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Geology and Petrogenesis of the Kanichee Layered Complex, Ontario

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Geology and Petrogenesis of the Kanichee Layered Complex, Ontario Canadian Mineralogist Yol.22, pp. 93-109(1984) GEOLOGYAND PETROGENESISOF THE KANICHEELAYERED COMPLEX. ONTARIO RICHARD S. JAMES Department of Geology, Laurentian University, Sudbury, Ofiarto BE 2C6 DONALD HAWKE GettyMines Limited, 700 WestPender St/eet,Vancouver, British ColumbiaV6C IGB ABSTRACT tine, talc et caxbonate.Le complexeintrusif comprendcinq ryclesde cumulats.Dans les quatre cyclesinfdrieurs, la chro- The Kanicheelayered intrusive complex is the largestof mite, I'olivine et le clinopyroxene constituent des roches several mafic-ultramafic bodies in felsic and mafic i cumulats qui s'6chelonnentde la dunite d la clinopyrox6- metavolcanicrocks in the northern portion of the Tunagami nite. Dans le cinquibmecycle, une suite analoguede roches greenstonebelt, Ontario. An ultramafic apophysis along ultramafiques est r@ouvertede gabbrosd olivine et de gab- the northern margin of the intrusion contains a mineralized bros quartzifbres dans lesquels le plagioclase, le clinopy- zone of disseminatedand vein pynhotite, chalcopyrite and roxEneet une phased'oxyde de Fe-Ti sont les min6raux pentlandite; the host olivine peridotite has been altered to dominants. La hornblende ign6€est un accessoirecommun various serpentine-talc-carbonate assemblages,The in- desroches ultramafiques de tous les cycles;elle forme, dans trusive body consists of five cycles of cumulate rocks. In le premier cycle, une phase cumulative dans les clinopy- the lower four cycles, cumulus chromite, olivine and rox6nites. Les sulfures se prdsentent en gtains interstitiels clinopyroxene form rocks ranging from dunite to dissdmin6sdans les roches ultramafiques des cinq cycles, clinopyroxenite.ln cycle5 a similar suite of ultrama.ficrocks mais sont particuterement abondants dans les cumulats is overlain by olivine and quartz gabbros in which d'olivine de la basedu complex (c'est-i-dire, la zone min6- plagioclase, clinopyroxene and an Fe-Ti oxide phase are ralis6e,cycle l). Vu la similarit6 min€ralogiqueet chimi- the dominant minerals.Igneous hornblende is a common que desroches ultramafiques des cinq cycles, chaquecycle accessoryin the ultramafic rocks of all cycles;in cycle l, seserait form6 i partir d'un magma de m€mecomposition; it occursas a cumulusphase in the clinopyroxenites.The seulela dernibre pouss6ede magna est demeurdeen place sulfide minerals occur as disseminatedinterstitial grains in le temps n€cessairepour permettre le fractionnement du the ultramafic rocks of all five cycles, but are particularly liquide ainsi que la cristallisalion du gabbro i olivine et peut- abundantin the olivine cumulatesat the baseof the com- 6tre aussicelle du gabbro quartzifbre. L'ordre d'apparition plex (r'.e.,the ore zone, cycle 1). The similarity in mineralogy desphases cumulatives dans chaquecycle et le chimisme and chemistryof rle ultramafic rocks of the five cyclessug- du magmaparent (d6duit desproportions relativesdes types geststhat each one formed from magma of similar com- de roche du cycle 5) montrent que chacun des cyclesa cris- position; only the final pulse of magma remained in place tallis6 d'un maerna basaltique riche en magndsiumappa- long enough to form fractionated liquids from which the rente aux tholdiites magnesiennesde Jolly (1980). olivine gabbro and possibly the quartz gabbro crystalliz- (fraduit par la Rddaction) ed. The order of appearanceof cumulatephases in each rycle and the chemistry of the parent magma (estimated Mots<lds: filons<ouches, ma.fique-ultramafique, stratifi6, from the relativeproportions of rock typesin cycle5) sug- ryclesmagmatiques, olivine, clinopyroxbne,plagioclase, gest that each cycle crystallized from a high-magnesium Ni-Cu, 6l6ments du groupe du platine, Temagami, basaltic magma belonging to Jolly's (1980) magnesian Ontario. tholeiite suite. Keywords: sill, mafic-ultramafic, layered,magmatic cycles, INTRoDUcTIoN olivine, clinopyroxene,plagroclase, Ni-Cu, platinum- group elements,Temagami, Ontario. The Kanichee layered intrusive complex is the largest of several sill-like mafic and ultramafic syn- volcanic intrusive bodies that occur in the northern Sovrrr{arns portion of the Temagami greenstone belt. Various aspects of the geology of this volcanic belt have been Le complexeintrusif plus stratifi6 de Kanicheeest le grand reported by Bennett (1978), Bennett & Innes (1971a, de plusieursmassifs mafiques-ultramafiques dans les roches b), Bennett & McNally (1970a, b), Simony (19il) and m6tavolcaniquesfelsiques et mafiques de la partie nord de (1942). l, Kanichee in- la ceinture de roches vertes de Temagami (Ontario). Une Moorhouse In Figure the apophyseultramafique en bordure nord du massif renferme trusive complex is shown to be located within mafic une zone mindralisde en pyrrhotine, chalcopyrite et pent- and felsic metavolcanic rocks in the central portion landite soit en filons, soit sousforme diss€min6e;cette p6ri- of Strathy Township, approximately 6.5 km north- dotite e ofivine est alt€r6een divers assemblagesde serpen- west of the townsite of Temagami, Ontario. It was 93 94 THE CANADIAN MINERALOGIST lntrusionr t44ii r '?^Jn <(u J 1 ffi 3;iiin.r:i'#j Es c H:tg z'i '.7 MIDU-EPRECAMBRIAN Diobose 0) { ffi*pissins -#wW n^ I E+:liilillloowsondoForrmtion l\l ARoHEAN I r! -- I El f,Llil{i,f,lxl??i",nrusrons Formqlion e QJ-l-jh. lllllll{t'on *'# Q-i--.-3-3't"" fJreuc Mefovolconlcs FIc. 1. Regionalgeological plan of the Northeast Temagamiarea, after Bennett (1978). first reportedin the literatureby Knight (1920),who GENERAL GEOLOGICAL FEATURES recognizeda gossanzone 90 x 25 m at its northern extremity,that containsdisseminated and vein pyr- A plan view of the geology of the Kanicheein- rhotite, chalcopyrite and pentlandite mineralization. trusive complex is illustrated in Figure 2. The dimen- This zonehas beenintermittently exploredand mined sionsof the major and minor axesof this oval-shaped from as early as l9l0 (Bennett 1978).Most recent- body are approximatelty 1050 and 730 metres, ly, in the period 1972-1975,Ajax Minerals Ltd. respectively.A lenticularzone of quartz gabbro lies developedan open pit to excavateboth disseminated immediatelysouth of the main portion of the com- and vein ore to a depth of nearly 35 metres.Sandefur plex. It is not clearwhether it has a separateorigin (1943)described the geology of the intrusive com- from the olivine gabbro immediatelyto the north. plex in the immediate vicinity of this ore as well as As shown in Figure 2, and in more detail in Figure the mineralogy and paragenesisof the mineraliza- 4, the ore zone(cycle-l) rocks havea clearintrusive tion. Cabri & Laflamme (1974) documentedthe t'elationship to the metavolcanic country rocks. mineral chemistry of the major ore minerals in a few Within this part of the complex, the contact has been typical vein-specimensfrom the intrusivebody, and observedin severalplaces. Typically, it is eithervery Naldrert et ol. (1979)and Naldrett (1981)reported sharp with no contact aureole,or it is the location the concentrationof Au and Pt-group metals in a of a talc-chlorite-carbonatezone of alteration that variety of ore-zonespecimens. separatesserpentinized peridotite from greenschisl- In this paper, we describe the geology and faciesmetavolcanic rocks. The contact with the coun- geochemistryof the layeredrocks that form the in- try ro.ck has not been observedelsewhere in the trusive body and host the Ni - Cu - precious-metal complex. mineralization at the northern extremity of the In Figure2, the layeredcomplex is shownto con- complex. sist of five magmaticcycles, each of which consists THE KANICHEE LAYERED COMPLEX 95 B-B' OZ GABBRO CYCLE. t6@ o.-g-:P Fr 9_____!!p___89__i$r 4 Ftc. 2. Geologicalplan of theKanichee layered intrusive complex.Numerals l-5 referto ryclesof igneousrocks 3 illustratedin sectionsA-Al andB-Bl in Figure3. Cy- cle I is alsoreferred to asthe "Ore Zone", Shading for metavolcanicrocks as in Figurel. Two agesof mafic 2 CLINOPYROXENITE dyke-rocksare also iUustrated as linear outlines of solid o dotsand open, cobble-like symbols. Field relations by D. Hawke. FT Ftc. 3. Geologyof theigneous cycles 2-5 inclusiveas ex- hibitedby the stratigraphicsections A-Al andB-81. of one or more rock types.These range in composi- Soliddots indicate sample locations. tion from dunite and olivine peridotite, in which olivine is the only major cumulusphase, to peridotite and clinopyroxenite, which are olivine - clino- is shownin Figure 2. SectionA-Ar consistsof four pyroxenecumulates. Gabbro is only found in cycle separateigneous cycles, each consisting oflayers of 5. The contactbetween cycles I and 2lies within the one or more of dunite, olivine peridotite,peridotite, open pit of the ore zone, but it is not accessiblefor clinopyroxenite or olivine gabbro. Cycle 5 showsthe observationowing to flooding. The ore zone (cycle widest range of rock types and can be correlatedwith 1) and the lower portion of cycle2 are separatedfrom reasonableconfidence between the two stratigraphic the remainderof the complexby a fault zonewhose sections.Cycles 3 and 4 appearas truncated versions azimuthis 050'. The boundarybetween cycles 3 and of cycle 5 in that they contain only the more olivine- 4 and betweencycles 4 and 5 is approximately mark- rich cumulate portions of cycle 5; clinopyroxenite ed by narrow (10-20m wide) linear valleysoriented and olivine gabbro are absent.Only the uppermost parallel to stratigraphicboundaries between felsic portion of cycle2 is observed,i.e., clinopyroxenite. and mafic metavolcanicunits in the country rock ad- The baseof this rycle is probably
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