Rhyolite Geochemical Signatures and Association with Volcanogenic Massive Sulfide Deposits: Examples from the Abitibi Belt, Canada

DAMIEN GABOURY† Université du Québec à Chicoutimi, Centre d’études sur les ressources minérales (CERM) and Consortium de recherche en exploration minérale (CONSOREM), 555 boul. de l’Université, Chicoutimi, Québec, Canada G7H 2B1

AND VITAL PEARSON* Consortium de recherche en exploration minérale (CONSOREM), 555 boul. de l’Université, Chicoutimi, Québec, Canada G7H 2B1

Abstract The relationship between rhyolite geochemistry and volcanogenic massive sulfide (VMS) mineralization has been proposed as an exploration tool to discriminate prospective felsic volcanic centers. The most widely used classification discriminates between four types of rhyolite: FI, FII, FIIIa, and FIIIb. The FI rhyolites are calc- alkaline, with strongly fractionated REE patterns and strongly negative Ta and Nb anomalies. They are usually considered barren, unless associated with FII or FIII felsic volcanic rocks. The FII rhyolites are calc-alkaline to transitional with moderately fractionated REE patterns and moderate Ta and Nb anomalies. They range from barren to having a high potential to host VMS mineralization. The FIIIa and FIIIb rhyolites are tholeiitic and show weakly fractionated REE patterns and weak to absent Nb and Ta anomalies. They have the highest potential to host VMS mineralization. The FIIIb rhyolites are high-temperature rhyolites with flat REE patterns and no Ta or Nb anomalies. The Abitibi greenstone belt, especially in Quebec, is well known for its abundant and diverse VMS deposits. Representative samples of VMS-associated rhyolites within and outside of mining districts, including the classic Noranda VMS district, were analyzed for major and trace elements to validate their proposed favorability for hosting VMS deposits. Results indicate that all of the rhyolite types are prospective, but mineralization may differ from the classic Noranda-type VMS deposit. The FI-type rhyolites appear to be particularly associated with gold-rich VMS deposits, such as the world-class Laronde deposit, and are more prospective for Cu-Au replacement and vein-type deposits. The FII-type rhyolites account for about 70 percent of rhyolites in the Abitibi belt. Although considered less prospective, some districts dominated by FII rhyolites, such as Val-d’Or and Selbaie, have collectively produced in excess of 100 million metric tons (Mt) of ore. Deposits in these districts mainly consist of sulfide veins and disseminated ore with low Cu and Zn grades and are associated with abundant and highly vesicular volcaniclastic rocks that display a compositional continuum from andesite to rhyolite. Other weakly mineralized FII districts (e.g., Hunter mine, Gemini-Turgeon) are characterized instead by bimodal flow-dome sequences. The FIIIa-type rhyolites occur mainly in the Noranda district and form flow-dome complexes in bimodal sequences with associated Noranda-type VMS mineralization. In small felsic centers (Joutel, Normétal, Chibougamau, Quévillon) that show a volcanic evolution from FIIIa to FII to FI affinities, VMS deposits are directly associated with FIIIa rhyolites, thus demonstrating the usefulness of rhyolite geochemistry for exploration in these areas. The FIIIb rhyolites are rare in the Abitibi belt, with most occurring in the Matagami district where they are associated with Zn-Cu VMS deposits. Based on this analysis, we suggest that a combination of rhyolite geochemistry, volcanic facies, and style of the mineralization may be more meaningfully applied in exploration than rhyolite type alone, particularly in the case of FI and FII rhyolites.

Introduction account for the association of specific rhyolite geochemical FOR MORE than 25 years, the association between specific signatures with VMS deposits. The classification geochemi- rhyolite suites and volcanogenic massive sulfide (VMS) de- cally discriminates rhyolites as FI, FII, FIIIa, or FIIIb types. posits was promoted as an effective tool for exploration. The general conclusions drawn from Lesher et al. (1986), Thurston (1981) and Campbell et al. (1982) first identified Lentz (1998), and Hart et al. (2004) are that Archean VMS this relationship using Archean VMS deposits in the Canadian deposits are hosted mainly by FIII rhyolites, whereas most Shield. Lesher et al. (1986) and Barrie et al. (1993) subse- post-Archean VMS deposits are hosted predominantly by FII quently developed formal classifications for felsic volcanic rhyolites, and FI rhyolites are unfavorable for VMS mineral- rocks based on trace element concentrations and suggested ization. The link between VMS formation (hydrothermal ac- that certain types of rhyolites were more prospective for VMS tivity) and rhyolite petrogenesis invokes a particular geody- deposits than others. Recently, Hart et al. (2004) revitalized namic setting and, more specifically, the depth of rhyolite the concept by proposing a conceptual petrogenetic model to generation (Lentz 1998; Hart et al., 2004). Although exceptions and limitations were recognized, the concept was rapidly adopted by exploration companies, and † Corresponding author: e-mail, [email protected] *Present address: Mines Virginia Inc., 116 St-Pierre, Suite 200, Québec, rhyolites with the most potential were commonly selected Québec, Canada G1K 4A7. without any consideration for the mineral potential of other

0361-0128/08/3785/1531-32 1531 1532 GABOURY AND PEARSON rhyolites in the vicinity. Recently, the discovery of the world- by several isolated felsic centers, such as Joutel, Normétal, class, gold-rich VMS Laronde deposit in FI and FII rhyolites Matagami, Gemini, Selbaie, Hunter, and Chibougamau (Mercier-Langevin et al., 2007a, b) raised some doubt about (Lemoine). All these felsic centers have well-documented the application of rhyolite classification in VMS exploration. synvolcanic intrusions (Gaboury, 2006), felsic domes and The Archean Abitibi belt is one of the most prolific VMS lavas, and associated VMS mineralization. Cycle 2, from 2720 belts in the world (Rodney et al., 2002), hosting various types to 2705 Ma, is interpreted as an emerging and evolving arc, to of VMS and volcanogenic gold deposits. Consequently, this which some synvolcanic plutons have been linked (Chown et belt constitutes an ideal laboratory for testing the validity of al., 1992), such as the Chibougamau pluton with its Cu-Au rhyolite classification as a means for finding ore deposits. In vein-type deposits, the Kamiskotia pluton (Barrie and Davis, this paper, we reassess the use of rhyolite classification as an 1990) with VMS deposits in associated felsic lavas, and the exploration tool in the Abitibi greenstone belt and present a Mountain pluton, which has been indirectly dated at 2718 Ma compilation of the characteristics of ore-hosting rocks, alter- based on the age of cogenetic felsic lavas at the Langlois VMS ation types, and volcanic facies. Felsic volcanic rocks in and mine (Davis et al., 2005). The 2717 to 2711 Ma rhyolites at around VMS districts in the Abitibi belt of Quebec were sam- Kidd Creek (Bleeker et al., 1999) are compositionally distinct pled and analyzed for major and trace elements. Rhyolites from these other cycle 2 felsic rocks due to their high silica were classified using the parameters of Hart et al. (2004) and contents and their REE-HFSE patterns comparable to rhyo- compared with VMS tonnages, mineralization type, and vol- lites from the Iceland rift zone (Prior et al., 1999). The Kidd canic rock characteristics. This approach permits a semiquan- Creek VMS deposit is also exceptional due to its size and titative comparison of the favorability of various rhyolite types. metal content (Hannington et al., 1999a), as well as the apparent lack of an association with a synvolcanic intrusion Geology of the Abitibi Belt (Barrie et al., 1999). Cycle 3 is restricted to the Southern Vol- The Abitibi greenstone belt in Canada (Fig. 1) is the largest canic zone and is interpreted as arc volcanism (e.g., and best preserved Archean belt (Card, 1990) and also one of Daigneault et al., 2004). The Southern Volcanic zone includes the richest VMS-bearing belts in the world (Rodney et al., the Blake River Group (2703–2698 Ma) and the Malartic seg- 2002). These include syngenetic VMS and gold-rich VMS de- ment (2714–2701 Ma). The Blake River is thought to repre- posits, as well as sulfide-rich, gold-bearing quartz veins and sent the development of a multiphase megacaldera, recently Cu-Au–bearing sulfide veins. All are genetically associated proposed by Pearson and Daigneault (2009), which hosts with felsic volcanic complexes (e.g., Chartrand and Cattalani, major VMS deposits associated with three main synvolcanic 1990). The Abitibi belt includes three of the world’s largest intrusions, the Flavrian-Powell, Cléricy, and Mooshla intru- and richest VMS deposits (>50 Mt of ore)—Kidd Creek, sions and associated felsic rocks. The Malartic segment has Horne, and Laronde—of which the last two are gold rich. recorded a complex evolution (Scott et al., 2002) involving ko- Eight other large deposits (>15 Mt) also have been mined: matiitic rifting at the base (2714 Ma) followed by arc evolu- Selbaie, Mattagami Lake, Bouchard-Hébert, Louvicourt, tion and later arc rifting (2705–2701). The VMS deposits of East Sullivan, Bousquet-1, Dumagami-Bousquet-2, and Qué- the Val-d’Or mining district occur specifically in the arc-re- mont. Overall, more than 80 deposits are known, totaling lated volcanic sequence (Scott et al., 2002) associated with more than 675 Mt of metallurgically high-quality Cu ± Zn ± the synvolcanic Bourlamaque pluton (Fig. 1). Ag ± Au ore (Hannington et al., 1999a; Rodney et al., 2002). Daigneault et al. (2004) determined that the deformation The Abitibi greenstone belt is a linear east-trending vol- history is diachronous: 2710 to 2690 Ma in the North Volcanic cano-sedimentary sequence intruded by plutonic suites (Fig. zone and 2698 to 2640 Ma in the Southern Volcanic zone but 1). It is thought to have developed through arc formation, arc following the same pattern for both. In each case, the first evolution, arc-arc collision, and arc fragmentation dating phase consisted of north-south deformation dominated by from 2735 to 2670 Ma (Mueller et al., 1996; Daigneault et al., shortening that induced thrusting along major east-trending 2004). Wyman et al. (2002) proposed that the Abitibi-Wawa boundary faults (the Porcupine-Destor-Manneville and greenstone belt is the product of subduction tectonics, en- Cadillac-Larder Lake faults), folding, and the development of hanced and modified by mantle plume interaction. The belt a regional east-trending schistosity. The second phase was a is broadly divided into the 2735 to 2705 Ma North Volcanic dextral, transpressional late-stage increment responsible for zone and the 2715 to 2697 Ma Southern Volcanic zone dextral movement along major east-trending faults (the (Chown et al. 1992), although more recent compilations pre- Destor-Manneville and Cadillac-Larder Lake faults) and the sent a more complex evolution (e.g., Ayer et al., 2003, 2005; development of a southeast-trending fault system. Syntec- Goutier and Melancon, 2007). The east-trending Porcupine- tonic intrusions were emplaced locally during all stages of the Destor-Manneville fault separates the Northern and South- deformation history. As a consequence of this structural evo- ern Volcanic zones, and the Cadillac-Larder Lake fault de- lution, VMS-hosting sequences or districts occur as (1) mon- fines the southern boundary of the Southern Volcanic zone oclinal laterally extensive and tilted sequences located strati- (Fig. 1). In addition, the North Volcanic zone is also divided graphically above their synvolcanic pluton, as exemplified by into external (NVZ-ext) and internal (NVZ-int) segments the Normétal, Val-d’Or, Bousquet, Selbaie, Chibougamau (Fig. 1) separated by the linear, east-trending Chicobi sedi- (Lemoine), Langlois, and Gemini mining districts; (2) as se- mentary sequence (Daigneault et al., 2004). quences occurring on both flanks of an anticline centered on Three main volcanic cycles are recognized in the Quebec a synvolcanic intrusion, such as those found in the Noranda, segment (Daigneault et al., 2004). Cycle 1, from 2735 to 2720 Matagami, and Hunter districts; or (3) as a complexly folded Ma, corresponds to a subaqueous basaltic plain punctuated sequence, such as the Joutel district.

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50° 48°

74° ovince

nville Pr nville 4B Gre Chibougamau Synvolcanic pluton Undifferentiated intrusive rocks and sedimentary rocks Volcanic Major boundary fault NZV division (external - internal) Limit of the Abitibi belt R-107 dy. Locations of samples outside dy. MF) and the Cadillac-Larder Lake Volcanic zone (SVZ), the external North Volcanic Sample location, FI and FII respectively VMS or related deposit (resource) VMS or related deposit (closed active mine) Map location and figure number in circle Coniagas 4D 5A PDMF CLLF Quévillon NVZ-ext 5B N Val-d'Or 2 Matagami 100 5A R-114 R-115 External North Zone Volcanic 4A

R-119 Laronde R-105 Géant Dormant Joutel km NVZ-int R-101 R-102 R-103 R-104 R-100 Selbaie 79° R-117

R-118

Bousquet-2

Bousquet-1 Dumagami 050 R-50 Normétal Noranda

Hunter Gemini 3 4C R-120 R-121 R-122 R-123 SVZ Quebec map Ontario . 1. Simplified geologic map of the Abitibi belt, showing locations VMS and volcanogenic deposits considered in this stu IG F fault (CLLF). Map modified from Chown et al. (1992), Daigneault (2004), and Gaboury (2006). detailed sample areas are shown (see Figs. 2–5 for enlargements of areas). Major subdivisions the Southern fault (PD zone (NVZ-int). Major faults are the Porcupine-Destor-Manneville zone (NVZ-ext), and internal North Volcanic Volcanic Kidd Creek CANADA U.S.A.

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Methodology earlier visits to mines with deposits of interest. The aim was to obtain a uniform sample dataset analyzed as one batch Sampling using the best analytical procedures, thus avoiding compar- During the summer of 2003, more than 120 felsic rocks isons between different data sources representing a variety of (mainly rhyolite with minor quantities of dacite) were sam- analytical techniques, variable detection limits, and incom- pled from outcrop, with another four taken from drill cores plete analyses. The volcanic facies was taken into considera- (App. 1; Figs. 1–5). Four samples also were collected during tion when selecting samples. For example, in lobed felsic volcanic domes and flows, only the lobe center or the massive facies was sampled to reduce the possible influence of hydrothermal alteration. The goal of the sampling strategy was 5 km to compare (1) VMS-hosting rhyolites to surrounding rhyo- N lites, (2) rhyolites from different mining districts, and (3) rhy-

R-54 olites from areas considered relatively nonprospective for VMS deposits to rhyolites from known VMS districts. A special emphasis was given to rhyolites associated with docu- Matagami R-52 R-53 mented atypical (vein and disseminated) gold-rich vol- Persévérence canogenic deposits (e.g., Géant Dormant, Comtois, Agnico- Telbel, Duvan). Furthermore, dated rhyolites and felsic tuffs Lac Mattagami Bell River were also sampled to provide a temporal framework for the R-51 evolution of the felsic volcanism. Bell-Allard Geochemical analysis

Bracemac All samples were processed at the Université du Québec à McLeod Chicoutimi where they were cleaned to remove surface weathering, crushed, and then pulverized using an alumina Felsic volcanic rocks VMS deposit Road shatter box. The shatter box was cleaned with quartz between Mafic volcanic rocks Mine (active or closed) Town each sample and precontaminated with each new sample to Intrusive rocks Sample: FIIIb minimize sample-to-sample contamination. The powdered samples were shipped to the Geo Labs facility in Sudbury as FIG. 2. Simplified geologic map of the Matagami district, showing sample one batch. The major elements were analyzed using wave- and VMS deposit locations. Map modified from Piché et al. (1993). length-dispersive X-Ray florescence (WXRF) on fused pellets.

N R-97 R-84 Bouchard- Hébert R-95 R-94 R-83 R-89 R-96 R-86 R-90 R-88 R-99 R-87 BRG R-93

Inmont R-92 Flavrian R-73 R-91 R-78 R-80 Delbridge R-76 R-75 R-71 R-79 R-77 5 km R-74 Quémont Horne R-67 R-81 R-69 Rouyn- R-70 R-68 Aldermac Noranda

Felsic volcanic rocks Intrusive rocks VMS deposit Sample: FIIIa Road Mafic volcanic rocks Sedimentary rocks Mine (active or closed) Sample: ? Town

FIG. 3. Simplified geologic map of the Noranda district, showing sample and VMS deposit locations. BRG = Blake River Group. Map modified from Pearson and Daigneault (2009).

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A B Chibougamau Agnico-Telbec R-46 N N Lac Doré Joutel WF R-110 R-47 Lemoine Chibougamau JVC R-45 R-44 WF R-48 WF R-112 R-111 Explo Zinc R-113

Joutel Copper WF

Valrenne Poirier 5 km R-109

5 km R-108 C D R-36 10 km R-35 NVC R-34 N Normétal R-38 R-6 R-5 N R-4 R-37 R-41 R-8 Duvan Langlois La Sarre R-40 Mountain

R-9 R-39 R-1 R-2

Comtois R-66 R-65 R-3 5 km R-57 R-58 Quévillon Poularies R-59 HMG HMG Hunter R-64 R-61 R-56 R-62 Felsic volcanic rocks Intrusive rocks R-60 Lyndhurst R-55 R-63 Mafic volcanic rocks Sedimentary rocks

VMS deposit Major fault sample: FI sample: FII Mine (active or closed) Road Town sample: FIIIa

FIG. 4. Simplified geologic map, showing sample and VMS deposit locations. A. Joutel (modified from Legault et al., 2002). JVC = Joutel Volcanic Complex. B. Chibougamau (modified from Daigneault and Allard, 1990). WF = Waconichi For- mation. C. Normétal (upper part: modified from Lafrance et al., 2000) and Hunter (lower part: modified from Mueller and Donaldson (1992). HMG = Hunter Mine Group, NVC = Normétal Volcanic Complex. D. Quévillon area (modified from Lacroix et al., 1993).

Trace elements were determined by ICP-MS following a Petrographic study closed-beaker digestion method involving four acids over two Thin sections were made from all samples except for those weeks to ensure total digestion of all minerals. Three repli- from drill core and samples of insufficient size (App. 2). The cates and one reference sample were included in the batch. goal of the petrographic study was to establish, (1) the per- The precision and accuracy of the analytical values were ex- centage and size of phenocrysts, (2) the nature of any of cellent, including the results for potentially problematic Zr feldspar phenocryst alteration, and (3) the mineral assem- (standard deviation of <0.05% for trace elements). The ana- blage, overall composition, and intensity of the quartz- lytical results used in this study are provided in Appendix 1. feldspar matrix alteration.

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A 5 km N

Bourlamaque

Louvicourt

R-17 R-116

R-20 Val d'Or R-10 R-16 East Sullivan R-12 R-18 R-15 VDF R-19 Manitou R-11 Barvu Dunraine R-13 HF R-14 CLLF Akasaba

B Chicobi R-41 10 km N

R-40 R-43 R-42 R-39 R-27 Lamorandière NVZ-ext R-32 R-29 R-66 R-65 R-28

R-26 R-31 R-30 R-25 R-64 Amos Jay Copper R-62 R-22 R-23 R-63 R-33 Abcourt Lyndhurst Kinojevis formation Vendome R-85 R-21

PDMF

Felsic volcanic rocks Sedimentary rocks Major fault Sample: FI

Mafic volcanic rocks VMS deposit Road Sample: FII Intrusive rocks Mine (active or closed) Town Sample: FIIIa

FIG. 5. A. Simplified geologic map, showing sample and VMS deposit locations. B. Val-d’Or district (modified from Scott et al., 2002). CLLF = Cadillac-Larder Lake fault, HF = Heva Formation, VDF = Val-d’Or Formation. B. External North Volcanic zone (NVZ) area (modified from Chown et al., 1992). PDMF = Porcupine-Destor-Manneville fault.

Assessment of Rhyolite Type Versus VMS Potential difficult to obtain a uniform sampling pattern. The VMS dis- Assessing exploration vectors and prospectiveness indicators tricts, particularly the best studied ones, are invariably oversam- based on the presence of mineralization, number of deposits, pled, whereas smaller or remote districts are commonly under- and total ore tonnage is limited by the current state of knowl- represented, as are other areas considered to have low potential. edge and assumes that discovered orebodies represent high po- Although it is impossible to overcome all these limitations, this tential, and undiscovered mineralization represents low poten- study has the advantage of including a wide range of felsic vol- tial. Sampling bias is another limiting constraint because it is canic rocks, whether associated with VMS mineralization or not.

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In the following sections, mining districts and areas of in- generally immobile during hydrothermal alteration and are terest are described and classified in terms of predominant representative of petrogenetic processes. These elements rhyolite-VMS associations, with rhyolite types determined ac- were used to create Zr/Y versus Y and [La/Yb]CN versus YbCN cording to parameters of Hart et al. (2004). Although our ap- (chondrite-normalized: Nakamura, 1974) binary classification proach uses informal subdivisions of mining districts, effusive diagrams (Lesher et al., 1986; Barrie et al., 1993; Lentz, centers, and geographic sectors that may have multiple felsic 1998). A drawback of these classification parameters is the horizons, and in some cases, various rhyolite types, it has nu- overlap of some discriminating compositional ranges for the merous advantages described above. various rhyolite types. When plotted on the binary diagrams The geochemical signatures of rhyolites directly associated (Fig. 6), only 61 percent of the samples fall into the same clas- with VMS and VMS-related mineralization are compared to sification field on both plots. To overcome this discrepancy, other rhyolites from the same district, referred to here as primitive mantle-normalized multielement plots were used in “background rhyolites,” in an attempt to uncover any geo- this study. These plots allow for better discrimination be- chemical trends within districts. Tonnage values for the vari- tween rhyolite signatures, and distinguishing features, such as ous districts were compiled using data from Chartrand and negative Nb and Ta anomalies associated with subduction Cattalani (1990), Lacroix (1998), and Hannington et al. processes, Eu anomalies, and degree of REE fractionation, (1999a), in addition to data from companies where necessary. can be better visualized (e.g., Sun and McDonough, 1989; Ore, alteration, and volcanic host-rock characteristics were Kerrich and Wyman, 1997). also compared (Tables 1, 2). To overcome the effect of hydrothermal alteration in classi- FIIIb Rhyolites fying the rhyolite samples, only HFSE and REE were used. The FIIIb rhyolites are defined as tholeiitic high-silica, Some altered rhyolite (or dacite) samples in the footwall and high-temperature rhyolites with flat rare earth element lateral to VMS deposits have major element concentrations (REE) patterns expressed by [La/Yb]CN chondrite-normal- ranging from apparent andesite (<63%) to high-silica rhyolite ized values of 1.1 to 4.9, high concentrations of high field (>80% SiO2). Even trace elements (LREE) reputed to be im- strength elements (Y, Zr, Hf, and HREE), low Zr/Y ratios, mobile show some variations in strongly altered footwall rocks pronounced negative Eu anomalies, and a lack of subduction- and these particular samples are identified in the text. It related anomalies such as Nb and Ta (Hart et al., 2004). This should be noted, however, that with the exception of these type of rhyolite was initially identified at Kidd Creek, anomalous altered rhyolites, most samples display no differ- Kamiskotia, and in the Matagami district (Lesher et al., 1986). ences in REE and HFSE concentrations compared to the background rhyolites and are thus considered suitable for the Matagami mining district purpose of this study. The Matagami area (Fig. 2) is an important VMS district with total past production and current reserves of more than 50 Rhyolite Classification and Petrogenesis Mt of ore from 12 deposits, including the 5-Mt Zn-Cu Perse- Four types of rhyolite are identified by Lesher et al. (1986): verance deposit presently under development (Xstrata Zinc). FI, FII, FIIIa, and FIIIb. The FIV-type rhyolites (Hart et al., The volcanic succession is folded along the open northwest- 2004) are virtually absent from Archean suites and are not plunging Galinée anticline (Sharpe, 1968), which is centered discussed. The FI rhyolites are alkaline to calc-alkaline, with on the synvolcanic Bell River intrusion. The south flank is a strongly fractionated REE patterns and strongly negative Ta low-strain domain with the volcanic sequence facing and dip- and Nb anomalies. They are considered barren to rarely fa- ping 45º south, whereas the north flank is a highly strained, vorable for hosting VMS deposits. The FII rhyolites are calc- steeply dipping domain (Piché et al., 1993). The stratigraphic alkaline to transitional (following the nomenclature of Barrett succession comprises the 2721 Ma (Mortensen et al., 1993) and MacLean, 1994), with moderately fractionated REE pat- rhyolitic Watson Lake Group at the base overlain by the terns and moderate Ta and Nb anomalies. They are consid- basaltic Wabasse Group (Beaudry and Gaucher, 1986). The ered moderately favorable for hosting VMS deposits. The Watson Group consists of a 1,000-m-thick sequence of felsic FIIIa and FIIIb rhyolites are tholeiitic and considered to lava flows representing the footwall of VMS deposits in the re- have the greatest potential for hosting VMS deposits. The gion, with the exception of the newly discovered Bracemac and FIIIa rhyolites show weakly fractionated REE patterns and McLeod deposits. All the deposits, except Bracemac and weak to nonexistent Nb and Ta anomalies. The FIIIb rhyo- McLeod, lie along a cherty and sulfide-enriched unit called the lites are high-temperature rhyolites with flat REE patterns Key tuffite at the interface of both groups (Piché et al., 1993). that lack Ta and Nb anomalies. The south and north flanks of the Watson Group were sam- Recently, Hart et al. (2004) linked the geochemical signa- pled from: (1) the underground footwall at the Bell-Allard tures of various rhyolite types to partial melting depths within mine, (2) a surface stripping of the rhyolite hosting the Per- a rift environment. The FI, FII, and FIII magmas are inter- severance deposit, (3) the location of the rhyolite for which preted as having equilibrated with garnet-bearing residua at a Mortensen et al. (1993) determined a geochron U-Pb age of depth of >30 km, with amphibole-plagioclase residua at 30 to 2721 Ma (sample R-53 in this study), and (4) rhyolites north 10 km, and with plagioclase-dominant, garnet-amphibole– of the town (Fig. 2). All four samples have flat HFSE-REE free residua at <15-km depth, respectively. patterns as previously documented by Lesher et al. (1986) Hart et al. (2004) provided a list of compositional ranges to and Barrie et al. (1993), and the pattern for the Bell-Allard discriminate between the four rhyolite types. Four of the footwall rhyolite sample is the same as the pattern for the most useful elements are Zr, Y, La, and Yb because they are other three (Fig. 7).

0361-0128/98/000/000-00 $6.00 1537 1538 GABOURY AND PEARSON 993) 002) l. (1993) regionally) 1. Characteristics of Host Volcanic Sequences in Selected VMS Districts 1. Characteristics of Host Volcanic ABLE T flows with multicentered coalescent volcanism forming a unit of regional extent, well-documented synvolcanic faults multiple isolated to locally coalescent felsic centers, dominated by lobate lava flows; well-documented synvolcanic faults, some of regional extent felsic lavas with lesser tuffaceous rocks horizon hosting all deposits by flows and lesser clastic facies; isolated district scale felsic centers along synvolcanic faults multiple volcanic horizons defining bordering rift margins cycles district scalewith poorly preserved volcanic facies and architecture (not well-delineated dominated volcanism with local domes to transitional calc-alkaline and lava flows proximal to effusive formation at the top center; multicentered coalescent volcanism to tholeiitic of the host unit Flavriandominated volcanism with local dome and lava flows proximal to effusive Gibson (1993) center; multicentered coalescent Powell volcanism sediments abundant felsic flows, large discordant felsic dike swarmdominated volcanism with local dome and lava flows proximal to effusive sediments numerous felsic horizons centers; multicentered coalescent volcanism formation at the top of the host units Hutchinson (1993) Mortensen (2002) AreaMatagami Group FIIIb style Volcanic Noranda Bimodal mafic-felsic, lobate felsic lava FIIIa Low-medium Bimodal mafic-felsic volcanism with Joutel Key tuffite: main FIIIa Homogeneous at the Normétal Low FIIIa Bimodal volcanism dominated by lobate Vesicularity Bell RiverQuévillon Rift-related bimodal volcanism dominated Low hiatus Volcanic Multiple chert FIIIa Piché et al. ( 1 LowVal-d’Or Felsic composition evolution Homogenous at the Strongly deformed bimodal sequences FII Cherty horizons Intrusion Banded iron Low to noneSelbaie Evolution from tholeiitic Clericy Reference Andesite to rhyolite, volcaniclastic- Not documented FII Evolution from transitional Valrenne Kerr and at the district scale, Variable High UnknownHunter Legault et al. (2002) Andesite to rhyolite, volcaniclastic- Mountain FII Lafrance et al. (2000) Bousquet Lacroix et a Local fine-grained FI and FII High Caldera-related bimodal sequence, Andesite to rhyodacite, volcaniclastic- Similar at the district scale Bourlamaque High Local pyrite-rich Low to none Scott et al. (2 Banded iron Similar at the district scale None Brouillan Similar at the district scale Larsen and Poularies Similar at the district scale Mueller and Mooshla Lafrance et al. (2003)

0361-0128/98/000/000-00 $6.00 1538 RHYOLITE GEOCHEMICAL SIGNATURES AND ASSOCIATION WITH VMS, ABITIBI BELT, CANADA 1539 993) Tremblay et al. (1996) Tremblay Fe-carbonate Chlorite Sericite Sericite Daigneault (1999) pyrite with abundant magnetite Chlorite (H zones); sulfide dissemination and replacement of felsic volcaniclastic rocks (Zn-rich zone 5) discordant Cu-rich stringer zones in chloritic alteration ± Chlorite Silicification levels at the district scale disseminated and stringer Zn-rich sulfide mineralization in felsic volcaniclastic rocks, massive concordant pyritic lenses of low grade (A1) Sericitepile near iron formations and sediments Silicification Hutchinson (1993) hosted in tuffaceous volcaniclastic rocks Sericite 2. Characteristics of VMS Deposits in Selected Districts ABLE T Bell-AllardPerseveranceAnsilCorbetJoutel Copper regional cherty horizon with well-defined underlying discordant stringer zonesNormetmar regional cherty horizons with well-defined underlying discordant stringer and alteration zones Zone 97 Talc East SullivanManitou-Barvue in massive to brecciated and cherty rhyolite with associated Sericite sulfide lenses Sericite Gibson (1993) Sericite Lyndhurst very weak preservation of original volcanic characteristics stringer zone or chert; mineralization occurs at various stratigraphic type pods and lenses; no recognized well-defined discordant Bousquet 1 and 2Dumagami Fe-carbonate Au-Cu Sericite Sericite no associated chert, discordant stringer zone; mineralization Brown (1999) discordant stringer zones; deposits are at the top of volcanic Chlorite Sericite occurs at various stratigraphic levels the district scale Sericite Langevin (2005) Sericite FII volcaniclastic rocks with associated sulfide stringer zones Silicification Hoy (1991) FIFI Géant Dormant Duvan Au-Ag (Cu, Zn) oriented sulfide-rich quartz veins Variably Cu-Ag Disseminated to massive bands of Chlorite Gaboury and 1 1 Abbreviations: NVZ-ext = external North Volcanic zone, NVZ-int = internal North Volcanic zone zone, NVZ-int = internal North Volcanic Abbreviations: NVZ-ext = external North Volcanic 1 AreasMatagami Group FIIIbNoranda FIIIa Main depositsNoranda Mattagami Lake FIIIa Zn-Cu-Ag Metals QuémontJoutel Massive stratiform exhalative sulfide lenses above a HorneNormétal FIIIa Mineralization style Cu-Zn-Au-Ag FIIIaQuévillon Massive stratiform exhalative sulfide lenses above Poirier FIIIa Cu-AuVal-d’Or Chlorite Normétal FIISelbaie Langlois Lavallière (1995) massive sulfide lenses replacing felsic Cigar-shaped Zn- Cu-Ag Chlorite Zn-Cu-Au-Ag FII LouvicourtHunter Folded massive sulfide lenses with bedded pyrite hosted Strongly deformed, vertically plunging, cigar-shaped Zn-Cu-Au-Ag Kerr and FIIBousquet Sericite Alteration Strongly deformed and transposed as vertical tabular sulfide lenses; Zone A1, A2, B Cu-Zn, Au-Ag FI and FII Chlorite Chlorite Mostly disseminated sulfides and associated massive replacement-Joutel Reference Cu-Zn-Au-Ag Chlorite MacLean and Hunter Laronde Chlorite Legault et al. (2002) Lacroix et al. (1 Massive sulfide Cu- and Au-rich discordant lenses (A2 B), Quévillon FI Lafrance (2003) NVZ-int FI Jenkins and Chlorite Cu-Zn-Au-Ag Au-Cu-Zn-Ag NVZ-ext Agnico-Telbel Replacement-type gold-rich sulfide lenses in volcaniclastic horizons, Concordant, exhalative massive sulfide lenses with underlying Larsen and Comtois Aluminous Au-Ag Chlorite Mercier- Au-Ag Bonneau (1992) Disseminated to massive bands of gold-bearing pyrite gold-bearing pyritic mineralization Disseminated to stringer-style Fe-carbonate Aluminous Gauthier et al. (2003) Dupré et al. (2002)

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30 100 Dunraine Val-d'Or Dunraine Val-d'Or 25 Manitou-Barvue East-Sullivan 20 East-Sullivan Manitou-Barvue 10 15 Louvicourt Louvicourt 10 spherulitic rhyolite 5 1 spherulitic rhyolite 0 100 Matagami Matagami 25 Perseverance 20 Perseverance Bell-Allard 10 15 Bell-Allard 10

5 1 0 100 Joutel Joutel 25 Eagle-Telbel Eagle-Telbel 20 10 15 Poirier Poirier 10

5 1 0 100 Comtois Quévillon Quévillon 25 Comtois CN 20 Langlois 10 15 Langlois [La/Yb] Zr/Y 10

5 1 0 100 Hunter Hunter 25 Hunter Hunter Lyndhurst 20 10 15 10

5 1 LyndHurst 100 Duvan External North Volcanic Zone Duvan 25 External North Volcanic Zone 20 Abcourt Vendome 10 15 Abcourt Lamorandière Lamorandière 10

5 1 Vendome 0 100 Legend 25 Legend FI 20 FI 10 15 FII 10 FII FIIIa FIIIa FIIIb 5 FIIIb 1 0 0 25 50 75 100 125 150 0 25 50 75 100 125 150

Y YbCN

FIG. 6. Binary classification diagrams of Zr/Y vs. Y (Lesher et al., 1986) and [La/Yb]CN vs. YbCN (Barrie et al., 1993), showing some overlapping of discrimination fields leading to uncertainty in rhyolite classification. Classification fields are from Lentz (1998) and chondrite-normalizing values (CN) from Nakamura (1974).

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30 100 Noranda Noranda 25 Delbridge Delbridge 20 Bouchard-Hébert (1100) Horne Bouchard-Hébert (1100) 10 15 Inmont 10 Inmont 5 1 Horne 0 100 Bousquet Bousquet 25 Laronde zone 20 footwall Laronde zone 20 footwall 20 10 15 10

5 1 0 100 Selbaie Selbaie 25 Selbaie, zone A1 20 Selbaie, zone A1 10 15 10

5 1 100 Normétal Normétal 25 Normétal footwall

20 CN Normétal footwall Superhyolite (silification) 10 15

Zr/Y 10 [La/Yb] 5 1 Superhyolite (silification) 0 100 Chibougamau Chibougamau 25 20 Lemoine Lemoine 10 15 10 5 1 0 Gemini-Turgeon 100 25 Gemini-Turgeon 20 15 10 10 5 1 0 100 Géant Dormant Other 25 Géant Dormant Other 20 Coniagas 15 10 Coniagas 10 5 1 0 0 25 50 75 100 125 150 0 25 50 75 100 125 150 Y YbCN

FIG. 6. (Cont.)

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1000 from the Horne and Delbridge mines are from lateral exten- R-51 Bell-Allard Matagami sions of the host rhyolite. Figure 8A shows that 20 of the samples have the characteristics of FIIIa rhyolites. Sample 100 R-92 has lower mantle-normalized element abundances but n=2 a similar HFSE-REE pattern (except for Ti), whereas REE fractionation is more pronounced in sample R-90. Samples 10 from the VMS deposits plot within the range of background rhyolite compositions (shaded area in Fig. 8B), except samples R-74 and R-82. Sample R-74 from the Horne mine R- 52 Rock / Primitive Mantle 1 shows weak to intermediate REE depletion. Intense hy- Perseverance drothermal alteration, as indicated by strong sericitization in thin section (App. 2), likely explains the depletion of REE. 0.1 MacLean and Hoy (1991) documented similar LREE mobil- Rb BaTh UNb Ta La Ce SrNd Zr Hf Sm Eu Ti Gd Y Yb ity caused by intense hydrothermal alteration of rhyolite at FIG. 7. Multielement plot normalized to primitive mantle (Sun and Mc- the Horne mine. However, the lower abundances of the Donough, 1989) for FIIIb felsic volcanic samples from the Matagami district. more immobile elements, such as Y and Yb, suggest an un- Gray envelope includes samples R-53 and R-54. The values for Rb and Sr are derlying more fractionated initial REE signature, a feature not included in the shaded pattern due to their mobility. also documented by MacLean and Hoy (1991) at the Horne mine. These findings are consistent with those of Peloquin et al. (1996). FIIIa Rhyolites The FIIIa rhyolites are also considered to be tholeiitic, Joutel high-silica, high-temperature rhyolites, but they have slightly The Joutel volcanic complex is 5 to 7 km thick and consists fractionated REE patterns with [La/Yb]CN chondrite-normal- of bimodal basalt-rhyolite successions that formed during five ized values ranging from 1.5 to 3.5, low Zr/Y ratios, moderate episodes of volcanism, which evolved from tholeiitic to tran- HFSE contents relative to the primitive mantle, variable neg- sitional to calc-alkaline (Legault et al., 2002). Phase 2 (2728 ± ative Eu anomalies, and weak, subduction-related negative 2 Ma: Mortensen et al., 1993) is a 2- to 3-km-thick sequence Nb and Ta anomalies. This type of rhyolite was first described composed mostly of dacite and rhyolite flows hosting three in the Noranda mining district (Lesler et al. 1986). Similar Zn-Cu-Ag VMS deposits, the Poirier (7 Mt), Joutel Copper rhyolites have been identified in association with VMS de- (1.7 Mt), and Explo-Zinc (1 Mt) deposits (Fig. 4A). A limited posits in the Joutel, Chibougamau, Normétal, and Quévillon number of geochemical analyses were performed on rocks mining districts. from the major VMS-hosting unit. Phase 5 is represented by a 100- to 300-m-thick and laterally extensive (20 km) tuffa- Noranda ceous felsic calc-alkaline unit that hosts the volcanogenic The Noranda mining district, located in the Blake River Eagle-Telbel Au-Ag massive to semimassive sulfide deposit Group of the Southern Volcanic zone, is well known for its (Gauthier et al., 2003). These rocks are interpreted to be FI VMS deposits. More than 33 deposits totaling 135 Mt have type (see below). been mined, including the world-class, gold-rich Horne mine We collected samples from a rhyolite unit with U-Pb zircon (54 Mt). The 2706 to 2696 Ma (Pearson and Daigneault, ages of 2728 Ma (Mortensen et al., 1993: sample R-47), near 2009) Blake River Group comprises almost half of the South- known VMS deposits, and at locations some distance from the ern Volcanic zone, where it is considered to form a thick (up VMS deposits (Fig. 4A). The felsic tuff hosting the Eagle-Tel- to 10–15 km) and laterally extensive stratovolcano covering an bel Au-Ag deposit was also sampled. Two types of rhyolites, area of about 3,000 km2 (e.g., Pearson and Daigneault, 2009). FII and FIIIa, were found (Fig. 8C). The FIIIa rhyolites are The volcanic stratigraphy consists of a bimodal sequence of spatially associated with the Poirier and Joutel VMS deposits, rhyolite and andesite flows (Dimroth et al., 1982). Five vol- whereas FII rhyolites are located at the top (eastern part) of canic cycles were defined near the synvolcanic Flavrian plu- the Joutel volcanic complex. ton (Gibson, 1990). Cycle 3 hosts a number of felsic units, some of which are separated by chert horizons that constitute Chibougamau (Lemoine) the locus for VMS deposits (Gibson and Watkinson, 1990). The Chibougamau area is known for its epigenetic Cu-Au The Blake River Group differs from most other parts of the sulfide veins (Pilote et al., 1998), rather than VMS-type de- Abitibi belt by its exceptional state of preservation, with only posits. One exception is the small (0.75 Mt) but very high- weak deformation and subgreenschist facies metamorphism, grade and gold-rich Cu-Zn-Au-Ag Lemoine deposit hosted by and it has been the focus of numerous geochemical studies the felsic Waconichi Formation (Guha et al., 1988). This 2730 (e.g., Gélinas et al., 1984; Peloquin et al., 1996). Ma (Mortensen et al., 1993) formation forms a thin, domi- Twenty-two samples were collected across the Blake River nantly calc-alkaline belt that can be traced throughout the Group (Fig. 3). The strategy was to collect samples within Chibougamau area (Fig. 4B). It is mainly tuffaceous in na- and around the footwall of VMS deposits and away from ture, with lesser porphyritic intrusions (Daigneault and Al- known VMS deposits, and to cover most accessible and ex- lard, 1990). Near the now-closed Lemoine mine, the felsic posed rhyolite horizons. Samples from the Bouchard-Hébert rocks are tholeiitic (Gobeil, 1980) and have well-defined, and Inmont mines are from the immediate footwall. Samples lobed lava flow facies indicating a proximal effusive center.

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1000 1000 A Noranda B Inmont Noranda R-90 R-73 100 100

n=20 10 10

R-77 R-92 Delbridge Rock / Primitive Mantle Rock / Primitive Mantle 1 1

R-74 R-83 Horne (alteration) Bouchard-Hébert 0.1 0.1 Rb BaTh UNb Ta La Ce SrNd Zr Hf Sm Eu Ti Gd Y Yb Rb BaTh UNb Ta La Ce SrNd Zr Hf Sm Eu Ti Gd Y Yb

1000 1000 C Joutel D Chibougamau R-110 (Lemoine) 100 100 R-47 n=2 R-48

FIIIa 10 10

R-45 FII R-113

R-44 Rock / Primitive Mantle 1 Rock / Primitive Mantle 1

0.1 0.1 Rb BaTh UNb Ta La Ce SrNd Zr Hf Sm Eu Ti Gd Y Yb Rb BaTh UNb Ta La Ce SrNd Zr Hf Sm Eu Ti Gd Y Yb

1000 1000 E Normétal F Quévillon

100 100 R-38 n=3 R-36

10 10 R-5 Langlois R-34 Rock / Primitive Mantle 1 Rock / Primitive Mantle 1 Normétal R-6 R-35

0.1 0.1 Rb BaTh UNb Ta La Ce SrNd Zr Hf Sm Eu Ti Gd Y Yb Rb BaTh UNb Ta La Ce SrNd Zr Hf Sm Eu Ti Gd Y Yb

FIG. 8. Multielement plots normalized to primitive mantle (Sun and McDonough, 1989) for FIIIa felsic volcanic samples from various districts. A. Noranda district: gray envelope includes samples R-67 to -71, R-73, R-75 to -81, R-83, R-84, R-88, R-89, R-93, R-95 to -97, and R-99 away from VMS. B. Noranda district: plots of rhyolite samples directly associated with VMS deposits. C. Joutel district: dashed-line samples are FII rhyolites. D. Chibougamau area: gray envelope includes samples R-111 and R-112. E. Normétal district: dashed-line samples are FII rhyolites. F. Quévillon area: gray envelope includes samples R-4, R-8, and R-9.

Three samples were collected around the Lemoine deposit 1984; MacLean, 1988). Sample R-110 to the north has an FII and three others from the Waconichi Formation away from signature, and samples R-109 and R-108, as previously the deposit (Fig. 4B). Samples from Lemoine have HFSE- noted, are FI tuffs (see sections on FI and FII rhyolites REE patterns typical of FIIIa rhyolites (Fig. 8D). One below). The various signatures from the extensive Waconichi strongly chloritized, silicified, and sericitized sample (R-113; Formation suggest a volcanic evolution or an unrecognized App. 2) has lower LREE (La, Ce, Nd) contents presumably complexity including various volcanic vents of specific geo- caused by intense hydrothermal alteration (Campbell et al., chemical compositions.

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Normétal is supported by the petrographic data (App. 2), and this likely The 4-km-thick Normétal volcanic complex forms a south- accounts for the variability in REE concentrations. Other east- to east-trending, steeply dipping, monoclinal volcanic samples (R-1, R-2, and R-3) represent FI rhyolites and are succession that can be traced along strike for 35 km (Fig. 4C). discussed below. It consists of basaltic andesite, dacite, and rhyolite erupted FII Rhyolites during five distinct volcanic phases with an intervening sedimentary phase (Lafrance et al., 2000; Mueller et al., 2008). The FII rhyolites have calc-alkaline to transitional affini- Two VMS deposits were mined: the 11-Mt Cu-Zn-Au-Ag ties, gently sloping REE patterns indicated by [La/Yb]CN Normétal deposit and the smaller (0.2-Mt) Zn-rich Normet- chondrite-normalized values of 1.7 to 8.8, moderate Zr/Y ra- mar deposit. The associated volcanic center consists of a tios, intermediate HFSE concentrations, variable Eu anom- mafic-dominated shield volcano of transitional affinity which alies, and moderately negative Ta and Nb anomalies. They are evolved to a felsic-dominated composite volcano with three interpreted as arc-related rhyolites (Barrie et al., 1993; Hart principal vent sites of tholeiitic affinity dated at 2728 Ma et al., 2004). Rhyolites of the FII category host VMS deposits (Mortensen et al., 1993). The VMS deposits are associated in the Val-d’Or and Selbaie mining districts, and make up the with the last stage of tholeiitic felsic volcanism. Hunter volcanic complex and the largest portions of the ex- Samples were collected along the felsic horizon, 2.5 km ternal North volcanic zone and Gemini-Turgeon areas. west (sample R-36) and 14 km east (sample R-38) of the Nor- Val-d’Or métal deposit, and from its immediate vicinity (samples R-35, R-36: Fig. 4C). Rhyolites spatially associated with VMS min- The Val-d’Or mining district (Fig. 5A) may be best known eralization are typically FIIIa (Fig. 8E), whereas samples for its gold deposits, but it is also a major VMS district with away from the deposit have fractionated HFSE-REE patterns ore production and reserves in excess of 60 Mt from six Cu- with characteristics comparable to FII-type rhyolites (see FII Zn-Ag-Au deposits (Jenkins and Brown, 1999). The VMS de- section). posits are hosted within the south-facing, steeply dipping, and laterally extensive (40 km long) Val-d’Or Formation, measur- ing 3 to 5 km thick (Pilote et al., 1999; Scott et al., 2002). This Quévillon 2704 Ma formation comprises a complex subaqueous vol- The Quévillon area hosts the Zn-Cu-Ag Langlois mine cano-sedimentary sequence dominated by volcaniclastic de- (previously known as the Grevet mine) as well as other deposits ranging from andesitic to felsic compositions, overlying posits that are currently being explored (e.g., the Orphee the synvolcanic granodioritic Bourlamaque pluton (Scott et zone) or developed (e.g., the 97 zone of Breakwater Re- al., 2002). The VMS deposits are spatially associated with nu- sources Ltd). This area has past production and reserves to- merous, small, felsic-dominated volcanic centers of limited taling more than 20 Mt of ore (Lacroix et al., 1993). The extent (Pilote et al., 1999). The volcanic rocks are mainly of Grevet-Mountain volcanic complex, dated at 2718 Ma (Davis transitional affinity and are interpreted as the products of arc et al., 2005), is bound to the north by a tonalitic intrusion and volcanism (Scott et al., 2002). The 2701 Ma Heva Formation to the south by the synvolcanic Mountain pluton (Fig. 4D). is 2 to 3 km thick, overlies the Val-d’Or Formation, and in- The volcanic setting of the deposits is poorly understood be- cludes a laterally extensive, spherulitic dacitic unit that has cause the volcanic strata lie along a major southeast-trending been traced for 40 km along the base of the Heva Formation regional discontinuity known as the Cameron fault (Lacroix et (Scott et al., 2002). The Heva Formation consists mainly of al., 1993). The favorable, steeply dipping, 2-km-thick volcanic tholeiitic mafic rocks and is interpreted as a product of fis- sequence has been traced along strike for more than 20 km sure-type volcanism (Scott et al., 2002). VMS deposits are not (Fig. 4D). Around the Langlois mine, felsic rocks alternate known in the Heva Formation, with the possible exception of with mafic bands and are transposed by penetrative schistos- the Akasaba Au-Ag deposit (Chartrand, 1989; Vovobiev, 2000). ity (Lacroix et al., 1993). Regionally, the Quévillon area con- The lithogeochemistry of felsic volcanic rocks from the Val- sists of numerous southeast- to east-trending rhyolitic bands, d’Or Formation was studied in detail by Pilote et al. (1999) some of which consist of lava flows and domes, and others of and Scott et al. (2002). They concluded, using mainly Zr/Y ra- tuffaceous rocks (Fig. 4D). In addition to VMS mineraliza- tios, that felsic volcanism evolved from tholeiitic to calc-alka- tion, the Quévillon area hosts the Comtois gold deposit—an line near the top of the Val-d’Or Formation, although most atypical, volcanogenic disseminated sulfide deposit (Dupré et units are of transitional affinity. al., 2002) associated with FI rhyolite (see below). We collected samples underground from the footwall at the A rhyolite sample taken near the Langlois mine (Fig. 4D) Louvicourt mine and at surface along the host rhyolite hori- has an FIIIa signature (sample R-4), and other FIIIa rhyolites zons at the former East Sullivan, Manitou-Barvue, and Dun- were also found in the Quévillon area (samples R-8, R-9: Fig. raine mines (Fig. 5A). Samples were collected along a north- 8F). Sample R-6, collected near the mine, has a more frac- south transect within the Val-d’Or and Heva Formations and tionated REE pattern and lower amounts of mantle-normal- included the spherulitic dacitic unit and the eastern portion ized values (Fig. 8F). This sample may represent an in- of the Sleepy volcanic center (Fig. 5A). terbedded tuffaceous horizon within the FIIIa host sequence Multielement diagrams reveal that most rhyolite samples of the Langlois mine. The sample from the footwall of the form a coherent group with typical FII characteristics (Fig. Langlois mine (R-5) has lower mantle-normalized REE 9A). The spherulitic dacite sample (R-13) has an HFSE-REE abundances relative to Ta, Zr, Hf, and Y. The high concen- pattern typical of FIIIa rhyolites (Fig. 9A). The low SiO2 con- tration of SiO2 (86 wt %) indicates strong silicification, which tent (59.03%) suggests a more andesitic composition, but the

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1000 1000 A Val-d'Or Val-d'Or R-13 B Dunraine (Spherulitic dacite) R-15 100 100 Louvicourt R-116 n=9 10 10 R-11 East-Sullivan Rock / Primitive Mantle Rock / Primitive Mantle 1 1 R-19 R-14 (Héva) (Sleepy) R-10 Manitou-Barvue 0.1 Rb BaTh UNb Ta La Ce SrNd Zr Hf Sm Eu Ti Gd Y Yb Rb BaTh UNb Ta La Ce SrNd Zr Hf Sm Eu Ti Gd Y Yb

1000 1000 C Abcourt External North Volcanic Zone D Selbaie R-22 Selbaie R-27 R-117 100 100 Lamorandière

R-50 10 10 n=9 R-118 Rock / Primitive Mantle

1 Rock / Primitive Mantle 1

R-21 Vendome 0.1 0.1 Rb BaTh UNb Ta La Ce SrNd Zr Hf Sm Eu Ti Gd Y Yb Rb BaTh UNb Ta La Ce SrNd Zr Hf Sm Eu Ti Gd Y Yb

1000 1000 E Hunter F Hunter

100 100

n=11 10 10

R-64 R-63 R-61 Lyndhurst Rock / Primitive Mantle

Rock / Primitive Mantle 1 1 R-55 Hunter 0.1 0.1 Rb BaTh UNb Ta La Ce SrNd Zr Hf Sm Eu Ti Gd Y Yb Rb BaTh UNb Ta La Ce SrNd Zr Hf Sm Eu Ti Gd Y Yb

1000 1000 G Gemini-Turgeon H Other FII R-85 (Kinojevis) R-119 (Marbridge) 100 100

n=3

10 10 R-106 Coniagas Rock / Primitive Mantle 1 Rock / Primitive Mantle 1

R-120

0.1 0.1 Rb BaTh UNb Ta La Ce SrNd Zr Hf Sm Eu Ti Gd Y Yb Rb BaTh UNb Ta La Ce SrNd Zr Hf Sm Eu Ti Gd Y Yb

FIG. 9. Multielement plot normalized to primitive mantle (Sun and McDonough, 1989) for FII felsic volcanic samples from various districts. A. Val-d’Or district: gray envelope includes samples R-10 to R-12, R-15 to -18, R-20, and R-116 away from VMS. B. Val-d’Or district: plots of rhyolite samples directly associated with VMS deposits. C. External North Volcanic zone area: gray envelope includes samples R-23, R-25, R-26, R-28 to -31, R-42, and R-43. D. Selbaie district. E. Hunter district: gray envelope includes samples R-55 to -66, excluding R-61 away from VMS. F. Hunter district: plots of rhyolite samples directly associated with VMS deposits. G. Gemini-Turgeon area: gray envelope includes samples R-121 to -123. H. Other rhyolite samples with FII signatures.

0361-0128/98/000/000-00 $6.00 1545 1546 GABOURY AND PEARSON unusual magnetite alteration observed in this sample (and in yielded more than 50 Mt of ore (Larsen and Hutchinson, the unit generally) may account for the higher Fe2O3 and 1993). Mineralization occurs as veins and veinlets that cut the lower SiO2 content of this dacitic rock (App. 1). The Sleepy local stratigraphy at a high angle and as stratiform, massive to sample (R-19) is characterized by an unusual signature, with disseminated pyrite lenses of low metal content. La and Ce depletion relative to Zr and Hf, and lower HREE Barrie et al. (1993) concluded that rhyolitic rocks at Selbaie (Gd, Yb) and Y abundances compared to other samples. This were of Group III in their classification system, which is signature may reflect hydrothermal alteration (La, Ce mobil- equivalent to FII. For this study, two samples were collected ity) of a more fractionated rhyolite (lower HREE and Y). The from the open pit of the A1 mineralized zone and another presence of biotite (App. 2) suggests a higher metamorphic from rhyolite 5 km west of the mine (Fig. 1). The multiele- grade related to the proximity of the Grenville Province (Fig. ment diagram indicates that these are of FII type with mod- 1) and also may account for the anomalous signature. erately fractionated REE and well-defined Ta-Nb anomalies The tuff sample from the Heva Formation (R-14), dated at typical of calc-alkaline rocks (Fig. 9D). 2702 Ma (Pilote et al., 1999), has a HFSE-REE pattern similar to that of the rhyolite group, but with lower overall man- Hunter mine area tle-normalized values (Fig. 9A). The low Al2O3 content and The 2728 to 2724 Ma Hunter mine group is a 6- to 7-km- LOI (App. 1) suggest that the sample is silicified, which thick volcanic sequence composed mainly of felsic lava flows would explain the lower HFSE-REE abundances. Samples and domes with lesser volcaniclastic felsic rocks, iron forma- taken near VMS deposits plot within the range of background tions, and mafic pillowed and brecciated flows (Mueller and rhyolites (shaded field, Fig. 9B), except for the Louvicourt Mortensen, 2002). This group forms a 210-km2 area of tilted, footwall sample, which has the same REE-HFSE pattern but south-facing volcanic rocks overlying the synvolcanic, gran- higher mantle-normalized element abundances. odioritic Poularies intrusion (Fig. 4C). The main feature is a prominent north-trending felsic dike swarm, 5 to 7 km wide, External North Volcanic zone interpreted as a caldera structure (Mueller and Donaldson, The external North Volcanic zone covers a large area of 1992; Mueller et al., 2008). To date, only two small Cu-Zn- about 6,000 km2, spanning the towns of Lasarre, Amos, and Ag-Au VMS deposits have been discovered, Hunter and Lyn- Senneterre from east to west. It is bound by the linear dhurst, totaling less than 2 Mt of ore (Fig. 4C). Chicobi sedimentary unit to the north and by the Porcupine- We collected 12 samples east and west of the Poularies in- Destor-Manneville fault to the south (Fig. 5B). This large trusion (Fig. 4C). Included in this group are samples from the area is dominated by mafic lavas with lesser bands of felsic Hunter (R-55) and Lyndhurst mines (R-62, R-63), both past volcanic rocks and local synvolcanic plutons (Gaboury, 2006). producers. Another sample, R-57, is from the north-trending Ages range from 2727 to 2714 Ma (Labbé, 1999), indicating felsic dike swarm. With the exception of R-61, which has lower prolonged or multiphase volcanism. The large area is reputed mantle-normalized element abundances (Fig. 9E), the sam- to be a weakly favorable area for hosting VMS deposits. Ex- ples, including those from VMS deposits (Fig. 9F), define a cept for the Abcourt deposit, only small VMS deposits have coherent compositional group with a very restricted range of been discovered, including Jay Copper, Monpras, Trinity, REE-HFSE mantle-normalized abundances typical of FII Vendome 1 and 2, and Duvan (Fig. 5B). Although some de- rhyolites. These results are consistent with those of Dostal and posits were explored underground (Amos, Duvan, Vendome), Mueller (1996) and demonstrate the very restricted chemical only the Abcourt deposit has been mined, producing about 6 evolution of rhyolitic volcanism at the scale of the complex. Mt of ore grading 3 percent Zn and 40 g/t Ag (Labbé and Couture, 1999). Gemini-Turgeon area Fourteen samples of rhyolite were collected, four near the A felsic horizon with a thickness of about 2 km has been Abcourt, Duvan Vendome, and Lamorandière VMS deposits traced for more than 15 km in a north-south direction to the (Fig. 5B). Although the sampled area is large and contains west of the synvolcanic Mistaouac pluton (Fig. 1). Rhyolites rocks of various ages, the rhyolites define a coherent group of in this area are unexposed and all known geology has been de- FII type in Figure 9C. Two represent FI-type rhyolites (R-37 duced from drill core. The following description is from un- at Duvan and R-32) and are discussed in the FI section below. published data of the IAMGOLD and Cancor mining companies and from Gobeil (2006). The volcanic units consist of Selbaie mining district a bimodal assemblage of porphyritic lava flows with few vesi- The 2725 to 2730 Ma Brouillan Volcanic Complex (Barrie cles at the base, succeeded upward by predominantly felsic and Krogh, 1996) is mainly composed of felsic to intermedi- volcaniclastic rocks and a sedimentary sequence comprised of ate calc-alkaline pyroclastic rocks forming an intracaldera se- graywacke, siltstone, mudstone, and iron formations. U-Pb quence more than 1,200 m thick (Larsen and Hutchinson, dating of zircons from the top of the volcanic pile yielded an 1993). The caldera sequence, which developed above the syn- age of 2735 Ma (Davis et al., 2005). Numerous small, massive, volcanic Brouillan tonalitic batholith, records an evolution and disseminated volcanogenic sulfide lenses, with low Cu, from subaqueous to subaerial deposition. The south-facing Zn, Au, and Ag grades, occur mainly along the top of the vol- volcanic sequence is tilted and may be traced laterally 12 km canic sequence. westward (Taner, 2000), but no significant deposit occurs Four representative samples were provided by Cambior Inc. away from the Selbaie mines. Selbaie is an atypical large-ton- (now IAMGOLD) for this study. All samples are of FII-type nage, low-grade volcanogenic Cu-Zn-Ag-Au deposit with rhyolite (Fig. 9G), although the [La/Yb]MN mantle-normal- both stratiform and epithermal characteristics that has ized values are among the highest of the FII-type rhyolites.

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One sample (R-120), however, has lower REE-HFSE man- These authors interpreted some of the dacites and rhyolites of tle-normalized abundances, probably caused by silicification the upper member as belonging to the FI category, although (84.15 wt % SiO2). they are dominated by FII-type rhyolites. Other FII occurrences Other mineralized systems associated with FI rhyolites Figure 9H shows a multielement diagram for other felsic Figure 10B shows a plot of mineralized felsic rocks with FI rocks with FII signatures. Sample R-106 is from the mined- signatures from other locations, such as the Géant Dormant out 0.7-Mt Coniagas Zn-Pb-Ag VMS deposit (Fig. 1). Sample mine in the internal North Volcanic zone (Fig. 1), the Agnico- R-119 is a felsic tuff dated at 2718 Ma (Pilote et al., 1999), Telbel mine in the Joutel district (Fig. 4A), and the Comtois collected near the Marbridge Ni-Cu komatiite-hosted deposit Au deposit in the Quévillon area (Fig. 4D). Mineralization (Fig. 1). Sample R-85 is from the 2718 Ma (Zhang et al., styles range from sulfide-rich quartz veins (Géant Dormant: 1993) Kinojevis Formation (Fig. 5). Gaboury and Daigneault, 1999) to sulfide disseminations in zones of highly altered rocks (Agnico-Telbel: Gauthier et al., FI Rhyolites 2003; Comtois: Dupré et al., 2002). All these deposits are The FI rhyolites are calc-alkaline, with strongly fraction- hosted, at least in part, by felsic dikes and rhyolitic lavas of FI ated REE patterns, [La/Yb]CN chondrite-normalized values affinity (Géant Dormant, Comtois) or within FI-type felsic ranging from 5.8 to 34, low HFSE abundances, strong nega- tuffs (Agnico-Telbel). The Cu-Ag Duvan mine is another ex- tive Ta and Nb anomalies, and variable Eu anomalies. They ample of atypical volcanogenic-related mineralization within are interpreted as arc-related magmatic products (Barrie et FI felsic tuff. Mineralization occurs as concordant massive to al., 1993). These rhyolites occur in the Bousquet mining dis- disseminated pyrite and chalcopyrite associated with abun- trict and are spatially associated with other gold-rich vol- dant magnetite (Tremblay et al., 1996). canogenic deposits, namely the Géant Dormant (Sleeping Giant), Eagle-Telbel, and Comtois deposits, and the atypical Other FI occurrences Duvan Cu-Ag deposit. Numerous occurrences of tuffaceous rhyolite scattered across the Abitibi belt have FI signatures (Fig. 10C). They Bousquet mining district commonly occur as extensive regional units. Samples R-108 The Bousquet mining district is a world-class gold producer and R-109 are from the 2730 Ma (Mortensen et al., 1993) that includes Laronde—the world’s largest polymetallic gold- Waconichi Formation in the Chibougamau area (Fig. 4B), rich VMS deposit (Mercier-Langevin et al., 2007a)—and sample R-30 is from the Quévillon area (Fig. 4D), and two pyritic gold-bearing replacement-type deposits such as Bous- other samples (R-32, R-41) are from the North Volcanic zone quet 1 and Dumagami-Bousquet 2 (Fig. 1). Total production (Fig. 5B). These units may be products of explosive eruption and reserves amount to more than 100 Mt of ore. Recent re- of felsic calc-alkaline magma with a high volatile content (e.g., gional studies have traced the 1.5- to 3-km-thick, south-fac- Gibson et al., 1999). Other rhyolites from the Comtois (R-1) ing, vertically tilted, strongly foliated, and east-trending vol- and Géant Dormant (R-115) deposits and the rhyolite (R- canic Bousquet Formation for more than 20 km along strike 107) dated at 2791 Ma (Bandayera et al., 2004) are plotted in (Lafrance et al., 2003). This 2696 to 2698 Ma Formation, Figure 10D. The 2791 Ma rhyolite is unusually old relative to which is part of the Blake River Group, consists of volumi- the 2735 to 2700 Ma ages for felsic volcanism in the Abitibi nous dacitic to rhyolitic vesicular volcaniclastic rocks with belt. local felsic effusive lava flows and domes to which the VMS deposits are spatially associated (Lafrance et al., 2003). This Discussion sequence overlies the Mooshla synvolcanic tonalite-granodi- The results of this study reveal that in small volcanic cen- orite pluton that hosts two synvolcanic, sulfide-rich vein-type ters composed of various rhyolite types, such as Joutel, Chi- gold deposits, Doyon and Mouska, both active producers. bougamau (Lemoine), Normétal, and Quévillon (Fig. 8), The Bousquet Formation is divided into lower and upper vol- VMS deposits are specifically associated with FIIIa rhyolites. canic members. The lower member includes tholeiitic to This demonstrates the usefulness of the approach for dis- transitional, mafic to felsic volcanic rocks, whereas the upper criminating the most favorable sectors or horizons within member is dominated by transitional to calc-alkaline, inter- small felsic volcanic centers. The much larger Noranda dis- mediate to felsic rocks (Lafrance et al., 2003; Mercier- trict is also characterized by rhyolites with FIIIa signatures, Langevin et al., 2007a). but the application of rhyolite chemistry in the exploration of Sampling of the upper member was performed along a this camp is less useful because FIIIa rhyolites are distributed north-south section along Preissac Road, using the unit over such a vast area (more than 3,000 km2). nomenclature of Lafrance et al. (2003). One sample (R-105) Regardless of rhyolite classification, there does not appear from the underground Laronde mine rhyolite (unit 5.3, which to be any link between ore tonnage and REE fractionation. hosts the 20-N zone) was kindly provided by P. Mercier- VMS deposits are hosted by rhyolites with REE patterns Langevin (then of Agnico-Eagle) for this study. Overall, the ranging from low [La/Yb]MN mantle-normalized ratios or flat samples display strong REE fractionation, the Laronde foot- patterns (Matagami) to elevated [La/Yb]MN ratios or fraction- wall sample having the strongest, and very pronounced nega- ated patterns (Bousquet-Laronde; Fig. 11). Furthermore, tive Ta and Nb anomalies typical of FI rhyolites (Fig. 10A). moderately fractionated FII rhyolites (Selbaie, Hunter, Val- An exhaustive lithogeochemical study on the Laronde mine d’Or, and External North Volcanic zone) are variably mineral- was recently conducted by Mercier-Langevin et al. (2007b). ized, as was previously recognized by Lesher et al. (1986).

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1000 1000 A Bousquet B R-105 Laronde FI-mineralized

100 100

n=5 10 10 R-46 Agnico- Telbel Rock / Primitive Mantle 1 Rock / Primitive Mantle 1 R-114 Géant Dormant LaRonde (R-105) R-2 Comtois R-37 Duvan 0.1 0.1 Rb BaTh UNb Ta La Ce SrNd Zr Hf Sm Eu Ti Gd Y Yb Rb BaTh UNb Ta La Ce SrNd Zr Hf Sm Eu Ti Gd Y Yb

1000 1000 C FI-Tuff D Other FI

R-32 100 100 R-41 R-1

R-115

10 < 10 R-108

R-3 Rock / Primitive Mantle Rock / Primitive Mantle 1 1

R-109 R-107 0.1 0.1 Rb BaTh UNb Ta La Ce SrNd Zr Hf Sm Eu Ti Gd Y Yb Rb BaTh UNb Ta La Ce SrNd Zr Hf Sm Eu Ti Gd Y Yb

FIG. 10. Multielement plots normalized to primitive mantle (Sun and McDonough, 1989) for FI felsic volcanic samples. A. Samples from the Bousquet district. Gray envelope includes samples R-100 to -104. B. Mineralized samples from various locations. C. Samples from tuffaceous rhyolite at various locations. D. Other rhyolite samples with FI signatures.

1000 Matagami: 50 Mt Quévillon: 20 Mt Noranda: 132 Mt Val-d'Or: 60 Mt

100

1 n=4 n=3 n=24 n=13 0.1 Selbaie: 50 Mt External North Volcanic Hunter: 2 Mt Bousquet: > 100 Mt Zone : 10 Mt

Rock / Primitive Mantle 100

n=3 n=15 n=14 n=7 0.1 Th NbLa Sr ZrSm Ti Y Th NbLa Sr ZrSm Ti Y Th NbLa Sr ZrSm Ti Y Th NbLa Sr ZrSm Ti Y U Ta CeNd Hf EuGd Yb U Ta CeNd Hf EuGd Yb U Ta CeNd Hf EuGd Yb U Ta CeNd Hf EuGd Yb

FIG. 11. Summary multielement plots normalized to primitive mantle (Sun and McDonough, 1989) for felsic volcanic rocks from mining districts, showing ore tonnages (production and reserve) in millions of metric tons (Mt).

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Based on our dataset, it is not possible to attribute a greater The FI rhyolites, which are at the other end of the frac- VMS potential to specific rhyolite types based only on geo- tionation spectrum, are poorly represented in the Abitibi belt. chemical signatures. Volcanic rocks in the Bousquet district form a continuous compositional range from andesite to rhyodacite in volcani- Rhyolite petrogenesis and hydrothermal activity clastic-dominated sequences (Table 1). Vesicularity is intense The formation of VMS deposits is the product of convective and quiescent periods (cherty horizons) have not yet been hydrothermal activity induced by heat flux from an underly- identified (Lafrance et al., 2003; Mercier-Langevin et al., ing magma chamber (Franklin et al., 1981, 2005). Funda- 2007a). Other known FI rhyolites in the Superior province, mental factors that enable hydrothermal convection to occur such as at Obonga Lake (Tomlinson et al., 2002), in the include the structural permeability of the upper portion of Michipicoten belt (Sage et al., 1996), Meen-Dempster the crust and the porosity of the volcanic pile (e.g., Morton (Hollings et al., 2000), and in the North Caribou terrane and Franklin, 1987; Barrie and Hannington, 1999; Gibson et (Hollings and Kerrich, 1999), are also dominantly tuffaceous al., 1999; Davidson et al., 2004). Time is another key factor but are not mineralized. that is fundamental in maintaining the stability of the convec- The FII rhyolites, characterized by a moderate fractiona- tive system and in accumulating sulfides on or near the sea tion pattern, are variably dominated by either volcaniclastic or floor (e.g., Barrie and Hannington, 1999; Franklin et al., coherent flow facies. The Val-d’Or and Selbaie districts are 2005, and references therein). characterized by a continuous volcanic compositional range Rhyolites are the result of petrogenetic processes involving from andesite to rhyolite with large volumes of highly vesicu- partial melting, crystallization, fractionation, and assimilation lar volcaniclastic rocks (Table 1). On the other hand, the (e.g., Hart et al., 2004). The depths at which these processes Hunter district and the volcanic centers of the External North occur, the magma ascent rates, and the residence times in the Volcanic zone are dominated by flow and lava domes of low crust also influence rhyolite chemistry. The same factors in- vesicularity and bimodal composition (Table 1). fluence hydrothermal convection and VMS formation (e.g., in terms of thermal requirements). However, this study illus- Fractionation pattern and style of mineralization trates that different types of rhyolites are not necessarily more The VMS deposits associated with FIII rhyolites are typical favorable than others to host VMS deposits. This may be be- “Noranda-type” deposits forming high-grade but relatively cause VMS formation is mainly related to processes that low-tonnage deposits (1–4 Mt), with the largest examples occur at shallow levels in the crust (<5 km: see Franklin et al., being Mattagami Lake (25.6 Mt) and Quémont (13.8 Mt). A 2005) rather than at great depth (<30 km: see Hart et al., major exception to this trend is the giant 240-Mt Kidd Creek 2004) where the rhyolite magma is generated. VMS deposit in Ontario, which is also genetically related to High-temperature FIII-type rhyolites (e.g., Noranda and FIIIb rhyolites (Lesher et al., 1986). Kidd Creek) have low amounts of phenocrysts and microphe- The gold-rich Horne deposit, the largest VMS in the No- nocrysts (Hart et al., 2004). This generally aphyric texture is randa district, features replacement-style mineralization in thought to reflect a rift setting where magma is rapidly trans- strongly sericitized felsic volcaniclastic rocks (Table 2). Some ferred from the melt zone to the surface (Lentz, 1998; Hart of the host rhyolites are FII type with calc-alkaline affinity, as et al., 2004) and quartz and feldspar do not accumulate in previously documented by MacLean and Hoy (1991). The subvolcanic magma chambers. However, our data suggest presence of more than one rhyolite type may be explained by that most VMS districts in this study, except Normétal and the fact that the Horne mine is part of a different block than Val-d’Or, are dominated by quartz- and/or feldspar-phyric fel- the felsic rocks of the central Noranda district (Kerr and Gib- sic lava flows or volcaniclastic rocks. The apparent inconsis- son, 1993). The Horne block is interpreted as a parallel rift tency between phenocryst content, rhyolite type, and VMS environment to the central cauldron (Kerr and Gibson, 1993) favorability is difficult to explain with a model that involves a or the top of the proposed New Senator caldera (Pearson and genetic link between deep petrogenetic processes for rhyolite Daigneault, 2009). generation and VMS formation. The most likely explanation Deposits associated with FI rhyolites are commonly atypi- is the presence of subvolcanic magma chambers above zones cal Cu-Au–rich deposits, ranging in style from sulfide-rich of magma generation, which would account for phenocryst quartz veins to disseminations to sulfide replacements of per- formation. Such subvolcanic intrusions are well documented meable rocks (Table 2). Striking examples are the VMS de- for most VMS districts in the Abitibi belt (Galley, 2003; posits in the Bousquet area. Mineralization occurs mainly as Gaboury, 2006). massive sulfide replacements within highly permeable and highly vesicular volcaniclastic rocks. Well-defined Cu-rich Fractionation pattern and style of volcanism stringer zones in the chlorite-altered feeder pipes of strati- The FIII rhyolites are well known as volatile-poor rocks oc- form lenses are absent in many cases (Table 2). Aluminous al- curring in bimodal, basalt-rhyolite sequences (Lentz, 1998). teration in the Cu-Au deposits at Dumagami, Bousquet 1 and These sequences, as exemplified by the Noranda and 2, and Laronde (zone 20) has been compared to high-sulfida- Matagami districts, are dominated by isolated to coalescent tion alteration in epithermal Cu-Au deposits (Sillitoe et al., volcanic centers forming domes (e.g., cycle 3 of Noranda) and 1996; Hannington et al., 1999b; Dubé et al., 2007). extensive flows (e.g., Watson Group of Matagami) with rare Mineralization associated with FII rhyolites is quite vari- volcaniclastic horizons mainly of epiclastic origin (Table 1). able (Table 2). In the Selbaie area, mineralization occurs as Extensive cherty horizons or silicified tuffs indicating periods copper-rich stringers and zinc-rich disseminations with poorly of volcanic quiescence are also typical of these sequences. developed stratiform mineralization (Table 2). In the Val-d’Or

0361-0128/98/000/000-00 $6.00 1549 1550 GABOURY AND PEARSON district, VMS deposits form large accumulations of dissemi- The favorability of FIII rhyolites is commonly explained by nated sulfides with low Cu and Zn grades replacing perme- the rapid transfer of low-volatile magma to the surface, thus able volcaniclastic horizons (except for the Louvicourt de- inducing high heat flow (cf. Lentz, 1998). The extensional set- posit) and lack well-defined underlying chloritic and Cu-rich ting, manifested by well-defined calderas, rifts, or grabens fa- zones (Table 2). In the Hunter district, mineralization hosted vors magma ascent and provides enhanced structural perme- by FII rhyolite is more similar to that associated with FIII ability for the convective hydrothermal system (e.g., Hart et rhyolite, in that small massive sulfide lenses of exhalative ori- al., 2004). The bimodal sequences, with multicycle volcanism gin accumulated at the top of the volcanic sequence along and hiatuses in volcanic activity, provide enough time to ac- with banded iron formations during the waning stage of sub- cumulate significant quantities of sulfides on the sea floor, marine volcanic activity (Table 2). Well-developed discordant mainly by exhalative processes, with VMS deposits forming sulfide stringers and chlorite alteration zones are also associ- near-volcanic rhyolite lava flow centers and domes (Gibson et ated with these deposits (Table 2). al., 1999). The VMS deposits associated with FI rhyolites are com- Summary and Conclusions monly replacements of highly permeable volcaniclastic rocks. Rhyolites cover a complete spectrum of geochemical frac- These rocks are the main products of explosive eruption of tionation patterns that can be conveniently subdivided into calc-alkaline magma with a high volatile content. In such informal FI-FII-FIII types. Furthermore, there is a complete cases of replacement-style mineralization, a hiatus in volcanic spectrum of VMS deposits in terms of volcanic facies associa- activity is not necessary to form a VMS deposit by sea-floor tions, base metal and gold contents, and alteration character- exhalation, and these sequences commonly lack evidence of istics (Table 3). It emerges that there are no objectively bar- long pauses in volcanic activity. In addition to forming abun- ren rhyolite types, and that beyond any petrogenetic dant volcaniclastic rocks, the explosive volcanism may pro- considerations involving the depth of felsic magma genera- mote enhanced structural permeability and contribute to tion, other factors must be taken into account to explain the large variations in bathymetry and confining pressure. De- full spectrum of variations between geochemical signatures posits typically occur close to isolated volcanic vents, as ex- and volcanogenic hydrothermal activity. emplified by the Bousquet district (Lafrance et al, 2003) and Possible factors are temperature, viscosity, and volatile con- the Géant Dormant gold deposit (Gaboury and Daigneault, tent, all of which have a profound influence on the volcanic 1999). The high gold content of many of these deposits has products and consequently on the volcanic architecture been interpreted as a consequence of a magmatic gold con- (Touret, 1999). Submarine volcanic architecture in turn re- tribution (Hannington et al., 1999b, 2005; Gaboury et al., flects the growth history, topography, effusive rate, bathyme- 2000; Mercier-Langevin et al., 2007b). It is well known that try, and possible eruptive interference from other proximal magmas similar in composition to FI-type rhyolites emplaced volcanic centers (Cas, 1992; Gibson et al., 1999). in a subaerial setting are favorable hosts for Cu-Au porphyry deposits (Reich et al., 2003; Mungall, 2004). It is noteworthy that FII sequences represent about 70 per- TABLE 3. Style of Volcanism and Mineralization Associated with Different Rhyolite Types cent of rhyolites by surface area in the Abitibi (Pearson, 2005). For these moderately fractionated rhyolites, the trace Group Volcanism style Mineralization style element approach has some limitations when assessing relative prospectivity. Mineralized FII rhyolites, such as those of FIII Bimodal Exhalative stratiform lenses Val-d’Or, Selbaie, and Bousquet, have volcanic facies and Low volatile content High grade, low tonnage Domes and flows Cu-Zn ± Ag ± Au mineralizing characteristics that are more similar to FI se- Low vesicularity index Discrete alteration pipe and quences, whereas those of the Hunter, Gemini-Turgeon, and Few volcaniclastic rocks Cu-rich stringer zone External North Volcanic zone districts share characteristics Exhalite-chert: common Examples: Quémont with the FIIIa sequences, such as those of Noranda (Tables 3, Mattagami Lake Ansil 4). The FII sequences appear to be the most favorable hosts for VMS deposits when the volcanic style is dominated by FII Similar to FIII-type Similar to “FIII-type” highly vesicular volcaniclastic rocks derived by continuous Examples: Lyndhurst fractionation from andesite to rhyolite. Conversely, those Hunter mine sharing characteristics of the FIII rhyolites—such as low Gemini vesicularity and bimodal dome- and lava flow-dominated se- Similar to FI-type Similar to “FI-type” quences in the Hunter, External North Volcanic zone and Examples: Selbaie Gemini-Turgeon districts—host “Noranda-type” deposits but Manitou-Barvue appear less prospective. FI Continuum andesite to rhyolite Atypical Cu-Au The FI rhyolites appear highly favorable for VMS deposits Abundance of volcaniclastic veins, disseminations and but host styles of mineralization that differ from the classic rocks replacement of permeable strata-bound VMS lenses, including gold-bearing, sulfide-rich High vesicularity volcaniclastic rocks quartz veins, disseminations, and replacement-type sulfide Exhalite-chert: absent Diffuse alteration lenses. A similar conclusion was reached by Mercier- Examples: Laronde Bousquet 1 and 2 Langevin et al. (2007b) based on their study of felsic rocks at Comtois the Laronde mine. Some FII rhyolites have a high potential to host VMS, such as Val-d’Or and Selbaie, whereas others,

0361-0128/98/000/000-00 $6.00 1550 RHYOLITE GEOCHEMICAL SIGNATURES AND ASSOCIATION WITH VMS, ABITIBI BELT, CANADA 1551 such as in the Hunter, External North Volcanic zone, and Barrie, C.T., Cathles, L.M., and Erendi, A., 1999, Finite element heat and Gemini-Turgeon districts, appear only weakly mineralized. fluid-flow computer simulations of a deep ultramafic sill model for the giant Kidd Creek volcanic-associated massive sulfide deposit, Abitibi sub- The FII sequences host either Noranda-type VMS associated province, Canada: ECONOMIC GEOLOGY MONOGRAPH 10, p. 529–540. with flow-dome complexes or disseminated sulfide replace- Beaudry, C., and Gaucher, E., 1986, Cartographie géologique dans la region ments and veins in dominantly volcaniclastic rocks. Volcani- de Matagami: Ministère de l’Energie et des Ressources Report MB 86-32. clastic rocks appear to be the most favorable host for large- Bleeker, W., Parris, R.R., and Sager-Kinsman, A., 1999, High-precision U-Pb tonnage deposits and provide an important guide for geochronology of the Late Archean Kidd Creek deposit and Kidd volcanic complex: ECONOMIC GEOLOGY MONOGRAPH 10, p. 71–122. exploration. The dominance of highly prospective FIII rhyo- Bonneau, R-M., 1992, Minéralisation cuprifère dans le groupe archéen de lites in very large felsic centers, such as Noranda and Hunter Mine; exemple de l’indice Richard et de la mine Lyndhurst, région Matagami, is a less useful exploration guide at the target scale. de Rouyn-Noranda, Abitibi, Québec: Unpublished M.Sc. thesis, Ste-Foy, However, in small felsic centers that show an evolution from Quebec, Université Laval, 88 p. Campbell, I.H., Coad, P., Franklin, J.M., Gorton, M.P., Scott, S.D., Sowa, J., FIIIa to FII to FI, deposits are directly associated with FIIIa and Thurston, P.C., 1982, Rare earth elements in volcanic rocks associated rhyolites, and their presence is thus a much more useful tool with Cu-Zn massive sulfide mineralization. A preliminary report: Canadian for targeting horizons with the greatest potential. Journal of Earth Sciences, v. 19, p. 619–623. Campbell, I.H., Lesher, C.M., Coad, P., Franklin, J.M., Gorton, J., and Acknowledgments Thurston, P.C., 1984, Rare-earth element mobility in alteration pipes below massive sulfide deposits: Chemical Geology, v. 45, p. 181–202. G. Bouchard of Xstrata Zinc (previously Noranda-Falcon- Card, K.D., 1990, A review of the Superior province of the Canadian Shield, bridge) was instrumental to this study by suggesting it and a product of Archean accretion: Precambrian Research, v. 48, p. 99–156. providing technical support. P-L. Lajoie of the Université Cas, R.A.F., 1992, Submarine volcanism: Eruption styles, products, and rel- du Québec à Chicoutimi (UQAC) provided dedicated field evance to understanding the host-rock succession to volcanic-hosted massive sulfide deposits: ECONOMIC GEOLOGY, v. 87, p. 511–541. assistance during the 2003 sampling program and sample Chartrand, F., 1989, The Akasaba gold deposit: Geological Association of preparations. J. Lavoie (UQAC) performed the petrographic Canada-Mineralogical Association of Canada, Field Trip A7 Guidebook, p. study. This project benefited from numerous comments by 1–13. representatives on the CONSOREM Research Committee. Chartrand, F., and Cattalani, S., 1990, Massive sulfide deposits in North- We also acknowledge CONSOREM for permission to pub- western Quebec: Canadian Institute of Mines and Metallurgy Special Vol- ume 43, p. 77–91. lish this work. T. Gomwe of UQAC and V. Bodycomb of Vee Chown, E.H., Daigneault, R., Mueller, W., and Mortensen, J.K., 1992, Tec- Geoservices edited the English, and R. Daigneault of tonic evolution of the North Volcanic zone, Abitibi belt, Quebec: Canadian UQAC informally reviewed a preliminary version of the Journal of Earth Sciences, v. 29, p. 2211–2225. manuscript. The paper was substantially improved following Daigneault, R., and Allard, G.O., 1990, Le Complexe du Lac Doré et son en- reviews by T. Hart and P. Hollings. We are also grateful to vironnement géologique (Région de Chibougamau, sous-province de l’Abitibi): Ministère de l’énergie et des Ressources du Québec Report MM M. Hannington for his constructive comments and efficient 89-03, 275 p. editorial work. 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0361-0128/98/000/000-00 $6.00 1553 1554 GABOURY AND PEARSON APPENDIX 1 Analytical Results for Felsic Volcanic Rocks of the Abitibi Belt Analytical Results for Felsic Volcanic 0.232.37 0.15 1.04 0.28 3.40.11 0.19 0.07 2.07 0.16 0.07 3.65 0.22 0.03 1.66 0.52 0.02 6.02 0.23 0.05 0.7 0.09 0.07 3.08 0.4 0.04 2.63 1.1 0.02 1.86 0.91 0.2 9.8 0.57 0.23 2.85 0.76 0.2 6.2 0.47 0.13 4.42 0.45 0.34 2.45 1.07 0.1 1.78 0.27 0.25 15.58 14.67 15.81 8.44 6.45 15.14 12.03 11.98 6.56 15.41 14.54 12.61 8.9 14.41 11.23 13.98 14.38 3 (wt %) 69.39 72.47 67.43 83.37 85.95 71.21 69.12 78.17 85.17 67.69 67.78 59.03 79.57 65.25 68.14 70.86 75.8 3 5 2 2 O 6.29 4.11 4.08 3.55 0.28 4.96 4.25 5.38 0.15 2.33 5.02 4.64 3.49 0.31 2.95 5.82 0.27 O O 2 2 O 1.52 1.81 1.42 0.66 1.24 2.02 1.47 1.42 1.5 0.57 1.37 0.11 0.02 2.32 0.88 0.41 4.35 O 2 2 2 CaO Na 1.39 3.29 3.43 0.5 0.03 1.85 2.48 0.51 9.08 3.95 6.57 2.35 0.52 4.26 2.85 0.33 Al NumberZoneUTMEUTMN R-1SiO 340297 R-2 5444424 18TiO 340432Fe 5444249MgO 0.52 5432783 358939 R-3MnO 0.07 18 5455516K 379501 5456121 0.4 R-4 377993 0.01 5456351 18 5454944 377836LOI 0.24 5446415 0.08 R-5 99.08Total 362103 5329342 18 5327748 360550Ce (ppm) 0.12 99.83 0.05 R-6Cs 5328321 305875Dy 5326227 100.49 1.63 0.44Er 18 32.4 297896 5324932 0.02 R-8Eu 5327946 99.79 308145Gd 1.8 0.34 5330413Hf 48.06 0.03 309450 18 R-9 5330994Ho 99.66 0.987 1.347La 5328363 309026 11.03 0.72 4.25Lu 0.1 0.863 99.86 1.348 R-10 308708 0.609Nb 18 1.439 48.65 1.669Nd 0.847 310044 0.82 99.74 1.582Pr 4.062 3.8 0.02 R-11 0.821 0.922 0.281 37.13Rb 34.1 310158 1.983 18 15.86 0.526Sm 99.32 0.188 1.43 5.986 0.415 312853 R-12 9.46Sr 0.153 0.282 3.7 12.51 1.148 0.78 35.47 3.4 23.54Ta 6.146 99.53 14.99 0.458 1.35 2.417Tb 18 2.39 0.149 R-13 0.181 99.57 8.704 9.629Th 2.15 45.29 6.212 2.2 99.28 5.42 21.69 0.988Tm 3.6 0.999 0.05 6.915 0.073 2.35 2.012 2.95 R-14 98.33U 0.932 5.921 431.7 18.67 18 0.544 2.67Y 7.89 99.63 20.09 1.128 5.56 0.375 3.466 7.8 18.188Yb 0.928 0.29 1.975 0.05 43.57 1.7 R-15 1.141 3.14 12.28 327.8 0.91 35.79 0.21 101.14Zr 0.232 0.555 0.8 8.26 12.118 9.26 31.54 2.825 18Be 1.499 0.918 15.849 0.181 49.41 0.134 100.05 0.3 532614132134437252431888 Co 2.07 R-16 338.6 0.12 8.4 50.82 18.2 0.263 1.22 6.619 2.18 2.12 0.656 13.188Cu 3.669 15.47 2.139 12.52 0.475 5.01 6.23 0.081 100.71 2.07 3.983 51.72Li 0.13 18 37.4 R-17 0.166 2.425 2.63 43.5 0.05 12.932 17.2Ni 0.93 0.197 0.2 8.26 0.93 2.9 154.3 1.18 4.425 100.47 1.129 0.572 59.18 43.01 1.814Sc 6.02 4.548 2.384 45.84 2.67 0.074V 9.06 1.539 0.7 R-18 2.748 5.856 25.46 1.651 5.94 62 0.1 143 6.256 0.92 99.77 18 1.198Zn 4.31 0.34 3.51 13 6.3 2.1 51.94 41.37 0.872 56.66 1.12 5.709 47.32 0.778 23.7Ba 0.923 1.212 1.07 3.888 6.993 21.67 17.446 0.21 100.39 5.24Cd 1.521 0.56 0.43 207.6 0.49 17.84 0.397 54.48 10.37 6.877 1.23 0.15 0.499 5.03 0.89 35.2Cr 5.24 77.1 1.11 6.96 11.603 18 2.77 54.98 0.945 10.7 0.164 7.151 12.4Ga 18.64 3.039 58.94 2.8 4.84 0.029 2.813 15.044 109.31 19.26 0.474Mo 25.29 0.6 13.96 1.61 0.693 93.5 301.3 6.11 4.76 43.77 23.56 0.03 1.877 0.96 1.278 27.48 22.2 0.079 0.24Pb 3.8 2.801 368.24 7.262 1.25 16.39 3.86 39 4.1 18 1.371 1.95 0.543 3.303 4.28Sn 0.9 54.74 20.76 0.556 30.4 1.9 12.22 0.357 308.5 15.58 10.05 2.26 0.054 2.047 3.83Tl 0.21 698.23 60.98 64.4 1.836 6.18 0.74 2.015 6.64 0.02 4.21 3.263 46 17.7 2.08W 0.73 0.19 4.7 4.434 0.405 2.5 1.092 5.523 19.87 16.56 1.783 2.14 2.4 1.244 297.04 6.8 31.84 1 5.76 51.12 0.052 2.94 18 40.16 0.959 98.1 6.02 2.07 0.62 5.4 5.31 27.82 5 0.626 0.22 7.637 13.4 0.53 1.29 5.1 5.531 1.42 0.176 0.897 4.294 115.16 0.48 25.55 9.85 0.287 25.94 37.41 0.808 8.5 9.44 37.21 3.8 83.77 0.035 0.382 475.1 4.04 6.9 3.37 0.719 3.871 8.1 163.7 12.06 7.6 0.32 0.8 0.16 3 0.17 402.28 5.851 18 4.185 0.92 2.1 1.283 6.954 1.12 35.6 15.82 0.307 0.44 20.9 62.47 136 1.39 0.513 0.18 5 21.97 14.18 0.108 10.1 0.434 402.1 0.957 8.654 425.84 6.1 42.39 3.53 3.517 98.5 6.15 1.451 7.3 7.018 4.58 0.08 9.1 101.48 19.49 9.17 0.467 1.82 1.048 34.97 0.901 2.51 10.98 33.44 0.6 1.1 1.96 0.113 0.21 309.43 9.11 0.571 126.5 2.05 1.111 12.8 5.947 10.34 17.81 179.4 11.7 1.54 3.14 17.49 27.03 2.56 0.587 2.645 11.56 1.2 30.46 1.92 0.87 312.31 5.34 24.08 16.96 0.88 0.031 4.06 3.5 23.07 1.746 262.2 1.177 0.42 72.54 0.66 1.4 11.48 2.7 4.4 346.45 46.4 19.89 19.47 0.556 0.503 1.54 3.17 27.22 3.04 2.6 15.08 37.88 3.37 0.122 0.28 0.416 68.87 2.9 0.276 302.4 0.33 5.15 1.06 39.11 96.01 1.8 227.2 6.1 0.84 35.44 26.11 10.91 6.7 0.72 13.72 27.3 28.21 3.2 3.16 0.099 0.416 8.3 3.77 0.303 318 7.15 10.34 0.09 6.1 62.76 2.3 0.92 133.7 5.44 318.3 4.19 31.31 24.1 0.35 11.94 0.8 5.1 0.708 0.046 0.707 72.6 11.6 0.446 2.9 1.79 103.5 1.9 4.04 9.06 0.07 130.7 6.4 145.9 8.54 0.83 61.08 5.34 33.14 4.71 2.4 12.64 17.04 0.54 0.965 0.124 0.507 174.9 0.525 0.86 7.7 118.93 14.91 1.39 232.2 19.52 41.36 1.83 7.1 8.34 0.63 10.2 0.55 4.48 11.92 3.31 3.68 20.61 7.46 22.5 1.015 0.072 0.95 0.44 0.518 60 88.77 0.54 188 13.66 58.48 8.34 0.85 6.3 328 2.04 7.1 0.03 24.36 10.26 13.45 8.5 0.25 3.39 0.095 8 2.54 27.9 1.323 0.67 56.68 46.45 0.5 3.42 290.5 5.42 3.08 60.2 3.01 17.78 45.59 136.1 0.15 0.046 12.1 1.13 2.4 192 49.44 3.6 0.58 73.02 230.2 14.01 41.33 145.48 2.13 0.74 48.28 0.79 0.08 3.63 113.41 0.01 18.2 0.39 2.16 373.75 69.8 3.59 1.8 14.58 86.95 8.39 1.06 0.48 0.058 3.49 14.5 0.92 0.87 23.93 15.18 11.99 22.51 0.054 1.4 8.87 0.5 0.72 1.2 9.6 16.91 22.05 1.98 0.053 0.1 2.41 0.69 6.5 1.95 12.5 9.78 1.81 0.05 0.56 0.22 1.8 13.2 1.69 0.03 0.18 0.35 1.4 22.2 2.02 0.27 1.07 0.88 5.8 1.09 P

0361-0128/98/000/000-00 $6.00 1554 RHYOLITE GEOCHEMICAL SIGNATURES AND ASSOCIATION WITH VMS, ABITIBI BELT, CANADA 1555 (Cont.) APPENDIX 1 0.665.96 0.6 4.56 0.11 5.560.12 0.37 3.49 0.3 0.7 8.31 0.01 0.2 0.23 0.12 4.38 0.32 0.14 2.8 0.17 0.03 0.86 9.15 0.07 0.79 2.84 0.03 0.54 7.14 0.14 0.76 5.59 0.18 0.25 1.85 0.11 0.16 0.97 0.14 0.05 0.02 0.08 0.56 2.96 0.02 0.35 3.96 0.02 0.11 0.12 12.21 14.24 6.87 12.33 16.36 12.44 13.55 12.56 16.19 15.57 15.64 13.98 17.16 10.99 9.74 13.56 17.5 3 (wt %) 75.41 69.33 81.76 69.52 55.13 77.61 70.65 74.72 54.59 65.8 60.24 62.11 62.88 83.64 88.82 75.39 64.65 3 5 2 2 O 0.43 0.1 1.14 2.72 4.05 2.05 5.41 1.86 4.58 2.27 2.43 4.25 0.77 0.05 0.24 4.87 O O 2 2 O 1.39 2.94 2.2 2.17 1.61 1.95 2.36 1.22 0.72 2.65 1.32 1.75 4.14 2.18 0.53 3.01 1.82 O 2 2 2 CaO Na 0.15 0.44 0.02 3.62 5.79 1.23 2.41 0.7 8.71 5.6 7.56 4.54 3.77 0.03 0.03 0.18 2.68 Al NumberZoneUTMEUTMN R-19SiO R-20 323164 18 5326912TiO 311601 5330063Fe R-21MgO 1.87 5367105 303148MnO 0.12 18 5377870 R-22 302480K 5381228 4.15 718033 5387455 0.03 R-23 18 5387447 716415 0.22 5399513LOI 716415 R-25 100.19Total 5388917 18 0.89 5393938 296027Ce (ppm) 100.4 R-26 5388487Cs 711276 5389578 0.11Dy 5.62 100.58 17 2.39 701359 5394610 R-27Er 7.23Eu 5429078 700608 99.91 0.13Gd 5429499 3.38 R-28 29.74 17 684422Hf 5430259 99.4 0.921Ho 681858 5416389 1.08 R-29 3.72La 22.36 0.831Lu 0.68 619401 0.918 17 99.45 0.228Nb 54.42 R-30 2.502 6.14 1.226 618604Nd 1.671 100.04 0.513 0.03 0.71 3.3Pr 1.127 0.807 617237 33.9 18 0.249 4.629 R-31 3.668Rb 23.16 2.9 3.915 99.45 1.533 2.66 615340 Sm 3.881 0.666 0.05 4.93 0.174 0.512 6.048Sr 5.4 3.759 58.06 R-32 59.44 100.7 4 3.963 1.645Ta 17 10.76 2.961 1.72 1.757 5.63Tb 0.15 0.352 0.95 1.123 3.773 6.535 39.02 73.91 R-34 2.243Th 1.03 99.65 6.6 0.952 7.289 1.07 9.63 17.7Tm 3.54 0.787 116.95 17 1.284 6.349 8.3 1.41 0.08 3.933 48.21 3.94 100.96U 242.2 R-35 3.436 2.53 1.52Y 6.69 4.296 22.82 6.6 1.073 0.65 27.28 12.96 0.772 7.867 100.45 0.33 1.08Yb 6.867 58.76 12.9 4.22 0.11 4.932 3.1 R-36 17 0.177 49.8Zr 0.936 13.73 7.175 14.64 1.35 13.788 1.377 53.2 31.42Be 1.222 99.86 7.796 41.33 0.335 4.1 0.138 0.55 3.39 8.121 11.2Co 9.46 3.23 0.47 0.07 R-37 0.905 31.77 8.759 15.1 27.85 0.98 3.62 100.98Cu 1.428 3.2 14.022 17 0.38 17.32 1.633 45.86 0.495 28.61 0.27Li 2.228 0.96 0.63 14.652 6.1 4.6 0.134 35.06 7.25 0.661 226 0.02 1.02 34.05Ni 7.2 99.65 121.5 1.126 3.725 28.8 0.54 2.765 5.977 41.41 0.766 34.5 0.666Sc 1.48 3.642 17 0.664 3.513 0.47V 102.21 0.645 0.81 21.38 0.974 2.09 53.09 99.62 204.7 2604 3.82 0.01 1.527 2.03 5.863 7.1 255.6 10.9 0.756 2.994 5.13Zn 19.15 1.25 0.654 34.35 1.8 17.94 0.613 6.369 5.99Ba 100.26 11.59 1.292 29.61 0.623 11.95 1.3 14 215.4 0.6 5.98 0.761 3.063 17Cd 1.241 3.584 6.7 4.84 48.5 0.932 58.71 70.6 13.6 14.09 2.75 0.324 19.88 8.3Cr 0.336 3.439 8.24 2.364 11.3 45.83 1.087 7.82 2.196 24.92 251.9 4.26Ga 17.18 0.975 3.798 0.609 0.737 1.32 4.48 0.508 14.72 0.2 35.94 1.14Mo 24 4.23 39.28 0.543 18.19 78.9 23.9 3.57 17 0.502 7.68 69.09 4.195 1.71 72.29 1.277 9.41 0.334 12.97Pb 2.9 299.36 3.3 164.5 13.14 10 0.496 8.67 1.239 0.06 0.748 4.66 9.03 1.17 25.46Sn 1.2 2.24 1.66 48.34 0.266 32.51 1.1 1.33 0.749 13.47 63.66 2.215 2.22 0.037 138.4 0.81 54 7.55Tl 0.54 20.62 2.279 14.87 3.037 15.45 6 205.7 61.19 139.78 0.086 11.01 0.452 17 3.583 8 0.127W 0.56 1.31 3.2 13.83 6.6 0.09 8.796 75.57 0.316 35.98 0.739 1.223 0.42 12 2.117 0.043 1.5 263.88 1.77 1.99 3.35 34.39 0.602 3.31 51.43 6.193 0.63 2.68 4.91 2.82 0.1 240.6 11.76 1.036 18.58 208.1 0.273 8.44 6.341 0.999 2.67 17 6.93 0.25 10.7 3.83 12.8 68.94 0.042 492.65 2.136 17 0.321 2.648 0.049 3.4 183.83 2.22 17.04 8 0.974 4.302 3.07 324 247.3 16.46 3.115 0.48 5.58 19.31 133.1 5.01 0.481 2.27 5.589 7.2 0.94 0.53 1.73 1.979 21.87 7.31 259.62 0.487 0.34 0.921 0.54 0.66 4.11 1.81 38.2 0.3 6.97 5.9 20.46 0.503 0.408 4.23 132.5 12.73 8.78 15.95 1.98 159.5 0.737 12.48 1.702 4.9 339.31 2.65 31.06 1.447 0.91 2.98 8.34 15 0.79 22 2.17 3.92 85.66 6.78 0.966 41.84 1.046 251.62 0.262 0.55 0.603 4.467 2.37 384.06 257.5 19.21 3.47 115.3 5.2 0.084 20.46 4.96 0.156 150.88 8.4 8.1 0.96 8.24 6.81 0.53 3.71 2.11 13.13 0.618 2.3 1.14 1.85 8.36 47.88 0.476 157.88 12.55 0.319 0.155 3.4 138.6 1 0.58 18.45 28.5 213.5 1.39 0.05 41.56 66 3.79 29.51 12.37 0.14 2.1 16.74 0.052 3.55 278.89 0.66 1.7 2.2 76.37 3.54 0.49 0.75 0.84 15.02 0.046 0.709 4.8 199 18.24 40.73 0.42 56.4 42.9 2.91 0.05 635.19 86.38 20.88 7.3 15.97 52 77.38 0.12 92.59 3.9 0.22 11.9 10 0.465 1.73 1.283 3.9 0.61 0.491 0.48 2.34 18.66 58.69 260.17 4 1 16.92 38.92 5.63 0.073 87.9 111.49 7.38 5.86 1 96.88 4 114.14 0.963 1.091 0.16 0.982 293.61 0.86 15 15.29 2.06 41.48 0.54 9.59 0.62 4.46 8.4 15.3 0.101 159 41.27 77.37 4.24 59.3 2.86 549.41 0.9 14.95 0.631 0.199 0.504 7.3 17.86 0.09 0.68 37.1 1.43 0.3 18.5 3.84 0.71 1.66 0.59 4.46 0.125 19 12.1 94.94 263.98 6.3 3.32 74.2 0.055 73.63 2.7 0.892 79.4 20.14 417.4 2 0.09 0.22 2.7 0.9 10.6 0.066 5.07 1.05 3.48 1.15 20.51 2.71 3.13 5.46 126.07 65.76 14.1 2.6 0.898 294.3 16.48 2 0.14 0.072 0.66 696.87 14.6 1.18 0.96 2.67 1.5 2.09 0.22 18.86 6.37 25.16 1.16 103.8 15.09 2.2 389.46 0.049 49.11 0.14 10 0.18 32.61 10.41 11.6 2.7 0.1 1.77 1.59 9.43 4.1 23.16 2.12 0.035 52.35 4.4 0.18 0.34 19.8 3.58 44.71 2.44 6.22 24 9.82 3.3 1 0.64 0.36 5.2 0.43 58.03 0.57 21.57 11.48 3.54 0.4 1.6 11 0.94 70.21 30.57 0.14 0.79 0.061 6.6 5.39 0.65 1.2 15 0.082 0.02 0.81 10 1.6 0.29 5.2 0.29 3.79 2 40 0.81 1.38 0.23 5.1 0.29 11 1.42 7.2 48 P

0361-0128/98/000/000-00 $6.00 1555 1556 GABOURY AND PEARSON (Cont.) APPENDIX 1 0.360.27 0.32 3.21 0.81 70.03 0.12 0.09 1.58 0.45 0.17 5.16 0.53 0.02 3.17 0.52 0.08 6.36 0.09 0.11 1.52 0.41 0.1 5.16 0.49 0.02 3.76 0.3 0.07 5.8 0.26 0.15 4.37 0.64 0.05 12.62 0.89 10.33 0.03 0.31 6.73 0.12 0.6 2.05 0.2 0.28 3.9 0.07 0.15 0.06 13.97 18.25 14.86 9.89 12.32 13.45 16.15 11.6 12.2 13.09 11.41 9.61 10.59 12.65 10.94 13.43 12.73 3 (wt %) 76.14 64.02 61.06 82.32 68.87 72.39 62.68 79.73 70.62 67.35 73.39 78.48 65.88 65.19 71.15 70.22 73.01 3 5 2 2 O 0.12 4.5 4.28 3.31 2.33 4.22 5.88 2.06 2.29 1.36 2.24 2.62 4.46 0.17 5.41 3.74 O O 2 2 O 8.32 1.67 1.75 1.94 1.55 1.84 0.75 2.15 1.96 4 3.48 0.75 0.05 0.55 2.43 1.21 1.61 O 2 2 2 CaO Na 4.27 5.18 0.21 0.94 0.73 3.25 0.55 1.19 3.17 0.87 0.09 0.13 3.33 0.08 2.96 1.87 Al NumberZoneUTMEUTMN R-38SiO R-41 633686 17 5424766TiO 656675 5419254Fe R-42MgO 0.27 5405392 670257MnO 0.04 17 5409034 R-43 685822K 5479820 2.15 695000 5479815 0.11 R-44 17 5485776 695018 4.57 5482091LOI 0.03 691184 R-45 100.66Total 5479711 17 0.07 5520033 692819Ce (ppm) 100.18 0.07 R-46 5507623Cs 690587 5514904 100.96Dy 3.27 17 1.18 642978 5512540 R-47Er 47.56 0.06 100.41Eu 5516571 305709 0.44Gd 5379247 1.66 20.06 R-48 100.48 0.12 17 299515Hf 5378698 1.446Ho 1.92 305403 5388093 34.71 3.541 99.78 R-50 1.18La 0.04 2.041Lu 311479 2.022 17 100.34 1.078 50.1Nb 0.696 0.2 R-51 0.91 4.247 637049Nd 0.316 0.09 100.11 1.446 7.2Pr 5.767 0.634 3.564 634211 24.32 17 0.677 R-52 1.159Rb 93.4 2.59 5.45 2.083 21.06 99.5 0.484 620877 0.08Sm 13.305 2.396 1.111 0.341 33.06 0.122Sr 2.8 3.807 11.8 R-53 69.11 8.892 11.14 0.988Ta 17 1.02 2.85 22.85 2.643 99.99 4.417 1.134 0.07Tb 10.257 0.041 26.29 0.719 R-54 42.61 1.713 15.68Th 3.85 3.7 100.51 1.565 1.7 3.288 6.569 1.1 2.6 0.568 8.96Tm 2.564 0.295 0.05 61.59 17 2.94 4.85U 100.3 54.36 R-55 1.983 21.62 0.244 21.3 1.44 10 1.642Y 16.82 3.136 0.798 18.11 7.5 3.388 1.327 47.3 0.99 2.26 2.13Yb 0.05 0.566 100.53 1.58 25.87 0.906 10.85 R-56 0.469 18 0.639 602.4Zr 7.256 4.12 0.765 1.44 28.45 3.32 2.125 0.267Be 100.46 23.1 36.72 0.66 0.317 0.26 6.34 2.91 5.8 40.6 4.851 0.1 14.98Co 0.78 0.343 3.92 0.145 138.5 R-57 9.099 9282124052671139712102610 0.654 13.3 100.78 19.79Cu 3.186 4.84 6.291 0.305 18 0.873 91.73 0.044Li 5.991 12.62 0.323 1.06 0.62 1.57 0.595 5.53 8.3 15.44 4.417 5.66 7.69 4.8 32 1.731 2.2 0.14Ni 274.6 99.46 79.81 7.648 8.168 0.13 0.427 16.66 1.9 89.41Sc 0.303 2.833 26.39 1.579 20 18 1.962 40.23 0.58 24.83 101.08 V 6.79 1.36 1.66 2.12 1.79 0.938 113.7 14.76 2.9 6.447 6.1 0.08 4.248 0.363 12.52Zn 3.2 0.28 0.723 18.213 42.13 49.4 1.333 20.43 1.949 2.67 0.428 2.34 34.89Ba 42.2 3.344 20 0.56 155.4 0.25 0.119 0.72 17.37 0.21 1.78 4.539 20 18 13.791 1.29 30.18Cd 0.06 0.903 66.84 0.263 3.54 3.8 1.96 16.53 72.9 2.88 0.94Cr 6.6 0.536 79.52 4.53 114.46 13.472 3.097 1.96 11.067 332.6 0.032Ga 19.34 3.3 28.41 0.46 9.06 0.61 8.84 1 4.11 0.424 30.11 0.612 18.172 0.298Mo 35.54 138 15.68 16.529 17 2.47 0.297 12.999 8.74 79.04 11.104 5.817 40.23 6.9 9.1 2.054Pb 2.6 713.94 216.7 3.48 0.127 23.43 7.6 3.89 18.69 13.243 44.95 2.79 40.01 0.411 0.88Sn 3.49 110.12 16.961 4.53 3.8 0.43 0.134 1.19 34.47 1.107 6.39 0.05 13.2 249.18 1.036 4.464Tl 0.24 18.12 6.45 1.73 2.625 183.1 10.44 15 45.27 0.336 15.72 29.2 60.05 10.9 17 63.72 52.92W 0.45 2.2 5 64.22 0.463 1.741 16.76 0.726 4.5 1.926 16.2 242.63 0.56 0.7 1.33 15.1 0.88 6.64 1.405 1.567 3.596 9.835 0.353 0.036 0.7 1.04 127 8.01 31.07 31.69 0.958 7.03 12.75 77.24 2 0.72 61.97 25.98 32.7 496.58 0.975 2.723 0.894 0.42 8.4 1.643 11.24 17 0.41 17.7 0.698 2.63 2.103 25.11 2.686 0.33 3.606 0.85 3.13 3.633 1.084 0.07 1.58 1.6 14.98 84.66 2.1 92.62 0.448 17.94 120 88.74 31.5 0.08 4.1 6.41 202.6 69.37 0.606 2.62 4.424 0.424 43.9 1.678 0.18 28.2 3.886 3.326 13.85 0.87 4.06 0.348 7.74 15.5 5.057 4.06 1.212 0.43 1101.27 0.77 16.65 2.83 73.53 0.119 4.31 7.18 8.71 2.17 33.6 288.6 115.18 0.624 45.84 5.4 0.08 2.7 17.54 2.779 0.161 0.83 49.1 3.161 5.047 17.7 204.97 49.75 0.535 0.93 24.6 7.708 4.84 7.08 10.2 17.68 83.89 3.09 0.066 0.59 12.35 15.54 24.09 1.82 178.6 95.35 2.46 1.035 14.1 16.03 2.045 31.74 0.23 223.05 0.12 2.467 3.25 0.898 4 6.2 24.5 29.49 1.32 0.27 16.09 15.9 35.28 0.057 5.91 0.91 29.15 22.73 12 1.93 688.8 0.81 96.46 0.837 306.06 8.75 1.64 1.641 35.5 1.41 20.3 9.35 2.633 0.409 0.25 1.12 10.2 20.75 72.46 0.044 266.72 8.16 0.27 2.7 20.3 12.1 565.8 0.533 2.8 0.28 6.36 64.7 5.23 1.651 3.32 0.43 9.5 1.12 12.56 0.297 1.71 29.68 114.99 4.4 543.24 0.08 17.17 0.114 0.54 375.6 0.876 2.8 3.2 0.32 58.3 0.155 18.26 9.89 5.86 1.78 5.4 3.31 0.48 1.2 1.78 13.5 1.45 2.58 54.06 2.63 45.02 32.23 0.063 0.13 460.4 4 0.32 0.902 0.229 13.31 13.2 10.06 0.27 20.4 136.05 2.36 7.9 3.71 2.99 0.759 11.4 1.1 24.7 25.85 0.59 3.95 5.9 19.84 0.062 2.66 167 0.629 0.14 0.406 217 21.33 0.93 10.78 30.14 140.86 40.7 0.25 93.3 1.22 9.2 6.4 28.46 4.56 0.204 7.1 0.59 5.94 3.9 2.09 0.979 9.8 11.01 0.12 433.61 157.3 12.26 1.39 84.02 17.74 1.77 60.8 23.33 0.145 1.29 10 1.62 273.7 0.87 2.3 257.2 49.01 2.2 1.06 1.18 0.35 85.36 30.34 14.16 0.075 1.01 0.72 2.88 10.1 212.71 3.2 2.5 1.52 0.16 0.8 92.46 5.68 15.72 4.7 0.097 1.77 6.77 0.43 0.37 4.81 13.51 15.07 0.084 2.69 12.1 1.96 3.58 1.09 3.8 0.31 0.71 1.7 55.27 0.031 12.8 2.08 5 8.12 0.58 0.23 0.8 0.02 0.062 2.1 1.75 3.3 8.45 0.68 0.81 1.3 0.16 1.31 9.08 6.5 0.29 1.06 0.09 8.3 2.09 8.18 0.23 5.6 0.37 0.12 2 8.26 0.22 2.5 P

0361-0128/98/000/000-00 $6.00 1556 RHYOLITE GEOCHEMICAL SIGNATURES AND ASSOCIATION WITH VMS, ABITIBI BELT, CANADA 1557 (Cont.) APPENDIX 1 9.270.256.99 12.09 0.29 15.44 2.69 0.5 13.81 3.870.04 7.62 0.58 5.46 0.06 10.13 0.13 13.49 0.09 12.19 0.13 3.84 0.1 12.85 0.28 3.62 11.13 0.02 0.33 3.14 10.23 0.02 14.42 0.22 9.76 0.05 10.71 0.33 5.91 0.07 9.18 0.33 5.22 0.05 11.34 0.34 2.17 12.6 0.07 0.2 0.96 13.26 0.05 0.51 0.43 11.55 0.06 4.88 0.26 0.03 6.2 0.38 0.05 0.26 7.12 0.04 0.08 0.04 3 (wt %) 75.9 72.28 66.74 63.77 70.29 79.63 75.72 71.43 70.89 67.35 70.29 78.58 83.18 81.88 72.92 70.88 72.83 3 5 2 2 O 2.01 5.63 7.82 4.38 0.22 4.52 6.65 2.45 3.1 3.6 5.61 5.17 0.52 4.98 0.62 4.32 O O 2 2 O 0.8 0.87 0.66 1.28 0.24 1.95 0.84 0.36 0.9 1.05 3.1 0.39 0.08 3.32 1.22 3.53 0.22 O 2 2 2 CaO Na 1.72 2.82 1.22 4.21 0.02 0.02 0.13 2 0.71 5.96 1.29 0.91 0.32 0.19 0.97 0.07 1.05 Al NumberZoneUTMEUTMN R-58SiO R-59 615919 17 5387853TiO 617145 5386548Fe R-60MgO 0.81 5383127 622270MnO 0.18 17 5383134 R-61 622273K 5382153 0.34 650653 5381949 0.08 R-62 17 5383580 650447 1.79 5392084LOI 0.06 652983 R-63 100.74Total 5391921 17 3.26 5342561 657343Ce (ppm) 100.06 0.07 R-64 5341497Cs 654526 5342283Dy 4.08 99.78 17 2.76 634177 5342497 R-65Er 47.09 0.14Eu 5349906 631020 99.88 2.64Gd 5351508 2.9 62.39 R-66 0.01 17 630318Hf 101.13 5346168 0.145Ho 1.31 627893 5347494 47.45 3.929 R-67La 100.98 1.57 0.04 2.38Lu 626000 0.268 17 1.465 20.81Nb 4.74 100.16 0.59 R-68 4.025 624067Nd 2.94 0.05 0.097 2.767 4.9Pr 5.711 1.06 47.67 99.63 646573 17 0.806 4.008 R-69 1.88 5.081Rb 13.23 21.18 0.424 5.08 2.338 647630 0.09Sm 100.13 7.456 43.47 1.087 0.351 0.957 1.717Sr 6 4.373 22.51 R-70 0.75 8.7 28.81 100.53 0.062Ta 17 0.971 22.52 5.772 2.4 0.19 47.84Tb 0.618 0.407 0.805 3.785 1.941 100.25 R-71 7.64 19.87Th 3.22 0.331 0.61 2.171 28.54 2.526 5.8 9.7 48.86Tm 0.462 0.353 0.09 17 0.335 3.882 4.43 1.47 4.125U 99.41 22.38 R-73 0.137 38.1 2.395 9.95 4.4 22.88Y 22.07 5.599 0.25 33.49 0.546 0.139 0.761 3.482 0.75 2.4Yb 8 3.93 0.03 99.76 5.64 2.15 R-74 0.173 17 0.64 4.16 2.059 22.79Zr 26.88 5.256 81.7 33.67 9.92 0.24 1.045 4.02 0.294Be 0.789 4.048 100.26 0.352 0.88 3.829 0.01Co 5.21 0.279 4.8 2.05 3.9 R-75 31.95 2.351 19.76 93712151113597175345320 22.73 0.798 5.817 48.8 22.02 3.6Cu 97.5 0.924 0.381 17 0.78 0.703 2.007 99.87 0.45 1.42 0.407Li 3.953 0.484 0.77 15.6 1.229 22.55 2.45 0.674 5.6 5.848 2.28Ni 20.25 197.9 9.11 2.07 5.3 136.8 0.479 0.308 56.95 0.824 5.793 99.46 1.066 4.5Sc 0.35 0.83 2.95 2.24 17 2.961 3.684 22.34 0.4V 3.21 0.44 0.29 3.876 22.75 230.1 8.15 100.53 20.4 1.29 2.69 7.94 0.351 39.26 0.41 8.957 4.48 1.24Zn 0.987 17.81 5.1 4.8 0.13 0.134 0.14 0.28 4.12 5.322Ba 6.078 14.91 8 10.75 4.412 22.34 234.5 19.1 0.56 0.629 18.43 17 0.207 29.93Cd 0.62 6.58 21.38 1.687 2.31 0.357 1.226 4.28 0.36 0.94Cr 3.39 0.091 7.87 4.503 14.41 0.03 50.15 0.312 5.1 1.01 7.6 6.593 3.16 14.63Ga 12.04 5.2 0.626 25.56 0.579 54.58 96 15.36 0.78 18.86 1.145 0.753 0.53 1.952 5.79 6.8Mo 0.92 17 27.32 116.42 1.083 4.4 0.4 81.06 4.061 21.22 2.19 0.362 6.642 5.948Pb 3.3 134.02 19.26 0.22 15.46 0.588 39.9 3.47 64.97 0.97 22.67 4.6 0.708 8.6 0.985Sn 1.09 1.437 13.308 6.33 4.8 0.76 152.4 10.048 0.5 37.66 0.246 44.98 2.01 0.059 29.62 175.54 12.28Tl 0.04 6.13 0.302 7.2 5.145 4.692 28.82 4.44 16.7 1.57 0.656 104.4 17 10.992 10.9W 0.26 0.699 3.26 8.05 3.3 0.704 0.785 1.285 200.9 7.454 188.61 74.67 2.26 3.07 38.32 0.754 0.69 4.5 48.67 0.047 16.35 57.01 7.9 0.351 4.764 2.45 8.822 26 2.37 0.07 1.48 0.338 3.06 2.73 15.36 1.04 6 46.3 1.55 0.666 420.12 0.851 3.079 33.24 0.3 1.71 1.58 201 2.294 17 0.164 64.9 3.3 0.106 10.67 2.1 3.82 1.78 0.64 0.194 7.369 9.264 3.35 11.1 7.5 0.906 2.01 8.64 0.31 0.05 2.48 12.05 126.8 1.601 39.82 0.839 2.384 9.443 4.8 4.14 52.45 21 0.478 56.28 5.935 126.81 3.21 0.036 22 197.3 10.15 0.28 0.554 0.25 1.122 13.1 1.773 7.9 2.75 0.63 1.39 16.14 299.83 1.34 1.3 10.98 14.29 169.5 2.27 1.158 0.432 0.93 0.717 0.14 3.8 6.4 40.13 2.28 25.18 1.93 25.64 0.065 181.2 7.22 0.925 9.297 3.43 9.472 22.58 180.76 2.5 0.3 0.24 92.27 12.6 5.25 11.39 0.93 14.73 1.03 1.3 0.392 0.92 0.836 1.956 3.53 34.52 79.9 1.34 56.8 0.64 1.34 0.02 32.61 0.041 180.2 4.2 5.5 0.677 32.49 85.86 5.81 3.2 27.09 0.58 13.09 8.12 11.1 0.951 0.877 2.35 34.93 0.27 4.16 0.89 81.72 0.841 2.17 57.3 3.74 39.04 1.4 0.044 2.8 201.72 3.19 0.21 283.9 0.636 5.09 4.67 6 4.82 8.9 16.07 0.838 5.02 0.52 62.8 1.837 2.11 179.61 2.11 0.44 5.13 0.79 55.08 0.036 9.8 1.77 249.4 1.597 18.8 6.26 5.06 0.06 1.9 38.21 0.72 109.92 13.82 0.59 872.24 6.82 1.638 8.2 0.22 19.19 2.75 63.29 0.062 0.78 212.9 0.38 4.41 1.05 1.14 5 14.9 1.32 82.7 4.51 1.33 164.31 0.04 38.59 20.46 0.66 8.12 0.396 1.5 0.744 8.25 53.92 85.77 0.041 306.8 0.38 1.9 0.71 4.2 0.79 1.6 0.99 225 0.372 13.5 1.77 35.91 11.29 13.9 4.24 1.27 0.06 1.515 0.3 0.577 9.06 2.2 31.62 0.107 310.5 1.26 4.9 441.29 0.21 0.894 3.85 0.42 0.69 10.66 2.78 1.15 6.6 1.81 9.26 31.6 8.8 13.78 1.43 0.715 10.14 0.08 28.06 0.05 11.9 482.89 169.9 1 8.93 0.38 1.3 6.01 0.24 1.14 7.52 71.83 2.57 340.36 1.5 7.98 18.36 16.8 0.96 0.29 248.7 0.037 13.8 104.99 0.42 0.53 47.83 0.15 0.87 18.61 2.5 3.5 78.75 7.9 15.46 0.084 1.84 0.05 5000 20.59 8.4 0.29 15.34 8.07 0.68 0.37 0.071 1.8 6.06 4.5 1.58 3.14 225 22.01 4.1 0.41 0.3 0.22 0.36 0.93 2.15 1.3 0.73 0.68 7.6 0.52 0.71 0.141 2.73 1.21 8.39 3 0.3 0.08 13.1 0.94 2.56 8.91 0.52 1.3 0.44 1.69 7.4 3.51 11.34 0.04 1.88 0.98 9.4 10.8 9.08 3.38 3.2 P

0361-0128/98/000/000-00 $6.00 1557 1558 GABOURY AND PEARSON (Cont.) APPENDIX 1 0.255.43 0.33 2.08 0.28 3.990.04 0.23 5.23 0.06 0.45 4.71 0.07 0.21 1.69 0.04 0.2 2.18 0.08 0.84 6.23 0.04 0.22 2.92 0.05 0.56 4.71 0.13 0.3 3.21 0.03 0.25 1.49 0.16 1.03 9.03 0.07 0.25 4.35 0.05 0.26 3.95 0.14 0.23 3.5 0.03 0.31 4.4 0.05 0.04 0.07 11.33 11.56 10.36 10.72 12.55 9.61 10.92 17.16 13.25 15.06 10.16 11.26 16.33 12.46 12.26 11.56 12.54 3 (wt %) 72.95 74.28 70.49 72.79 70.95 73.92 76.05 61.94 73.96 64.15 76.42 77.4 55.75 73.25 72.65 74.88 73.59 3 5 2 2 O 4.98 4.42 2.9 1.12 3.97 5.03 5.74 3.88 1.27 3.6 2.29 4.64 5.09 3.61 5.38 1.67 4.56 O O 2 2 O 0.29 1.09 1.2 2.73 1.51 0.33 0.63 1.51 4.78 2.2 1.53 3 1.13 2.1 0.61 4.07 1.36 O 2 2 2 CaO Na 1.26 2.67 3.08 0.92 2.01 4.62 1.34 2.6 0.68 4.25 2.53 0.55 6.37 1.6 1.53 3.04 1.1 Al NumberZoneUTMEUTMN R-76SiO R-77 646889 17 5347743TiO 651001 5347863Fe R-78MgO 0.85 5350159 652251MnO 0.08 17 5347769 R-79 649609K 5350329 0.57 645584 5344213 0.03 R-80 17 5361370 648033 2.4 5366108LOI 0.13 655360 R-81 99.12Total 5371275 17 5358894 650991 2.19Ce (ppm) 100 0.27 R-83 5358869Cs 652434 5358411Dy 1.24 17 1.66 669310 5351864 R-84 100.4Er 54.47 0.08Eu 5357028 662609Gd 100.18 5360526 0.1 2.9 34.09 R-85 0.13 17 654355Hf 5358232 0.126Ho 100.48 642730 5365459 55.45 9.573 R-88La 0.33 5.49 0.03 6.328Lu 641207 0.72 17 99.27 1.964 46.98Nb 5.297 R-89 8.526 629641Nd 3.17 3.95 3.513 0.08 99.38 6.5 0.652Pr 7.264 0.857 41.67 7.018 623607 17 2.054 R-90 4.718Rb 6.52 100.23 4.986 23.29 0.8 2.93 620443 0.02Sm 1.405 4.23 1.274 47.96 7.707 0.985 1.139Sr 5.5 100.3 7.315 32.78 15 R-92 5.151 15.94 Ta 17 31.49 0.336 23134211258726 3.59 1.707 0.08 56.87 6.233 7.504 2.79Tb 0.551 1.504 7.198 23.25 R-93 99.27 4.152 22.5Th 2.66 6.7 17.7 10.1 0.3 1.141 32.93Tm 8.247 6.313 1.9 0.916 0.05 17 1.682 7.95 1.14 100.24 5.814 38.5U R-95 4.694 68.2 19.82 3.13Y 55.77 1.978 80.22 32.5 6.3 6.45 15.3 5.548 0.82 1.342 0.344 1.05Yb 99.17 7.62 0.04 4.32 0.09 2.69 22.68 4.316 R-96 17 1.481 17.73Zr 30.61 46.1 1.24 3.97 55.88 6.481 101.4 27.75Be 1.669 4.561 14.5 1.239 0.693 6.9 0.966 0.77 6.147 2.931 0.13 179910113 Co 2.16 7.94 4.76 0.821 2.37 R-97 8.06 20.43 41.39 59.27Cu 7.027 58.2 1.19 100.39 2.64 17 0.691 23.83 1.392 7.764 2.351 0.58 12.2 0.547Li 4.309 5.052 1.18 1.15 0.06 26.19 4.6 2.7 40.67 6.86 1.18 1.7 6.42 8.61Ni 96.91 249.4 4.33 99.19 0.875 28.66 0.965 2.513 1.62 24.6 1.298 3.85Sc 0.799 7.926 0.721 1.328 10.7 17 14.08 0.41V 1.76 1.02 35.45 1.223 26.46 0.06 23.31 217.3 5.56 0.57 10.242 3.63 99.97 1.004 28.25 7.3 1.642 7.69 3.88 247 2.55Zn 1.352 1.234 0.794 55.8 1.95 3.679 0.446 5.388 110.9Ba 35.67 11.4 11.16 44.76 0.978 100.09 57.15 0.24 223.2 0.96 7.015 0.1 17 0.686 18.45Cd 0.475 11.053 6.92 0.18 1.155 5.67 0.28 0.322 0.644 0.4 6.761 0.817 7.346 4 1.28Cr 36.1 3.51 10.04 26.81 15.7 10 38 1.309 64.81 40.86 232.3Ga 16.94 7.319 1.02 41.03 0.55 8.1 1.684 2.808 0.77 1.168 10.046 0.199 0.653 6.06 0.86 Mo 5.3 0.07 0.185 1.626 5.06 17 58.65 26.89 1.98 1.62 1.021 53.2 11.713 2.11 36.49 3.6Pb 3.4 55.77 10.843 266.7 13.46 73.47 27.71 2.368 2.94 9.3 0.953 3.019 25.38 0.434 0.6Sn 1.2 16.5 0.621 0.89 0.68 0.886 7.112 5.9 4.18 19.1 0.155 46.2 0.67Tl 0.03 0.711 149.1 2.998 4.36 38.1 114.88 62.08 2.35 8.584 168.2 14.51 1.51 6.5 17 30.13 0.565 16.1W 0.38 1.892 2.54 1.5 9.387 44.09 0.845 0.163 1.161 5.803 0.64 0.445 3.3 0.066 271.09 0.47 1.42 4.4 8.44 1.253 75.08 7.639 10.11 5.3 1.67 2.36 0.16 9.912 301.6 18.1 20.6 4.05 20.28 46.25 1.22 2.31 1.88 1.306 6.909 12.93 0.554 0.331 0.18 3.51 8.27 0.23 6.677 578.29 17 2.73 0.77 120.59 1.6 0.09 13.25 1.38 0.472 5.483 24.33 0.3 1.14 12.7 23.04 155.7 4.98 6.8 741.2 48.97 12.81 0.28 0.09 15.9 4.53 1.801 8.823 8.1 289.55 45.71 1.525 2.28 1.888 0.263 0.71 8.979 0.22 61.25 5.08 9.42 1.109 2.97 0.186 1.158 7.557 0.054 16.69 351.6 0.43 3.2 15.14 11.846 1.26 33.28 17.7 2.89 6.57 38.1 1.885 0.18 38.1 63.39 1.028 0.84 2.151 0.08 8.1 2.92 1.4 158.34 8.18 1.23 17.43 9.9 0.885 0.856 0.54 1.736 8.62 5.8 8.64 0.053 22.96 127.4 76.9 23.95 20.59 0.98 148.47 14.9 1.4 1.213 2.868 9.72 24.6 303 1.3 0.56 1.29 4.8 0.04 15.39 5.15 1.07 2.7 9.84 1.151 0.47 21.24 0.056 25.94 1.95 247.2 0.26 6.6 371.41 33.1 1.22 24.44 1.289 3.02 1.29 185.8 62.65 94.29 2.86 1.22 1.16 0.59 14.7 0.02 19.75 0.236 1.22 2.7 47.32 0.281 1.422 381.1 52.22 67.48 272.8 1.673 8.4 0.23 0.314 39.62 113.1 3.12 5.9 51.02 0.86 10.72 0.45 8.1 20.36 1.079 44.7 0.04 0.82 4.5 0.49 936.66 11.6 49.24 0.59 108 5.78 1.279 40 6.92 0.836 0.27 56.71 10.21 31.38 6.8 56.4 2.5 15.5 315.97 9.11 1.02 17.2 0.879 71.88 1.52 23.65 0.09 0.54 1.17 13.6 90.08 0.11 5.79 7.7 323.9 1.09 0.696 74.46 502.76 224.45 0.19 108.5 8.12 1.7 1.18 1.031 46.78 7.9 0.86 12.36 2.81 8 21.43 2.076 0.075 258 0.44 0.57 14 2.08 0.717 262.58 0.47 8 3.28 1.52 2.7 3.2 1.398 76.3 27.43 1.69 14.16 79.9 2.2 872 0.98 3.28 0.074 0.846 7.5 0.39 4.96 1.82 0.46 10.5 298.7 1.09 125.33 7.13 10.32 19.19 0.77 2.63 0.34 0.058 1.01 3.9 48.72 9.1 248.6 60.94 98.83 0.89 1.13 0.12 55.63 3.41 6.8 20.72 5.72 0.095 2.07 2.67 0.18 673.17 12.3 1.11 32.36 9.2 0.64 0.58 5 0.17 17.35 4.8 6.9 315.08 0.074 5.4 4.74 0.29 154.66 26.07 1.13 23.38 0.61 0.84 0.14 2.95 0.048 1.6 19.3 9.28 2.2 71.46 0.14 19.23 1.54 0.059 0.66 0.32 0.19 3.33 10.9 1.52 0.26 9.5 0.06 1.26 0.8 0.06 8.02 10.6 2.4 0.69 2.2 66.88 0.14 0.97 10.4 0.21 2.79 0.8 0.09 0.4 10.9 0.24 3.52 3.9 0.32 2 P

0361-0128/98/000/000-00 $6.00 1558 RHYOLITE GEOCHEMICAL SIGNATURES AND ASSOCIATION WITH VMS, ABITIBI BELT, CANADA 1559 (Cont.) APPENDIX 1 9.150.121.8 13.12 0.36 15.88 3.85 0.25 14.03 2.320.03 14.98 0.32 1.87 0.05 11.65 0.62 3.94 0.04 12.03 0.22 11.52 1.5 0.08 0.17 13.29 0.15 0.95 0.35 15.75 0.06 9.19 13.83 0.1 0.04 0.5 10.29 0.57 0.08 12.7 5.71 0.06 0.06 12.42 0.48 0.19 10.87 0.12 3.53 0.39 14.35 0.03 4.16 0.45 10.82 0.03 4.56 0.16 0.06 7.83 0.36 0.09 3.45 0.22 0.02 1.37 0.1 0.08 3 (wt %) 80.52 70.41 69.93 72.06 66.46 72.45 76.92 63.43 76.59 62.62 74.42 77.15 69.32 73.08 74.66 68.7 74.4 3 5 2 2 O 1.99 0.22 1.81 2.55 1.91 3.63 1.98 1.07 5.83 3.87 3.94 1.03 3.06 5.18 0.24 0.33 2.15 O O 2 2 O 2.04 4.02 4.37 2.91 1.74 1.45 3.09 1.02 1.25 1.44 3.01 2.22 2.43 0.72 1.79 4.43 2.1 O 2 2 2 CaO Na 1.41 2.58 1.51 2.87 4.68 4.23 1.75 11.64 0.39 4.61 1.32 1.92 3.48 1.34 2.35 3.95 Al NumberZoneUTMEUTMN R-99SiO R-100 647642 17 5358250TiO R-101 682691 5347877Fe MgO 0.54 5347240 690128 R-102MnO 0.04 17 5347192 690120K 5347379 R-103 0.41 690141 5347279 0.09 17 R-104 5347500 690131 1.16 5483070LOI 0.06 691000 R-105 99.76Total 5431392 17 0.58 5495949 415336Ce (ppm) R-106 0.06 98.6 5499618Cs 485960 5524237Dy R-107 1.71 17 2.11 531686 5513155Er 68.14 0.11 99.63Eu 5513845 R-108 534514 0.83 117.46Gd 5512701 3.5 99.53 0.07 17 532847Hf R-109 5446802 1.539Ho 89.68 10.377 0.43 565339 5446202 99.73La R-110 2.29 0.03 7.238Lu 565322 0.536 17 92.37 7.791 1.274 99.48Nb R-111 1.44 9.256 563604Nd 2.19 4.701 0.37 6.636 81.43 3.228 8.3Pr 9.145 1.923 R-112 99.9 283202 18 2.278 0.01 7.994Rb 33.99 2.213 28.27 2.815 13.921 3.42 283202 49.54Sm 3.664 R-113 0.837 100.88 1.245 1.577Sr 7.4 3.407 81.33 18.7 3.55 2.31 56.29 2.713Ta 18 9.315 72.78 38.67 R-114 4.174 3.4 1.307 98.71Tb 138.05 0.718 0.691 4.281 10.288 15.6 48.08Th 3.73 4.2 0.09 1.615 R-115 0.35 2.753 53.77 52.51 100.55 2.462 1.472Tm 85.22 0.447 18 0.744 8.94 2.51 4.838U 9.586 46.86 15 2.875 18.1 14.8 1.799 32.63 30.64 99.56 2.143 0.02Y 60.25 0.47 0.484 4.7 51.63 0.413 0.882 1.38Yb 2.48 9.78 0.77 5.489 39.58 100.04 0.196 18 1.6 1.496Zr 35.51 36.98 5.989 41.49 14.1 0.687 14.3 0.05 13.86 0.23 58.52 0.486Be 0.548 4.3 1.156 1.04 7.38 2.433 25.43 99.84Co 3.59 0.567 4.51 0.68 3.987 19.91 36.5 1.515 23261616129242231266726 19.91 117.2 1.387 11.97 1.275Cu 91.68 0.374 18 0.891 0.454 0.09 0.97 8.2 100.21 0.721Li 6.43 40.73 15.39 0.937 1.27 6.954 1.037 68.75 3.1 2.369 20.55 5.96 2.22 179.1 0.334 7.88Ni 19.24 293.5 0.531 18.54 0.296 3.891 1.29 100.24 9.77Sc 0.05 0.365 2.09 11.3 23.04 18 0.917 2.357 1.251 1.428 93.73 0.47 1.177 1.91V 5.67 1.09 24.82 236.2 0.799 23.86 302.7 6.44 0.625 2.11 4.81 26.99 0.695 3.338 3.1 99.06Zn 0.327 9.85 0.362 10.78 134.56 0.03 2.79 0.941 0.87 4.07 11.4 2.715Ba 0.746 8.923 16.6 194 0.317 28.97 0.85 154.5 1.85 6.46 0.62 0.711 18 39.48 0.182 2.711Cd 99.36 3.23 3.18 2.68 0.484 10.79 0.435 17.34 6.5 2.46Cr 15.543 58.98 0.218 1.252 6.078 5.38 0.07 0.42 2.312 11.8 1.086 197.7 16.81Ga 11.73 4.9 13.11 0.389 63.68 0.212 2.251 8.16 1.02 106.6 6.64 0.98 0.245 20 0.304 3.4 3.91Mo 2.57 10.528 3.61 18 15.18 0.123 11.84 8.353 8.44 42.07 1.51 8.826 1.91Pb 1.6 200.03 3.3 0.03 174.5 18.04 35.86 0.362 38.31 0.128 2.476 15.71 9.59 7.4 13.548 0.94Sn 1.49 52.8 1.964 2.4 6.1 1.05 0.243 13.829 0.202 1.34 29.32 12.586 3.02 0.069 29.24 834.09 38.34 7.23Tl 0.08 3.38 6.5 20 1.5 116.7 15.92 0.996 2.518 18 47.14 0.967 19.709 2.724 59.87 9.99W 0.1 4.4 20 7.59 3.7 108.6 3.434 0.618 18.395 770.95 0.63 5.87 2.699 0.9 26.34 7.1 0.092 38.46 0.69 13.21 3.4 2.56 2.21 0.22 3.46 0.15 113.9 14.54 0.232 1.137 13.02 1.68 0.766 0.859 12.96 1.45 13.19 596.12 36.24 2.19 226.3 4.55 0.166 1.281 18 1.461 1.336 1.68 45.75 7.9 0.044 54.06 2.2 0.6 1.12 12.42 13.616 25.1 11 257.6 0.88 15.63 4.06 0.398 1.76 0.604 22.98 2.34 695.2 2.119 0.32 1.8 0.22 4.3 1.953 54.2 9.84 2.96 7.67 0.208 4.659 2.43 86.5 5.993 3.091 54.69 0.064 2.134 0.58 1.26 1.46 0.34 102.3 10.01 0.196 0.962 7.6 89.26 6.9 0.71 332.89 0.992 5.34 0.7 3.82 4.33 3.019 1.26 14.7 0.21 22.03 53.91 0.12 4.464 81.77 0.272 4.97 8.9 1.53 29.1 0.072 1.98 98.5 2.96 20.71 578.8 20.1 145.3 1.1 10.82 1.39 75.28 1.58 0.729 10.92 14.5 0.114 12.1 0.44 90.32 1.16 0.24 26.2 0.706 0.45 1.9 1 0.939 0.048 9.75 5.32 8.14 17.29 17.53 0.97 85.7 3 15.26 80.4 1.197 48.6 120 2.401 0.419 0.99 0.16 1.8 0.52 10.7 0.68 1.641 1.37 143.67 9.3 16.65 0.59 28.4 0.15 99.24 12.65 18.27 5.87 17.27 264.95 1.193 84.8 236.4 3.41 1.04 120 0.79 3.23 43.54 0.36 2.009 18.5 2.3 16.6 0.51 17.02 19.54 0.8 0.64 293.35 45.8 0.19 1.75 18.05 5.1 1.23 1.261 6.97 443.6 13.4 3.291 1.63 0.094 3.05 2.59 8.09 611.59 2.55 1.92 0.33 66.56 0.75 7.08 15.22 7.9 3.8 0.33 66.6 1.545 0.15 3.59 367 7.75 6.3 12.8 6.4 2.66 0.277 367.53 37.8 1.76 0.112 17.2 2.61 8.19 5.03 9.42 0.36 14.48 0.72 0.774 2.77 19.8 0.47 550.06 0.12 6.13 10.98 0.475 0.8 477.6 6.8 1.18 4.9 6.3 6.4 93.4 0.371 2.94 21.42 68.17 1.8 1.295 245.23 9.4 1.86 0.61 1.21 16.04 3.19 13.06 0.045 142.7 0.45 0.15 11.2 2.34 361.75 20.79 3 54.7 0.7 10.86 3.54 0.3 19.96 250.6 1.26 1.34 1.31 0.51 0.3 200.14 1.61 25.07 1 47.53 1.02 2.18 199.08 2.71 45.2 0.75 0.85 2.48 2.1 0.18 0.14 16.98 5.74 0.13 24 0.064 187 4.2 10.93 2.6 0.57 2.88 0.24 10.47 2.83 4.1 1.79 0.101 0.13 27.27 44.76 0.39 3.34 8 0.23 0.46 0.073 126.93 7.8 2.1 0.03 23.7 10 0.083 0.16 0.28 0.06 7.7 5.35 2.1 0.118 0.99 0.22 1.04 0.6 1.7 2.1 0.096 0.98 0.98 0.72 0.61 4.5 3.3 0.35 0.53 2.2 2 9.15 14.81 11.2 P

0361-0128/98/000/000-00 $6.00 1559 1560 GABOURY AND PEARSON (Cont.) APPENDIX 1 0.462.79 0.11 4.93 0.11 5.510.34 0.18 0.43 0.02 0.12 6.23 0.03 0.13 1.98 0.03 0.32 3.43 0.02 0.39 3.68 0.02 0.05 0.03 15.55 5.49 5.72 8.59 4.65 10.51 12.61 12.92 3 (% wt) 69.04 83.36 79.13 84.15 83.38 78.24 72.6 73.36 3 5 2 2 O 6.31 0.17 0.11 1.62 0.02 0.72 0.33 0.23 O O 2 Projection = NAD 83 2 O 1.58 1.8 0.05 4.19 0.04 3.66 2.98 3.95 O 2 2 2 CaO Na 0.73 0.24 0.41 0.01 0.27 0.06 0.04 Al NumberZoneUTMEUTMN R-116SiO R-117 313280 5330673TiO 18 R-118 647800Fe 5519200MgO 1.07 5519500 647800 R-119MnO 0.03 17 5358713K 707947 R-120 5468000 0.55 630000 5471000 R-121 17 5474000 628000 5.54LOI 5475000 99.21Total R-122 627080 0.1 0.05 17Ce (ppm) 628025 R-123 99.8Cs Dy 2.57 1.31Er 85.17 99.44 17Eu Gd 100.08 1.69 3.35 43.31Hf 17Ho 0.799 0.04 98.88La 24.72 8.776 4.33 2.9Lu 5.759 0.446 100.51 127.65Nb 1.686 0.02 2.762 17 10.355Nd 1.91 100.86 1.563 0.41 0.034Pr 11.78 8 1.938 9.54 1.75 3.52 1.857Rb 35.7 0.06 100.28 33.92 1.13Sm 17 0.26 1.79 0.59 5.206Sr 0.972 74.04 0.548 12.4 7.793 1.955 33.47 0.05 Ta 21.03 2.7 51.67 5.19Tb 0.022 2.859 3.27 0.236 56.53 2.007 0.369Th 5.01 1.71 9.364 11.73 1.24 5.1 20.11Tm 15.781 2.8 11.9 1.369 1.09 0.194 42.54 U 0.19 1.658 4.07 110 1.341 1.97 5.133 54.34Y 51.5 42.33 11.04 1.148 0.768Yb 4.4 0.81 0.816 3.471 0.363 8.8 4.03 0.457 5.635Zr 1.482 3.72 3.463 62.21 1.93 4.24 14.56 8.445 0.94Be 1.392 3.5 0.16 2.174 0.894 1.085 13.8Co 2.6 0.54 0.894 4.05 0.502 3.444 2.22Cu 34.45 2.1 10.34 6.604 92.22 4.63 1.202 5.11Li 2.108 0.234 0.716 0.555 0.825 5 0.288 0.47Ni 12.11 3.445 6.11 3.1 7.31 300.4 25.7 42.49 5.094 56.65 30.75 0.612Sc 1.38 6.2 0.18 0.705 0.327V 21.26 0.93 1.326 1.08 101.9 104.5 1.06 10.28Zn 1.55 66.88 167 12.2 6.54 24.86 0.467 18.85 Ba 8.54 0.334 0.799 0.25 6.2 4.57 18 0.38Cd 111.2 29.58 0.41 19.4 1.195 6.2 1.23 11 1.77Cr 1.4 115.66 5.23 14.8 0.16Ga 15.79 4.07 0.86 313.7 2.82 19.77 0.24Mo 0.427 6 111.21 104.7 12.59 1.39 5.3 4 12.3Pb 12.4 4.7 4.52 317.34 0.539 5.59 2.92 9.8 Sn 2.68 19.73 2790 2.7 0.595 86.1 2.183 4.57 0.38 6.35Tl 0.26 0.231 257.56 1.76 1.02 15.25 14.2 40 1.04W 0.42 1.06 0.32 13.71 3.74 16 0.557 177.6 1559 1.163 1.16 14.53 8.94 0.3 3.4 2 0.63 9.52 3.73 0.9 13.51 9.32 52.5 5.28 1.17 3.68 0.322 237.3 1.218 40 1.8 177.33 4.72 2.07 74.35 5 0.88 0.3 4.5 5.87 6.46 238.1 9.24 0.38 2.16 0.06 0.87 14.64 40.07 6.66 22.3 3.42 2.92 0.34 13.55 10 0.299 2.4 3.97 0.31 2.16 203.23 0.43 0.6 45.41 31.79 27.85 1.91 14.63 0.5 5 161.29 2.04 0.4 2.3 36.68 10 1.19 245.47 19.58 3.67 374 2.1 2.76 0.47 0.44 3.3 0.043 13 7.27 0.18 2.4 0.86 0.04 1.4 10 3.7 0.21 4 0.68 0.3 5.7 3.07 0.86 3.92 8.09 P

0361-0128/98/000/000-00 $6.00 1560 RHYOLITE GEOCHEMICAL SIGNATURES AND ASSOCIATION WITH VMS, ABITIBI BELT, CANADA 1561

APPENDIX 2 Mineralogy of Felsic Volcanic Rocks as Determined from Thin Section

Phenocrysts Alteration Pl Matrix Sample District Group Qz Pl Tot Chl Ser Car Qz-Pl Chl Ser Car Epi Hbl Bio Zir Op

R-2003-1 Quévillon FI 10 15 25 10-100 50 6 12 6 1 R-2003-2 Quévillon FI 2 2 64 0.5 18 5 0.5 10 R-2003-3 Quévillon FI 15 15 15 20 15 35 15 R-2003-4 Quévillon FIIIa 4 2 6 5 0.5 70 5 15 1 1 2 R-2003-5 Quévillon FIIIa 83 4 10.5 0.5 2 R-2003-8 Quévillon FIIIa 4 5 9 5 5 15 15 57 3 1 R-2003-9 Quévillon FIIIa 1 2 3 3 3 87 7 3 R-2003-10 Val-d'Or FII 80 1 15 4 R-2003-11 Val-d'Or FII 60 18 20 2 R-2003-12 Val-d'Or FII R-2003-13 Val-d'Or FIIIa R-2003-14 Val-d'Or FII R-2003-15 Val-d'Or FII 28 34 34 1 3 R-2003-16 Val-d'Or FII 1 1 2 10 70 10 10 6 2 R-2003-17 Val-d'Or FII R-2003-18 Val-d'Or FII 52 28 20 R-2003-19 Val-d'Or FII ? 64 8 17 10 1 R-2003-20 Val-d'Or FII 69 30 1 R-2003-116 Val-d'Or FII 2 2 0-10 20-70 0-7 75 5 15 1 2 R-2003-21 NVZ-Ext FII 73 19 8 R-2003-22 NVZ-Ext FII 34 34 31 1 R-2003-23 NVZ-Ext FII R-2003-25 NVZ-Ext FII 2 2 4 3-25 20 67 26 2 1 R-2003-26 NVZ-Ext FII 10 10 20 20 10-70 42 12 20 5 1 R-2003-27 NVZ-Ext FII 3 3 86 10 1 R-2003-28 NVZ-Ext FII R-2003-29 NVZ-Ext FII 5 5 10 90 75 15 2 3 R-2003-30 NVZ-Ext FII 1 1 90 30 39 10 20 R-2003-31 NVZ-Ext FII 1 3 4 3 20 47 13 23 10 3 R-2003-32 NVZ-Ext FII 10 10 0-10 10 0-2 53 1 20 15 1 R-2003-37 NVZ-Ext FII 90 5 5 R-2003-42 NVZ-Ext FII 0.5 1 1.5 30 33 15 25 3 0.5 11 11 R-2003-43 NVZ-Ext FII 0.5 0.5 89.5 7 3 R-2003-34 Normétal FIIIa 40 59 1 R-2003-35 Normétal FIIIa 81 13 6 R-2003-36 Normétal FII 80 5 15 R-2003-38 Normétal FII R-2003-44 Joutel FII R-2003-45 Joutel FII 1 3 4 6 10 70 11 12 3 R-2003-46 Joutel FI 1 3 4 5-20 15 69 10 15 1 1 R-2003-47 Joutel FIIIa 3 3 64 30 3 R-2003-48 Joutel FIIIa 10 4 14 2 10-80 52 15 15 3 1 R-2003-51 Matagami FIIIb 0.5 0.5 1 3 65 8 10 10 6 R-2003-52 Matagami FIIIb 0.5 0.5 3 3 75.5 16 3 5 R-2003-53 Matagami FIIIb 51 47 2 R-2003-54 Matagami FIIIb 70 70 5 20 5 R-2003-55 Hunter FII 6 6 100 67 15 10 2 R-2003-56 Hunter FII 0.5 0.5 2 5 71 0.5 15 10 3 R-2003-57 Hunter FII 2 10 12 5 10 63 5 15 3 2 R-2003-58 Hunter FII 1 1 2 5 3-10 2 71 12 10 3 2 R-2003-59 Hunter FII 1 6 7 5 10-70 73539 3 R-2003-60 Hunter FII 1 15 16 0-15 3 0-98 52 18 6 8 R-2003-61 Hunter FII 3 17 20 0-80 0-95 13 51 6 10 R-2003-62 Hunter FII 0.5 0.5 61.5 19 17 2 R-2003-63 Hunter FII 1 1 82 5 10 1 1 R-2003-64 Hunter FII 3 3 0-100 76 15 3 3 R-2003-65 Hunter FII 5 15 20 10 5-15 55 10 5 5 5 R-2003-66 Hunter FII 3 3 51 20 13 7 5 1 R-2003-108 Chibougamau FI 15 15 20 60 25 18 35 7 R-2003-109 Chibougamau FI 1 3 4 20 1 81.5 7 7 0.5 R-2003-110 Chibougamau FII ? 52.5 5 37 0.5 5 R-2003-111 Chibougamau FIIIa 2 2 4 1 3 7 20 7 60 7 2 R-2003-112 Chibougamau FIIIa 4 10 14 1 10 3 61.5 10 10 1.5 3 R-2003-113 Chibougamau FIIIa 4 4 65.5 20 10 0.5 R-2003-50 Selbaie FII 0.5 0.5 1 25 5 20 68 5 6 R-2003-117 Selbaie FII 3 3 100 65 1 30 1

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APPENDIX 2 (Cont.)

Phenocrysts Alteration Pl Matrix Sample District Group Qz Pl Tot Chl Ser Car Qz-Pl Chl Ser Car Epi Hbl Bio Zir Op

R-2003-118 Selbaie FII 0.5 0.5 65 33 1 0.5 R-2003-67 Noranda FIIIa Tr 62 15 6 12 5 R-2003-68 Noranda FIIIa 0.5 3 3.5 40 3 33.5 8 47 6 2 R-2003-69 Noranda FIIIa 0.5 2 2.5 3 3 81.5 3 2 7 4 R-2003-70 Noranda FIIIa 1 2 3 91.5 2 1 0.5 2 R-2003-71 Noranda FIIIa 67 31 2 R-2003-72 Noranda FIIIa 82 10 7 1 R-2003-73 Noranda FIIIa 1 1 20 15 52 26 19 2 R-2003-74 Noranda FIIIa ? 0.5 0.5 54.5 2 38 5 R-2003-75 Noranda FIIIa 5 1 6 10 5-65 2 70 20 3 1 R-2003-76 Noranda FIIIa 6 3 9 5 15 3 75833 2 R-2003-77 Noranda FIIIa 75 6 15 2 2 R-2003-78 Noranda FIIIa 1 1 5 5 90 75.5 6 10 7 0.5 R-2003-79 Noranda FIIIa 7 7 60 7 15 10 1 R-2003-80 Noranda FIIIa 0.5 0.5 2-10 0-10 82.5 1 7 6 3 R-2003-81 Noranda FIIIa 79 2 5 12 2 R-2003-82 Noranda FIIIa 1 24 25 10 90 15 15 40 5 R-2003-83 Noranda FIIIa 0.5 0.5 3 0.5 84.5 4 6 5 R-2003-84 Noranda FIIIa 1 1 2 65 12 13 64.5 12 3 0.5 5 R-2003-88 Noranda FIIIa 9 1 10 38 2 65867 3 1 R-2003-89 Noranda FIIIa 0.5 0.5 1 1 5 40 5 50 2 2 R-2003-90 Noranda FIIIa 0.5 1 1.5 3 88 5 1 2.5 2 R-2003-92 Noranda FIIIa ? 33 33 5 80 5 20 15 10 15 7 R-2003-93 Noranda FIIIa R-2003-95 Noranda FIIIa R-2003-96 Noranda FIIIa 7 3 10 1 1 2 60.5 25 3 1 0.5 R-2003-97 Noranda FIIIa 8 15 23 3 10 3 49 12 12 2 2 R-2003-98 Noranda FIIIa 3 77 80 5 5 0.5 9 3 1 7 R-2003-99 Noranda FIIIa 3 0.5 3.5 5 2 71.5 2 7 15 1 R-2003-100 Bousquet FI 0.5 0.5 68 0.5 25 3 3 R-2003-101 Bousquet FI 5 10 15 3 20 10 50 3 24 3 5 R-2003-102 Bousquet FI 50.5 3 40 1 0.5 5 R-2003-103 Bousquet FI R-2003-104 Bousquet FI 4 5 9 22 1 60 5 20 5 1 R-2003-105 Bousquet FI 3 10 13 5-10 6-10 71.5 1 10 3.5 0.5 0.5 R-2003-41 NVZ-ext FI 15 10 25 3-60 48 10 10 7 R-2003-85 Kinojevis FII 5 2 7 4 0.5 77.5 15 0.5 R-2003-106 Coniagas FII 0.5 1 1.5 1 3 25 15 0.5 55.5 0.5 2 R-2003-107 Lac Hébert FI 10 10 20 7 68.5 0.5 9 0.5 0.5 1 R-2003-114 NVZ-int FI 3 3 51 35 5 6 R-2003-115 NVZ-int FI 0.5 0.5 53 2 25 19 0.5 R-2003-119 Marbridge FII 93.5 1 3 2 0.5

Notes: Phenocryst >0.5 mm; abbreviations: Bio = biotite, Car = carbonate, Chl = chlorite, Epi = epidote, Hbl = hornblende, Op = opaque, Pl = plagioclase, Qz = quartz, Ser = sericite, Zir = zircon

0361-0128/98/000/000-00 $6.00 1562