Depositional systems and seismic stratigraphy of a Quaternary basin: north Okanagan Valley, British Columbia
Seismic and core data from north Okanagan Valley, a deep (~700 m of fill), elongate (~3 km wide by 45 km long) basin located in the Cordillera of south-central British Columbia, reveal a thick sequence of fine and coarse elastics. The architecture of the basin fill was delineated using 16 km of high-resolution, reflection seismic profiles, and 30 lithologic logs. Using a depositional systems approach, four systems were identified: subglacial fluvial, glaciolacustrine, alluvial fan, and channel. The subglacial fluvial system consists of a basal suite of compact, stratified to poorly stratified coarse clastics deposited beneath glacial ice under high hydrostatic pressure. Older sediments were almost completely excavated from the basin fill during periods of maximum subglacial flow during Late Wisconsinan glaciation. One of the outcomes of this study is that it lends support to the notion that Late Wisconsinan glaciers were capable of almost totally eroding older Pleistocene basin deposits while depositing t...