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TitleNew geochronological constraints on Jurassic deformation of the western edge of North America, southeastern Canadian Cordillera
AuthorMurphy, D C; van der Heyden, P; Parrish, R R; Klepacki, D W; McMillan, W; Struik, L C; Gabites, J
SourceJurassic magmatism and tectonics of the North American Cordillera; by Miller, D M (ed.); Busby, C (ed.); Geological Society of America, Special Paper 299, 1995 p. 159-171,
Alt SeriesGeological Survey of Canada, Contribution Series 52091
PublisherGeological Society of America
Mediapaper; on-line; digital
File formatpdf
ProvinceBritish Columbia
NTS82L; 92P; 92I; 92O; 93A; 93B; 82M
AreaKootenay; Cariboo Mountain
Lat/Long WENS-122.0000 -118.0000 53.0000 49.0000
Subjectsgeochronology; general geology; structural geology; uranium lead dates; zircon dates; biochronology; sedimentary basins; terranes; geochronometry; deformation; continental margins; Toarcian; folding; Omineca Belt; Kootenay Terrane; Monashee Complex; Quesnellia-North America Terrane; Mesozoic
Illustrationslocation maps; geological sketch maps; schematic cross-sections; tables; Concordia diagrams
ProgramNSERC Natural Sciences and Engineering Research Council of Canada
ProgramBritish Columbia Ministry of Energy, Mines and Petroleum Resources, Geological Survey Branch, Funding Program
Released1995 01 01
AbstractThis report presents four U/Pb zircon dates from the Kootenay arc and Cariboo Mountains of southeastern British Columbia. When combined with existing biochronological data, two of these dates tightly constrain the age of shortening of the sedimentary basin between the North American continental margin and the Triassic-Jurassic Quesnellia volcanic arc to mid-Toarcian (late Early Jurassic, ca. 187 - 185 Ma). The other two dates affirm a Mesozoic age of the prominent phase of southwest-vergent folding in the Omineca crystalline belt and permit correlation of these structures with similar folds of the mid-Toarcian Quesnellia - North America terrane boundary. Previously published dates and geological relationships show that this latter southwest-vergent folding was finished by the end of the Aalenian (earliest Middle Jurassic, 174 Ma). Taken together, these data show that the earliest two "phases" of Jurassic deformation of the western edge of North America occurred in a ca. 10-million year interval spanning the Early to Middle Jurassic boundary. Although this deformation consists of two phases, given the short time interval, it is likely that they are part of the same continuous episode of shortening of the continental margin.

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