GEOSCAN Search Results: Fastlink


TitleBedrock geology of the Uncha Mountain area, northwestern Nechako River map area, central British Columbia
DownloadFree download (whole publication) (pdf 116617 KB)
AuthorBarnes, E M; Anderson, R G
SourceCordillera and Pacific margin / Interior Plains and Arctic Canada/Cordillère et marge du Pacifique / Plaines intérieures et régions arctique du Canada; by Geological Survey of Canada; Geological Survey of Canada, Current Research no. 1999-A/B, 1999 p. 129-138,
PublisherNatural Resources Canada
RelatedThis publication is contained in Geological Survey of Canada; Geological Survey of Canada; (1999). Cordillera and Pacific margin / Interior Plains and Arctic Canada, Geological Survey of Canada, Current Research no. 1999-A/B
ProvinceBritish Columbia
AreaFrancois Lake; Uncha Lake; Uncha Mountain
Lat/Long WENS-125.7500 -125.5000 54.0000 53.9167
Subjectsstructural geology; stratigraphy; bedrock geology; stratigraphic analyses; faults; structural features; lithology; plutonic rocks; igneous rocks; conglomerates; greywackes; mudstones; sedimentary rocks; volcanic rocks; rhyolites; dacites; structural trends; hydrothermal alteration; alteration; field relations; granites; basalts; mineralization; chloritization; silicification; Neogene; Eocene; Hazelton Group; Ootsa Lake Group; Chilcotin Group; Uncha fault; Tertiary; Jurassic
Illustrationssketch maps; photographs
ProgramNechako NATMAP Project
Released1999 02 01
AbstractMesozoic and Tertiary strata and various high-level, Tertiary, aphanitic, porphyry and plutonic intrusions are recognized between Uncha Lake and Uncha Mountain (NTS 93 F/13 NW). Poorly sorted, poorly to moderately bedded epiclastic conglomerate, greywacke, and pebbly mudstone, and rare, chloritized, andesite flow rocks characterize the Lower to Middle Jurassic Hazelton Group. Fine- grained to aphanitic, leucocratic felsic porphyry, rhyolite, rhyodacite, and dacite, with associated autoclastic breccia and tuff, and rare andesite flows, constitute the Ootsa Lake Group. Tertiary intrusions include rhyolitic, dacitic, andesitic, basaltic, syenitic, and granitic compositions.
Faults define north-northeast-trending panels encompassing the stratified units and have imparted a penetrative and widespread fracture cleavage on all but the youngest units. This study emphasizes the importance of Tertiary faulting and associated small-scale deformation to the juxtaposition of Hazelton and Ootsa Lake groups rocks and to the localization of synkinematic, high-level aphanitic, porphyry, and miarolitic granite intrusions and hydrothermal alteration.