UBC Undergraduate Research

The geologic evolution of the Okanagan Valley shear zone near Oliver, British Columbia, Canada Towell, Moses Jesus

Abstract

The Okanagan Valley shear zone (OVsz) is approximately 1.5 km thick and delineates the western margin of the Shuswap metamorphic complex (SMC). The western contact of the OVsz is defined by the Okanagan Valley detachment fault (OVdf), an approximately 20° west-dipping, extensional detachment that facilitated exhumation of the Shuswap metamorphic complex during the orogenic collapse of the southeastern Canadian Cordillera in the Eocene. The field area studied is located to the north of Oliver, B.C. and west of Vaseaux Lake. This study observes and constrains its geologic evolution through petrographic and structural analysis of the rocks within the footwall. Two main lithologies are observed within the OVsz, the Green Lake metasedimentary complex (GLmc), the host rock, and the Mt. Keogan intrusive complex. Intense ductile deformation is observed through a penetrative mylonitic fabric that overprints both lithologies. A top-to-the-westnorth- west sense of shear has been suggested through kinematic indicators.

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Attribution-NonCommercial-NoDerivs 2.5 Canada