy8ts ed stealsrda us€d). Colllm 1 sd 3 and this amountwas addedto the compositionof each !qr@t tbo aveEgs Eult of fro Btnt-amllEs of dmltlerlto of their twelve specimens.Beukes et al. (1987) cav- fen a sqrls of goblst @lloct€d fEm e @torp md fron a plae of dtlll or, GFcdvsly. Colm 2 md 4 Ft@t tltosE tionedthat moisturein the KBr pellet could be expecied @Btpsttlo$ @t @rdlng to fru Nurpdom lfull mtmsy to mask such lo'w concentrationsof H2O. Werding & of the tstran€dnUy @ldlmtsd ett€ ud tlre bopn slte, prus@ of 0.26 @cV itr tbe Af(l) sia,bsdnlly @ralhated slte, ud Schreyer (1990) showed that *re water in the IR olaotlostafta mtautyl ed Bunmd to 108. Slltrotml fouiuho spectrumis indeed structurallybound by synthesizing e Ffpltod b tbe tsxt. Colm 5 FID'te the ldal orpoettto! of dumortieritewith deuteriumin the place of hydrogen. the Tt-, ![g!, P-, md FFfE @d memb€r tiat hes tbs w 758 @rfralrcTr t! ths Al(1) stto s Bumd hffi (U@E & Anld 19?8, They found that without tracesof water in their experi- Table 6). M! ed F re sugbt, but mt fmd. Total lrcn tu ments, no dumortierite could be synthesized.They -n Hssd ap FeO. As porrted ml by Alemd* g!3L (1988), botb F€z'ed F€s tf,

Or Ab+An Ftc. 8. Plot of normativeQ, Or, AbrAn, and C (molar basis)of a suite of rocks sampled from study arca (Fig.2). Symbols:1 dumortierite-bearingaluminosilicate-rich zone (n = 9), 2 hydrothermallyaltered znne(n = 33), 3 dioritic rocks with opalescentquartz "eyes" (n = 1l), 4 Bevconpluton (n = 7), 5 disseminatedmagnetite-bearing volcanic rocks (n = 7), 6 sampleofthe mafic dyke that cross-cutsthe dioritic rocks (n = l). The laner plots in the expectedposition for a basall and is unaffectedby the metasomatic overprintthat transformedthe other rocks. DI,JMORTIERITEIN AN ALIJMINOSILICATE.RICH ALTERATION ZONE t45 ite - rutile schist to representthe end stageof locally The Louvicourt dumortierite-bearing andalusite intensehydrothermal alteration of a meta-igneoussuite schistis the manifestationof a zoneof aluminosilicate- of rocks. Geochemicalstudies of zones of modern rich alteration:as in other occurrences"we considerit to geothermalactivity (e.9., Henley & Ellis 1983)and of be the result ofhydrothermal alterationand subsequent ancientanalogues (e.9., Barrett & Maclean 1991,Taner metamorphismand deformationof the Al- and Si-rich & Trudel l99l) provideexamples of buildupof Al by leachedprotolith. The assemblageis a mineralogical intenseleaching ofprotoliths, presumablyas a result of anomaly,and has the sameimportance as a geophysical interaction with a low-pH fluid (cl Ririe 1990). No or geochemicalanomaly. It may, therefore,constitute a evidenceof the former presenceof clay minerals and reliable targetfor explorationof Cu and Au depositsin alunite expectedin the original leachedzone has sur- the Val d'Or mining district and in analogoussettings vived in the Louvicourt suite.Deformation and regional elsewhere. metamorphismof the leached rocks in the field of stabilify ofandalusiteand chloritoid led to thenear-com- AcrNoW-SDGSMENTS plete recrystallizationof the Al-enrichedsuite of rocks; the local preservationof relict quartz phenocrystspro- The first author thanksAline Leclerc of La Soci6td vides the only clear evidencethat somerocks at least Minibre t ouvem,who providedthe first sample,and Dr. were rhyolitic. Boron was probably introducedlate in GastonPouliot, for helpfuldiscussions and access to the the episodeof deformationand ,as the laboratory of the Ecole Polyfechnique.We thank D. dumortierite replaced deformed grains of andalusite. Bubarof Aur ResourcesInc., who allowedus to publish Thepresence of Ti in thedumortierite suggests thatrutile proprietary information. This work has been made also was a reactantin the replacementreaction. possibleby NSERCgrant to R.F.Matin (A-7721).We Assemblagesof peraluminousminerals are known to extendour thanksto V. Kubat for the boron analysis,to be spatially associatedwith somedeposits of gold and Dr. M. Mackinnonand Glenn Poirier for help with the the base metals @irie 1990). In two examples,the electron-microprobeanalyses, and to two anonymous Chetwynd mine, in southwestern Newfoundland refereesand Associate Editor Philip C. Goodell for (McKenzie1986) and the Big Bell mine, in Western useful comments. Australia(Chown et al. 1984),the gold deposit contains a dumortierite-bearingaluminosilicate horizon. Addi- REFERENCES tional examplesin the Abitibi belt are provided by the sericite-richschist horizon (ore-bearingfelsic unit) of GRTFFEN,D.T. & Mnnm, TJ. (1986t: gold ALEXANDER,V.D., the Doyon, Bousquet and Dumagami deposits Crystal chemistryof someFe- and Ti-poor dumortierites. (Valliant et al. 1983,Savoie et al. 1986,Stone 1989, Am-M incral. 71. 786:7 94. Tourigny et aL 1989, Marquis et al. l99A), wlnch containsseveral Al-silicates, e. 9., pyrophyllite, andalu- Benngm,T.J. &MAcLEAN,W.H. (1991): Chemical,mass, and site, kyanite, Mn-rich garnet and diaspore,as well as oxygen isotope changes during extreme hydrothermal wavellite and vivianite. Some of these minerals have alterationof an Archeanrhyolite, Noranda,Quebec. Ecoz. beenidentified at or near the contactbetween the host Geol.E6.4A6414. rocks and mineralizedquartz veins. Thesehorizons are interpretedas a result of the metamorphismof rocks Beurrs, G.J.,SLABBERT, MJ., or BnuvN, H., BorHA,B.J.V., enrichedin Al and Mn during the concentrationof Au ScHmr, A.E. & vAN osn WnsntuaN, W.A. (1987): (Stone 1989, cl Ririe 1990),and as an exampleof Ti-dumortierite from the Keimoesare4 Namaquamobile Abh. 157, metamorphismof a zon€of advancedargillic alteration belt, South Afica, Neups Jahrb, Mineral. 303-318. (Marquiset al.1990). Tourmalinehas been found to be importantgangue an CHowN,E.H., Hcrs, J.,Prm,lps, G.N. & TowwnNo,R. ( 1984): mineral in the lode gold depositsin the Abitibi - The disseminatedArchean Big Bell gold deposits,Murchi- stonebelt. For example,it occursin the Bevcon mine son Province,Westem Australia: an exampleof premeta- (Frg.2; Sauv61985), the Sigma-2(Fig. 2; Hdbertet al. morphic hydrothemtalalteradon. /z hoceedings of Gold '82: 1988, l99l), Sigma @obert & 1984), and the Geology, Geochemistryand Genesis of Gold Belmoral(Yu et aL 1987)gold minesin the Val d'Or Deposits(R.P. Foster, e.d.).Geol. Suw, Zimbabwe,Spec. mining distict Its presenceindicaiesan importantrole for Publ.1.305-324. boronin rocksthat show signs ofhydrothermal alteration and mineralization.Presumably, dumortierite develo@ Dnvrnorn,E.,IMnsH, L., Gou-El, N. & RocttsLEAU,M. (1983): here instead of tourmaline because of the marked Evolution of the south-centralsegment of the Archean Itr. Plutonic andmetamorphic evolu- depletionof thebulk compositionsin Fe,Mg, Ca andNa Abitibi belt Quebec. geotectonicmcdrel, Can. J. Eanh Sci.20, l37L prior tion and to the addition of boron. We contend that the 1388. developmentof dumortieriteis a mineralogicalexpression of the associationof acid metasomatismwith precious- -, -, RrcrulBau, M. & Gou,iE'r,N. (1982):Evolu- metal andbase-metal mineralization (cf, Ririe 1990). tion of the south-centralpart of the ArcheanAbitibi Belt, t46 THE CANADIAN MINERALOGIST

Quebec.I. Stratigraphyand paleogeographicmodel. Car. Intemational Symposiumon the Geology of Gold (A.J. J. Earth Sci.19, 1729-1758. MacDonald,ed.). Konsult lntemationalInc., Willowdale, Ontario(77-107). HEBERT,R., GAT,DREAU,R., hnnmn, B., GrcuERE,C., Rocm- r-EAU,M. & Lacosrt, P. (1988): l,e gisementaurifbre de Scmnn, H.-P., Scunnysn,W. & CuoprN,C. (1991):The Sigma-2-r6giondeYald'Or. Minist?re de l'Energie et des pyrope - coesiterocks and their country mcks at Parigi, Ressourcesdu Qudbec,rapp. MBJ&17. Dora Maira Massif, Westem Alps: detailedpetrography, mineral chemistryand PT-path.Contrib. Mineral. Petrol. -, Rocnrrreu, M., GrcuBnr, C., Prnnrer, B. & Geu- 108.l-21. DREAU,R. (1991):Pdtrologie etgltologie d'unfilon-couche diff6renci6 et min6ralis6 archeen: le gisement aurifdre Snanrn, J.I. (1968): Canton de Louvicourt, comtd d'Abitibi- Sigma-2,canton de Louvicourt, Qudbec.Can. J. Earth Sci. Ex;t,Mini$ere de I'Energie et des Ressourcesd.u Qudbec, 2,f..1731-t743. Rapp. GCol.L35. llsvmy, R.W. & Er-r-ls,A.J. (1983): Geothermalsystems SroNE,W.E. (1989): Significanceof metamorphismto gold ancientand modem: a geochemicalreview. Eanh Sci.Rev. distribution, Bousquet district, Abiribi greenstonebelt, 19,l-50. .In Preciousand Rare Metal Technologies(A.E. Torma& I.H. Gundiler,eds.). Elsevier, New York (2941). IIImEH,L. (1984):Sillon delaMotte-Vassan et sonavant-pays m6ridional:synthese volcanologique. lithostratigraphique TANER,M.F. (1984): Dumorti6rite dans le canton de Louvi- et gltologrque.Ministdre de I'Energie et des Ressources court, Qudbec; rapport d'identification. Instint de Re- nnturellesdu Qudbec,rapp. MM82J)4. chercheen Etploration Minerab, projet E441 , Manqus, P.,HunERr, C., BRowN, A.C. & Rrcc,D.M. (1990): - (1990): Final Report on the 1990 Diamond Drilling Overprinting of early, redistributedFe and Pb-Zn minera- Program, CourageousProperty, Louvicourt Township, lizatiori by late-sageAu-Ag-Cu depositionar the D!ma- Quebec.Aur Resourceslnc., Torcnto (unpubl.report). gami mine, Bousquet district, Abitibi, Qtebec. Can. J. Eanh Sci.n. rc51-1671. - & TnuonLP. (1991):Gold distribution in theVal d'Or Formationand a modelfor the formation of the Lamaque- McKsNm, C.B. (1986):Geology and mineralizationof the Sigma mines, Val-d'Or, Can, J, Eanh Sci. 28, Chetwynddeposits, southwestem Newfoundland, Canada. Quebec. '86: 706-720. /n ProceedingsofGold anInternational Symposium on the Geology of Gold (A.J. MacDonald, ed.). Konsult IntemationalInc., Willowdale, Ontario (137-148). TouRrcNy,G., HuBERr,C., Bnomq, A.C. & CnEpeeu,R. (1989): Structural conuol of gold mineralization at tle MooRE, P.B. & ARAKI, T. (1978): Dumortierite, Bousquetmine, Abitibi, Quebec.Can. J. Earth Sci.26, Si3B[A16.75tr0.25O17.25(OtI)e.75]: a detailed structure analy- 157-r75. sis,Neues Jahrb. Mineral. Abh. L32.23L-241. VALLTANT,R.I., BARNEm,R.L. & HoDDER,R.W. (1983): RRE, G.T. (1990): A comparisonof alteration assemblages Aluminum silicate-bearingrock and its relation to gold associatedwith Archeangold depositsin WesternAustralia mineralization,Bousquet mine, BousquetTownship, Que- and Paleozoicgold depositsin the southeastUnited States. bec.Can. Min. Metall.Bull.79(850),81-90. Can.J. Eanh Sci.n. fi6Gr15'76. Vu, L., Daru-wc,R., B6uqrn, J. & Poeov,V. (1987):Structue RoBERr,F. & Bnoml, A.C. (1984): hogressive alteration of the Ferbergergold deposit"Belmoral Mines Ltd., Val associatedv/ith gold-quartz-tourmalineveins at the Sigma d'Or, Quebec.Can. Inst. Min. Metall.80(907),68J7. mine, Abitibi greenstonebelt Quebec.Econ. Geol.79, 393-399. WERDnlc,G. & ScHnsyER,W. (1990):Synthetic dumortierite: its PTX-dependentcompositional variations in the system SeuvE,P. (1985):G6ologie de la mine Bevcon,Val-d'Or, Al2O3- B2O3- S|O2-H2O.Contrib. Mineral. Petrol,105, Qudbec. Minist\re de I'Energie et des Ressourcesdu tt-24. Qulbec, rapp. MB 8544. Wrr-lNrn,A.P. & SCHREvER,W. ( 199 1 ) : A dumortierite- topaz Savore,A., Pnnnewr, G. & FrLroN,G. (1986):Geological - white micafels from theperaluminous metamorphic suite sening of tle Doyon gold deposits,Bousquet Township, of Bushmanland(South Africa). NeuesJahrb, Mineral. Abitibi, Quebec,Canada. .lz hoceedings of Gold'86: an Monatsh.223-240.