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TitleTiming and tectonic setting of Stikine Terrane magmatism, Babine-Takla Lakes area, central British Columbia
AuthorMacIntyre, D G; Villeneuve, M E; Schiarizza, P
SourceCanadian Journal of Earth Sciences 38, 4, 2001 p. 579-601,
Alt SeriesGeological Survey of Canada, Contribution Series 2000095
PublisherNRC Research Press
Mediapaper; on-line; digital
ProvinceBritish Columbia
NTS93K/11; 93K/12; 93K/13; 93K/14; 93L/09; 93L/10; 93L/15; 93L/16; 93M/01; 93M/02; 93M/07; 93M/08; 93N/03; 93N/04; 93N/05; 93N/06
AreaBabine lake; Takla lake
Lat/Long WENS-127.0000 -125.0000 55.5000 54.5000
Subjectstectonics; regional geology; geochronology; geochemistry; tectonic setting; tectonic interpretations; magmatism; bedrock geology; volcanic rocks; intrusive rocks; radiometric dating; uranium lead dating; argon argon dating; trace element geochemistry; Stikine Terrane; Asitka Group; Takla Group; Hazelton Group; Topley Intrusive Suite; Spike Peak Intrusive Suite; Saddle Hill Formation; Smithers Formation; Ashman Formation; plutonism; Jurassic; Triassic; Paleozoic; Permian; Mesozoic
Illustrationssketch maps; tables; Concordia diagrams; cross-sections; graphs
ProgramNechako NATMAP Project
AbstractNew bedrock mapping completed as part of the Nechako NATMAP Project indicates that the area between Babine and Takla lakes in central British Columbia is underlain by rocks of the Early Permian Asitka, Late Triassic Takla, and Early to Middle Jurassic Hazelton volcanic-arc assemblages of the Stikine Terrane. These are cut by large composite stocks of quartz diorite, granodiorite, and quartz monzonite previously mapped as the Late Triassic to Early Jurassic Topley intrusions. New U/Pb (n = 6) and laser 40Ar/39Ar (n = 10) isotopic age dates reported in this paper suggest there are two distinct ages of plutons: the Topley intrusive suite with isotopic ages between 218 and 193 Ma; and, east of Babine Lake, the new Spike Peak intrusive suite with isotopic ages ranging from 179 to 166 Ma. West of the main plutonic belt is a thick volcanic succession of subaerial, porphyritic andesite flows, volcanic breccias, and
rhyolitic ash-flow tuffs that have isotopic ages between 185 and 174 Ma. These rocks are assigned to the Saddle Hill Formation of the Hazelton Group. The plutonic roots of this proximal arc assemblage are most likely the coeval and compositionally similar plutons of the Spike Peak intrusive suite that have been unroofed in the area east of the Takla Fault. Major oxide and trace element data support the interpretation that the Topley and Spike Peak granitic rocks formed in a juvenile volcanic-arc environment and that magmatism is related to melts generated above a long-lived subduction zone of unknown orientation.