Introduction of Gold into Archean Crust, Superior Province, Ontario—Coupling between Mantle-Initiated Magmatism and Lower Crustal Thermal Maturation
J. A. Fyon, D. G. Troop, S. Marmont, A. J. Macdonald, 1989. "Introduction of Gold into Archean Crust, Superior Province, Ontario—Coupling between Mantle-Initiated Magmatism and Lower Crustal Thermal Maturation", The Geology of Gold Deposits: The Perspective in 1988, Reid R. Keays, W. R. H. Ramsay, David I. Groves
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In parts of the Superior province, anomalous concentrations of gold and CO2 were introduced into regionally extensive zones of deformation during late Archean magmatic, tectonic, and thermal activity leading to cratonization. A similar sequence of activity is recorded in all subprovinces, but the absolute timing of equivalent magmatic and metallogenic events may differ. In the Abitibi-Wawa subprovince, calc-alkaline volcanism and coeval intrusion of tonalite-trondhjemite plutons terminated at approximately 2,700 Ma. During a relatively short period (30 Ma) following 2,700 Ma, compositionally diverse plutons were emplaced into the crust. This period of late plutonism was coupled temporally and thermally with granulite and amphibolite facies metamorphism and partial melting of lower to middle crust. These crustal magmatic and thermal events may have been initiated by mantle diapirism which supplied magma, heat, and volatiles to existing crust. Gold mineralization and large volumes of CO2 were introduced into regionally extensive zones of deformation during this period of late magmatic and thermal activity. A scenario linking cratonization and gold metallogenesis with magmatic underplating is developed to account for the contemporaneity between the late tectonism and auriferous hydrothermal events.