Overview of Results from the Greenstone ... - Geology Ontario

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66 Figure 26. A generalized map of the Timmins–Porcupine gold camp, covering Tisdale, Deloro, Mountjoy, Ogden, Whitney and Hoyle townships (modified from Bateman et al 2005, p.7; modified after Ferguson et al. 1968).
sheet flow facies, channelized sheet flow facies, lava channel facies, lava pond facies, lava lobe facies, and distal pyroclastic and/or epiclastic facies. Worldwide, most Ni-Cu-PGE mineralization is hosted by lava channels, channelized sheet flows and, rarely, within vent facies. Komatiite flow fields have never been mapped directly, but komatiite volcanic facies have been interpreted to vary on the scale of an entire flow field and also on the scale of individual flow units. This complexity of lava facies makes it difficult to predict the locations of mineralized lava channel or channelized sheet flows, except that they most often (but not always) occur at or near the bases of individual komatiite sequences. Our work suggests that the identification of variations within barren volcanic facies is particularly important as it can potentially vector toward ore-forming environments. As these types of deposits are usually found within deformed Archean and Proterozoic greenstone belts, a multidisciplinary approach including geological mapping, volcanic facies mapping, geophysical surveys, and geochemical studies are required to aid in the exploration for these deposits and to facilitate the recognition of favourable volcanic sequences that may host magmatic Ni-Cu-(PGE) sulphide mineralization. GOLD MINERALIZATION SUBPROJECTS Timmins Subproject The Timmins–Porcupine gold camp is the largest lode gold camp in Earth’s Archean greenstone belts (Witwatersrand aside). It hosts several deposits are dispersed over 35 km, and together produced 63.7 million ounces gold, which is far ahead of other districts in the province (Groves et al. 2005). These deposits are distributed along the northern margin of an originally south-dipping Porcupine–Destor deformation zone (PDDZ). Herein lies one of the structural anomalies to be resolved: Why the gold deposits apparently lie in the footwall of this shear zone, contrary to other Archean gold camps such as Val d’Or and Kalgoorlie? Other uncertainties concerning these gold deposits include the kinematics and timings of deformations; the presence or absence of foliation predating the deposition of the Timiskaming assemblage; the relative timing of the several generations of quartz-carbonate veins and styles that have long been known (at least in general terms) in this camp; and the way in which an evolving orogenesis determines the geometry and kinematics of coeval gold mineralization. Research carried out involved mapping, and geochemical analysis of samples north of the PDDZ, principally in Tisdale, Hoyle and Whitney townships. A structural scheme, with refinements to the stratigraphic column and geochronology, has been constructed for the Timmins–Porcupine gold camp in order to develop the constraints applying to these matters (Figure 26; Bateman et al. 2005). Unconformities or disconformities have been identified between each assemblage (Ayer, Amelin et al. 2002) mapped in the gold camp: between Tisdale and Deloro; between Porcupine and Tisdale; and a long recognized unconformity between the Timiskaming and the Porcupine–Tisdale assemblages. Some formations have been shown to be correlatives: the terms Beatty and Hoyle formations apply to turbidites that occur in different parts of the camp, and have been shown to be of the same age (~2688 Ma). The age of the albitite dikes at the McIntyre Mine has been confirmed at 2672.8±1.1 Ma, and a second albitite dike and a porphyry intrusion in the vicinity of the Pamour Mine have ages of 2676.5±1.6 Ma and 2677.5±2.0 Ma, respectively, the latter being considerably younger than the 2685 to 2690 Ma age of the other dated porphyries and the Krist formation. Geochemical sampling and analysis (compared with unpublished Porcupine Joint Venture data) of basalts and komatiites have allowed the subdivision of the Tisdale assemblage into 4 formations that have been traditionally defined on lithological and textural grounds. These formations—the Hersey Lake komatiite (2 subgroups), Central formation (3 subgroups), Vipond formation and Gold Centre formation—are distinguished on the basis of Fe total -MgO-TiO 2 -V-Zr- Y-Ni-Cr-REE. Lavas in one Central formation subgroup show distinct boninitic affinities (Kerrich et al. 67
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ISBN 0-7794-8652-8 THESE TERMS GOVE
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ONTARIO GEOLOGICAL SURVEY Open File
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Contents Abstract .................
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Appendix 1. Thermal Ionization Mass
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Miscellaneous Release—Data 155 Di
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The Timmins area and Kirkland Lake-
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Overview of Results from the Greens
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3. The geophysical subproject funct
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The following Preliminary Maps have
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Samples with zircons analyzed by SH
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Figure 4. U/Pb concordia plots of T
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Figure 6. U/Pb concordia plot of TI
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Targeting of several of these overg
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Figure 10. U/Pb SHRIMP results from
Page 42 and 43: In northwest Cleaver Township, a fe
Page 44 and 45: SHRIMP U/Pb dating was carried out
Page 46 and 47: Stratigraphic Framework In this sec
Page 48 and 49: PACAUD ASSEMBLAGE The 2750 to 2735
Page 50 and 51: The iron formation and chert brecci
Page 52 and 53: (thickness) of banded iron-poor iro
Page 54 and 55: clast conglomerates at the top of t
Page 56 and 57: BLAKE RIVER ASSEMBLAGE Lower Part T
Page 58 and 59: The Krist formation consists of cal
Page 60 and 61: Timmins Area In the Timmins area, t
Page 62 and 63: Kirkland Lake-Larder Lake Area Hyde
Page 64 and 65: Intrusion Framework The plutonic ro
Page 66 and 67: The youngest dated synvolcanic mafi
Page 68 and 69: Albitite dikes are crosscut by gold
Page 70 and 71: Worming Geophysical Data Treatment
Page 72 and 73: In Timmins, the first generation of
Page 74 and 75: Figure 20. Geological sketch map of
Page 76 and 77: from Halfmoon Lake, only 2 km to th
Page 78 and 79: The Blake River Group is divided in
Page 80 and 81: Figure 22. Geological map of Munro
Page 82 and 83: Mine stratigraphic succession, have
Page 84 and 85: Figure 24. Geological map of Currie
Page 86 and 87: Table 5. Simplified classification
Page 88 and 89: mesocumulate). The Stoughton-Roquem
Page 90 and 91: Shaw Dome Area GEOLOGICAL SETTING T
Page 94 and 95: 1999) in their REE patterns and oth
Page 96 and 97: plumbing system geometrically stabl
Page 98 and 99: GOLD MINERALIZATION Production comm
Page 100 and 101: The Narrows Break mineralized zone,
Page 102 and 103: Table 7. Diagnostic mineral assembl
Page 104 and 105: anomaly and the Dome Mine (Figures
Page 106 and 107: Recommendations • Further testing
Page 108 and 109: of the inversion product. (Recent a
Page 110 and 111: the evidence for pre-Pacaud strata
Page 112 and 113: plutonism suggests the onset of reg
Page 114 and 115: Watkinson and Comba 1989; Gibson an
Page 116 and 117: The Kirkland Lake giant gold deposi
Page 118 and 119: The Timmins and Kirkland Lake-Larde
Page 120 and 121: References Ames, D.E., Bleeker, W.,
Page 122 and 123: Bleeker, W., Parrish, R.R. and Sage
Page 124 and 125: Galley, A.G., Pilote, P. and Davis,
Page 126 and 127: Heather, K.B., Percival, J.A., Mose
Page 128 and 129: Lesher, C.M., 1989. Komatiite-assoc
Page 130 and 131: Péloquin, A.S., Verpaelst, P., and
Page 132 and 133: Stern, R.A. 1997. The GSC sensitive
Page 134 and 135: 108 This page left blank intentiona
Page 136 and 137: THERMAL IONIZATION MASS SPECTROMETR
Page 138 and 139: 04BHA-0462 Granophyre, Kamiskotia G
Page 140 and 141: contrastingly have been dated near
Page 142 and 143:
The revised age of 2672.8±1.1 Ma f
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fraction (A1a) also overlaps concor
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04JAA-0010 Albitite dike cutting Ti
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Therefore, on geochronological grou
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Three individual grains were analyz
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03VOI-0422-1 Trachytic lava, Timisk
Page 154 and 155:
03SJP-115-1 Monzonite, Clifford sto
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the original Corfu (1993) age, only
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Table A1. U/Pb isotopic data for zi
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206 Sample Analysis Description Wei
Page 162 and 163:
Appendix 2 Sensitive High-Resolutio
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Table A2. Ion microprobe (SHRIMP II
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Table A2. continued Struct. U Th Pb
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Table A2. continued 204 U Th Pb* Pb
Page 170 and 171:
Table A2. continued 204 U Th Pb* Pb
Page 172:
Metric Conversion Table Conversion
Page 175 and 176:
Chart A. Magnetic and Gravity Three
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