Preliminary Map 39 describes the geology of the Kelowna Tertiary outlier (west half) along the north side of Okanagan Lake in southern British Columbia. The 1:50 000 scale geology map includes a legend and cross sections.
The basement rocks to the Tertiary sequence consists of pre-Cenozoic sediments, including chert, argillaceous rocks, metavolcanic and schistose units, and mainly granitic intrusions of the Early Cretaceous to Late Jurassic Okanagan batholith. Early Cenozoic rocks of the Springbrook Formation, the Kettle River Formation, the Marron Formation, the Marama Formation, and the White Lake Formation are exposed. The Springbrook Formation consists mainly of conglomerate channel deposits. The Kettle River Formation consists primarily of the Trepannier rhyolitic lava and breccia unit. The Marron Formation has a lower andesitic flow and breccia unit cut by Coryell granite to syenite intrusions, the Kitchley Lake member, which is made up of trachyte and trachyandesite flows, and the Nimpit Lake member with mainly trachyandesite flows and minor ash flow units. Marama Formation is represented by the Mount Boucherie dacite dome, which is comprised of flows and breccias. The White Lake Formation consists of conglomerate, sandstone, and minor shale. Much younger plateau alkali basalt (11.8 Ma) and valley basalt (0.7 Ma) also occur.
Block faults with mainly north and northwest trends dominate the Tertiary map pattern. Normal and reverse movement have tilted the Tertiary strata.
The area is prospective for epithermal precious metal deposits.
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