Geologic and Structural Setting of Gold Mineralization in the Kirkland Lake-Larder Lake Gold Belt, Ontario

The Kirkland Lake-Larder Lake gold belt includes the giant Kirkland Lake and world-class Kerr-Addison-Chesterville gold deposits, along with several smaller deposits and occurrences. It corresponds to an east-trending band of Timiskaming clastic and volcanic rocks that unconformably overlie older volcanic assemblages in the southern Abitibi greenstone belt of the Archean Superior province. The gold belt is bounded to the south by the Larder Lake-Cadillac deformation zone, which roughly follows the contact between the younger Timiskaming rocks and the older volcanic units. Three generations of fabrics formed during post-Timiskaming regional deformation (D2, D3, and D4) of the belt. North-south shortening during D2 produced a penetrative, generally east-striking, steeply dipping, S2 foliation, and an east-plunging, L2 stretching lineation. S2 is most intense within the syn-D2 Larder Lake-Cadillac deformation zone and its northeast-trending splay, the Upper Canada deformation zone. The D2 structures are overprinted by a north-trending crenulation cleavage S3, which formed during east-west D3 shortening across the belt. A northeast-trending regional S4 foliation associated with Z-shaped F4 folds and overprinting both S2 and S3 formed during northwest-southeast D4 shortening. Gold mineralization is localized along the Larder Lake-Cadillac deformation zone (Anoki and McBean deposits), the Upper Canada deformation zone (Upper Canada deposit), and the brittle Kirkland Lake fault and ‘04 Break (Kirkland Lake deposit). The Upper Canada, McBean, and Anoki deposits formed during D2, and, along with Kerr-Addison-Chesterville, Omega, and Cheminis deposits, are probably related to a regionally extensive hydrothermal system associated with the Larder Lake-Cadillac deformation zone. The sulfide-poor gold- and telluride-bearing quartz veins of the Kirkland Lake deposit are interpreted to have been emplaced during D4, synchronous with reverse-dextral movement along the ore-controlling brittle Kirkland Lake fault. The Kirkland Lake mineralization has a distinct metal signature (Te>Au, Mo, Pb, Ag, high Au/Ag, low As) and probably represents a separate hydrothermal system linked to a deep magmatic (alkalic) fluid source and unrelated to mineralization along the syn-D2 deformation zones.

[1]  G. P. Watson,et al.  The Macassa Mine Archean lode gold deposit, Kirkland Lake, Ontario; geology, patterns of alteration, and hydrothermal regimes , 1984 .

[2]  R. Kerrich,et al.  Hydrothermal alteration zoning and gold concentration at the Kerr-Addison Archean lode gold deposit, Kirkland Lake, Ontario , 1987 .

[3]  R. Hyde.  Sedimentary facies in the Archean Timiskaming Group and their tectonic implications, abitibi greenstone belt, Northeastern Ontario, Canada , 1980 .

[4]  François Robert,et al.  Vein Formation and Deformation in Greenstone Gold Deposits , 2001 .

[5]  W. T. Jolly.  Metamorphic History of the Archean Abitibi Belt , 1977 .

[6]  F. Robert,et al.  Syenite-associated disseminated gold deposits in the Abitibi greenstone belt, Canada , 2001 .

[7]  R. W. Le Maitre,et al.  A Chemical Classification of Volcanic Rocks Based on the Total Alkali-Silica Diagram , 1986 .

[8]  K. Card.  A review of the Superior Province of the Canadian Shield, a product of Archean accretion , 1990 .

[9]  T. McCuaig,et al.  P—T—t—deformation—fluid characteristics of lode gold deposits: evidence from alteration systematics , 1998 .

[10]  F. Robert,et al.  World‐class Archaean gold deposits in Canada: An overview , 1997 .

[11]  E. M. Cameron,et al.  Archean gold mineralization and oxidized hydrothermal fluids , 1987 .

[12]  B. Lafrance,et al.  Overview of results from the Greenstone Architecture Project: Discover Abitibi Initiative , 2005 .

[13]  T. Irvine,et al.  A Guide to the Chemical Classification of the Common Volcanic Rocks , 1971 .

[14]  R. Sillitoe.  Some metallogenic features of gold and copper deposits related to alkaline rocks and consequences for exploration , 2002 .

[15]  G. N. Phillips,et al.  An epigenetic origin for Archean banded iron-formation-hosted gold deposits , 1984 .

[16]  D. Groves,et al.  Crustal-scale shear zones and their significance to Archaean gold mineralization in Western Australia , 1989 .

[17]  E. M. Cameron,et al.  Petrogenesis of the late Archean syenitic Murdock Creek Pluton, Kirkland Lake, Ontario; evidence for an extensional tectonic setting , 1993 .

[18]  W. Mueller,et al.  Volcanic and tectono-plutonic influences on sedimentation in the Archaean Kirkland Basin, Abitibi greenstone belt, Canada , 1994 .

[19]  F. Corfu,et al.  U-Pb zircon geochronology in the southwestern Abitibi greenstone belt, Superior Province , 1989 .

[20]  J. Morgan,et al.  The remarkable Re–Os chronometer in molybdenite: how and why it works , 2001 .

[21]  N. Arndt,et al.  Geochemistry and age of Timiskaming alkali volcanics and the Otto syenite stock, Abitibi, Ontario , 1990 .

[22]  John G. Ramsay,et al.  The techniques of modern structural geology , 1987 .

[23]  R. Creaser,et al.  Macroscale NTIMS and microscale LA-MC-ICP-MS Re-Os isotopic analysis of molybdenite: Testing spatial restrictions for reliable Re-Os age determinations, and implications for the decoupling of Re and Os within molybdenite , 2004 .

[24]  W. McDonough,et al.  Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes , 1989, Geological Society, London, Special Publications.

[25]  A. H. Jaffey,et al.  Precision Measurement of Half-Lives and Specific Activities of U-235 and U238 , 1971 .

[26]  D. Davis,et al.  U-Pb evidence for Abitibi gold mineralization postdating greenstone magmatism and metamorphism , 1990, Nature.

[27]  J. Böhlke.  Carbonate-sulfide equilibria and “stratabound” disseminated epigenetic gold mineralization: a proposal based on examples from Alleghany, California, U.S.A. , 1988 .

[28]  F. Corfu,et al.  U–Pb ages and tectonic significance of late Archean alkalic magmatism and nonmarine sedimentation: Timiskaming Group, southern Abitibi belt, Ontario , 1991 .

[29]  R. Mustard.  Granite-hosted gold mineralization at Timbarra, northern New South Wales, Australia , 2001 .

[30]  L. Wilkinson,et al.  Timing and kinematics of post-Timiskaming deformation within the Larder Lake - Cadillac deformation zone, southwest Abitibi greenstone belt, Ontario, Canada , 1999 .