Publication Type:Book Chapter
Source:Geological Society of America, 2011 annual meeting, Geological Society of America (GSA), Boulder, CO, United States, Volume 43, p.514 (2011)
Keywords:alteration, asthenosphere, back-arc basins, basins, Canada, Canadian Shield, copper ores, crust, facies, faults, Flin Flon Belt, geochemistry, geologic thermometry, gold ores, greenschist facies, high temperature, host rocks, igneous rocks, intrusions, mafic composition, magmatism, Manitoba, massive deposits, massive sulfide deposits, melts, metal ores, Metamorphic rocks, mineral deposits, genesis, North America, oceanic crust, ore grade, Paleoproterozoic, plate tectonics, Precambrian, proterozoic, rhyolites, sills, silver ores, subduction, Temperature, thrust faults, upper Precambrian, upwelling, volcanic rocks, Western Canada, zinc ores
The Trout Lake deposit (ca. 1878 + or - 1 Ma) is a rhyolite-hosted, bimodal-mafic, volcanogenic massive sulfide deposit (VMS). It is one of the largest VMS deposits in the Flin Flon mining district containing 23.6 Mt of ore grading 1.79% Cu, 4.96% Zn, 1.53 g/t Au, and 15.48 g/t Ag. The deposit underwent greenschist facies metamorphism and polyphase synvolcanic to postvolcanic alteration. The Trout Lake deposit formed during a period of high-temperature magmatism in a rifted arc that evolved into a backarc basin. The volcanic stratigraphy the deposit occurs as an upright homoclinal sequence that dips steeply to the northeast. The deposit consists of several massive sulphide ore lenses hosted by rhyolitic volcaniclastic rocks within a localized felsic eruptive center composed of FIII-type tholeiitic rhyolite flows and sills. This eruptive center occurs lateral to high-Mg andesite (HMA; MgO > 5.0 wt%) and Nb-enriched andesite (NEA; Nb > 10 ppm) flows that are underlain by footwall basaltic flows with a low-Ti tholeiitic composition (LOTI; TiO (sub 2) 900 degrees C during partial melting of mafic crust. These petrologic characteristics suggest that the Trout Lake deposit formed in a hot, intraoceanic, extensional-arc setting. Asthenospheric upwelling, subduction of young and hot oceanic crust, and ridge subduction are all mechanisms that explain the high-temperature magmatism and the formation of the massive sulfide ore lenses. The BABB geochemical signatures of the postvolcanic gabbros suggest that the tectonic environment of the Trout Lake area evolved from an intra-arc rift during the deposition of the ore lenses, to an incipient backarc basin during the intrusion of the gabbros.
GeoRef, Copyright 2018, American Geological Institute.<br/>2013-037317<br/>Trout Lake Deposit