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TitleStratigraphy and structure of the Mount Selwyn area, Rocky Mountains, northeastern British Columbia
AuthorMcMechan, M E
SourceGeological Survey of Canada, Paper 85-28, 1987, 34 pages (3 sheets), (Open Access)
PublisherGeological Survey of Canada
MapsPublication contains 3 maps
Map Info.geological, bedrock geology, 1:50,000
Map Info.geological, general, 1:250,000
ProjectionTransverse Mercator Projection; Universal Transverse Mercator Projection
Mediapaper; on-line; digital
RelatedThis publication contains the following publications
File formatpdf; JPEG2000
ProvinceBritish Columbia
NTS93O/11; 93O/12NW; 93O/12SW; 93O/13NW; 93O/13SW; 93O/14
AreaRocky Mountains
Lat/Long WENS-123.7500 -123.0000 56.0000 55.5000
Subjectseconomic geology; paleontology; tectonics; stratigraphy; structural geology; fossils; carbonate rocks; sedimentary rocks; metamorphic rocks; sedimentary structures; metamorphism; greenschist facies; metamorphism, regional; structural features; faults; folds; faults, thrust; lithology; magnetite; hematite; oxides; Rocky Mountain Trench; Rocky Mountain Thrust Belt; Rocky Mountain Fold Belt; Minnes Group; Stoddart Group; Kechika Group; Conodonts; Trilobita; Brachiopoda; Gastropoda; Bryozoa; Corals; Stromatoporoids; Charophytes; Pelecypoda; Ostracoda; Misinchinka Group; Gog Group; Fort St John Group; Bullhead Group; Precambrian; Proterozoic; Paleozoic; Mesozoic; Cenozoic
Illustrationslocation maps; stratigraphic charts; photographs; geoscientific sketch maps; stratigraphic columns; schematic representations; photomicrographs; block diagrams; stereonets; cross-sections; index maps
Released1987 04 01; 2018 10 09
AbstractUpper Proterozoic to Middle Jurassic, miogeoclinal, clastic and carbonate deposits, Upper Jurassic to Lower Cretaceous foredeep deposits, and Upper Cretaceous to Tertiary intermontane basin deposits outcrop in the Mount Selwyn area. Three structural levels, each characterized by distinctive structural styles, are recognized in the Rocky Mountains. Middle Devonian and older strata of the lower structural level form large thrust sheets and folds. Predominantly incompetent, disharmonically folded and faulted Upper Devonian to Middle Triassic strata of the middle structural level have been shortened approximately twice as much as the folded, more competent, Upper Triassic to Upper Cretaceous strata of the upper structural level, across the Foothills belt. Shortening across the Rocky Mountains is approximately 70 km. Pre-Late Cretaceous strata exposed adjacent to and within the Rocky Mountain Trench were regionally metamorphosed to greenschist facies and penetratively deformed prior to Late Cretaceous Paleocene thrust faulting in the Rocky Mountains. The disappearance of folded and faulted Upper Cambrian to Middle Devonian strata, and the folding of major thrust faults in the southern part of the Mount Selwyn area are probably a consequence of southeastward convergence in the position of ramps through Upper Proterozoic to Middle Devonian strata in the hanging walls of the Murray Range and Hidden faults, and the juxtaposition of the intervening deformed wedge of rock along a flat in the footwall of the Hidden Fault. Prospective structures for petroleum accumulation may occur at the leading edges of the 'blind' (nonsurfacing) thrust sheets carrying Middle Devonian and older strata under the western part of the Foothills, and in faulted anticlines of Lower Carboniferous carbonate strata.