Evidence for an Early Pleistocene glaciation in the Okanagan Valley, southern British Columbia

Depositional evidence of Early Pleistocene glaciations in British Columbia are documented at only a few sites. Near Kelowna, in southern British Columbia, a construction project exposed glacial sediments beneath Lambly Creek Basalt, providing a minimum age for this glaciation. The basalt is composed of a number of flows yielding ages that range from 0.76 ± 0.11 to 1.5 ± 0.1 Ma. The sediments consist of a diamicton, interpreted to be till, up to 3 m thick mantled by a weakly developed paleosol. The diamicton is underlain by fluvial sands up to 5 m thick, in places revealing injection features, and minor faulting. A unit of stratified gravel underlain by grey clay is inferred to underlie the exposed sediments, based on nearby outcrops and excavations. Sediments and overlying basalts are normally magnetized and are assigned to the Jaramillo normal subchron (1.069–0.987 Ma). The till is here referred to as the Westbank First Nation Till. It is Early Pleistocene in age and represents the earliest evidence of g...