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TitleBedrock geology of Yukon-Tanana terrane in southern Stewart River map area, Yukon Territory
AuthorRyan, J J; Gordey, S P
SourceGeological Survey of Canada, Current Research (Online) no. 2002-A1, 2002, 11 pages,
PublisherNatural Resources Canada
Mediapaper; on-line; digital
RelatedThis publication is contained in Geological Survey of Canada; Geological Survey of Canada; (2002). Current Research 2002, winter release, Geological Survey of Canada, Current Research no. 2002
File formatpdf
NTS115O/02; 115O/03; 115O/04; 115O/05; 115O/06; 115O/07
AreaStewart River
Lat/Long WENS-140.0000 -138.5000 63.4167 63.0000
Subjectsstructural geology; regional geology; tectonics; bedrock geology; igneous rocks; plutons; mafic rocks; ultramafic rocks; metavolcanic rocks; metasedimentary rocks; clastics; deformation; metamorphism; faults; tectonostratigraphic zones; foliation; Mesozoic; Cretaceous; Jurassic; Paleozoic
Illustrationsphotographs; sketch maps
ProgramAncient Pacific Margin NATMAP Project
Released2002 01 22
AbstractPolydeformed and metamorphosed Paleozoic rocks of the Yukon-Tanana terrane underlie a large part of the Stewart River area, Yukon Territory. Quartz-rich metaclastic rocks (quartzite, quartz-mica schist, psammite) are regionally widespread, and are locally interstratified with, as well structurally interdigitated with, metavolcanic rock (mafic and intermediate garnet-amphibolite). Mafic to felsic ortho-gneiss
is almost exclusively associated with the amphibolite, and rarely with metasiliciclastic rock. Complexes of mafic-ultramafic rock and associated orthogneiss are exposed at structurally high levels, and are thought to be part of an erosionally dismembered, originally continuous tectonic sheet, emplaced on top of the metasiliciclastic rock. Emplacement occurred prior to regional transposition deformation and metamor-phism. Post-tectonic Early Jurassic and (?)mid-Cretaceous plutons crosscut the older fabrics. Sporadically
preserved, fault-disrupted felsic to mafic volcanic rocks of the late Cretaceous Carmacks Group unconformably overlie all older units. Local felsic porphyritic intrusions (? mostly dykes) are probably Eocene.