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

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Figure 22. Geological map of Munro Township (from Péloquin, Houlé and Gibson 2005, p.4). Mineral occurrence and deposit numbers are listed in Péloquin, Houlé and Gibson (2005, Table 2); the Potter Mine (formerly known as the Centre Hill Mine) and Potterdoal Mine (numbers 11 and 9, respectively) are discussed in the text. 54
Munro–Currie Subproject The goal of the Munro and Currie townships VMS subprojects of the Discover Abitibi Initiative is to reach a better understanding of the volcanic stratigraphy in the 2 townships, and of the stratigraphic position of the volcanogenic mineralization in both. In Munro Township, the mineralization at both the Potter Mine (formerly known as the Centre Hill Mine) and Potterdoal Mine is hosted in thin volcaniclastic and sedimentary units at mafic–ultramafic flow contacts; in Currie Township, the mineralization at the Currie (Tillex) occurrence is hosted in the volcaniclastic and sedimentary units of the upper Tisdale assemblage. MUNRO TOWNSHIP In Munro Township, the Kidd–Munro assemblage rocks consist of subaqueous tholeiitic basalt and ultramafic flows; felsic and intermediate volcanic rocks are rare. The area is divided into 3 blocks: South Munro, Central Munro and North Munro. The South Munro block corresponds to the area of the Kidd– Munro assemblage south of, and including, the southern ultramafic unit cut by the Munro fault zone, referred to as the “First Komatiitic Lava Succession” (after Johnstone 1991). The Central Munro block corresponds to the area located between the southern ultramafic unit and the Centre Hill fault. The North Munro block corresponds to the area located north of the Centre Hill fault (Figure 22; Péloquin, Houlé and Gibson 2005). The South Munro block is characterized by a basal interlayered spherulitic rhyolite and basalt unit, followed by a basaltic unit, within which a thin rhyolite unit (the Beatty rhyolite) occurs; the uppermost unit in the south block is the “First Komatiitic Lava Succession” of Johnstone (1991). The Central Munro block is characterized by basaltic to komatiitic basaltic units. The difference between the South and Central Munro blocks lies in the presence of rhyolites and andesites in the former. As the displacement along the Munro fault and the folding in the area appear to be of limited extent, it is possible that the South and Central Munro blocks form a continuous stratigraphic sequence consisting of a lower tholeiitic unit comprised of interlayered tholeiitic basalts, tholeiitic andesites and rhyolites capped by the “First Komatiitic Lava Succession” (South Munro block), and an upper tholeiitic basalt unit (Central Munro block) (Péloquin, Houlé and Gibson 2005). The Centre Hill fault between the Central and North Munro blocks constitutes a major stratigraphic break. In the North Munro block, ultramafic volcanic and intrusive rocks are dominant. The stratigraphic sequence is interpreted to be repeated 3 times within the block by folding (the McCool syncline) and faulting (the Warden Hill fault) (Arndt, Naldrett and Pyke 1977; Coad 1976; Johnstone 1991; Epp 1997; Péloquin, Houlé and Gibson 2005). The Potter and Potterdoal mines are located in the North Munro block: Potter Mine on the south limb of McCool syncline and Potterdoal in the Warden Hill fault repetition of the north limb of the syncline. The most complete stratigraphic section is defined at Potter Mine on the south limb of McCool syncline. There, the volcanic succession is divided into 3 units: 1) a Lower Komatiitic Unit, 2) the Middle Tholeiitic Unit; and 3) the Upper Komatiitic Unit (Gamble 2000, Gibson and Gamble 2000). The mineralization at Potter Mine is hosted in the Middle Tholeiitic Unit, which consists of basaltic volcaniclastic rocks, intact and autobrecciated sills and/or dikes of basalt, thin argillaceous and carbonaceous sedimentary units, chert, massive sulphide, and lesser komatiitic flows. The sulphides are hosted within the lapillistone facies of the basaltic volcaniclastic rocks; this facies is interpreted to have accumulated within a primary graben (Gibson and Gamble 2000). The magnetic signatures of the stratigraphic succession at Potter Mine can be traced around the closure of the McCool syncline. North of Potter Mine, on the north limb of the syncline, the succession observed is a mafic unit, overlain by an ultramafic unit. The units are massive, thick, and coarse grained and exhibit no internal structure. They were recognized as flows based on the presence of flow-top breccias (Arndt 1977; Arndt Naldrett and Pyke 1977). These flows, the lateral extensions of the Potter 55
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ISBN 0-7794-8652-8 THESE TERMS GOVE
Page 5:
ONTARIO GEOLOGICAL SURVEY Open File
Page 9:
Contents Abstract .................
Page 13:
Appendix 1. Thermal Ionization Mass
Page 17:
Miscellaneous Release—Data 155 Di
Page 21:
The Timmins area and Kirkland Lake-
Page 25:
Overview of Results from the Greens
Page 28 and 29:
3. The geophysical subproject funct
Page 30 and 31: The following Preliminary Maps have
Page 32 and 33: Samples with zircons analyzed by SH
Page 34 and 35: Figure 4. U/Pb concordia plots of T
Page 36 and 37: Figure 6. U/Pb concordia plot of TI
Page 38 and 39: Targeting of several of these overg
Page 40 and 41: 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 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 92 and 93: 66 Figure 26. A generalized map of
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
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04BHA-0462 Granophyre, Kamiskotia G
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contrastingly have been dated near
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The revised age of 2672.8±1.1 Ma f
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fraction (A1a) also overlaps concor
Page 146 and 147:
04JAA-0010 Albitite dike cutting Ti
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Therefore, on geochronological grou
Page 150 and 151:
Three individual grains were analyz
Page 152 and 153:
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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