0361-0128/08/3785/1531-32 1531
IntroductionFOR MORE than 25 years, the association between specificrhyolite suites and volcanogenic massive sulfide (VMS) de-posits was promoted as an effective tool for exploration.Thurston (1981) and Campbell et al. (1982) first identifiedthis relationship using Archean VMS deposits in the CanadianShield. Lesher et al. (1986) and Barrie et al. (1993) subse-quently developed formal classifications for felsic volcanicrocks based on trace element concentrations and suggestedthat certain types of rhyolites were more prospective for VMSdeposits than others. Recently, Hart et al. (2004) revitalizedthe concept by proposing a conceptual petrogenetic model to
account for the association of specific rhyolite geochemicalsignatures with VMS deposits. The classification geochemi-cally discriminates rhyolites as FI, FII, FIIIa, or FIIIb types.The general conclusions drawn from Lesher et al. (1986),Lentz (1998), and Hart et al. (2004) are that Archean VMSdeposits are hosted mainly by FIII rhyolites, whereas mostpost-Archean VMS deposits are hosted predominantly by FIIrhyolites, and FI rhyolites are unfavorable for VMS mineral-ization. The link between VMS formation (hydrothermal ac-tivity) and rhyolite petrogenesis invokes a particular geody-namic setting and, more specifically, the depth of rhyolitegeneration (Lentz 1998; Hart et al., 2004).
Although exceptions and limitations were recognized, theconcept was rapidly adopted by exploration companies, andrhyolites with the most potential were commonly selectedwithout any consideration for the mineral potential of other
Rhyolite Geochemical Signatures and Association with Volcanogenic Massive SulfideDeposits: 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
AbstractThe 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 usedclassification 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 usuallyconsidered barren, unless associated with FII or FIII felsic volcanic rocks. The FII rhyolites are calc-alkalineto transitional with moderately fractionated REE patterns and moderate Ta and Nb anomalies. They rangefrom barren to having a high potential to host VMS mineralization. The FIIIa and FIIIb rhyolites are tholei-itic and show weakly fractionated REE patterns and weak to absent Nb and Ta anomalies. They have the high-est potential to host VMS mineralization. The FIIIb rhyolites are high-temperature rhyolites with flat REE pat-terns 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 clas-sic Noranda VMS district, were analyzed for major and trace elements to validate their proposed favorabilityfor hosting VMS deposits. Results indicate that all of the rhyolite types are prospective, but mineralizationmay differ from the classic Noranda-type VMS deposit. The FI-type rhyolites appear to be particularly asso-ciated with gold-rich VMS deposits, such as the world-class Laronde deposit, and are more prospective forCu-Au replacement and vein-type deposits. The FII-type rhyolites account for about 70 percent of rhyolitesin the Abitibi belt. Although considered less prospective, some districts dominated by FII rhyolites, such asVal-d’Or and Selbaie, have collectively produced in excess of 100 million metric tons (Mt) of ore. Deposits inthese districts mainly consist of sulfide veins and disseminated ore with low Cu and Zn grades and are asso-ciated with abundant and highly vesicular volcaniclastic rocks that display a compositional continuum fromandesite to rhyolite. Other weakly mineralized FII districts (e.g., Hunter mine, Gemini-Turgeon) are charac-terized instead by bimodal flow-dome sequences. The FIIIa-type rhyolites occur mainly in the Noranda dis-trict 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 FIIIato FII to FI affinities, VMS deposits are directly associated with FIIIa rhyolites, thus demonstrating the use-fulness 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 onthis analysis, we suggest that a combination of rhyolite geochemistry, volcanic facies, and style of the miner-alization may be more meaningfully applied in exploration than rhyolite type alone, particularly in the case ofFI and FII rhyolites.
† Corresponding author: e-mail, [email protected]*Present address: Mines Virginia Inc., 116 St-Pierre, Suite 200, Québec,
Québec, Canada G1K 4A7.
©2008 Society of Economic Geologists, Inc.Economic Geology, v. 103, pp. 1531–1562
rhyolites in the vicinity. Recently, the discovery of the world-class, gold-rich VMS Laronde deposit in FI and FII rhyolites(Mercier-Langevin et al., 2007a, b) raised some doubt aboutthe application of rhyolite classification in VMS exploration.
The Archean Abitibi belt is one of the most prolific VMSbelts in the world (Rodney et al., 2002), hosting various typesof VMS and volcanogenic gold deposits. Consequently, thisbelt constitutes an ideal laboratory for testing the validity ofrhyolite classification as a means for finding ore deposits. Inthis paper, we reassess the use of rhyolite classification as anexploration tool in the Abitibi greenstone belt and present acompilation of the characteristics of ore-hosting rocks, alter-ation types, and volcanic facies. Felsic volcanic rocks in andaround VMS districts in the Abitibi belt of Quebec were sam-pled and analyzed for major and trace elements. Rhyoliteswere classified using the parameters of Hart et al. (2004) andcompared with VMS tonnages, mineralization type, and vol-canic rock characteristics. This approach permits a semiquan-titative comparison of the favorability of various rhyolite types.
Geology of the Abitibi BeltThe Abitibi greenstone belt in Canada (Fig. 1) is the largest
and best preserved Archean belt (Card, 1990) and also one ofthe richest VMS-bearing belts in the world (Rodney et al.,2002). These include syngenetic VMS and gold-rich VMS de-posits, as well as sulfide-rich, gold-bearing quartz veins andCu-Au–bearing sulfide veins. All are genetically associatedwith felsic volcanic complexes (e.g., Chartrand and Cattalani,1990). The Abitibi belt includes three of the world’s largestand richest VMS deposits (>50 Mt of ore)—Kidd Creek,Horne, and Laronde—of which the last two are gold rich.Eight other large deposits (>15 Mt) also have been mined:Selbaie, Mattagami Lake, Bouchard-Hébert, Louvicourt,East Sullivan, Bousquet-1, Dumagami-Bousquet-2, and Qué-mont. Overall, more than 80 deposits are known, totalingmore than 675 Mt of metallurgically high-quality Cu ± Zn ±Ag ± Au ore (Hannington et al., 1999a; Rodney et al., 2002).
The Abitibi greenstone belt is a linear east-trending vol-cano-sedimentary sequence intruded by plutonic suites (Fig.1). It is thought to have developed through arc formation, arcevolution, arc-arc collision, and arc fragmentation datingfrom 2735 to 2670 Ma (Mueller et al., 1996; Daigneault et al.,2004). Wyman et al. (2002) proposed that the Abitibi-Wawagreenstone belt is the product of subduction tectonics, en-hanced and modified by mantle plume interaction. The beltis broadly divided into the 2735 to 2705 Ma North Volcaniczone and the 2715 to 2697 Ma Southern Volcanic zone(Chown et al. 1992), although more recent compilations pre-sent a more complex evolution (e.g., Ayer et al., 2003, 2005;Goutier and Melancon, 2007). The east-trending Porcupine-Destor-Manneville fault separates the Northern and South-ern Volcanic zones, and the Cadillac-Larder Lake fault de-fines the southern boundary of the Southern Volcanic zone(Fig. 1). In addition, the North Volcanic zone is also dividedinto external (NVZ-ext) and internal (NVZ-int) segments(Fig. 1) separated by the linear, east-trending Chicobi sedi-mentary sequence (Daigneault et al., 2004).
Three main volcanic cycles are recognized in the Quebecsegment (Daigneault et al., 2004). Cycle 1, from 2735 to 2720Ma, corresponds to a subaqueous basaltic plain punctuated
by several isolated felsic centers, such as Joutel, Normétal,Matagami, Gemini, Selbaie, Hunter, and Chibougamau(Lemoine). All these felsic centers have well-documentedsynvolcanic intrusions (Gaboury, 2006), felsic domes andlavas, and associated VMS mineralization. Cycle 2, from 2720to 2705 Ma, is interpreted as an emerging and evolving arc, towhich some synvolcanic plutons have been linked (Chown etal., 1992), such as the Chibougamau pluton with its Cu-Auvein-type deposits, the Kamiskotia pluton (Barrie and Davis,1990) with VMS deposits in associated felsic lavas, and theMountain pluton, which has been indirectly dated at 2718 Mabased on the age of cogenetic felsic lavas at the Langlois VMSmine (Davis et al., 2005). The 2717 to 2711 Ma rhyolites atKidd Creek (Bleeker et al., 1999) are compositionally distinctfrom these other cycle 2 felsic rocks due to their high silicacontents and their REE-HFSE patterns comparable to rhyo-lites from the Iceland rift zone (Prior et al., 1999). The KiddCreek VMS deposit is also exceptional due to its size andmetal content (Hannington et al., 1999a), as well as the ap-parent lack of an association with a synvolcanic intrusion(Barrie et al., 1999). Cycle 3 is restricted to the Southern Vol-canic zone and is interpreted as arc volcanism (e.g.,Daigneault et al., 2004). The Southern Volcanic zone includesthe Blake River Group (2703–2698 Ma) and the Malartic seg-ment (2714–2701 Ma). The Blake River is thought to repre-sent the development of a multiphase megacaldera, recentlyproposed by Pearson and Daigneault (2009), which hostsmajor VMS deposits associated with three main synvolcanicintrusions, the Flavrian-Powell, Cléricy, and Mooshla intru-sions and associated felsic rocks. The Malartic segment hasrecorded a complex evolution (Scott et al., 2002) involving ko-matiitic rifting at the base (2714 Ma) followed by arc evolu-tion and later arc rifting (2705–2701). The VMS deposits ofthe Val-d’Or mining district occur specifically in the arc-re-lated volcanic sequence (Scott et al., 2002) associated withthe synvolcanic Bourlamaque pluton (Fig. 1).
Daigneault et al. (2004) determined that the deformationhistory is diachronous: 2710 to 2690 Ma in the North Volcaniczone and 2698 to 2640 Ma in the Southern Volcanic zone butfollowing the same pattern for both. In each case, the firstphase consisted of north-south deformation dominated byshortening that induced thrusting along major east-trendingboundary faults (the Porcupine-Destor-Manneville andCadillac-Larder Lake faults), folding, and the development ofa regional east-trending schistosity. The second phase was adextral, transpressional late-stage increment responsible fordextral movement along major east-trending faults (theDestor-Manneville and Cadillac-Larder Lake faults) and thedevelopment of a southeast-trending fault system. Syntec-tonic intrusions were emplaced locally during all stages of thedeformation history. As a consequence of this structural evo-lution, VMS-hosting sequences or districts occur as (1) mon-oclinal laterally extensive and tilted sequences located strati-graphically above their synvolcanic pluton, as exemplified bythe Normétal, Val-d’Or, Bousquet, Selbaie, Chibougamau(Lemoine), Langlois, and Gemini mining districts; (2) as se-quences occurring on both flanks of an anticline centered ona synvolcanic intrusion, such as those found in the Noranda,Matagami, and Hunter districts; or (3) as a complexly foldedsequence, such as the Joutel district.
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RHYOLITE GEOCHEMICAL SIGNATURES AND ASSOCIATION WITH VMS, ABITIBI BELT, CANADA 1533
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Syn
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Vol
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.1.
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of
the
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elt,
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loca
tions
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oury
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06).
Methodology
Sampling
During the summer of 2003, more than 120 felsic rocks(mainly rhyolite with minor quantities of dacite) were sam-pled from outcrop, with another four taken from drill cores(App. 1; Figs. 1–5). Four samples also were collected during
earlier visits to mines with deposits of interest. The aim wasto obtain a uniform sample dataset analyzed as one batchusing the best analytical procedures, thus avoiding compar-isons between different data sources representing a variety ofanalytical techniques, variable detection limits, and incom-plete analyses. The volcanic facies was taken into considera-tion when selecting samples. For example, in lobed felsic vol-canic domes and flows, only the lobe center or the massivefacies was sampled to reduce the possible influence of hy-drothermal alteration. The goal of the sampling strategy wasto compare (1) VMS-hosting rhyolites to surrounding rhyo-lites, (2) rhyolites from different mining districts, and (3) rhy-olites from areas considered relatively nonprospective forVMS deposits to rhyolites from known VMS districts. Aspecial emphasis was given to rhyolites associated with docu-mented atypical (vein and disseminated) gold-rich vol-canogenic deposits (e.g., Géant Dormant, Comtois, Agnico-Telbel, Duvan). Furthermore, dated rhyolites and felsic tuffswere also sampled to provide a temporal framework for theevolution of the felsic volcanism.
Geochemical analysis
All samples were processed at the Université du Québec àChicoutimi where they were cleaned to remove surfaceweathering, crushed, and then pulverized using an aluminashatter box. The shatter box was cleaned with quartz betweeneach sample and precontaminated with each new sample tominimize sample-to-sample contamination. The powderedsamples were shipped to the Geo Labs facility in Sudbury asone batch. The major elements were analyzed using wave-length-dispersive X-Ray florescence (WXRF) on fused pellets.
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R-54
Bell-Allard
5 km
R-52
R-51
R-53Persévérence
Matagami
Bell River
Felsic volcanic rocks
Mafic volcanic rocks
Intrusive rocks
VMS deposit
Mine (active or closed)
Road
Town
Sample: FIIIb
Lac Mattagami
N
Bracemac
McLeod
FIG. 2. Simplified geologic map of the Matagami district, showing sampleand VMS deposit locations. Map modified from Piché et al. (1993).
R-70
R-67
R-68
R-69
Aldermac
Inmont
R-96
R-97
R-95 R-94
R-93
R-80R-78
R-81
R-76 R-75
R-91
R-92
R-77R-79
R-99
R-84
R-83
R-90R-86
R-87
R-89
R-88
Bouchard-Hébert
Horne
Delbridge
R-74 Quémont
Rouyn-Noranda
BRG
Flavrian
5 km
Felsic volcanic rocks
Mafic volcanic rocks
VMS deposit
Mine (active or closed)
Road
Town
Sample: FIIIa Intrusive rocks
Sedimentary rocks
R-73
Sample: ?
N
R-71
FIG. 3. Simplified geologic map of the Noranda district, showing sample and VMS deposit locations. BRG = Blake RiverGroup. Map modified from Pearson and Daigneault (2009).
Trace elements were determined by ICP-MS following aclosed-beaker digestion method involving four acids over twoweeks to ensure total digestion of all minerals. Three repli-cates and one reference sample were included in the batch.The precision and accuracy of the analytical values were ex-cellent, including the results for potentially problematic Zr(standard deviation of <0.05% for trace elements). The ana-lytical results used in this study are provided in Appendix 1.
Petrographic studyThin sections were made from all samples except for those
from drill core and samples of insufficient size (App. 2). Thegoal of the petrographic study was to establish, (1) the per-centage and size of phenocrysts, (2) the nature of any offeldspar phenocryst alteration, and (3) the mineral assem-blage, overall composition, and intensity of the quartz-feldspar matrix alteration.
RHYOLITE GEOCHEMICAL SIGNATURES AND ASSOCIATION WITH VMS, ABITIBI BELT, CANADA 1535
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Agnico-Telbec
Poirier
Joutel Copper
R-46
R-48
R-47
R-45R-44
Joutel
Explo Zinc
Valrenne
5 km
La Sarre
Lyndhurst
Normétal
Duvan
Hunter
R-38
R-41
R-40
R-39
R-66 R-65
R-64
R-63R-62
R-57R-58
R-59
R-61R-60
R-37
R-36R-35
R-34
R-56R-55
Poularies
10 km
Quévillon
Comtois
R-8
R-3
R-2
R-1R-9
R-6
Langlois
R-4R-5
Mountain
5 km
Felsic volcanic rocks
Mafic volcanic rocks
VMS deposit
Mine (active or closed) Road Town
sample: FI
Intrusive rocks
Sedimentary rocks
Major fault
A Chibougamau
Lemoine
R-108
R-109
R-113R-111
R-112
R-110
Chibougamau
Lac Doré
WF
WF
WFWF
5 km
B
C DNVC
HMG HMG
JVC
sample: FII
sample: FIIIa
NN
NN
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 andDonaldson (1992). HMG = Hunter Mine Group, NVC = Normétal Volcanic Complex. D. Quévillon area (modified fromLacroix et al., 1993).
Assessment of Rhyolite Type Versus VMS PotentialAssessing exploration vectors and prospectiveness indicators
based on the presence of mineralization, number of deposits,and total ore tonnage is limited by the current state of knowl-edge and assumes that discovered orebodies represent high po-tential, and undiscovered mineralization represents low poten-tial. Sampling bias is another limiting constraint because it is
difficult to obtain a uniform sampling pattern. The VMS dis-tricts, particularly the best studied ones, are invariably oversam-pled, whereas smaller or remote districts are commonly under-represented, as are other areas considered to have low potential.Although it is impossible to overcome all these limitations, thisstudy has the advantage of including a wide range of felsic vol-canic rocks, whether associated with VMS mineralization or not.
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R-13
Val d'Or
Louvicourt
Akasaba
Dunraine
ManitouBarvu
East SullivanR-15
R-14
R-10R-12
R-11
R-116
R-18
R-19
R-17
R-20R-16
Abcourt
Lamorandière
Jay Copper
Vendome
Lyndhurst
Amos
R-41
R-40 R-43
R-32
R-31
R-42
R-39
R-65R-66
R-64
R-85
R-63
R-62
R-29
R-33
R-27
R-30
R-21
R-22
R-26
R-23
VDF
HF
Bourlamaque
CLLF
PDMF
Kinojevisformation
Chicobi
NVZ-ext
5 km
Felsic volcanic rocks
Mafic volcanic rocks VMS deposit
Mine (active or closed)
Road
Town
Sample: FI
Intrusive rocks
Sedimentary rocks Major fault
B
A
R-25
Sample: FII
Sample: FIIIa
10 km
N
N
R-28
FIG. 5. A. Simplified geologic map, showing sample and VMS deposit locations. B. Val-d’Or district (modified from Scottet al., 2002). CLLF = Cadillac-Larder Lake fault, HF = Heva Formation, VDF = Val-d’Or Formation. B. External NorthVolcanic zone (NVZ) area (modified from Chown et al., 1992). PDMF = Porcupine-Destor-Manneville fault.
In the following sections, mining districts and areas of in-terest are described and classified in terms of predominantrhyolite-VMS associations, with rhyolite types determined ac-cording to parameters of Hart et al. (2004). Although our ap-proach uses informal subdivisions of mining districts, effusivecenters, and geographic sectors that may have multiple felsichorizons, and in some cases, various rhyolite types, it has nu-merous advantages described above.
The geochemical signatures of rhyolites directly associatedwith VMS and VMS-related mineralization are compared toother rhyolites from the same district, referred to here as“background rhyolites,” in an attempt to uncover any geo-chemical trends within districts. Tonnage values for the vari-ous districts were compiled using data from Chartrand andCattalani (1990), Lacroix (1998), and Hannington et al.(1999a), in addition to data from companies where necessary.Ore, alteration, and volcanic host-rock characteristics werealso compared (Tables 1, 2).
To overcome the effect of hydrothermal alteration in classi-fying the rhyolite samples, only HFSE and REE were used.Some altered rhyolite (or dacite) samples in the footwall andlateral to VMS deposits have major element concentrationsranging from apparent andesite (<63%) to high-silica rhyolite(>80% SiO2). Even trace elements (LREE) reputed to be im-mobile show some variations in strongly altered footwall rocksand these particular samples are identified in the text. Itshould be noted, however, that with the exception of theseanomalous altered rhyolites, most samples display no differ-ences in REE and HFSE concentrations compared to thebackground rhyolites and are thus considered suitable for thepurpose of this study.
Rhyolite Classification and PetrogenesisFour types of rhyolite are identified by Lesher et al. (1986):
FI, FII, FIIIa, and FIIIb. The FIV-type rhyolites (Hart et al.,2004) are virtually absent from Archean suites and are notdiscussed. The FI rhyolites are alkaline to calc-alkaline, withstrongly fractionated REE patterns and strongly negative Taand Nb anomalies. They are considered barren to rarely fa-vorable for hosting VMS deposits. The FII rhyolites are calc-alkaline to transitional (following the nomenclature of Barrettand MacLean, 1994), with moderately fractionated REE pat-terns and moderate Ta and Nb anomalies. They are consid-ered moderately favorable for hosting VMS deposits. TheFIIIa and FIIIb rhyolites are tholeiitic and considered tohave the greatest potential for hosting VMS deposits. TheFIIIa rhyolites show weakly fractionated REE patterns andweak to nonexistent Nb and Ta anomalies. The FIIIb rhyo-lites are high-temperature rhyolites with flat REE patternsthat lack Ta and Nb anomalies.
Recently, Hart et al. (2004) linked the geochemical signa-tures of various rhyolite types to partial melting depths withina rift environment. The FI, FII, and FIII magmas are inter-preted as having equilibrated with garnet-bearing residua at adepth of >30 km, with amphibole-plagioclase residua at 30 to10 km, and with plagioclase-dominant, garnet-amphibole–free residua at <15-km depth, respectively.
Hart et al. (2004) provided a list of compositional ranges todiscriminate between the four rhyolite types. Four of themost useful elements are Zr, Y, La, and Yb because they are
generally immobile during hydrothermal alteration and arerepresentative of petrogenetic processes. These elementswere used to create Zr/Y versus Y and [La/Yb]CN versus YbCN
(chondrite-normalized: Nakamura, 1974) binary classificationdiagrams (Lesher et al., 1986; Barrie et al., 1993; Lentz,1998). A drawback of these classification parameters is theoverlap of some discriminating compositional ranges for thevarious rhyolite types. When plotted on the binary diagrams(Fig. 6), only 61 percent of the samples fall into the same clas-sification field on both plots. To overcome this discrepancy,primitive mantle-normalized multielement plots were used inthis study. These plots allow for better discrimination be-tween rhyolite signatures, and distinguishing features, such asnegative Nb and Ta anomalies associated with subductionprocesses, Eu anomalies, and degree of REE fractionation,can be better visualized (e.g., Sun and McDonough, 1989;Kerrich and Wyman, 1997).
FIIIb RhyolitesThe FIIIb rhyolites are defined as tholeiitic high-silica,
high-temperature rhyolites with flat rare earth element(REE) patterns expressed by [La/Yb]CN chondrite-normal-ized values of 1.1 to 4.9, high concentrations of high fieldstrength elements (Y, Zr, Hf, and HREE), low Zr/Y ratios,pronounced negative Eu anomalies, and a lack of subduction-related anomalies such as Nb and Ta (Hart et al., 2004). Thistype of rhyolite was initially identified at Kidd Creek,Kamiskotia, and in the Matagami district (Lesher et al., 1986).
Matagami mining district
The Matagami area (Fig. 2) is an important VMS districtwith total past production and current reserves of more than 50Mt of ore from 12 deposits, including the 5-Mt Zn-Cu Perse-verance deposit presently under development (Xstrata Zinc).The volcanic succession is folded along the open northwest-plunging Galinée anticline (Sharpe, 1968), which is centeredon the synvolcanic Bell River intrusion. The south flank is alow-strain domain with the volcanic sequence facing and dip-ping 45º south, whereas the north flank is a highly strained,steeply dipping domain (Piché et al., 1993). The stratigraphicsuccession comprises the 2721 Ma (Mortensen et al., 1993)rhyolitic Watson Lake Group at the base overlain by thebasaltic Wabasse Group (Beaudry and Gaucher, 1986). TheWatson Group consists of a 1,000-m-thick sequence of felsiclava flows representing the footwall of VMS deposits in the re-gion, with the exception of the newly discovered Bracemac andMcLeod deposits. All the deposits, except Bracemac andMcLeod, lie along a cherty and sulfide-enriched unit called theKey tuffite at the interface of both groups (Piché et al., 1993).
The south and north flanks of the Watson Group were sam-pled from: (1) the underground footwall at the Bell-Allardmine, (2) a surface stripping of the rhyolite hosting the Per-severance deposit, (3) the location of the rhyolite for whichMortensen et al. (1993) determined a geochron U-Pb age of2721 Ma (sample R-53 in this study), and (4) rhyolites northof the town (Fig. 2). All four samples have flat HFSE-REEpatterns as previously documented by Lesher et al. (1986)and Barrie et al. (1993), and the pattern for the Bell-Allardfootwall rhyolite sample is the same as the pattern for theother three (Fig. 7).
RHYOLITE GEOCHEMICAL SIGNATURES AND ASSOCIATION WITH VMS, ABITIBI BELT, CANADA 1537
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1538 GABOURY AND PEARSON
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TAB
LE
1. C
hara
cter
istic
s of
Hos
t Vol
cani
c Se
quen
ces
in S
elec
ted
VM
S D
istr
icts
Are
aG
roup
Volc
anic
sty
leVe
sicu
lari
tyVo
lcan
ic h
iatu
sF
elsi
c co
mpo
sitio
n ev
olut
ion
Intr
usio
nR
efer
ence
Mat
agam
iF
IIIb
Bim
odal
maf
ic-f
elsi
c, lo
bate
fels
ic la
va
Low
-med
ium
Key
tuff
ite: m
ain
Hom
ogen
eous
at t
he
Bel
l Riv
erPi
ché
et a
l. (
1993
)flo
ws
with
mul
ticen
tere
d co
ales
cent
ho
rizo
n ho
stin
g di
stri
ct s
cale
volc
anis
m fo
rmin
g a
unit
of r
egio
nal
all d
epos
itsex
tent
, wel
l-doc
umen
ted
synv
olca
nic
faul
ts
Nor
anda
FII
IaB
imod
al m
afic
-fel
sic
volc
anis
m w
ith
Low
Mul
tiple
che
rt
Hom
ogen
ous
at th
e C
leri
cyK
err
and
mul
tiple
isol
ated
to lo
cally
coa
lesc
ent
hori
zons
def
inin
g di
stri
ct s
cale
Fla
vria
nG
ibso
n (1
993)
fels
ic c
ente
rs, d
omin
ated
by
loba
te fe
lsic
m
ultip
le v
olca
nic
Pow
ell
lava
flow
s; w
ell-d
ocum
ente
d sy
nvol
cani
c cy
cles
faul
ts, s
ome
of r
egio
nal e
xten
t
Jout
elF
IIIa
Bim
odal
vol
cani
sm d
omin
ated
by
loba
te
Low
Che
rty
hori
zons
E
volu
tion
from
thol
eiiti
c Va
lren
neL
egau
lt et
al.
(200
2)fe
lsic
lava
s w
ith le
sser
tuff
aceo
us r
ocks
(not
wel
l-del
inea
ted
to tr
ansi
tiona
l to
calc
-alk
alin
ere
gion
ally
)
Nor
mét
alF
IIIa
Rift
-rel
ated
bim
odal
vol
cani
sm d
omin
ated
L
owB
ande
d ir
on
Evo
lutio
n fr
om tr
ansi
tiona
l U
nkno
wn
Laf
ranc
e et
al.
(200
0)by
flow
s an
d le
sser
cla
stic
faci
es; i
sola
ted
form
atio
n at
the
top
to th
olei
itic
fels
ic c
ente
rs a
long
syn
volc
anic
faul
ts
of th
e ho
st u
nit
bord
erin
g ri
ft m
argi
ns
Qué
villo
nF
IIIa
Stro
ngly
def
orm
ed b
imod
al s
eque
nces
L
ow to
non
eN
ot d
ocum
ente
dVa
riab
le a
t the
dis
tric
t sca
le,
Mou
ntai
nL
acro
ix e
t al.
(199
3)w
ith p
oorl
y pr
eser
ved
volc
anic
faci
es
num
erou
s fe
lsic
hor
izon
san
d ar
chite
ctur
e
Val-d
’Or
FII
And
esite
to r
hyol
ite, v
olca
nicl
astic
-H
igh
Loc
al fi
ne-g
rain
ed
Sim
ilar
at th
e di
stri
ct s
cale
B
ourl
amaq
ueSc
ott e
t al.
(200
2)do
min
ated
vol
cani
sm w
ith lo
cal d
omes
se
dim
ents
and
lava
flow
s pr
oxim
al to
eff
usiv
e ce
nter
; mul
ticen
tere
d co
ales
cent
vo
lcan
ism
Selb
aie
FII
And
esite
to r
hyol
ite, v
olca
nicl
astic
-H
igh
Loc
al p
yrite
-ric
h Si
mila
r at
the
dist
rict
sca
le
Bro
uilla
nL
arse
n an
d do
min
ated
vol
cani
sm w
ith lo
cal d
ome
sedi
men
tsH
utch
inso
n (1
993)
and
lava
flow
s pr
oxim
al to
eff
usiv
e ce
nter
; mul
ticen
tere
d co
ales
cent
vo
lcan
ism
Hun
ter
FII
Cal
dera
-rel
ated
bim
odal
seq
uenc
e,
Low
to n
one
Ban
ded
iron
Si
mila
r at
the
dist
rict
sca
le
Poul
arie
sM
uelle
r an
d ab
unda
nt fe
lsic
flow
s, la
rge
disc
orda
nt
form
atio
n at
the
top
Mor
tens
en (
2002
)fe
lsic
dik
e sw
arm
of th
e ho
st u
nits
Bou
sque
tF
I an
d F
IIA
ndes
ite to
rhy
odac
ite, v
olca
nicl
astic
-H
igh
Non
eSi
mila
r at
the
dist
rict
sca
le
Moo
shla
Laf
ranc
e et
al.
(200
3)do
min
ated
vol
cani
sm w
ith lo
cal d
ome
and
lava
flow
s pr
oxim
al to
eff
usiv
e ce
nter
s; m
ultic
ente
red
coal
esce
nt
volc
anis
m
RHYOLITE GEOCHEMICAL SIGNATURES AND ASSOCIATION WITH VMS, ABITIBI BELT, CANADA 1539
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TAB
LE
2. C
hara
cter
istic
s of
VM
S D
epos
its in
Sel
ecte
d D
istr
icts
Are
asG
roup
Mai
n de
posi
tsM
etal
sM
iner
aliz
atio
n st
yle
Alte
ratio
nR
efer
ence
Mat
agam
iF
IIIb
Mat
taga
mi L
ake
Zn-C
u-A
gM
assi
ve s
trat
iform
exh
alat
ive
sulfi
de le
nses
abo
ve a
C
hlor
iteL
aval
lière
(19
95)
Bel
l-Alla
rdre
gion
al c
hert
y ho
rizo
n w
ith w
ell-d
efin
ed u
nder
lyin
g Ta
lcPe
rsev
eran
cedi
scor
dant
str
inge
r zo
nes
Seri
cite
Nor
anda
FII
IaQ
uém
ont
Cu-
Zn-A
u-A
gM
assi
ve s
trat
iform
exh
alat
ive
sulfi
de le
nses
abo
ve
Chl
orite
Ker
r an
d A
nsil
regi
onal
che
rty
hori
zons
with
wel
l-def
ined
und
erly
ing
Seri
cite
Gib
son
(199
3)C
orbe
tdi
scor
dant
str
inge
r an
d al
tera
tion
zone
s
Nor
anda
FII
Ia
Hor
neC
u-A
uC
igar
-sha
ped
mas
sive
sul
fide
lens
es r
epla
cing
fels
ic
Seri
cite
Mac
Lea
n an
d F
IIvo
lcan
icla
stic
roc
ks w
ith a
ssoc
iate
d su
lfide
str
inge
r zo
nes
Silic
ifica
tion
Hoy
(19
91)
(H z
ones
); su
lfide
dis
sem
inat
ion
and
repl
acem
ent o
f ±
Chl
orite
fels
ic v
olca
nicl
astic
roc
ks (
Zn-r
ich
zone
5)
Jout
elF
IIIa
Poir
ier
Zn-
Cu-
Ag
Fol
ded
mas
sive
sul
fide
lens
es w
ith b
edde
d py
rite
hos
ted
Chl
orite
Leg
ault
et a
l. (2
002)
Jout
el C
oppe
rin
mas
sive
to b
recc
iate
d an
d ch
erty
rhy
olite
with
ass
ocia
ted
Seri
cite
disc
orda
nt C
u-ri
ch s
trin
ger
zone
s in
chl
oriti
c al
tera
tion
Silic
ifica
tion
Nor
mét
alF
IIIa
Nor
mét
alZn
-Cu-
Au-
Ag
Stro
ngly
def
orm
ed, v
ertic
ally
plu
ngin
g, c
igar
-sha
ped
Chl
orite
Laf
ranc
e (2
003)
Nor
met
mar
sulfi
de le
nses
Seri
cite
Fe-
carb
onat
e
Qué
villo
nF
IIIa
Lan
gloi
sZn
-Cu-
Au-
Ag
Stro
ngly
def
orm
ed a
nd tr
ansp
osed
as
vert
ical
tabu
lar
sulfi
de le
nses
; C
hlor
iteL
acro
ix e
t al.
(199
3)
Zone
97
very
wea
k pr
eser
vatio
n of
ori
gina
l vol
cani
c ch
arac
teri
stic
sSe
rici
te
Val-d
’Or
FII
Lou
vico
urt
Cu-
Zn, A
u-A
gM
ostly
dis
sem
inat
ed s
ulfid
es a
nd a
ssoc
iate
d m
assi
ve r
epla
cem
ent-
Chl
orite
Jenk
ins
and
Eas
t Sul
livan
type
pod
s an
d le
nses
; no
reco
gniz
ed w
ell-d
efin
ed d
isco
rdan
t Se
rici
teB
row
n (1
999)
Man
itou-
Bar
vue
stri
nger
zon
e or
che
rt; m
iner
aliz
atio
n oc
curs
at v
ario
us s
trat
igra
phic
F
e-ca
rbon
ate
leve
ls a
t the
dis
tric
t sca
le
Selb
aie
FII
Zone
A1,
A2,
BC
u-Zn
-Au-
Ag
Mas
sive
sul
fide
Cu-
and
Au-
rich
dis
cord
ant l
ense
s (A
2 an
d B
), C
hlor
iteL
arse
n an
d di
ssem
inat
ed a
nd s
trin
ger
Zn-r
ich
sulfi
de m
iner
aliz
atio
n in
fels
ic
Seri
cite
Hut
chin
son
(199
3)vo
lcan
icla
stic
roc
ks, m
assi
ve c
onco
rdan
t pyr
itic
lens
es o
f low
Si
licifi
catio
ngr
ade
(A1)
Hun
ter
FII
Hun
ter
Cu-
Zn-A
u-A
gC
onco
rdan
t, ex
hala
tive
mas
sive
sul
fide
lens
es w
ith u
nder
lyin
g C
hlor
iteB
onne
au (
1992
)L
yndh
urst
disc
orda
nt s
trin
ger
zone
s; d
epos
its a
re a
t the
top
of th
e vo
lcan
ic
Seri
cite
pile
nea
r ir
on fo
rmat
ions
and
sed
imen
ts
Bou
sque
tF
I an
d F
IIL
aron
deA
u-C
u-Zn
-Ag
Rep
lace
men
t-ty
pe g
old-
rich
sul
fide
lens
es in
vol
cani
clas
tic h
oriz
ons,
A
lum
inou
sM
erci
er-
Bou
sque
t 1 a
nd 2
Au-
Cu
no a
ssoc
iate
d ch
ert,
no d
isco
rdan
t str
inge
r zo
ne; m
iner
aliz
atio
n C
hlor
iteL
ange
vin
(200
5)D
umag
ami
occu
rs a
t var
ious
str
atig
raph
ic le
vels
at t
he d
istr
ict s
cale
Seri
cite
Jout
elF
IA
gnic
o-Te
lbel
Au-
Ag
Dis
sem
inat
ed to
mas
sive
ban
ds o
f gol
d-be
arin
g py
rite
Fe-
carb
onat
eG
auth
ier
et a
l. (2
003)
Chl
orite
Seri
cite
Qué
villo
nF
IC
omto
isA
u-A
gD
isse
min
ated
to s
trin
ger-
styl
e go
ld-b
eari
ng p
yriti
c m
iner
aliz
atio
nA
lum
inou
sD
upré
et a
l. (2
002)
NV
Z-in
t1F
IG
éant
Dor
man
tA
u-A
g (C
u, Z
n)Va
riab
ly o
rien
ted
sulfi
de-r
ich
quar
tz v
eins
Chl
orite
Gab
oury
and
Se
rici
teD
aign
eaul
t (19
99)
NV
Z-ex
t1F
ID
uvan
Cu-
Ag
Dis
sem
inat
ed to
mas
sive
ban
ds o
f pyr
ite w
ith a
bund
ant m
agne
tite
Chl
orite
Trem
blay
et a
l. (1
996)
host
ed in
tuff
aceo
us v
olca
nicl
astic
roc
ks
Seri
cite
1 A
bbre
viat
ions
: NV
Z-ex
t = e
xter
nal N
orth
Vol
cani
c zo
ne, N
VZ-
int =
inte
rnal
Nor
th V
olca
nic
zone
1540 GABOURY AND PEARSON
0361-0128/98/000/000-00 $6.00 1540
0
5
10
15
20
25Joutel
0
5
10
15
20
25Matagami
0
5
10
15
20
25Quévillon
0
5
10
15
20
25
30Val-d'Or
0
5
10
15
20
25External North Volcanic Zone
5
10
15
20
25Hunter
0
5
10
15
20
25
0 25 50 75 100 125 150
Legend
FI
FII FIIIaFIIIb
Y
Zr/
YDunraine
Manitou-Barvue
Louvicourt
East-Sullivan
spherulitic rhyolite
Duvan
Lamorandière
Vendome
Abcourt
Hunter
LyndHurst
Langlois
Comtois
Eagle-Telbel
Poirier
Bell-AllardPerseverance
1
10
100Quévillon
1
10
100Val-d'Or
1
10
100
0 25 50 75 100 125 150
1
10
100Hunter
1
10
100Joutel
1
10
100Matagami
100
1
10
LegendFI
FII
FIIIa FIIIb
Langlois
Comtois
Eagle-Telbel
Poirier
Bell-Allard
Perseverance
Dunraine
Manitou-Barvue
Louvicourt
East-Sullivan
spherulitic rhyolite
Hunter
Lyndhurst
Duvan
Lamorandière
Vendome
Abcourt
[La/
Yb]
CN
YbCN
External North Volcanic Zone
FIG. 6. Binary classification diagrams of Zr/Y vs. Y (Lesher et al., 1986) and [La/Yb]CN vs. YbCN (Barrie et al., 1993), show-ing some overlapping of discrimination fields leading to uncertainty in rhyolite classification. Classification fields are fromLentz (1998) and chondrite-normalizing values (CN) from Nakamura (1974).
RHYOLITE GEOCHEMICAL SIGNATURES AND ASSOCIATION WITH VMS, ABITIBI BELT, CANADA 1541
0361-0128/98/000/000-00 $6.00 1541
0
5
10
15
20
25Bousquet
0
5
10
15
20
25Gemini-Turgeon
5
10
15
20
25Selbaie
0
5
10
15
20
25Normétal
0
5
10
15
20
25
30Noranda
0
5
10
15
20
25
0 25 50 75 100 125 150
Other
0
5
10
15
20
25Chibougamau
Y
Zr/
Y
Géant Dormant
Coniagas
Lemoine
Normétal footwall
Superhyolite (silification)
Selbaie, zone A1
Laronde zone 20 footwall
Bouchard-Hébert (1100)Horne
Delbridge
Inmont
1
10
0 25 50 75 100 125 150
Other
1
10
100Noranda
1
10
100Bousquet
1
10
100Gemini-Turgeon
1
10
100Chibougamau
1
10
100Normétal
1
10
100Selbaie
100
Laronde zone 20 footwall
Selbaie, zone A1
Normétal footwall
Superhyolite (silification)
Lemoine
Géant Dormant
Coniagas
Bouchard-Hébert (1100)
Horne
Delbridge
Inmont
[La/
Yb]
CN
YbCN
FIG. 6. (Cont.)
FIIIa RhyolitesThe FIIIa rhyolites are also considered to be tholeiitic,
high-silica, high-temperature rhyolites, but they have slightlyfractionated REE patterns with [La/Yb]CN chondrite-normal-ized values ranging from 1.5 to 3.5, low Zr/Y ratios, moderateHFSE contents relative to the primitive mantle, variable neg-ative Eu anomalies, and weak, subduction-related negativeNb and Ta anomalies. This type of rhyolite was first describedin the Noranda mining district (Lesler et al. 1986). Similarrhyolites have been identified in association with VMS de-posits in the Joutel, Chibougamau, Normétal, and Quévillonmining districts.
Noranda
The Noranda mining district, located in the Blake RiverGroup of the Southern Volcanic zone, is well known for itsVMS deposits. More than 33 deposits totaling 135 Mt havebeen mined, including the world-class, gold-rich Horne mine(54 Mt). The 2706 to 2696 Ma (Pearson and Daigneault,2009) Blake River Group comprises almost half of the South-ern Volcanic zone, where it is considered to form a thick (upto 10–15 km) and laterally extensive stratovolcano covering anarea of about 3,000 km2 (e.g., Pearson and Daigneault, 2009).The volcanic stratigraphy consists of a bimodal sequence ofrhyolite and andesite flows (Dimroth et al., 1982). Five vol-canic cycles were defined near the synvolcanic Flavrian plu-ton (Gibson, 1990). Cycle 3 hosts a number of felsic units,some of which are separated by chert horizons that constitutethe locus for VMS deposits (Gibson and Watkinson, 1990).The Blake River Group differs from most other parts of theAbitibi belt by its exceptional state of preservation, with onlyweak deformation and subgreenschist facies metamorphism,and it has been the focus of numerous geochemical studies(e.g., Gélinas et al., 1984; Peloquin et al., 1996).
Twenty-two samples were collected across the Blake RiverGroup (Fig. 3). The strategy was to collect samples withinand around the footwall of VMS deposits and away fromknown VMS deposits, and to cover most accessible and ex-posed rhyolite horizons. Samples from the Bouchard-Hébertand Inmont mines are from the immediate footwall. Samples
from the Horne and Delbridge mines are from lateral exten-sions of the host rhyolite. Figure 8A shows that 20 of thesamples have the characteristics of FIIIa rhyolites. SampleR-92 has lower mantle-normalized element abundances buta similar HFSE-REE pattern (except for Ti), whereas REEfractionation is more pronounced in sample R-90. Samplesfrom the VMS deposits plot within the range of backgroundrhyolite compositions (shaded area in Fig. 8B), except sam-ples R-74 and R-82. Sample R-74 from the Horne mineshows weak to intermediate REE depletion. Intense hy-drothermal alteration, as indicated by strong sericitization inthin section (App. 2), likely explains the depletion of REE.MacLean and Hoy (1991) documented similar LREE mobil-ity caused by intense hydrothermal alteration of rhyolite atthe Horne mine. However, the lower abundances of themore immobile elements, such as Y and Yb, suggest an un-derlying more fractionated initial REE signature, a featurealso documented by MacLean and Hoy (1991) at the Hornemine. These findings are consistent with those of Peloquin etal. (1996).
Joutel
The Joutel volcanic complex is 5 to 7 km thick and consistsof bimodal basalt-rhyolite successions that formed during fiveepisodes of volcanism, which evolved from tholeiitic to tran-sitional to calc-alkaline (Legault et al., 2002). Phase 2 (2728 ±2 Ma: Mortensen et al., 1993) is a 2- to 3-km-thick sequencecomposed mostly of dacite and rhyolite flows hosting threeZn-Cu-Ag VMS deposits, the Poirier (7 Mt), Joutel Copper(1.7 Mt), and Explo-Zinc (1 Mt) deposits (Fig. 4A). A limitednumber of geochemical analyses were performed on rocksfrom the major VMS-hosting unit. Phase 5 is represented bya 100- to 300-m-thick and laterally extensive (20 km) tuffa-ceous felsic calc-alkaline unit that hosts the volcanogenicEagle-Telbel Au-Ag massive to semimassive sulfide deposit(Gauthier et al., 2003). These rocks are interpreted to be FItype (see below).
We collected samples from a rhyolite unit with U-Pb zirconages of 2728 Ma (Mortensen et al., 1993: sample R-47), nearknown VMS deposits, and at locations some distance from theVMS deposits (Fig. 4A). The felsic tuff hosting the Eagle-Tel-bel Au-Ag deposit was also sampled. Two types of rhyolites,FII and FIIIa, were found (Fig. 8C). The FIIIa rhyolites arespatially associated with the Poirier and Joutel VMS deposits,whereas FII rhyolites are located at the top (eastern part) ofthe Joutel volcanic complex.
Chibougamau (Lemoine)
The Chibougamau area is known for its epigenetic Cu-Ausulfide veins (Pilote et al., 1998), rather than VMS-type de-posits. One exception is the small (0.75 Mt) but very high-grade and gold-rich Cu-Zn-Au-Ag Lemoine deposit hosted bythe felsic Waconichi Formation (Guha et al., 1988). This 2730Ma (Mortensen et al., 1993) formation forms a thin, domi-nantly calc-alkaline belt that can be traced throughout theChibougamau area (Fig. 4B). It is mainly tuffaceous in na-ture, with lesser porphyritic intrusions (Daigneault and Al-lard, 1990). Near the now-closed Lemoine mine, the felsicrocks are tholeiitic (Gobeil, 1980) and have well-defined,lobed lava flow facies indicating a proximal effusive center.
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FIG. 7. Multielement plot normalized to primitive mantle (Sun and Mc-Donough, 1989) for FIIIb felsic volcanic samples from the Matagami district.Gray envelope includes samples R-53 and R-54. The values for Rb and Sr arenot included in the shaded pattern due to their mobility.
Three samples were collected around the Lemoine depositand three others from the Waconichi Formation away fromthe deposit (Fig. 4B). Samples from Lemoine have HFSE-REE patterns typical of FIIIa rhyolites (Fig. 8D). Onestrongly chloritized, silicified, and sericitized sample (R-113;App. 2) has lower LREE (La, Ce, Nd) contents presumablycaused by intense hydrothermal alteration (Campbell et al.,
1984; MacLean, 1988). Sample R-110 to the north has an FIIsignature, and samples R-109 and R-108, as previouslynoted, are FI tuffs (see sections on FI and FII rhyolitesbelow). The various signatures from the extensive WaconichiFormation suggest a volcanic evolution or an unrecognizedcomplexity including various volcanic vents of specific geo-chemical compositions.
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FIG. 8. Multielement plots normalized to primitive mantle (Sun and McDonough, 1989) for FIIIa felsic volcanic samplesfrom 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 withVMS deposits. C. Joutel district: dashed-line samples are FII rhyolites. D. Chibougamau area: gray envelope includes sam-ples R-111 and R-112. E. Normétal district: dashed-line samples are FII rhyolites. F. Quévillon area: gray envelope includessamples R-4, R-8, and R-9.
Normétal
The 4-km-thick Normétal volcanic complex forms a south-east- to east-trending, steeply dipping, monoclinal volcanicsuccession that can be traced along strike for 35 km (Fig. 4C).It consists of basaltic andesite, dacite, and rhyolite eruptedduring five distinct volcanic phases with an intervening sedi-mentary phase (Lafrance et al., 2000; Mueller et al., 2008).Two VMS deposits were mined: the 11-Mt Cu-Zn-Au-AgNormétal deposit and the smaller (0.2-Mt) Zn-rich Normet-mar deposit. The associated volcanic center consists of amafic-dominated shield volcano of transitional affinity whichevolved to a felsic-dominated composite volcano with threeprincipal vent sites of tholeiitic affinity dated at 2728 Ma(Mortensen et al., 1993). The VMS deposits are associatedwith the last stage of tholeiitic felsic volcanism.
Samples were collected along the felsic horizon, 2.5 kmwest (sample R-36) and 14 km east (sample R-38) of the Nor-métal deposit, and from its immediate vicinity (samples R-35,R-36: Fig. 4C). Rhyolites spatially associated with VMS min-eralization are typically FIIIa (Fig. 8E), whereas samplesaway from the deposit have fractionated HFSE-REE patternswith characteristics comparable to FII-type rhyolites (see FIIsection).
Quévillon
The Quévillon area hosts the Zn-Cu-Ag Langlois mine(previously known as the Grevet mine) as well as other de-posits that are currently being explored (e.g., the Orpheezone) or developed (e.g., the 97 zone of Breakwater Re-sources Ltd). This area has past production and reserves to-taling more than 20 Mt of ore (Lacroix et al., 1993). TheGrevet-Mountain volcanic complex, dated at 2718 Ma (Daviset al., 2005), is bound to the north by a tonalitic intrusion andto the south by the synvolcanic Mountain pluton (Fig. 4D).The volcanic setting of the deposits is poorly understood be-cause the volcanic strata lie along a major southeast-trendingregional discontinuity known as the Cameron fault (Lacroix etal., 1993). The favorable, steeply dipping, 2-km-thick volcanicsequence has been traced along strike for more than 20 km(Fig. 4D). Around the Langlois mine, felsic rocks alternatewith mafic bands and are transposed by penetrative schistos-ity (Lacroix et al., 1993). Regionally, the Quévillon area con-sists of numerous southeast- to east-trending rhyolitic bands,some of which consist of lava flows and domes, and others oftuffaceous rocks (Fig. 4D). In addition to VMS mineraliza-tion, the Quévillon area hosts the Comtois gold deposit—anatypical, volcanogenic disseminated sulfide deposit (Dupré etal., 2002) associated with FI rhyolite (see below).
A rhyolite sample taken near the Langlois mine (Fig. 4D)has an FIIIa signature (sample R-4), and other FIIIa rhyoliteswere also found in the Quévillon area (samples R-8, R-9: Fig.8F). Sample R-6, collected near the mine, has a more frac-tionated REE pattern and lower amounts of mantle-normal-ized values (Fig. 8F). This sample may represent an in-terbedded tuffaceous horizon within the FIIIa host sequenceof the Langlois mine. The sample from the footwall of theLanglois mine (R-5) has lower mantle-normalized REEabundances relative to Ta, Zr, Hf, and Y. The high concen-tration of SiO2 (86 wt %) indicates strong silicification, which
is supported by the petrographic data (App. 2), and this likelyaccounts for the variability in REE concentrations. Othersamples (R-1, R-2, and R-3) represent FI rhyolites and arediscussed below.
FII RhyolitesThe FII rhyolites have calc-alkaline to transitional affini-
ties, gently sloping REE patterns indicated by [La/Yb]CN
chondrite-normalized values of 1.7 to 8.8, moderate Zr/Y ra-tios, intermediate HFSE concentrations, variable Eu anom-alies, and moderately negative Ta and Nb anomalies. They areinterpreted as arc-related rhyolites (Barrie et al., 1993; Hartet al., 2004). Rhyolites of the FII category host VMS depositsin the Val-d’Or and Selbaie mining districts, and make up theHunter volcanic complex and the largest portions of the ex-ternal North volcanic zone and Gemini-Turgeon areas.
Val-d’Or
The Val-d’Or mining district (Fig. 5A) may be best knownfor its gold deposits, but it is also a major VMS district withore production and reserves in excess of 60 Mt from six Cu-Zn-Ag-Au deposits (Jenkins and Brown, 1999). The VMS de-posits are hosted within the south-facing, steeply dipping, andlaterally extensive (40 km long) Val-d’Or Formation, measur-ing 3 to 5 km thick (Pilote et al., 1999; Scott et al., 2002). This2704 Ma formation comprises a complex subaqueous vol-cano-sedimentary sequence dominated by volcaniclastic de-posits ranging from andesitic to felsic compositions, overlyingthe synvolcanic granodioritic Bourlamaque pluton (Scott etal., 2002). The VMS deposits are spatially associated with nu-merous, small, felsic-dominated volcanic centers of limitedextent (Pilote et al., 1999). The volcanic rocks are mainly oftransitional affinity and are interpreted as the products of arcvolcanism (Scott et al., 2002). The 2701 Ma Heva Formationis 2 to 3 km thick, overlies the Val-d’Or Formation, and in-cludes a laterally extensive, spherulitic dacitic unit that hasbeen traced for 40 km along the base of the Heva Formation(Scott et al., 2002). The Heva Formation consists mainly oftholeiitic mafic rocks and is interpreted as a product of fis-sure-type volcanism (Scott et al., 2002). VMS deposits are notknown in the Heva Formation, with the possible exception ofthe Akasaba Au-Ag deposit (Chartrand, 1989; Vovobiev, 2000).
The lithogeochemistry of felsic volcanic rocks from the Val-d’Or Formation was studied in detail by Pilote et al. (1999)and Scott et al. (2002). They concluded, using mainly Zr/Y ra-tios, that felsic volcanism evolved from tholeiitic to calc-alka-line near the top of the Val-d’Or Formation, although mostunits are of transitional affinity.
We collected samples underground from the footwall at theLouvicourt mine and at surface along the host rhyolite hori-zons at the former East Sullivan, Manitou-Barvue, and Dun-raine mines (Fig. 5A). Samples were collected along a north-south transect within the Val-d’Or and Heva Formations andincluded the spherulitic dacitic unit and the eastern portionof the Sleepy volcanic center (Fig. 5A).
Multielement diagrams reveal that most rhyolite samplesform a coherent group with typical FII characteristics (Fig.9A). The spherulitic dacite sample (R-13) has an HFSE-REEpattern typical of FIIIa rhyolites (Fig. 9A). The low SiO2 con-tent (59.03%) suggests a more andesitic composition, but the
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FIG. 9. Multielement plot normalized to primitive mantle (Sun and McDonough, 1989) for FII felsic volcanic samplesfrom 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 awayfrom VMS. B. Val-d’Or district: plots of rhyolite samples directly associated with VMS deposits. C. External North Volcaniczone 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 dis-trict: gray envelope includes samples R-55 to -66, excluding R-61 away from VMS. F. Hunter district: plots of rhyolite sam-ples directly associated with VMS deposits. G. Gemini-Turgeon area: gray envelope includes samples R-121 to -123. H.Other rhyolite samples with FII signatures.
unusual magnetite alteration observed in this sample (and inthe unit generally) may account for the higher Fe2O3 andlower SiO2 content of this dacitic rock (App. 1). The Sleepysample (R-19) is characterized by an unusual signature, withLa and Ce depletion relative to Zr and Hf, and lower HREE(Gd, Yb) and Y abundances compared to other samples. Thissignature may reflect hydrothermal alteration (La, Ce mobil-ity) of a more fractionated rhyolite (lower HREE and Y). Thepresence of biotite (App. 2) suggests a higher metamorphicgrade related to the proximity of the Grenville Province (Fig.1) and also may account for the anomalous signature.
The tuff sample from the Heva Formation (R-14), dated at2702 Ma (Pilote et al., 1999), has a HFSE-REE pattern sim-ilar to that of the rhyolite group, but with lower overall man-tle-normalized values (Fig. 9A). The low Al2O3 content andLOI (App. 1) suggest that the sample is silicified, whichwould explain the lower HFSE-REE abundances. Samplestaken near VMS deposits plot within the range of backgroundrhyolites (shaded field, Fig. 9B), except for the Louvicourtfootwall sample, which has the same REE-HFSE pattern buthigher mantle-normalized element abundances.
External North Volcanic zone
The external North Volcanic zone covers a large area ofabout 6,000 km2, spanning the towns of Lasarre, Amos, andSenneterre from east to west. It is bound by the linearChicobi sedimentary unit to the north and by the Porcupine-Destor-Manneville fault to the south (Fig. 5B). This largearea is dominated by mafic lavas with lesser bands of felsicvolcanic rocks and local synvolcanic plutons (Gaboury, 2006).Ages range from 2727 to 2714 Ma (Labbé, 1999), indicatingprolonged or multiphase volcanism. The large area is reputedto be a weakly favorable area for hosting VMS deposits. Ex-cept for the Abcourt deposit, only small VMS deposits havebeen discovered, including Jay Copper, Monpras, Trinity,Vendome 1 and 2, and Duvan (Fig. 5B). Although some de-posits were explored underground (Amos, Duvan, Vendome),only the Abcourt deposit has been mined, producing about 6Mt of ore grading 3 percent Zn and 40 g/t Ag (Labbé andCouture, 1999).
Fourteen samples of rhyolite were collected, four near theAbcourt, Duvan Vendome, and Lamorandière VMS deposits(Fig. 5B). Although the sampled area is large and containsrocks of various ages, the rhyolites define a coherent group ofFII type in Figure 9C. Two represent FI-type rhyolites (R-37at Duvan and R-32) and are discussed in the FI section below.
Selbaie mining district
The 2725 to 2730 Ma Brouillan Volcanic Complex (Barrieand Krogh, 1996) is mainly composed of felsic to intermedi-ate calc-alkaline pyroclastic rocks forming an intracaldera se-quence more than 1,200 m thick (Larsen and Hutchinson,1993). The caldera sequence, which developed above the syn-volcanic Brouillan tonalitic batholith, records an evolutionfrom subaqueous to subaerial deposition. The south-facingvolcanic sequence is tilted and may be traced laterally 12 kmwestward (Taner, 2000), but no significant deposit occursaway from the Selbaie mines. Selbaie is an atypical large-ton-nage, low-grade volcanogenic Cu-Zn-Ag-Au deposit withboth stratiform and epithermal characteristics that has
yielded more than 50 Mt of ore (Larsen and Hutchinson,1993). Mineralization occurs as veins and veinlets that cut thelocal stratigraphy at a high angle and as stratiform, massive todisseminated pyrite lenses of low metal content.
Barrie et al. (1993) concluded that rhyolitic rocks at Selbaiewere of Group III in their classification system, which isequivalent to FII. For this study, two samples were collectedfrom the open pit of the A1 mineralized zone and anotherfrom rhyolite 5 km west of the mine (Fig. 1). The multiele-ment diagram indicates that these are of FII type with mod-erately fractionated REE and well-defined Ta-Nb anomaliestypical of calc-alkaline rocks (Fig. 9D).
Hunter mine area
The 2728 to 2724 Ma Hunter mine group is a 6- to 7-km-thick volcanic sequence composed mainly of felsic lava flowsand domes with lesser volcaniclastic felsic rocks, iron forma-tions, and mafic pillowed and brecciated flows (Mueller andMortensen, 2002). This group forms a 210-km2 area of tilted,south-facing volcanic rocks overlying the synvolcanic, gran-odioritic Poularies intrusion (Fig. 4C). The main feature is aprominent north-trending felsic dike swarm, 5 to 7 km wide,interpreted as a caldera structure (Mueller and Donaldson,1992; Mueller et al., 2008). To date, only two small Cu-Zn-Ag-Au VMS deposits have been discovered, Hunter and Lyn-dhurst, totaling less than 2 Mt of ore (Fig. 4C).
We collected 12 samples east and west of the Poularies in-trusion (Fig. 4C). Included in this group are samples from theHunter (R-55) and Lyndhurst mines (R-62, R-63), both pastproducers. Another sample, R-57, is from the north-trendingfelsic dike swarm. With the exception of R-61, which has lowermantle-normalized element abundances (Fig. 9E), the sam-ples, including those from VMS deposits (Fig. 9F), define acoherent compositional group with a very restricted range ofREE-HFSE mantle-normalized abundances typical of FIIrhyolites. These results are consistent with those of Dostal andMueller (1996) and demonstrate the very restricted chemicalevolution of rhyolitic volcanism at the scale of the complex.
Gemini-Turgeon area
A felsic horizon with a thickness of about 2 km has beentraced for more than 15 km in a north-south direction to thewest of the synvolcanic Mistaouac pluton (Fig. 1). Rhyolitesin this area are unexposed and all known geology has been de-duced from drill core. The following description is from un-published data of the IAMGOLD and Cancor mining com-panies and from Gobeil (2006). The volcanic units consist ofa bimodal assemblage of porphyritic lava flows with few vesi-cles at the base, succeeded upward by predominantly felsicvolcaniclastic rocks and a sedimentary sequence comprised ofgraywacke, siltstone, mudstone, and iron formations. U-Pbdating of zircons from the top of the volcanic pile yielded anage of 2735 Ma (Davis et al., 2005). Numerous small, massive,and disseminated volcanogenic sulfide lenses, with low Cu,Zn, Au, and Ag grades, occur mainly along the top of the vol-canic sequence.
Four representative samples were provided by Cambior Inc.(now IAMGOLD) for this study. All samples are of FII-typerhyolite (Fig. 9G), although the [La/Yb]MN mantle-normal-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-tle-normalized abundances, probably caused by silicification(84.15 wt % SiO2).
Other FII occurrences
Figure 9H shows a multielement diagram for other felsicrocks with FII signatures. Sample R-106 is from the mined-out 0.7-Mt Coniagas Zn-Pb-Ag VMS deposit (Fig. 1). SampleR-119 is a felsic tuff dated at 2718 Ma (Pilote et al., 1999),collected near the Marbridge Ni-Cu komatiite-hosted deposit(Fig. 1). Sample R-85 is from the 2718 Ma (Zhang et al.,1993) Kinojevis Formation (Fig. 5).
FI RhyolitesThe FI rhyolites are calc-alkaline, with strongly fraction-
ated REE patterns, [La/Yb]CN chondrite-normalized valuesranging from 5.8 to 34, low HFSE abundances, strong nega-tive Ta and Nb anomalies, and variable Eu anomalies. Theyare interpreted as arc-related magmatic products (Barrie etal., 1993). These rhyolites occur in the Bousquet mining dis-trict and are spatially associated with other gold-rich vol-canogenic deposits, namely the Géant Dormant (SleepingGiant), Eagle-Telbel, and Comtois deposits, and the atypicalDuvan Cu-Ag deposit.
Bousquet mining district
The Bousquet mining district is a world-class gold producerthat includes Laronde—the world’s largest polymetallic gold-rich VMS deposit (Mercier-Langevin et al., 2007a)—andpyritic gold-bearing replacement-type deposits such as Bous-quet 1 and Dumagami-Bousquet 2 (Fig. 1). Total productionand reserves amount to more than 100 Mt of ore. Recent re-gional studies have traced the 1.5- to 3-km-thick, south-fac-ing, vertically tilted, strongly foliated, and east-trending vol-canic Bousquet Formation for more than 20 km along strike(Lafrance et al., 2003). This 2696 to 2698 Ma Formation,which is part of the Blake River Group, consists of volumi-nous dacitic to rhyolitic vesicular volcaniclastic rocks withlocal felsic effusive lava flows and domes to which the VMSdeposits are spatially associated (Lafrance et al., 2003). Thissequence overlies the Mooshla synvolcanic tonalite-granodi-orite pluton that hosts two synvolcanic, sulfide-rich vein-typegold deposits, Doyon and Mouska, both active producers.The Bousquet Formation is divided into lower and upper vol-canic members. The lower member includes tholeiitic totransitional, mafic to felsic volcanic rocks, whereas the uppermember is dominated by transitional to calc-alkaline, inter-mediate to felsic rocks (Lafrance et al., 2003; Mercier-Langevin et al., 2007a).
Sampling of the upper member was performed along anorth-south section along Preissac Road, using the unitnomenclature of Lafrance et al. (2003). One sample (R-105)from the underground Laronde mine rhyolite (unit 5.3, whichhosts the 20-N zone) was kindly provided by P. Mercier-Langevin (then of Agnico-Eagle) for this study. Overall, thesamples display strong REE fractionation, the Laronde foot-wall sample having the strongest, and very pronounced nega-tive Ta and Nb anomalies typical of FI rhyolites (Fig. 10A).
An exhaustive lithogeochemical study on the Laronde minewas recently conducted by Mercier-Langevin et al. (2007b).
These authors interpreted some of the dacites and rhyolites ofthe upper member as belonging to the FI category, althoughthey are dominated by FII-type rhyolites.
Other mineralized systems associated with FI rhyolites
Figure 10B shows a plot of mineralized felsic rocks with FIsignatures from other locations, such as the Géant Dormantmine in the internal North Volcanic zone (Fig. 1), the Agnico-Telbel mine in the Joutel district (Fig. 4A), and the ComtoisAu deposit in the Quévillon area (Fig. 4D). Mineralizationstyles range from sulfide-rich quartz veins (Géant Dormant:Gaboury and Daigneault, 1999) to sulfide disseminations inzones of highly altered rocks (Agnico-Telbel: Gauthier et al.,2003; Comtois: Dupré et al., 2002). All these deposits arehosted, at least in part, by felsic dikes and rhyolitic lavas of FIaffinity (Géant Dormant, Comtois) or within FI-type felsictuffs (Agnico-Telbel). The Cu-Ag Duvan mine is another ex-ample of atypical volcanogenic-related mineralization withinFI felsic tuff. Mineralization occurs as concordant massive todisseminated pyrite and chalcopyrite associated with abun-dant magnetite (Tremblay et al., 1996).
Other FI occurrences
Numerous occurrences of tuffaceous rhyolite scatteredacross the Abitibi belt have FI signatures (Fig. 10C). Theycommonly occur as extensive regional units. Samples R-108and R-109 are from the 2730 Ma (Mortensen et al., 1993)Waconichi Formation in the Chibougamau area (Fig. 4B),sample R-30 is from the Quévillon area (Fig. 4D), and twoother samples (R-32, R-41) are from the North Volcanic zone(Fig. 5B). These units may be products of explosive eruptionof felsic calc-alkaline magma with a high volatile content (e.g.,Gibson et al., 1999). Other rhyolites from the Comtois (R-1)and Géant Dormant (R-115) deposits and the rhyolite (R-107) dated at 2791 Ma (Bandayera et al., 2004) are plotted inFigure 10D. The 2791 Ma rhyolite is unusually old relative tothe 2735 to 2700 Ma ages for felsic volcanism in the Abitibibelt.
DiscussionThe results of this study reveal that in small volcanic cen-
ters composed of various rhyolite types, such as Joutel, Chi-bougamau (Lemoine), Normétal, and Quévillon (Fig. 8),VMS deposits are specifically associated with FIIIa rhyolites.This demonstrates the usefulness of the approach for dis-criminating the most favorable sectors or horizons withinsmall felsic volcanic centers. The much larger Noranda dis-trict is also characterized by rhyolites with FIIIa signatures,but the application of rhyolite chemistry in the exploration ofthis camp is less useful because FIIIa rhyolites are distributedover such a vast area (more than 3,000 km2).
Regardless of rhyolite classification, there does not appearto be any link between ore tonnage and REE fractionation.VMS deposits are hosted by rhyolites with REE patternsranging from low [La/Yb]MN mantle-normalized ratios or flatpatterns (Matagami) to elevated [La/Yb]MN ratios or fraction-ated patterns (Bousquet-Laronde; Fig. 11). Furthermore,moderately fractionated FII rhyolites (Selbaie, Hunter, Val-d’Or, and External North Volcanic zone) are variably mineral-ized, as was previously recognized by Lesher et al. (1986).
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0.1
1
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1000
ThRb Ba TaU Nb SrLa Ce HfNd Zr TiSm Eu YbGd Y
Roc
k /
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itive
Man
tle
FI-mineralizedR-105 Laronde
R-46Agnico-Telbel
R-2 Comtois
R-114Géant Dormant
R-37 Duvan
B
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ThRb Ba TaU Nb SrLa Ce HfNd Zr TiSm Eu YbGd Y
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FI-Tuff
R-109
R-108
R-32
R-3
R-41
<
C
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ThRb Ba TaU Nb SrLa Ce HfNd Zr TiSm Eu YbGd Y
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R-115
R-107
R-1
D
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ThRb Ba TaU Nb SrLa Ce HfNd Zr TiSm Eu YbGd Y
n=5
LaRonde (R-105)
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itive
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tle
BousquetA
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 variouslocations. C. Samples from tuffaceous rhyolite at various locations. D. Other rhyolite samples with FI signatures.
Bousquet: > 100 Mt
n=7
Val-d'Or: 60 Mt
n=13
Hunter: 2 Mt
n=14
Noranda: 132 Mt
n=24
External North Volcanic Zone : 10 Mt
n=15
1
10
100
1000Matagami: 50 Mt
n=4
0.1
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ThTaU
Nb SrLaCe HfNd
Zr TiSmEu YbGd
Y
Selbaie: 50 Mt
n=3
Quévillon: 20 Mt
n=3
ThTaU
Nb SrLaCe HfNd
Zr TiSmEu YbGd
Y ThTaU
Nb SrLaCe HfNd
Zr TiSmEu YbGd
Y ThTaU
Nb SrLaCe HfNd
Zr TiSmEu YbGd
Y
0.1
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itive
Man
tle
FIG. 11. Summary multielement plots normalized to primitive mantle (Sun and McDonough, 1989) for felsic volcanicrocks from mining districts, showing ore tonnages (production and reserve) in millions of metric tons (Mt).
Based on our dataset, it is not possible to attribute a greaterVMS potential to specific rhyolite types based only on geo-chemical signatures.
Rhyolite petrogenesis and hydrothermal activity
The formation of VMS deposits is the product of convectivehydrothermal activity induced by heat flux from an underly-ing magma chamber (Franklin et al., 1981, 2005). Funda-mental factors that enable hydrothermal convection to occurinclude the structural permeability of the upper portion ofthe crust and the porosity of the volcanic pile (e.g., Mortonand Franklin, 1987; Barrie and Hannington, 1999; Gibson etal., 1999; Davidson et al., 2004). Time is another key factorthat is fundamental in maintaining the stability of the convec-tive system and in accumulating sulfides on or near the seafloor (e.g., Barrie and Hannington, 1999; Franklin et al.,2005, and references therein).
Rhyolites are the result of petrogenetic processes involvingpartial melting, crystallization, fractionation, and assimilation(e.g., Hart et al., 2004). The depths at which these processesoccur, the magma ascent rates, and the residence times in thecrust also influence rhyolite chemistry. The same factors in-fluence hydrothermal convection and VMS formation (e.g., interms of thermal requirements). However, this study illus-trates that different types of rhyolites are not necessarily morefavorable than others to host VMS deposits. This may be be-cause VMS formation is mainly related to processes thatoccur at shallow levels in the crust (<5 km: see Franklin et al.,2005) rather than at great depth (<30 km: see Hart et al.,2004) where the rhyolite magma is generated.
High-temperature FIII-type rhyolites (e.g., Noranda andKidd Creek) have low amounts of phenocrysts and microphe-nocrysts (Hart et al., 2004). This generally aphyric texture isthought to reflect a rift setting where magma is rapidly trans-ferred from the melt zone to the surface (Lentz, 1998; Hartet al., 2004) and quartz and feldspar do not accumulate insubvolcanic magma chambers. However, our data suggestthat most VMS districts in this study, except Normétal andVal-d’Or, are dominated by quartz- and/or feldspar-phyric fel-sic lava flows or volcaniclastic rocks. The apparent inconsis-tency between phenocryst content, rhyolite type, and VMSfavorability is difficult to explain with a model that involves agenetic link between deep petrogenetic processes for rhyolitegeneration and VMS formation. The most likely explanationis the presence of subvolcanic magma chambers above zonesof magma generation, which would account for phenocrystformation. Such subvolcanic intrusions are well documentedfor most VMS districts in the Abitibi belt (Galley, 2003;Gaboury, 2006).
Fractionation pattern and style of volcanism
The FIII rhyolites are well known as volatile-poor rocks oc-curring in bimodal, basalt-rhyolite sequences (Lentz, 1998).These sequences, as exemplified by the Noranda andMatagami districts, are dominated by isolated to coalescentvolcanic centers forming domes (e.g., cycle 3 of Noranda) andextensive flows (e.g., Watson Group of Matagami) with rarevolcaniclastic horizons mainly of epiclastic origin (Table 1).Extensive cherty horizons or silicified tuffs indicating periodsof volcanic quiescence are also typical of these sequences.
The FI rhyolites, which are at the other end of the frac-tionation spectrum, are poorly represented in the Abitibi belt.Volcanic rocks in the Bousquet district form a continuouscompositional range from andesite to rhyodacite in volcani-clastic-dominated sequences (Table 1). Vesicularity is intenseand quiescent periods (cherty horizons) have not yet beenidentified (Lafrance et al., 2003; Mercier-Langevin et al.,2007a). Other known FI rhyolites in the Superior province,such as at Obonga Lake (Tomlinson et al., 2002), in theMichipicoten belt (Sage et al., 1996), Meen-Dempster(Hollings et al., 2000), and in the North Caribou terrane(Hollings and Kerrich, 1999), are also dominantly tuffaceousbut are not mineralized.
The FII rhyolites, characterized by a moderate fractiona-tion pattern, are variably dominated by either volcaniclastic orcoherent flow facies. The Val-d’Or and Selbaie districts arecharacterized by a continuous volcanic compositional rangefrom andesite to rhyolite with large volumes of highly vesicu-lar volcaniclastic rocks (Table 1). On the other hand, theHunter district and the volcanic centers of the External NorthVolcanic zone are dominated by flow and lava domes of lowvesicularity and bimodal composition (Table 1).
Fractionation pattern and style of mineralization
The VMS deposits associated with FIII rhyolites are typical“Noranda-type” deposits forming high-grade but relativelylow-tonnage deposits (1–4 Mt), with the largest examplesbeing Mattagami Lake (25.6 Mt) and Quémont (13.8 Mt). Amajor exception to this trend is the giant 240-Mt Kidd CreekVMS deposit in Ontario, which is also genetically related toFIIIb rhyolites (Lesher et al., 1986).
The gold-rich Horne deposit, the largest VMS in the No-randa district, features replacement-style mineralization instrongly sericitized felsic volcaniclastic rocks (Table 2). Someof the host rhyolites are FII type with calc-alkaline affinity, aspreviously documented by MacLean and Hoy (1991). Thepresence of more than one rhyolite type may be explained bythe fact that the Horne mine is part of a different block thanthe felsic rocks of the central Noranda district (Kerr and Gib-son, 1993). The Horne block is interpreted as a parallel riftenvironment to the central cauldron (Kerr and Gibson, 1993)or the top of the proposed New Senator caldera (Pearson andDaigneault, 2009).
Deposits associated with FI rhyolites are commonly atypi-cal Cu-Au–rich deposits, ranging in style from sulfide-richquartz veins to disseminations to sulfide replacements of per-meable rocks (Table 2). Striking examples are the VMS de-posits in the Bousquet area. Mineralization occurs mainly asmassive sulfide replacements within highly permeable andhighly vesicular volcaniclastic rocks. Well-defined Cu-richstringer zones in the chlorite-altered feeder pipes of strati-form lenses are absent in many cases (Table 2). Aluminous al-teration in the Cu-Au deposits at Dumagami, Bousquet 1 and2, and Laronde (zone 20) has been compared to high-sulfida-tion alteration in epithermal Cu-Au deposits (Sillitoe et al.,1996; Hannington et al., 1999b; Dubé et al., 2007).
Mineralization associated with FII rhyolites is quite vari-able (Table 2). In the Selbaie area, mineralization occurs ascopper-rich stringers and zinc-rich disseminations with poorlydeveloped stratiform mineralization (Table 2). In the Val-d’Or
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district, VMS deposits form large accumulations of dissemi-nated sulfides with low Cu and Zn grades replacing perme-able volcaniclastic horizons (except for the Louvicourt de-posit) and lack well-defined underlying chloritic and Cu-richzones (Table 2). In the Hunter district, mineralization hostedby FII rhyolite is more similar to that associated with FIIIrhyolite, in that small massive sulfide lenses of exhalative ori-gin accumulated at the top of the volcanic sequence alongwith banded iron formations during the waning stage of sub-marine volcanic activity (Table 2). Well-developed discordantsulfide stringers and chlorite alteration zones are also associ-ated with these deposits (Table 2).
Summary and ConclusionsRhyolites cover a complete spectrum of geochemical frac-
tionation patterns that can be conveniently subdivided intoinformal FI-FII-FIII types. Furthermore, there is a completespectrum of VMS deposits in terms of volcanic facies associa-tions, base metal and gold contents, and alteration character-istics (Table 3). It emerges that there are no objectively bar-ren rhyolite types, and that beyond any petrogeneticconsiderations involving the depth of felsic magma genera-tion, other factors must be taken into account to explain thefull spectrum of variations between geochemical signaturesand volcanogenic hydrothermal activity.
Possible factors are temperature, viscosity, and volatile con-tent, all of which have a profound influence on the volcanicproducts and consequently on the volcanic architecture(Touret, 1999). Submarine volcanic architecture in turn re-flects the growth history, topography, effusive rate, bathyme-try, and possible eruptive interference from other proximalvolcanic centers (Cas, 1992; Gibson et al., 1999).
The favorability of FIII rhyolites is commonly explained bythe rapid transfer of low-volatile magma to the surface, thusinducing high heat flow (cf. Lentz, 1998). The extensional set-ting, manifested by well-defined calderas, rifts, or grabens fa-vors magma ascent and provides enhanced structural perme-ability for the convective hydrothermal system (e.g., Hart etal., 2004). The bimodal sequences, with multicycle volcanismand hiatuses in volcanic activity, provide enough time to ac-cumulate significant quantities of sulfides on the sea floor,mainly by exhalative processes, with VMS deposits formingnear-volcanic rhyolite lava flow centers and domes (Gibson etal., 1999).
The VMS deposits associated with FI rhyolites are com-monly replacements of highly permeable volcaniclastic rocks.These rocks are the main products of explosive eruption ofcalc-alkaline magma with a high volatile content. In suchcases of replacement-style mineralization, a hiatus in volcanicactivity is not necessary to form a VMS deposit by sea-floorexhalation, and these sequences commonly lack evidence oflong pauses in volcanic activity. In addition to forming abun-dant volcaniclastic rocks, the explosive volcanism may pro-mote enhanced structural permeability and contribute tolarge variations in bathymetry and confining pressure. De-posits typically occur close to isolated volcanic vents, as ex-emplified by the Bousquet district (Lafrance et al, 2003) andthe Géant Dormant gold deposit (Gaboury and Daigneault,1999). The high gold content of many of these deposits hasbeen interpreted as a consequence of a magmatic gold con-tribution (Hannington et al., 1999b, 2005; Gaboury et al.,2000; Mercier-Langevin et al., 2007b). It is well known thatmagmas similar in composition to FI-type rhyolites emplacedin a subaerial setting are favorable hosts for Cu-Au porphyrydeposits (Reich et al., 2003; Mungall, 2004).
It is noteworthy that FII sequences represent about 70 per-cent of rhyolites by surface area in the Abitibi (Pearson,2005). For these moderately fractionated rhyolites, the traceelement approach has some limitations when assessing rela-tive prospectivity. Mineralized FII rhyolites, such as those ofVal-d’Or, Selbaie, and Bousquet, have volcanic facies andmineralizing characteristics that are more similar to FI se-quences, whereas those of the Hunter, Gemini-Turgeon, andExternal North Volcanic zone districts share characteristicswith the FIIIa sequences, such as those of Noranda (Tables 3,4). The FII sequences appear to be the most favorable hostsfor VMS deposits when the volcanic style is dominated byhighly vesicular volcaniclastic rocks derived by continuousfractionation from andesite to rhyolite. Conversely, thosesharing characteristics of the FIII rhyolites—such as lowvesicularity and bimodal dome- and lava flow-dominated se-quences in the Hunter, External North Volcanic zone andGemini-Turgeon districts—host “Noranda-type” deposits butappear less prospective.
The FI rhyolites appear highly favorable for VMS depositsbut host styles of mineralization that differ from the classicstrata-bound VMS lenses, including gold-bearing, sulfide-richquartz veins, disseminations, and replacement-type sulfidelenses. A similar conclusion was reached by Mercier-Langevin et al. (2007b) based on their study of felsic rocks atthe Laronde mine. Some FII rhyolites have a high potentialto host VMS, such as Val-d’Or and Selbaie, whereas others,
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TABLE 3. Style of Volcanism and Mineralization Associated with Different Rhyolite Types
Group Volcanism style Mineralization style
FIII Bimodal Exhalative stratiform lensesLow volatile content High grade, low tonnageDomes and flows Cu-Zn ± Ag ± AuLow vesicularity index Discrete alteration pipe and Few volcaniclastic rocks Cu-rich stringer zoneExhalite-chert: common Examples: Quémont
Mattagami LakeAnsil
FII Similar to FIII-type Similar to “FIII-type”Examples: Lyndhurst
Hunter mineGemini
Similar to FI-type Similar to “FI-type”Examples: Selbaie
Manitou-Barvue
FI Continuum andesite to rhyolite Atypical Cu-AuAbundance of volcaniclastic veins, disseminations and
rocks replacement of permeable High vesicularity volcaniclastic rocksExhalite-chert: absent Diffuse alteration
Examples: Laronde Bousquet 1 and 2Comtois
such as in the Hunter, External North Volcanic zone, andGemini-Turgeon districts, appear only weakly mineralized.The FII sequences host either Noranda-type VMS associatedwith flow-dome complexes or disseminated sulfide replace-ments and veins in dominantly volcaniclastic rocks. Volcani-clastic rocks appear to be the most favorable host for large-tonnage deposits and provide an important guide forexploration. The dominance of highly prospective FIII rhyo-lites in very large felsic centers, such as Noranda andMatagami, is a less useful exploration guide at the target scale.However, in small felsic centers that show an evolution fromFIIIa to FII to FI, deposits are directly associated with FIIIarhyolites, and their presence is thus a much more useful toolfor targeting horizons with the greatest potential.
AcknowledgmentsG. Bouchard of Xstrata Zinc (previously Noranda-Falcon-
bridge) was instrumental to this study by suggesting it andproviding technical support. P-L. Lajoie of the Universitédu Québec à Chicoutimi (UQAC) provided dedicated fieldassistance during the 2003 sampling program and samplepreparations. J. Lavoie (UQAC) performed the petrographicstudy. This project benefited from numerous comments byrepresentatives on the CONSOREM Research Committee.We also acknowledge CONSOREM for permission to pub-lish this work. T. Gomwe of UQAC and V. Bodycomb of VeeGeoservices edited the English, and R. Daigneault ofUQAC informally reviewed a preliminary version of themanuscript. The paper was substantially improved followingreviews by T. Hart and P. Hollings. We are also grateful toM. Hannington for his constructive comments and efficienteditorial work.
November 14, 2006; September 2, 2008
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AP
PE
ND
IX 1
Ana
lytic
al R
esul
ts fo
r F
elsi
c Vo
lcan
ic R
ocks
of t
he A
bitib
i Bel
t
Num
ber
R-1
R-2
R-3
R-4
R-5
R-6
R-8
R-9
R-1
0R
-11
R-1
2R
-13
R-1
4R
-15
R-1
6R
-17
R-1
8
Zone
1818
1818
1818
1818
1818
1818
1818
1818
18U
TM
E34
0297
3404
3235
8939
3795
0137
7993
3778
3636
2103
3605
5030
5875
2978
9630
8145
3094
5030
9026
3087
0831
0044
3101
5831
2853
UT
MN
5444
424
5444
249
5432
783
5455
516
5456
121
5456
351
5454
944
5446
415
5329
342
5327
748
5328
321
5326
227
5324
932
5327
946
5330
413
5330
994
5328
363
SiO
2(w
t %)
69.3
972
.47
67.4
383
.37
85.9
571
.21
69.1
278
.17
85.1
767
.69
67.7
859
.03
79.5
765
.25
68.1
470
.86
75.8
Al 2O
315
.58
14.6
715
.81
8.44
6.45
15.1
412
.03
11.9
86.
5615
.41
14.5
412
.61
8.9
14.4
111
.23
13.9
814
.38
TiO
20.
230.
150.
280.
190.
160.
220.
520.
230.
090.
41.
10.
910.
570.
760.
470.
451.
07F
e 2O
32.
371.
043.
42.
073.
651.
666.
020.
73.
082.
631.
869.
82.
856.
24.
422.
451.
78M
gO
0.52
0.4
0.24
0.12
0.44
0.34
0.72
0.78
0.21
2.12
1.18
6.3
2.77
1.25
0.19
MnO
0.
070.
010.
080.
050.
020.
030.
10.
020.
050.
050.
120.
050.
10.
150.
030.
02K
2O
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
CaO
1.
393.
293.
430.
50.
031.
852.
480.
519.
083.
956.
572.
350.
524.
262.
850.
33N
a 2O
6.
294.
114.
083.
550.
284.
964.
255.
380.
152.
335.
024.
643.
490.
312.
955.
820.
27P 2
O5
0.11
0.07
0.07
0.03
0.02
0.05
0.07
0.04
0.02
0.2
0.23
0.2
0.13
0.34
0.1
0.27
0.25
LO
I
1.63
1.8
4.25
0.82
1.43
2.39
2.95
0.91
2.18
0.93
3.51
5.03
0.96
4.21
5.1
1.39
1.96
Tota
l 99
.08
99.8
310
0.49
99.7
999
.66
99.8
699
.74
99.3
299
.53
99.2
899
.63
101.
1410
0.05
100.
7110
0.47
99.7
710
0.39
Ce
(pp
m)
32.4
48.0
611
.03
48.6
537
.13
12.5
199
.57
98.3
343
.57
49.4
151
.72
45.8
423
.754
.98
27.4
860
.98
40.1
6C
s
0.98
71.
348
1.58
20.
188
0.45
80.
988
1.12
80.
555
0.65
60.
197
1.65
10.
210.
029
1.37
10.
405
0.17
64.
185
Dy
1.
347
1.43
90.
922
9.46
8.70
40.
932
18.1
8812
.118
3.66
94.
425
6.25
617
.446
3.03
93.
864.
434
5.53
15.
851
Er
0.
863
0.84
70.
526
6.14
66.
212
0.54
412
.28
6.61
92.
425
2.74
83.
888
11.6
031.
877
2.04
72.
943.
373.
517
Eu
0.
609
0.82
10.
415
2.41
70.
999
0.37
52.
825
2.13
91.
129
1.19
81.
521
2.81
30.
543
1.09
20.
897
1.28
31.
451
Gd
1.
669
1.98
31.
148
9.62
95.
921
1.14
115
.849
12.5
24.
548
5.70
96.
877
15.0
443.
303
5.52
34.
294
6.95
47.
018
Hf
3.8
3.7
2.2
7.8
8.4
2.9
1310
.74.
16.
88.
19.
13.
56.
15.
17.
76.
3H
o
0.28
10.
282
0.18
12.
012
1.97
50.
181
3.98
32.
384
0.77
80.
891.
278
3.83
0.62
60.
719
0.95
71.
111
1.17
7L
a
15.8
623
.54
5.42
20.0
99.
266.
2343
.01
41.3
717
.84
19.2
620
.76
16.5
69.
4421
.97
10.9
824
.08
15.0
8L
u
0.15
30.
149
0.07
30.
928
0.91
80.
081
1.81
40.
872
0.39
70.
474
0.55
61.
783
0.28
70.
307
0.46
70.
587
0.55
6N
b
3.4
3.6
1.7
18.2
17.2
2.1
35.2
22.2
4.7
8.5
10.1
12.8
4.4
8.3
6.4
10.2
8N
d
14.9
921
.69
5.56
31.5
415
.47
6.02
56.6
654
.48
25.2
930
.431
.84
37.2
114
.18
33.4
416
.96
37.8
828
.21
Pr
4.06
25.
986
1.35
6.91
53.
466
1.49
913
.188
12.9
325.
856
6.99
37.
151
7.26
23.
263
7.63
73.
871
8.65
45.
947
Rb
34.1
35.4
745
.29
18.6
735
.79
50.8
237
.425
.46
21.6
712
.439
2.07
0.32
42.3
917
.81
11.4
896
.01
Sm
2.35
3.14
1.22
8.26
4.31
1.23
13.9
612
.22
5.76
6.9
7.3
11.5
63.
377.
154.
048.
347.
1Sr
43
1.7
327.
833
8.6
43.5
6220
7.6
93.5
64.4
13.4
163.
798
.517
9.4
46.4
27.3
72.6
174.
960
Ta
0.29
0.3
0.2
1.12
1.11
0.24
2.08
1.42
0.44
0.6
0.66
0.84
0.35
0.54
0.44
0.67
0.58
Tb
0.
232
0.26
30.
166
1.53
91.
212
0.16
42.
801
2.01
50.
620.
81.
048
2.64
50.
503
0.72
0.70
80.
965
1.01
5T
h 2.
152.
670.
82.
072.
671.
074.
844.
282.
44.
043.
531.
541.
543.
21.
94.
483.
39T
m
0.13
40.
130.
074
0.92
30.
945
0.07
91.
836
0.95
90.
382
0.43
40.
571
1.74
60.
276
0.30
30.
446
0.52
50.
518
U
0.47
50.
572
0.34
0.49
90.
693
0.35
71.
244
0.80
80.
513
0.90
10.
870.
416
0.41
60.
707
0.50
70.
951.
323
Y 7.
898.
265.
0159
.18
51.9
45.
2410
9.31
54.7
419
.87
25.5
535
.610
1.48
17.4
919
.89
26.1
131
.31
33.1
4Yb
0.
930.
920.
496.
116.
180.
5312
.06
6.15
2.56
3.04
3.77
11.6
1.83
2.04
3.01
3.63
3.49
Zr
154.
314
377
.130
1.3
308.
598
.147
5.1
402.
112
6.5
262.
230
2.4
318
130.
723
2.2
188
290.
523
0.2
Be
0.
70.
560.
60.
741.
290.
921.
820.
880.
330.
920.
830.
550.
251.
130.
390.
921.
2C
o 2.
072.
635.
940.
431.
612.
265.
310.
164.
581.
25.
1510
.34
9.06
14.9
18.
345.
422.
13C
u
47.3
26.
9623
.56
6.64
27.8
23
9.11
23.0
768
.87
6.1
103.
519
.52
13.6
63.
4273
.02
3.59
23.9
3L
i 53
2614
13
213
44
37
252
4318
88
Ni
10.3
74.
7615
.58
6.02
7.6
9.17
5.34
2.9
4.19
4.71
7.46
13.4
545
.59
41.3
38.
398.
872.
41Sc
2.
81.
95.
42.
11.
12.
76.
72.
97.
18.
512
.118
.214
.59.
612
.513
.222
.2V
9.
065.
2458
.94
1.95
2.14
25.9
420
.92.
051.
435
.44
133.
761
.08
118.
9388
.77
56.6
849
.44
113.
41Zn
43
.77
10.0
551
.12
83.7
713
610
.34
72.5
439
.11
62.7
68.
5441
.36
58.4
846
.45
192
69.8
11.9
916
.91
Ba
36
8.24
698.
2329
7.04
115.
1640
2.28
425.
8430
9.43
312.
3134
6.45
227.
231
8.3
145.
93.
6832
813
6.1
145.
4837
3.75
Cd
0.
054
0.05
20.
035
0.10
80.
113
0.03
10.
122
0.09
90.
046
0.12
40.
072
0.09
50.
046
0.08
0.05
80.
054
0.05
3C
r
4637
.41
62.4
734
.97
30.4
627
.22
13.7
211
.94
12.6
411
.92
24.3
660
.248
.28
86.9
522
.51
22.0
59.
78G
a 18
.64
16.3
917
.79.
8515
.82
19.4
927
.03
19.4
710
.91
24.1
17.0
420
.61
10.2
617
.78
14.0
114
.58
15.1
8M
o
55
3.14
3.17
3.16
1.79
1.39
0.85
3.08
0.74
1.06
0.5
1.95
0.22
0.35
0.88
1.09
Pb
3.8
2.5
3.8
6.1
11.7
2.6
2.3
2.4
22.5
27.9
3.6
1.8
1.4
6.5
1.8
1.4
5.8
Sn
0.9
11.
122.
514.
061.
065.
445.
343.
312.
542.
42.
160.
871.
981.
811.
692.
02T
l 0.
210.
220.
170.
081.
920.
280.
090.
070.
630.
030.
150.
010.
10.
050.
030.
27W
0.
730.
480.
180.
210.
421.
80.
80.
860.
540.
50.
790.
480.
720.
690.
560.
181.
07
RHYOLITE GEOCHEMICAL SIGNATURES AND ASSOCIATION WITH VMS, ABITIBI BELT, CANADA 1555
0361-0128/98/000/000-00 $6.00 1555
Num
ber
R-1
9R
-20
R-2
1R
-22
R-2
3R
-25
R-2
6R
-27
R-2
8R
-29
R-3
0R
-31
R-3
2R
-34
R-3
5R
-36
R-3
7
Zone
1818
1818
1717
1718
1717
1717
1717
1717
17U
TM
E32
3164
3116
0130
3148
3024
8071
8033
7164
1571
6415
2960
2771
1276
7013
5970
0608
6844
2268
1858
6194
0161
8604
6172
3761
5340
UT
MN
5326
912
5330
063
5367
105
5377
870
5381
228
5387
455
5387
447
5399
513
5388
917
5393
938
5388
487
5389
578
5394
610
5429
078
5429
499
5430
259
5416
389
SiO
2(w
t %)
75.4
169
.33
81.7
669
.52
55.1
377
.61
70.6
574
.72
54.5
965
.860
.24
62.1
162
.88
83.6
488
.82
75.3
964
.65
Al 2O
312
.21
14.2
46.
8712
.33
16.3
612
.44
13.5
512
.56
16.1
915
.57
15.6
413
.98
17.1
610
.99
9.74
13.5
617
.5Ti
O2
0.66
0.6
0.11
0.37
0.7
0.2
0.32
0.17
0.86
0.79
0.54
0.76
0.25
0.16
0.05
0.56
0.35
Fe 2
O3
5.96
4.56
5.56
3.49
8.31
0.23
4.38
2.8
9.15
2.84
7.14
5.59
1.85
0.97
0.02
2.96
3.96
MgO
1.
874.
150.
220.
895.
620.
680.
714.
930.
953.
943.
10.
980.
541.
322.
24M
nO
0.12
0.03
0.11
0.13
0.03
0.05
0.15
0.08
0.11
0.07
0.02
0.01
0.06
0.09
K2O
1.
392.
942.
22.
171.
611.
952.
361.
220.
722.
651.
321.
754.
142.
180.
533.
011.
82C
aO
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
Na 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
P 2O
50.
120.
30.
010.
120.
140.
030.
070.
030.
140.
180.
110.
140.
080.
020.
020.
110.
12L
OI
2.
393.
383.
726.
142.
91.
723.
541.
083.
390.
632.
095.
984.
481.
660.
422.
221.
98To
tal
100.
1910
0.4
100.
5899
.91
99.4
99.4
510
0.04
99.4
510
0.7
99.6
510
0.96
100.
4599
.86
100.
9899
.65
99.6
210
0.26
Ce
(pp
m)
7.23
29.7
422
.36
54.4
233
.959
.44
73.9
111
6.95
27.2
853
.228
.61
34.5
17.9
419
.88
18.1
932
.51
35.9
8C
s
0.92
10.
918
0.51
31.
533
1.64
50.
952
2.53
0.93
60.
905
0.13
40.
645
1.29
22.
364
1.71
0.08
61.
036
3.11
5D
y
1.08
2.50
24.
629
6.04
83.
773
6.34
97.
867
13.7
883.
625.
977
2.99
43.
584
0.73
74.
668.
796
6.93
0.92
1E
r
0.83
11.
671
3.91
53.
963
2.24
33.
436
4.93
28.
121
2.22
83.
642
1.8
2.19
60.
334
3.03
76.
193
4.30
20.
408
Eu
0.
228
0.80
70.
666
1.75
71.
071.
073
1.37
71.
428
1.12
61.
527
0.76
10.
975
0.49
60.
452
0.27
30.
481
0.73
7G
d
1.22
63.
668
3.75
96.
535
3.93
36.
867
7.79
614
.022
3.72
55.
863
3.06
33.
798
1.23
93.
583
6.34
15.
589
1.70
2H
f 3.
35.
46.
66.
64.
16.
17.
18.
33.
36.
63.
44.
92.
34.
84
7.3
2.7
Ho
0.
249
0.51
21.
123
1.28
40.
772
1.22
21.
633
2.76
50.
756
1.24
10.
609
0.74
80.
127
0.99
91.
979
1.44
70.
156
La
2.
6610
.76
9.63
22.8
214
.64
27.8
534
.05
53.0
911
.95
24.9
212
.97
15.4
58.
447.
316.
7813
.13
16.7
4L
u
0.17
40.
352
0.78
70.
650.
335
0.49
50.
766
1.25
0.32
40.
543
0.26
60.
316
0.04
20.
487
0.96
60.
618
0.05
2N
b
48.
312
.911
.27.
210
.913
.623
.96
10.7
5.9
8.1
2.2
1015
.312
.12.
6N
d
5.63
17.7
12.9
631
.42
17.3
228
.834
.35
58.7
114
.72
25.4
613
.83
178.
788.
412
.37
15.9
716
.92
Pr
1.12
73.
881
2.96
17.
289
4.29
67.
175
8.75
914
.652
3.51
36.
369
3.43
94.
195
2.21
52.
117
2.64
84.
114.
467
Rb
23.1
658
.06
39.0
248
.21
58.7
641
.33
45.8
641
.41
19.1
548
.539
.28
48.3
475
.57
68.9
46.
9741
.84
47.8
8Sm
1.
414.
223.
237.
253.
826.
77.
6813
.47
3.35
5.58
2.98
3.71
1.7
2.34
4.46
4.46
2.71
Sr
242.
249
.815
.122
625
5.6
70.6
78.9
5420
8.1
133.
115
9.5
115.
321
3.5
42.9
137
.141
7.4
Ta
0.33
0.55
0.96
0.81
0.6
1.14
1.33
1.99
0.48
0.91
0.53
0.66
0.22
0.86
1.43
0.9
0.22
Tb
0.
177
0.47
0.66
10.
974
0.62
31.
087
1.27
72.
279
0.60
20.
974
0.50
30.
603
0.15
50.
709
1.28
31.
091
0.19
9T
h 1.
031.
521.
353.
21.
485.
997.
828.
671.
313.
831.
812.
371.
392.
915.
632.
862.
7T
m
0.13
80.
270.
664
0.61
30.
336
0.50
20.
749
1.22
30.
321
0.54
0.26
20.
319
0.04
60.
465
0.96
30.
631
0.05
5U
0.
380.
666
0.65
40.
932
0.50
81.
170.
739
2.13
60.
341.
046
0.47
60.
750.
491
0.98
20.
504
0.89
20.
898
Y 6.
6913
.73
31.7
735
.06
21.3
829
.61
45.8
372
.29
20.6
234
.39
17.0
420
.46
3.47
28.5
56.4
38.9
24.
24Yb
1.
022.
034.
844.
232.
223.
315.
018.
342.
113.
541.
732.
060.
33.
136.
374.
10.
36Zr
12
1.5
204.
721
5.4
251.
916
4.5
205.
724
0.6
247.
313
2.5
257.
513
8.6
199
87.9
159
79.4
294.
310
3.8
Be
0.
471.
30.
20.
810.
630.
940.
791.
140.
490.
610.
540.
711.
050.
960.
11
0.94
Co
9.46
4.6
5.13
2.75
35.9
41.
12.
821.
7331
.06
6.81
29.5
120
.88
5.86
0.9
21.
1610
.41
Cu
26
048.
249.
4114
.87
51.4
32.
2712
.48
20.4
641
.56
40.7
358
.69
41.4
83.
845.
071.
182.
744
.71
Li
1424
88
221
5215
192
1024
1115
211
48N
i 14
.09
3.57
7.55
4.91
183.
834.
234.
963.
7986
.38
7.38
77.3
794
.94
20.5
12.
091.
596.
2221
.57
Sc
11.3
101.
57.
215
3.4
7.3
418
.510
.614
.611
.63.
31.
61.
25.
25.
1V
10
2.21
11.5
94.
269.
0313
9.78
2.67
21.8
73.
9215
0.88
6692
.59
111.
4941
.27
3.32
49.1
152
.35
Zn
69.0
963
.66
1232
485
.66
8.36
76.3
777
.38
96.8
859
.373
.63
65.7
625
.16
32.6
13.
5858
.03
70.2
1B
a
299.
3613
8.4
263.
8849
2.65
259.
6233
9.31
384.
0615
7.88
278.
8963
5.19
260.
1729
3.61
549.
4126
3.98
5.46
696.
8738
9.46
Cd
0.
037
0.04
30.
049
0.3
0.08
40.
050.
050.
073
0.10
10.
125
0.06
60.
072
0.04
90.
035
0.06
10.
082
Cr
61
.19
11.7
616
.46
12.7
325
1.62
12.5
515
.02
11.9
114.
1414
.95
74.2
126.
0718
.86
9.43
9.82
11.4
830
.57
Ga
17.1
813
.14
11.0
118
.58
19.3
115
.95
19.2
118
.45
18.2
418
.66
15.2
917
.86
20.1
416
.48
15.0
923
.16
19.8
Mo
2.
680.
532.
171.
850.
840.
480.
620.
591.
151.
52.
120.
640.
40.
650.
291.
381.
42Pb
2.
93.
212
.838
.25.
22.
13.
98.
46.
314
.12.
24.
45.
26.
61.
640
7.2
Sn
1.2
1.77
3.07
2.65
8.24
3.55
3.9
9.59
1.66
3.48
2.67
1.77
2.44
3.54
5.39
100.
81T
l 0.
540.
10.
960.
140.
120.
160.
090.
090.
140.
140.
180.
430.
140.
020.
290.
23W
0.
560.
250.
660.
550.
580.
421
0.68
0.22
0.66
0.18
0.34
0.57
0.79
0.81
3.79
0.29
APP
EN
DIX
1(C
ont.)
1556 GABOURY AND PEARSON
0361-0128/98/000/000-00 $6.00 1556
Num
ber
R-3
8R
-41
R-4
2R
-43
R-4
4R
-45
R-4
6R
-47
R-4
8R
-50
R-5
1R
-52
R-5
3R
-54
R-5
5R
-56
R-5
7
Zone
1717
1717
1717
1717
1717
1818
1818
1717
17U
TM
E63
3686
6566
7567
0257
6858
2269
5000
6950
1869
1184
6928
1969
0587
6429
7830
5709
2995
1530
5403
3114
7963
7049
6342
1162
0877
UT
MN
5424
766
5419
254
5405
392
5409
034
5479
820
5479
815
5485
776
5482
091
5479
711
5520
033
5507
623
5514
904
5512
540
5516
571
5379
247
5378
698
5388
093
SiO
2(w
t %)
76.1
464
.02
61.0
682
.32
68.8
772
.39
62.6
879
.73
70.6
267
.35
73.3
978
.48
65.8
865
.19
71.1
570
.22
73.0
1A
l 2O3
13.9
718
.25
14.8
69.
8912
.32
13.4
516
.15
11.6
12.2
13.0
911
.41
9.61
10.5
912
.65
10.9
413
.43
12.7
3Ti
O2
0.36
0.32
0.81
0.12
0.45
0.53
0.52
0.09
0.41
0.49
0.3
0.26
0.64
0.89
0.31
0.6
0.28
Fe 2
O3
0.27
3.21
71.
585.
163.
176.
361.
525.
163.
765.
84.
3712
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10.3
36.
732.
053.
9M
gO
0.27
2.15
4.57
0.07
3.27
0.44
1.92
0.2
2.59
1.02
1.1
2.26
6.34
1.57
2.12
0.21
1M
nO
0.04
0.11
0.03
0.07
0.06
0.12
0.04
0.09
0.08
0.07
0.05
0.05
0.1
0.14
0.08
0.06
K2O
8.
321.
671.
751.
941.
551.
840.
752.
151.
964
3.48
0.75
0.05
0.55
2.43
1.21
1.61
CaO
4.
275.
180.
210.
940.
733.
250.
551.
193.
170.
870.
090.
133.
330.
082.
961.
87N
a 2O
0.
124.
54.
283.
312.
334.
225.
882.
062.
291.
362.
242.
624.
460.
175.
413.
74P 2
O5
0.03
0.09
0.17
0.02
0.08
0.11
0.1
0.02
0.07
0.15
0.05
0.03
0.12
0.2
0.07
0.15
0.06
LO
I
1.18
1.66
1.18
0.91
5.45
2.85
2.6
2.13
2.91
5.53
1.79
1.78
4.11
1.19
6.64
3.13
2.83
Tota
l 10
0.66
100.
1810
0.96
100.
4110
0.48
99.7
810
0.34
100.
1199
.599
.99
100.
5110
0.3
100.
5310
0.46
100.
7899
.46
101.
08
Ce
(pp
m)
47.5
620
.06
34.7
150
.124
.32
33.0
626
.29
61.5
947
.336
.72
91.7
389
.41
42.1
366
.84
30.1
140
.01
64.2
2C
s
1.44
62.
022
1.44
60.
484
0.98
81.
565
0.24
40.
469
0.34
31.
061.
360.
119
0.03
20.
127
0.33
60.
958
0.44
8D
y
3.54
10.
696
3.56
413
.305
2.64
33.
288
1.64
27.
256
9.09
94.
417
2020
16.5
2916
.961
1.74
12.
723
4.42
4E
r
2.04
10.
316
2.08
38.
892
1.71
31.
983
0.90
64.
851
5.99
12.
833
18.2
1313
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11.0
6711
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1.03
61.
567
2.68
6E
u
1.07
80.
634
1.11
11.
134
0.56
80.
798
0.76
50.
654
1.73
10.
938
3.34
43.
097
2.05
42.
625
0.35
31.
084
1.21
2G
d
4.24
71.
159
3.80
710
.257
2.56
43.
388
2.12
56.
291
8.16
84.
248
2018
.172
13.2
4315
2.10
33.
326
5.04
7H
f 7.
22.
83.
710
5.8
4.8
3.2
6.6
7.6
4.5
17.7
15.5
10.2
124.
44
6.4
Ho
0.
677
0.12
20.
719
2.94
0.56
60.
660.
323
1.57
91.
949
0.94
5.81
74.
464
3.59
63.
606
0.34
80.
535
0.89
8L
a
21.0
611
.14
15.6
821
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10.8
514
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12.6
226
.39
20.4
316
.53
35.5
434
.47
16.2
25.1
113
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17.7
29.4
9L
u
0.34
10.
041
0.29
51.
327
0.26
70.
305
0.13
0.72
30.
903
0.42
42.
791.
926
1.64
31.
678
0.16
10.
230.
409
Nb
11
.81.
77.
523
.18.
36.
13.
89.
110
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428
.224
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45.
99.
8N
d
22.8
58.
9618
.11
28.4
513
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.66
12.5
230
.18
28.4
118
.69
63.7
261
.97
31.5
45.8
414
.120
.329
.68
Pr
5.76
72.
396
4.41
76.
569
3.13
64.
123.
186
7.64
86.
447
4.53
913
.472
12.9
996.
399.
835
3.63
35.
057
7.70
8R
b 93
.469
.11
42.6
154
.36
25.8
740
.615
.44
40.2
334
.89
79.5
279
.04
13.2
0.72
6.41
33.6
31.7
435
.5Sm
4.
851.
583.
927.
692.
93.
542.
476.
457.
034.
117
.54
16.0
39.
3512
.56
2.58
3.95
5.94
Sr
21.3
602.
413
8.5
3249
.472
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829
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.743
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.124
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758
.320
.493
.360
.8Ta
0.
990.
260.
621.
660.
720.
610.
430.
880.
850.
771.
821.
641.
121.
450.
590.
590.
87T
b
0.63
90.
145
0.59
51.
962
0.42
80.
536
0.29
71.
107
1.40
50.
698
3.88
63.
161
2.46
72.
633
0.29
70.
480.
759
Th
3.85
1.44
1.44
4.84
1.9
2.34
1.96
3.89
2.2
2.63
4.06
3.09
1.93
3.32
3.31
2.99
4.56
Tm
0.
317
0.04
40.
303
1.33
30.
263
0.29
80.
134
0.72
60.
894
0.42
42.
779
2.04
51.
641
1.65
10.
155
0.22
90.
406
U
0.87
30.
427
0.36
31.
290.
612
0.41
10.
463
0.97
50.
606
0.62
41.
035
0.83
70.
533
0.87
60.
902
0.62
90.
979
Y 16
.82
3.32
19.7
979
.81
14.7
617
.37
8.84
44.9
552
.92
25.9
812
011
5.18
95.3
596
.46
9.5
13.5
24.7
Yb
2.2
0.28
1.96
8.74
1.73
20.
874.
845.
912.
818
.26
13.3
110
.78
11.0
11.
061.
522.
69Zr
27
4.6
113.
715
5.4
332.
621
6.7
183.
112
720
2.6
288.
617
8.6
688.
856
5.8
375.
646
0.4
167
157.
325
7.2
Be
0.
580.
560.
460.
880.
560.
330.
430.
590.
810.
431.
781.
11.
010.
430.
310.
58C
o 0.
785.
6624
.83
0.25
9.06
4.53
16.7
60.
417.
747.
080.
910.
289.
8913
.29.
21.
623.
2C
u
2.67
4.53
40.2
318
.12
8.01
14.9
87.
1812
.35
29.1
56.
365.
8610
.06
30.1
412
.26
49.0
12.
51.
96L
i 9
2821
240
526
711
39
712
102
610
Ni
2.88
15.6
811
0.12
1.33
11.2
44.
0649
.75
1.32
8.16
2.8
2.36
1.22
1.29
2.88
4.81
1.7
2.1
Sc
3.3
3.8
15.1
2.1
2.7
6.2
10.2
3.2
7.9
7.1
2.3
0.8
12.1
12.8
3.3
6.5
5.6
V
6.79
42.2
114.
463.
4845
.27
31.6
992
.62
2.17
24.0
922
.73
5.23
1.78
3.71
40.7
17.7
430
.34
6.77
Zn
6.9
60.0
577
.24
88.7
473
.53
83.8
935
.28
72.4
611
4.99
54.0
613
6.05
217
84.0
285
.36
92.4
613
.51
55.2
7B
a
713.
9424
9.18
242.
6349
6.58
69.3
711
01.2
720
4.97
223.
0530
6.06
266.
7254
3.24
45.0
225
.85
140.
8643
3.61
273.
721
2.71
Cd
0.
050.
036
0.07
0.11
90.
066
0.05
70.
044
0.11
40.
063
0.06
20.
204
0.14
50.
075
0.09
70.
084
0.03
10.
062
Cr
10
.44
31.0
784
.66
8.71
15.5
48.
7564
.721
.33
10.1
8.12
8.45
9.08
8.18
8.26
Ga
19.3
423
.43
15.7
212
.75
17.9
416
.65
17.6
816
.09
20.7
517
.17
32.2
319
.84
28.4
623
.33
14.1
615
.72
15.0
7M
o
0.7
2.62
0.83
3.25
1.12
0.54
0.32
0.93
1.39
0.35
1.77
1.09
50.
811.
060.
370.
22Pb
2.
65
1.6
5.4
412
.11.
211
.43.
92.
24.
73.
80.
81.
38.
32
2.5
Sn
3.49
0.7
1.58
4.31
2.46
1.41
1.71
2.63
2.66
2.09
105.
683.
582.
081.
751.
312.
09T
l 0.
241.
040.
080.
080.
120.
250.
080.
130.
140.
121.
180.
160.
020.
160.
090.
12W
0.
450.
420.
180.
930.
270.
270.
320.
270.
251.
770.
720.
370.
710.
230.
680.
290.
23
APP
EN
DIX
1(C
ont.)
RHYOLITE GEOCHEMICAL SIGNATURES AND ASSOCIATION WITH VMS, ABITIBI BELT, CANADA 1557
0361-0128/98/000/000-00 $6.00 1557
Num
ber
R-5
8R
-59
R-6
0R
-61
R-6
2R
-63
R-6
4R
-65
R-6
6R
-67
R-6
8R
-69
R-7
0R
-71
R-7
3R
-74
R-7
5
Zone
1717
1717
1717
1717
1717
1717
1717
1717
17U
TM
E61
5919
6171
4562
2270
6222
7365
0653
6504
4765
2983
6573
4365
4526
6341
7763
1020
6303
1862
7893
6260
0062
4067
6465
7364
7630
UT
MN
5387
853
5386
548
5383
127
5383
134
5382
153
5381
949
5383
580
5392
084
5391
921
5342
561
5341
497
5342
283
5342
497
5349
906
5351
508
5346
168
5347
494
SiO
2(w
t %)
75.9
72.2
866
.74
63.7
770
.29
79.6
375
.72
71.4
370
.89
67.3
570
.29
78.5
883
.18
81.8
872
.92
70.8
872
.83
Al 2O
39.
2712
.09
15.4
413
.81
7.62
10.1
312
.19
12.8
511
.13
10.2
314
.42
10.7
19.
1811
.34
12.6
13.2
611
.55
TiO
20.
250.
290.
50.
580.
130.
130.
280.
330.
220.
330.
330.
340.
20.
430.
260.
380.
26F
e 2O
36.
992.
693.
875.
4613
.49
3.84
3.62
3.14
9.76
5.91
5.22
2.17
0.96
0.51
4.88
6.2
7.12
MgO
0.
810.
341.
793.
264.
082.
641.
310.
591.
880.
750.
610.
250.
240.
450.
830.
281.
01M
nO
0.18
0.08
0.06
0.07
0.14
0.01
0.04
0.05
0.09
0.19
0.09
0.03
0.01
0.13
0.03
0.22
K2O
0.
80.
870.
661.
280.
241.
950.
840.
360.
91.
053.
10.
390.
083.
321.
223.
530.
22C
aO
1.72
2.82
1.22
4.21
0.02
0.02
0.13
20.
715.
961.
290.
910.
320.
190.
970.
071.
05N
a 2O
2.
015.
637.
824.
380.
224.
526.
652.
453.
13.
65.
615.
170.
524.
980.
624.
32P 2
O5
0.04
0.06
0.09
0.1
0.02
0.02
0.05
0.07
0.05
0.07
0.05
0.06
0.03
0.05
0.04
0.08
0.04
LO
I
2.76
2.9
1.57
2.94
5.08
2.4
1.47
2.15
2.05
5.6
1.24
0.36
0.4
1.57
1.04
4.14
1.93
Tota
l 10
0.74
100.
0699
.78
99.8
810
1.13
100.
9810
0.16
99.6
310
0.13
100.
5310
0.25
99.4
199
.76
100.
2699
.87
99.4
610
0.53
Ce
(pp
m)
47.0
962
.39
47.4
520
.81
47.6
743
.47
47.8
448
.86
33.4
933
.67
48.8
56.9
539
.26
29.9
354
.58
8.6
74.6
7C
s
0.14
50.
268
0.09
70.
424
0.06
20.
331
0.13
70.
173
0.27
90.
484
2.96
10.
134
0.09
11.
083
0.24
60.
754
0.16
4D
y
3.92
94.
744.
008
1.71
73.
785
3.88
23.
482
4.04
82.
007
5.79
38.
957
6.58
5.79
13.3
0810
.992
3.06
9.44
3E
r
2.38
2.76
72.
338
0.97
12.
171
2.39
52.
059
2.35
11.
229
3.68
46.
078
4.50
34.
061
10.0
487.
454
2.29
45.
935
Eu
1.
465
1.06
1.08
70.
618
0.46
20.
546
1.04
50.
924
0.47
91.
291.
687
1.14
50.
708
0.69
91.
550.
478
2.28
Gd
4.
025
5.08
14.
373
1.94
14.
125
3.93
3.82
93.
953
2.24
5.32
27.
875.
948
4.69
28.
822
9.26
41.
773
9.47
2H
f 4.
96
5.8
2.4
3.9
5.3
5.1
5.1
4.6
4.5
7.5
6.4
5.5
8.9
8.2
4.2
6.6
Ho
0.
806
0.95
70.
805
0.33
50.
761
0.78
90.
703
0.82
40.
411.
226
1.95
21.
437
1.28
53.
079
2.38
40.
717
1.95
6L
a
21.1
828
.81
19.8
79.
9522
.79
19.7
622
.55
22.3
414
.91
14.4
121
.22
29.6
216
.35
10.6
722
3.53
34.9
3L
u
0.35
10.
407
0.35
30.
139
0.29
40.
381
0.30
80.
351
0.20
70.
579
0.97
0.70
40.
666
1.60
11.
158
0.39
20.
951
Nb
8.
79.
78
3.6
4.5
86.
87.
26
7.9
12.6
11.1
9.8
14.9
13.5
8.8
16.8
Nd
22
.52
28.5
422
.88
9.92
22.0
220
.25
22.7
522
.34
14.6
319
.26
28.8
226
2122
.58
32.4
94.
6738
.21
Pr
5.71
17.
456
5.77
22.
526
5.59
95.
256
5.81
75.
848
3.87
64.
412
6.59
36.
642
5.14
54.
764
7.36
91.
122
9.29
7R
b 13
.23
22.5
17.
6422
.38
4.16
31.9
515
.67.
9418
.43
25.5
664
.97
8.05
1.58
56.2
825
.18
56.8
5.09
Sm
4.43
5.64
4.8
2.07
4.48
4.28
4.4
4.44
2.73
4.8
7.22
5.81
4.82
6.82
8.25
1.26
8.93
Sr
38.1
81.7
97.5
136.
84.
87.
639
.910
4.4
46.3
126.
816
9.5
79.9
57.3
18.8
82.7
13.9
31.6
Ta
0.75
0.88
0.77
0.44
0.56
0.78
0.76
0.69
0.64
0.63
0.93
0.89
0.79
1.05
0.99
0.69
1.14
Tb
0.
640.
798
0.67
40.
290.
629
0.62
60.
588
0.65
60.
338
0.90
61.
391.
030.
841
1.83
71.
638
0.39
61.
515
Th
3.22
4.4
4.02
1.42
2.95
4.12
3.16
3.47
3.26
1.71
3.21
3.43
3.2
2.11
2.75
1.9
2.78
Tm
0.
352
0.40
70.
350.
140.
312
0.36
20.
302
0.35
10.
194
0.55
40.
925
0.67
70.
636
1.59
71.
140.
372
0.89
4U
0.
781.
066
0.98
70.
357
0.75
30.
985
0.78
50.
851
0.83
90.
432
0.83
60.
877
0.83
80.
590.
744
0.57
70.
715
Y 22
.07
26.8
822
.73
9.11
20.4
21.3
818
.86
22.6
710
.933
.24
52.4
540
.13
34.5
281
.72
62.8
19.1
953
.92
Yb
2.28
2.69
2.31
0.92
2.01
2.45
2.01
2.27
1.34
3.74
6.26
4.51
4.24
10.6
67.
522.
56.
06Zr
19
7.9
230.
123
4.5
9615
2.4
200.
920
119
7.3
181.
218
0.2
283.
924
9.4
212.
930
6.8
310.
516
9.9
248.
7B
e
0.4
0.62
0.53
0.5
0.28
0.3
0.27
0.44
0.38
0.79
0.42
0.24
0.15
0.68
0.22
0.52
Co
5.21
2.45
8.15
19.1
15.3
66.
333.
073.
8210
.15
2.5
2.35
2.11
0.78
0.71
3.85
6.01
0.53
Cu
17
.81
3.39
27.3
237
.66
38.3
21.
782.
755.
2527
.09
5.02
109.
9238
.59
225
13.7
871
.83
104.
9920
.59
Li
93
712
1511
135
97
175
34
53
20N
i 0.
942.
1912
.28
57.0
13.
351.
31.
343.
195.
061.
331.
271.
430.
961.
843.
142.
151.
21Sc
5.
24.
87.
911
.13.
84.
26
52.
211
.913
.88.
44.
17.
613
.17.
410
.8V
3.
2110
.75
50.1
511
6.42
6.13
1.48
2.48
10.9
811
.39
4.16
5.13
4.41
1.6
1.81
1.5
15.4
61.
8Zn
81
.06
44.9
848
.67
64.9
126.
8125
.64
32.6
139
.04
55.0
863
.29
85.7
731
.62
28.0
618
.36
78.7
550
0022
5B
a
134.
0217
5.54
188.
6142
0.12
39.8
229
9.83
180.
7685
.86
201.
7217
9.61
872.
2416
4.31
35.9
144
1.29
482.
8934
0.36
47.8
3C
d
0.05
90.
047
0.10
60.
036
0.06
50.
041
0.04
40.
036
0.06
20.
041
0.10
70.
050.
037
0.08
40.
071
0.3
0.14
1C
r
8.64
16.1
492
.27
8.12
8.12
9.06
10.1
48.
078.
398.
9111
.34
9.08
Ga
12.0
415
.46
16.7
15.3
612
.05
14.2
914
.73
13.0
916
.07
13.8
220
.46
11.2
99.
267.
9818
.61
15.3
422
.01
Mo
2.
370.
310.
930.
642.
80.
720.
660.
31
0.87
0.37
0.36
0.71
0.94
1.69
0.98
3.38
Pb
3.3
3.3
3.3
13.1
1.3
1.4
1.9
1.5
4.9
1.3
3.5
4.5
1.3
31.
39.
43.
2Sn
1.
092.
262.
11.
340.
922.
171.
771.
321.
771.
152.
577.
91.
580.
932.
732.
563.
51T
l 0.
040.
070.
050.
140.
020.
210.
060.
040.
060.
080.
290.
050.
680.
080.
520.
04W
0.
260.
30.
250.
240.
580.
520.
220.
380.
210.
380.
420.
290.
410.
730.
30.
441.
88
APP
EN
DIX
1(C
ont.)
1558 GABOURY AND PEARSON
0361-0128/98/000/000-00 $6.00 1558
Num
ber
R-7
6R
-77
R-7
8R
-79
R-8
0R
-81
R-8
3R
-84
R-8
5R
-88
R-8
9R
-90
R-9
2R
-93
R-9
5R
-96
R-9
7
Zone
1717
1717
1717
1717
1717
1717
1717
1717
17U
TM
E64
6889
6510
0165
2251
6496
0964
5584
6480
3365
5360
6509
9165
2434
6693
1066
2609
6543
5564
2730
6412
0762
9641
6236
0762
0443
UT
MN
5347
743
5347
863
5350
159
5347
769
5350
329
5344
213
5361
370
5366
108
5371
275
5358
894
5358
869
5358
411
5351
864
5357
028
5360
526
5358
232
5365
459
SiO
2(w
t %)
72.9
574
.28
70.4
972
.79
70.9
573
.92
76.0
561
.94
73.9
664
.15
76.4
277
.455
.75
73.2
572
.65
74.8
873
.59
Al 2O
311
.33
11.5
610
.36
10.7
212
.55
9.61
10.9
217
.16
13.2
515
.06
10.1
611
.26
16.3
312
.46
12.2
611
.56
12.5
4Ti
O2
0.25
0.33
0.28
0.23
0.45
0.21
0.2
0.84
0.22
0.56
0.3
0.25
1.03
0.25
0.26
0.23
0.31
Fe 2
O3
5.43
2.08
3.99
5.23
4.71
1.69
2.18
6.23
2.92
4.71
3.21
1.49
9.03
4.35
3.95
3.5
4.4
MgO
0.
850.
572.
42.
191.
240.
10.
333.
170.
82.
791.
140.
094.
761.
180.
570.
180.
86M
nO
0.08
0.03
0.13
0.27
0.08
0.13
0.03
0.08
0.02
0.08
0.05
0.04
0.13
0.06
0.06
0.1
0.07
K2O
0.
291.
091.
22.
731.
510.
330.
631.
514.
782.
21.
533
1.13
2.1
0.61
4.07
1.36
CaO
1.
262.
673.
080.
922.
014.
621.
342.
60.
684.
252.
530.
556.
371.
61.
533.
041.
1N
a 2O
4.
984.
422.
91.
123.
975.
035.
743.
881.
273.
62.
294.
645.
093.
615.
381.
674.
56P 2
O5
0.04
0.06
0.07
0.04
0.08
0.04
0.05
0.13
0.03
0.16
0.07
0.05
0.14
0.03
0.05
0.04
0.07
LO
I
1.66
2.9
5.49
3.95
2.93
3.59
1.9
2.69
2.37
1.7
2.55
0.4
1.62
1.51
1.88
0.71
1.23
Tota
l 99
.12
100
100.
410
0.18
100.
4899
.27
99.3
810
0.23
100.
399
.27
100.
2499
.17
101.
410
0.39
99.1
999
.97
100.
09
Ce
(pp
m)
54.4
734
.09
55.4
546
.98
41.6
747
.96
56.8
732
.93
80.2
255
.88
59.2
796
.91
23.3
157
.15
40.8
655
.77
62.0
8C
s
0.12
60.
720.
652
1.40
50.
336
0.3
0.34
41.
239
2.35
11.
621.
234
0.32
20.
199
0.62
10.
163
0.33
10.
263
Dy
9.
573
5.29
77.
018
7.70
76.
233
8.24
76.
454.
561
7.76
42.
513
7.69
11.0
532.
808
10.8
438.
584
9.91
213
.25
Er
6.
328
3.51
34.
986
5.15
14.
152
4.69
44.
316
2.93
15.
052
1.32
85.
388
7.34
61.
626
7.11
25.
803
6.67
78.
979
Eu
1.
964
0.85
71.
274
1.70
71.
141
1.97
81.
241.
191.
298
1.35
21.
155
1.16
80.
953
1.89
21.
306
1.80
11.
885
Gd
8.
526
4.71
87.
315
7.19
85.
814
7.62
6.14
74.
309
7.92
63.
679
6.76
110
.046
3.01
99.
387
6.90
98.
823
11.8
46H
f 6.
55.
56.
76.
36.
94.
67.
34
9.3
3.3
6.8
8.1
2.7
8.4
6.8
7.9
7.5
Ho
2.
054
1.13
91.
504
1.68
21.
342
1.66
91.
392
0.96
51.
642
0.47
51.
684
2.36
80.
565
2.31
1.88
82.
151
2.86
8L
a
23.2
915
.94
22.5
19.8
217
.73
20.4
326
.19
14.0
835
.67
26.8
126
.89
46.2
10.1
124
.33
16.6
922
.96
25.9
4L
u
0.98
50.
551
0.91
60.
820.
693
0.58
0.72
10.
446
0.81
70.
185
0.88
61.
161
0.23
1.10
90.
885
1.07
1.42
2N
b
1510
.115
.314
.512
.210
.711
.48.
116
.54.
412
.717
.74.
814
.711
.613
.614
Nd
31
.49
17.7
32.5
27.7
523
.83
28.6
628
.25
18.4
541
.03
27.7
130
.13
46.2
512
.81
33.2
823
.95
33.1
39.6
2Pr
7.
264
4.23
7.50
46.
313
5.54
86.
481
7.02
74.
3310
.242
7.01
57.
319
11.7
132.
998
7.63
95.
483
7.55
78.
62R
b 6.
5232
.78
23.2
538
.522
.68
8.06
8.61
26.4
611
0.9
64.8
136
.49
38.1
20.2
848
.97
15.1
476
.924
.44
Sm
7.95
4.32
7.94
6.86
5.56
6.92
6.06
4.18
8.44
4.98
6.57
9.72
2.86
8.1
5.79
810
.32
Sr
68.2
46.1
58.2
24.6
55.8
36.1
53.2
149.
120
.674
1.2
38.1
24.6
185.
811
3.1
56.4
108.
576
.3Ta
1.
050.
771.
181.
020.
960.
770.
890.
641.
380.
430.
981.
290.
451.
020.
860.
981.
01T
b
1.48
10.
821
1.15
1.22
30.
978
1.30
91.
021
0.71
11.
253
0.47
21.
158
1.73
60.
471.
673
1.27
91.
522.
076
Th
2.66
3.13
3.97
2.64
3.85
1.95
3.51
2.11
6.5
3.51
5.08
5.8
1.22
3.12
2.5
2.81
3.28
Tm
0.
966
0.54
70.
799
0.79
40.
644
0.65
30.
680.
445
0.77
0.18
60.
856
1.15
10.
236
1.07
90.
879
1.03
11.
398
U
0.69
10.
875
1.00
40.
686
1.02
0.43
40.
845
0.55
41.
525
1.02
81.
213
1.28
90.
314
0.83
60.
696
0.71
70.
846
Y 55
.77
30.6
141
.39
40.6
735
.45
44.7
638
25.3
844
.09
12.9
345
.71
63.3
914
.962
.65
51.0
256
.71
74.4
6Yb
6.
423.
635.
675.
34.
364.
054.
532.
925.
151.
225.
787.
71.
527.
135.
726.
99.
28Zr
24
9.4
217.
322
3.2
232.
326
6.7
168.
230
1.6
155.
735
1.6
127.
424
7.2
272.
810
832
3.9
258
298.
724
8.6
Be
0.
410.
240.
550.
60.
470.
30.
180.
561.
220.
820.
540.
440.
390.
890.
640.
610.
66C
o 2.
162.
73.
880.
285.
060.
672.
3623
.04
2.89
20.5
93.
020.
8631
.38
1.18
1.69
0.77
2.07
Cu
24
710
.04
3.6
2.54
8.27
9.42
8.64
21.2
447
.32
44.7
23.6
521
.43
79.9
3.9
9.2
2.95
3.33
Li
179
910
113
2313
4211
25
87
26
Ni
1.28
1.98
2.35
1.22
2.28
1.4
1.95
52.2
26.
9290
.08
2.08
1.82
48.7
21.
111.
131.
541.
26Sc
10
5.9
5.3
8.1
9.9
6.6
5.9
15.5
810
.56.
85.
419
.310
.910
.610
.410
.9V
1.
7611
.16
15.7
2.94
16.1
2.73
2.97
158.
3415
.39
94.2
910
.72
9.11
224.
452.
72.
632.
674.
74Zn
58
.65
19.1
75.0
812
0.59
61.2
517
.43
303
67.4
849
.24
71.8
846
.78
27.4
312
5.33
55.6
332
.36
26.0
771
.46
Ba
73
.47
114.
8827
1.09
578.
2928
9.55
38.1
148.
4737
1.41
381.
193
6.66
315.
9750
2.76
262.
5887
298
.83
673.
1731
5.08
Cd
0.
155
0.06
60.
090.
054
0.05
30.
056
0.28
10.
040.
090.
075
0.07
40.
058
0.09
50.
074
0.04
80.
059
0.06
Cr
10
.21
8.12
60.9
412
.315
4.66
8.02
66.8
8G
a 16
.94
13.4
614
.51
18.1
15.9
8.18
9.84
19.7
520
.36
17.2
12.3
614
.16
19.1
920
.72
17.3
523
.38
19.2
3M
o
1.67
0.28
0.84
1.29
0.59
0.49
1.17
0.57
4.96
1.13
0.58
0.84
0.32
0.8
0.97
0.4
0.32
Pb
3.4
1.5
1.6
3.2
1.3
2.7
401.
72.
29.
15
2.2
9.5
2.2
0.8
3.9
2Sn
1.
21.
421.
141.
261.
41.
164.
51.
093.
281.
093.
414.
81.
61.
522.
42.
793.
52T
l 0.
030.
160.
090.
080.
040.
020.
590.
110.
470.
460.
120.
170.
140.
190.
060.
140.
09W
0.
380.
180.
220.
540.
260.
230.
270.
193.
20.
340.
180.
290.
140.
260.
690.
210.
24
APP
EN
DIX
1(C
ont.)
RHYOLITE GEOCHEMICAL SIGNATURES AND ASSOCIATION WITH VMS, ABITIBI BELT, CANADA 1559
0361-0128/98/000/000-00 $6.00 1559
Num
ber
R-9
9R
-100
R-1
01R
-102
R-1
03R
-104
R-1
05R
-106
R-1
07R
-108
R-1
09R
-110
R-1
11R
-112
R-1
13R
-114
R-1
15
Zone
1717
1717
1717
1718
1818
1818
1818
1818
18U
TM
E64
7642
6826
9169
0128
6901
2069
0141
6901
3169
1000
4153
3648
5960
5316
8653
4514
5328
4756
5339
5653
2256
3604
2832
0228
3202
UT
MN
5358
250
5347
877
5347
240
5347
192
5347
379
5347
279
5347
500
5483
070
5431
392
5495
949
5499
618
5524
237
5513
155
5513
845
5512
701
5446
802
5446
202
SiO
2(w
t %)
80.5
270
.41
69.9
372
.06
66.4
672
.45
76.9
263
.43
76.5
962
.62
74.4
277
.15
69.3
273
.08
74.6
668
.774
.4A
l 2O3
9.15
13.1
215
.88
14.0
314
.98
11.6
512
.03
11.5
213
.29
15.7
513
.83
10.2
912
.712
.42
10.8
714
.35
10.8
2Ti
O2
0.12
0.36
0.25
0.32
0.62
0.22
0.17
0.35
0.1
0.57
0.06
0.19
0.39
0.45
0.16
0.36
0.22
Fe 2
O3
1.8
3.85
2.32
1.87
3.94
1.5
0.95
9.19
0.5
5.71
0.48
3.53
4.16
4.56
7.83
3.45
1.37
MgO
0.
540.
411.
160.
581.
710.
830.
431.
440.
013.
550.
350.
470.
230.
972.
090.
870.
42M
nO
0.04
0.09
0.06
0.06
0.11
0.07
0.03
0.37
0.09
0.02
0.05
0.09
0.05
0.03
0.07
0.03
K2O
2.
044.
024.
372.
911.
741.
453.
091.
021.
251.
443.
012.
222.
430.
721.
794.
432.
1C
aO
1.41
2.58
1.51
2.87
4.68
4.23
1.75
11.6
40.
394.
611.
321.
923.
481.
342.
353.
95N
a 2O
1.
990.
221.
812.
551.
913.
631.
981.
075.
833.
873.
941.
033.
065.
180.
240.
332.
15P 2
O5
0.03
0.05
0.04
0.08
0.15
0.06
0.04
0.08
0.06
0.12
0.03
0.03
0.06
0.09
0.02
0.1
0.08
LO
I
2.11
3.5
2.29
2.19
3.42
3.4
2.51
0.77
0.68
2.22
2.11
3.18
3.91
1.34
2.56
4.06
3.82
Tota
l 99
.76
98.6
99.6
399
.53
99.7
399
.48
99.9
100.
8898
.71
100.
5599
.56
100.
0499
.84
100.
2110
0.24
99.0
699
.36
Ce
(pp
m)
68.1
411
7.46
89.6
892
.37
81.4
349
.54
72.7
853
.77
32.6
335
.51
19.9
168
.75
93.7
313
4.56
5.38
42.0
738
.34
Cs
1.
539
0.53
66.
636
2.81
52.
713
1.61
52.
875
0.19
60.
567
0.93
70.
917
0.94
10.
218
0.12
30.
202
2.69
91.
336
Dy
10
.377
7.79
13.
228
3.66
44.
174
2.46
22.
143
5.98
91.
515
2.36
91.
177
8.92
315
.543
2020
1.46
13.
091
Er
7.
238
4.70
12.
213
2.31
2.75
31.
799
1.49
63.
987
1.03
71.
428
0.74
66.
078
10.5
2813
.548
19.7
090.
766
2.34
Eu
1.
274
1.92
30.
837
1.30
71.
472
0.48
40.
687
1.38
70.
334
0.79
90.
317
1.08
61.
912.
518
1.13
70.
604
0.96
2G
d
9.25
67.
994
3.40
74.
281
4.83
82.
482.
433
6.43
1.25
12.
715
1.25
28.
353
13.8
2920
13.6
162.
134
2.96
Hf
8.3
7.4
4.2
4.7
4.3
3.1
3.1
6.5
3.3
3.7
2.2
6.9
12.1
10.7
16.6
3.8
6.8
Ho
2.
278
1.57
70.
691
0.74
40.
882
0.54
80.
454
1.29
0.32
70.
484
0.24
51.
964
3.43
44.
555.
993
0.27
20.
706
La
28
.27
56.2
948
.08
46.8
639
.58
25.4
340
.73
23.0
410
.78
17.3
48.
4429
.24
38.4
654
.06
1.26
20.7
117
.53
Lu
1.
245
0.71
80.
447
0.41
30.
486
0.37
40.
296
0.69
50.
182
0.21
20.
128
0.96
71.
681.
953
3.01
90.
114
0.41
9N
b
18.7
15.6
14.8
14.3
8.2
11.3
11.4
11.8
7.4
7.1
1114
.726
.228
.445
.86.
46.
4N
d
38.6
752
.51
30.6
436
.98
36.5
19.2
423
.86
28.9
78.
1615
.71
7.59
36.2
454
.281
.77
9.75
16.6
517
.02
Pr
9.14
513
.921
9.31
510
.288
9.58
65.
489
7.38
6.95
42.
357
4.07
2.31
28.
826
12.5
8618
.395
1.28
14.
659
4.46
4R
b 33
.99
81.3
313
8.05
85.2
251
.63
58.5
291
.68
18.5
426
.99
39.4
863
.68
38.3
147
.14
13.0
222
.98
89.2
675
.28
Sm
8.94
9.78
4.51
5.96
6.44
3.23
3.4
6.5
1.45
2.96
1.53
8.14
12.6
519
.54
7.08
2.77
3.19
Sr
18.1
14.1
117.
217
9.1
236.
219
410
6.6
52.8
108.
622
6.3
86.5
98.5
85.7
84.8
13.4
37.8
93.4
Ta
1.38
1.04
1.27
1.09
0.62
0.98
1.05
0.9
0.88
0.7
11.
041.
631.
762.
940.
71.
02T
b
1.6
1.27
50.
531
0.62
50.
711
0.38
90.
362
0.99
60.
232
0.39
80.
196
1.39
2.40
13.
413.
291
0.27
70.
475
Th
3.73
1513
.86
11.9
79.
779.
8510
.79
3.61
7.23
3.46
1.8
4.97
5.32
5.87
6.97
2.66
4.9
Tm
1.
156
0.72
10.
365
0.36
20.
435
0.30
40.
243
0.61
80.
166
0.20
80.
120.
939
1.64
12.
009
3.05
0.11
20.
371
U
0.89
13.
891
3.33
82.
711
2.25
12.
476
2.72
40.
859
2.11
90.
992
0.72
91.
197
1.19
31.
261
1.54
50.
774
1.29
5Y
60.2
541
.49
19.9
120
.55
24.8
216
.613
.11
35.8
69.
9913
.19
7.67
53.9
190
.32
120
120
7.75
19.8
Yb
7.88
4.81
2.68
2.57
3.02
2.21
1.76
4.33
1.16
1.37
0.8
6.3
10.9
813
.06
19.9
60.
752.
6Zr
29
3.5
302.
715
4.5
197.
717
4.5
116.
711
3.9
257.
610
2.3
145.
348
.623
6.4
443.
636
747
7.6
142.
725
0.6
Be
0.
470.
851.
020.
940.
630.
60.
710.
440.
680.
510.
750.
721.
211.
260.
850.
570.
39C
o 3.
5915
.39
1.91
1.85
6.64
2.4
0.69
12.4
20.
3420
.10.
163.
232.
555.
039.
410
.86
2.18
Cu
2.
7958
.98
15.1
83.
3813
.21
25.1
5.34
10.9
21.
843
.54
1.92
9.42
1.86
3.54
2.71
187
44.7
6L
i 2
326
1616
129
24
223
126
67
26
Ni
2.46
1.51
1.5
2.19
2.43
1.98
0.97
18.2
71.
2366
.61.
182.
341.
615.
741.
797.
85.
35Sc
4.
96.
13.
44.
38.
93
2.3
7.9
0.8
11.2
14.
28
7.7
1.7
4.5
2.2
V
5.67
6.46
16.8
19.
5959
.87
12.9
69.
8422
.03
1.9
99.2
41.
753.
596.
1316
.04
1.31
45.2
10.9
3Zn
11
.84
29.3
226
.34
45.7
554
.69
29.1
17.2
914
3.67
18.5
66.5
617
.268
.17
54.7
47.5
324
27.2
723
.7B
a
200.
0383
4.09
770.
9559
6.12
695.
233
2.89
578.
880
.426
4.95
293.
3561
1.59
367.
5355
0.06
245.
2336
1.75
200.
1419
9.08
Cd
0.
069
0.09
20.
044
0.06
40.
072
0.04
80.
094
0.04
50.
064
0.10
10.
073
0.08
30.
118
0.09
6C
r
8.09
8.19
126.
939.
1514
.81
11.2
Ga
11.7
318
.04
15.9
214
.54
15.6
310
.01
10.8
215
.26
17.2
718
.05
15.2
214
.48
21.4
220
.79
25.0
716
.98
10.4
7M
o
0.22
0.32
1.26
0.24
0.59
0.64
0.33
0.47
0.45
0.51
0.14
2.83
0.46
0.28
0.22
0.98
0.53
Pb
1.6
4.4
7.9
7.6
14.5
9.3
5.1
12.8
6.3
32.
14.
12.
12.
12.
13.
32
Sn
1.49
5.87
1.12
1.46
1.58
0.99
0.79
2.59
2.61
1.8
1.34
2.48
2.88
3.34
101.
040.
72T
l 0.
080.
150.
220.
210.
450.
150.
190.
150.
120.
150.
30.
130.
130.
030.
060.
60.
61W
0.
11.
680.
581.
10.
520.
360.
330.
360.
610.
30.
180.
240.
230.
160.
990.
980.
35
APP
EN
DIX
1(C
ont.)
1560 GABOURY AND PEARSON
0361-0128/98/000/000-00 $6.00 1560
Num
ber
R-1
16R
-117
R-1
18R
-119
R-1
20R
-121
R-1
22R
-123
Zone
1817
1717
1717
1717
UT
ME
3132
8064
7800
6478
0070
7947
6300
0062
8000
6270
8062
8025
UT
MN
5330
673
5519
200
5519
500
5358
713
5468
000
5471
000
5474
000
5475
000
SiO
2(%
wt)
69.0
483
.36
79.1
384
.15
83.3
878
.24
72.6
73.3
6A
l 2O3
15.5
55.
495.
728.
594.
6510
.51
12.6
112
.92
TiO
20.
460.
110.
110.
180.
120.
130.
320.
39F
e 2O
32.
794.
935.
510.
436.
231.
983.
433.
68M
gO
1.07
0.55
5.54
0.05
2.57
1.69
4.33
1.91
MnO
0.
030.
10.
040.
020.
060.
05K
2O
1.58
1.8
0.05
4.19
0.04
3.66
2.98
3.95
CaO
0.
730.
240.
410.
010.
270.
060.
04N
a 2O
6.
310.
170.
111.
620.
020.
720.
330.
23P 2
O5
0.34
0.02
0.03
0.03
0.02
0.02
0.05
0.03
LO
I
1.31
3.35
2.9
0.41
1.79
3.27
4.07
3.72
Tota
l 99
.21
99.8
99.4
410
0.08
98.8
810
0.51
100.
8610
0.28
Ce
(pp
m)
85.1
743
.31
24.7
212
7.65
9.54
74.0
456
.53
42.5
4C
s
0.79
90.
446
0.03
40.
260.
022
1.36
90.
768
1.39
2D
y
8.77
62.
762
1.75
7.79
31.
715.
133
3.46
33.
444
Er
5.
759
1.56
31.
135.
191.
093.
471
2.17
42.
108
Eu
1.
686
1.93
80.
592.
007
0.19
0.45
70.
894
0.82
5G
d
10.3
553.
521.
955
9.36
41.
341
5.63
54.
053.
445
Hf
82.
72.
88.
82.
16.
26.
26
Ho
1.
857
0.54
80.
369
1.65
80.
363
1.08
50.
716
0.70
5L
a
33.9
221
.03
11.7
354
.34
4.24
34.4
525
.718
.85
Lu
0.
972
0.23
60.
194
0.81
60.
160.
555
0.32
70.
334
Nb
12
.45.
14.
413
.83.
112
.211
9.8
Nd
51
.67
20.1
111
.04
62.2
14.
6330
.75
24.8
619
.4Pr
11
.78
5.20
62.
859
15.7
811.
148
8.44
56.
604
5.09
4R
b 35
.733
.47
1.24
42.3
30.
9492
.22
56.6
566
.88
Sm
11.9
4.03
2.22
12.1
11.
066.
24.
73.
74Sr
11
03.
55
104.
51.
412
.314
.252
.5Ta
0.
810.
540.
471.
080.
411.
391.
020.
9T
b
1.48
20.
502
0.28
81.
326
0.25
0.86
0.59
50.
557
Th
5.01
1.97
1.93
5.11
1.38
8.54
4.07
2.92
Tm
0.
894
0.23
40.
180.
799
0.16
0.53
90.
320.
322
U
1.20
20.
612
0.46
71.
195
0.42
72.
183
1.16
31.
218
Y 51
.514
.56
10.3
442
.49
10.2
829
.58
19.7
719
.73
Yb
6.11
1.55
1.23
5.3
1.06
3.68
2.16
2.16
Zr
300.
410
1.9
111.
231
3.7
86.1
177.
623
7.3
238.
1B
e
0.93
0.38
0.24
0.38
0.87
0.6
1.19
Co
2.6
7.31
6.54
1.77
12.5
91.
763.
735.
87C
u
167
115.
6611
1.21
6.35
14.5
34.
722.
9227
.85
Li
184
165
1010
134
Ni
5.23
4.52
1.04
5.28
9.24
3.97
2.04
2.76
Sc
14.8
2.7
3.4
4.5
2.4
2.3
3.3
3.7
V
21.2
64.
572.
824.
578.
942.
0714
.64
45.4
1Zn
10
4.7
2790
1559
74.3
540
.07
31.7
936
.68
374
Ba
31
7.34
257.
569.
5217
7.33
6.66
203.
2316
1.29
245.
47C
d
0.23
10.
30.
30.
299
0.04
30.
040.
3C
r
15.2
59.
328.
09G
a 15
.79
5.59
13.7
113
.51
6.46
13.5
514
.63
19.5
8M
o
0.63
0.88
0.34
50.
470.
860.
683.
92Pb
12
.440
4022
.30.
52.
12.
45.
7Sn
2.
681.
161.
83.
421.
913.
677.
2710
Tl
0.26
20.
060.
430.
180.
210.
86W
0.
421.
170.
380.
310.
40.
441.
43.
07
Proj
ectio
n =
NA
D 8
3
APP
EN
DIX
1(C
ont.)
RHYOLITE GEOCHEMICAL SIGNATURES AND ASSOCIATION WITH VMS, ABITIBI BELT, CANADA 1561
0361-0128/98/000/000-00 $6.00 1561
APPENDIX 2Mineralogy 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 1R-2003-2 Quévillon FI 2 2 64 0.5 18 5 0.5 10R-2003-3 Quévillon FI 15 15 15 20 15 35 15R-2003-4 Quévillon FIIIa 4 2 6 5 0.5 70 5 15 1 1 2R-2003-5 Quévillon FIIIa 83 4 10.5 0.5 2R-2003-8 Quévillon FIIIa 4 5 9 5 5 15 15 57 3 1R-2003-9 Quévillon FIIIa 1 2 3 3 3 87 7 3R-2003-10 Val-d'Or FII 80 1 15 4R-2003-11 Val-d'Or FII 60 18 20 2R-2003-12 Val-d'Or FIIR-2003-13 Val-d'Or FIIIaR-2003-14 Val-d'Or FIIR-2003-15 Val-d'Or FII 28 34 34 1 3R-2003-16 Val-d'Or FII 1 1 2 10 70 10 10 6 2R-2003-17 Val-d'Or FIIR-2003-18 Val-d'Or FII 52 28 20R-2003-19 Val-d'Or FII ? 64 8 17 10 1R-2003-20 Val-d'Or FII 69 30 1R-2003-116 Val-d'Or FII 2 2 0-10 20-70 0-7 75 5 15 1 2R-2003-21 NVZ-Ext FII 73 19 8R-2003-22 NVZ-Ext FII 34 34 31 1R-2003-23 NVZ-Ext FIIR-2003-25 NVZ-Ext FII 2 2 4 3-25 20 67 26 2 1R-2003-26 NVZ-Ext FII 10 10 20 20 10-70 42 12 20 5 1R-2003-27 NVZ-Ext FII 3 3 86 10 1R-2003-28 NVZ-Ext FIIR-2003-29 NVZ-Ext FII 5 5 10 90 75 15 2 3R-2003-30 NVZ-Ext FII 1 1 90 30 39 10 20R-2003-31 NVZ-Ext FII 1 3 4 3 20 47 13 23 10 3R-2003-32 NVZ-Ext FII 10 10 0-10 10 0-2 53 1 20 15 1R-2003-37 NVZ-Ext FII 90 5 5R-2003-42 NVZ-Ext FII 0.5 1 1.5 30 33 15 25 3 0.5 11 11R-2003-43 NVZ-Ext FII 0.5 0.5 89.5 7 3R-2003-34 Normétal FIIIa 40 59 1R-2003-35 Normétal FIIIa 81 13 6R-2003-36 Normétal FII 80 5 15R-2003-38 Normétal FIIR-2003-44 Joutel FIIR-2003-45 Joutel FII 1 3 4 6 10 70 11 12 3R-2003-46 Joutel FI 1 3 4 5-20 15 69 10 15 1 1R-2003-47 Joutel FIIIa 3 3 64 30 3R-2003-48 Joutel FIIIa 10 4 14 2 10-80 52 15 15 3 1R-2003-51 Matagami FIIIb 0.5 0.5 1 3 65 8 10 10 6R-2003-52 Matagami FIIIb 0.5 0.5 3 3 75.5 16 3 5R-2003-53 Matagami FIIIb 51 47 2R-2003-54 Matagami FIIIb 70 70 5 20 5R-2003-55 Hunter FII 6 6 100 67 15 10 2R-2003-56 Hunter FII 0.5 0.5 2 5 71 0.5 15 10 3R-2003-57 Hunter FII 2 10 12 5 10 63 5 15 3 2R-2003-58 Hunter FII 1 1 2 5 3-10 2 71 12 10 3 2R-2003-59 Hunter FII 1 6 7 5 10-70 73 5 3 9 3R-2003-60 Hunter FII 1 15 16 0-15 3 0-98 52 18 6 8R-2003-61 Hunter FII 3 17 20 0-80 0-95 13 51 6 10R-2003-62 Hunter FII 0.5 0.5 61.5 19 17 2R-2003-63 Hunter FII 1 1 82 5 10 1 1R-2003-64 Hunter FII 3 3 0-100 76 15 3 3R-2003-65 Hunter FII 5 15 20 10 5-15 55 10 5 5 5R-2003-66 Hunter FII 3 3 51 20 13 7 5 1R-2003-108 Chibougamau FI 15 15 20 60 25 18 35 7R-2003-109 Chibougamau FI 1 3 4 20 1 81.5 7 7 0.5R-2003-110 Chibougamau FII ? 52.5 5 37 0.5 5R-2003-111 Chibougamau FIIIa 2 2 4 1 3 7 20 7 60 7 2R-2003-112 Chibougamau FIIIa 4 10 14 1 10 3 61.5 10 10 1.5 3R-2003-113 Chibougamau FIIIa 4 4 65.5 20 10 0.5R-2003-50 Selbaie FII 0.5 0.5 1 25 5 20 68 5 6R-2003-117 Selbaie FII 3 3 100 65 1 30 1
1562 GABOURY AND PEARSON
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R-2003-118 Selbaie FII 0.5 0.5 65 33 1 0.5R-2003-67 Noranda FIIIa Tr 62 15 6 12 5R-2003-68 Noranda FIIIa 0.5 3 3.5 40 3 33.5 8 47 6 2R-2003-69 Noranda FIIIa 0.5 2 2.5 3 3 81.5 3 2 7 4R-2003-70 Noranda FIIIa 1 2 3 91.5 2 1 0.5 2R-2003-71 Noranda FIIIa 67 31 2R-2003-72 Noranda FIIIa 82 10 7 1R-2003-73 Noranda FIIIa 1 1 20 15 52 26 19 2R-2003-74 Noranda FIIIa ? 0.5 0.5 54.5 2 38 5R-2003-75 Noranda FIIIa 5 1 6 10 5-65 2 70 20 3 1R-2003-76 Noranda FIIIa 6 3 9 5 15 3 75 8 3 3 2R-2003-77 Noranda FIIIa 75 6 15 2 2R-2003-78 Noranda FIIIa 1 1 5 5 90 75.5 6 10 7 0.5R-2003-79 Noranda FIIIa 7 7 60 7 15 10 1R-2003-80 Noranda FIIIa 0.5 0.5 2-10 0-10 82.5 1 7 6 3R-2003-81 Noranda FIIIa 79 2 5 12 2R-2003-82 Noranda FIIIa 1 24 25 10 90 15 15 40 5R-2003-83 Noranda FIIIa 0.5 0.5 3 0.5 84.5 4 6 5R-2003-84 Noranda FIIIa 1 1 2 65 12 13 64.5 12 3 0.5 5R-2003-88 Noranda FIIIa 9 1 10 38 2 65 8 6 7 3 1R-2003-89 Noranda FIIIa 0.5 0.5 1 1 5 40 5 50 2 2R-2003-90 Noranda FIIIa 0.5 1 1.5 3 88 5 1 2.5 2R-2003-92 Noranda FIIIa ? 33 33 5 80 5 20 15 10 15 7R-2003-93 Noranda FIIIaR-2003-95 Noranda FIIIaR-2003-96 Noranda FIIIa 7 3 10 1 1 2 60.5 25 3 1 0.5R-2003-97 Noranda FIIIa 8 15 23 3 10 3 49 12 12 2 2R-2003-98 Noranda FIIIa 3 77 80 5 5 0.5 9 3 1 7R-2003-99 Noranda FIIIa 3 0.5 3.5 5 2 71.5 2 7 15 1R-2003-100 Bousquet FI 0.5 0.5 68 0.5 25 3 3R-2003-101 Bousquet FI 5 10 15 3 20 10 50 3 24 3 5R-2003-102 Bousquet FI 50.5 3 40 1 0.5 5R-2003-103 Bousquet FIR-2003-104 Bousquet FI 4 5 9 22 1 60 5 20 5 1R-2003-105 Bousquet FI 3 10 13 5-10 6-10 71.5 1 10 3.5 0.5 0.5R-2003-41 NVZ-ext FI 15 10 25 3-60 48 10 10 7R-2003-85 Kinojevis FII 5 2 7 4 0.5 77.5 15 0.5R-2003-106 Coniagas FII 0.5 1 1.5 1 3 25 15 0.5 55.5 0.5 2R-2003-107 Lac Hébert FI 10 10 20 7 68.5 0.5 9 0.5 0.5 1R-2003-114 NVZ-int FI 3 3 51 35 5 6R-2003-115 NVZ-int FI 0.5 0.5 53 2 25 19 0.5R-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 = plagio-clase, Qz = quartz, Ser = sericite, Zir = zircon
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
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