UBC Theses and Dissertations
Structural geology and Rb-Sr geochronology of the anarchist mountain area Southcentral British Columbia Ryan, Barry Desmond
. High grade metamorphic rocks belonging to the Shuswap Complex crop out in the southern Okanagan region of British Columbia. An area of these rocks previously mapped by Bostock (1940) as the Vaseaux Formation was studied. A local structural lithologic succession is postulated comprising. of four units, whose present thicknesses are variable but do not generally exceed 100 ft. Four phases of penetrative deformation are recognized. The first, recumbent isoclinal with northerly trends, was succeeded by a second recumbent isoclinal phase, with northwesterly trends. Phase 3 produced easterly trending upright close folds, and later open upright northwesterly and northerly trending folds characterize phase 4. Five intrusive events punctuate the structural history. Two precede phase 2 and three postdate it. Rb-Sr isotopic dating of these intrusions provides a Tertiary age for phase 4, and a pre-mid-Jurassic age for phase 2. The existence of a mid-Jurassic metamorphism can also be inferred from the isotopic data. Based on interpretations of data from adjacent areas it appears that phases 1, 2 and 3, and related events are all facets of the Lower Mississippian Caribooan Orogeny.
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