Quaternary stratigraphy and evidence for multiple glacial episodes in the north Okanagan Valley, British Columbia

Abstract

This study investigates the Quaternary stratigraphy of the north Okanagan Valley to inform hydrogeological studies. The north Okanagan Valley extends from the north end of Okanagan Lake to Enderby in the southern interior of British Columbia, Canada. Prior surficial geology mapping, provincial and private borehole data, historical seismic profiling, and a new 5 km high-resolution seismic reflection profile were examined to characterize up to 580 m thickness of unconsolidated sediments. A mixture of glacial and interglacial sediments of uncertain Pleistocene age infills bedrock lows that extend below sea level. These are unconformably overlain by a sand and gravel unit of at least Early Wisconsin age (>65 000 years BP). It is in turn unconformably onlapped by nonglacial, organic-rich, lacustrine and alluvial deposits of Middle Wisconsin age (65 000 – 23 000 years BP). This unit was eroded and overlain by a fine sand to silty sand unit deposited immediately prior to, or during, the Fraser Glaciation advance...