Stratigraphic, structural and U-Pb geochronologic investigation of lower Paleozoic eugeoclinal strata in the Kootenay Arc, NE Washington and SE British Columbia
The Kootenay Arc in northwestern Washington and southeastern British Columbia is transitional between: (1) lower Paleozoic autochthonous miogeoclinal strata and Paleozoic to Mesozoic eugeoclinal terranes of uncertain paleogeographic affinity (e.g., the Quesnel terrane); and (2) areas where Devono-Mississippian tectonism was of a compressional nature, and areas in northern British Columbia and southern Yukon Territory where coeval deformation was evidently of an extensional nature. Stratigraphic, structural, and U-Pb geochronologic studies focussed primarily on portions of the Lardeau Group in the Trout Lake area in the northern Kootenay Arc and the Covada Group in the southern Kootenay Arc. As a result of these studies, the following concepts are proposed: (1) lower Paleozoic eugeoclinal strata can be correlated along the length of the Arc; (2) these strata are in fault contact with miogeoclinal strata along the length of the Arc; (3) a contractional event of pre-Mississippian and perhaps Devono-Mississippian age is recorded in the Kootenay Arc; (4) despite faulted contacts, the eugeoclinal strata are parautochthonous and derived from adjacent portions of North America; and (5) structures and stratigraphy in the Kootenay Arc are broadly correlative with those in the Roberts Mountains allochthon in central Nevada. Two important implications of this study are that: (1) through a series of stratigraphic linkages it can be demonstrated that the Quesnel terrane, a Mesozoic arc-related assemblage often regarded on the basis of faunal evidence to be exotic, is parautochthonous; and (2) the Antler Orogeny, often regarded as a localized disturbance, affected at least 1,200 km of the Cordilleran margin, and perhaps the entire Cordilleran margin.
- Research Organization:
- Arizona Univ., Tucson, AZ (United States)
- OSTI ID:
- 6092809
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
540211 -- Environment
Terrestrial-- Basic Studies-- Radiometric Techniques-- (1990-)
58 GEOSCIENCES
580000* -- Geosciences
ACTINIDE ISOTOPES
AGE ESTIMATION
BRITISH COLUMBIA
CANADA
CARBONIFEROUS PERIOD
CONTINENTAL MARGIN
CORRELATIONS
DEFORMATION
DEVELOPED COUNTRIES
DEVONIAN PERIOD
FEDERAL REGION IX
FEDERAL REGION X
GEOLOGIC AGES
GEOLOGIC FAULTS
GEOLOGIC FORMATIONS
GEOLOGIC FRACTURES
GEOLOGIC MODELS
GEOLOGIC STRATA
GEOLOGIC STRUCTURES
GEOLOGY
ISOTOPE DATING
ISOTOPE RATIO
ISOTOPES
LEAD ISOTOPES
MESOZOIC ERA
NEVADA
NORTH AMERICA
PALEOZOIC ERA
STRATIGRAPHY
TECTONICS
URANIUM ISOTOPES
USA
WASHINGTON