Timing and tectonic setting of Stikine Terrane magmatism, Babine-Takla lakes area, central British Columbia

New bedrock mapping completed as part of the Nechako NATMAP Project indicat es that the area between Babine and Takla lakes in central British Columbia is underlain by rocks of the Early Permian Asitka, Late Triassic Takla, an d Early to Middle Jurassic Hazelton volcanic-arc assemblages of the Stikine Terrane. These are cut by large composite stocks of quartz diorite, granod iorite, and quartz monzonite previously mapped as the Late Triassic to Earl y Jurassic Topley intrusions. New U/Pb (n = 6) and laser Ar-40/Ar-39 (n = 1 0) 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 w ith isotopic ages ranging from 179 to 166 Ma. West of the main plutonic bel t is a thick volcanic succession of subaerial, porphyritic andesite flows, volcanic breccias, and rhyolitic ash-flow tuffs that have isotopic ages bet ween 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 a re 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 t he Topley and Spike Peak granitic rocks formed in a juvenile volcanic-arc e nvironment and that magmatism is related to melts generated above a long-li ved subduction zone of unknown orientation.