THE HIGHLAND VALLEY FORMATION: CONTINUOUS EARLY TO MIDDLE PLEISTOCENE DEPOSITS IN SOUTH CENTRAL BRITISH COLUMBIA, CANADA

The Teck Highland Valley Copper open pit mine has exposed a roughly 150 m thick sequence of lake beds bounded by glacially derived sediments. Paleomagnetic analysis reveals this sequence straddles the Brunhes-Matuyama reversal at the boundary between the Early and Middle Pleistocene (~781 ka) and provides a rare record of the mid-Pleistocene Transition in Canada. Lake sediments, here-in named the Highland Valley Formation, contain diverse, well-preserved macrofossils of vertebrates, invertebrates and plants above and below the magnetic reversal (late-Early Pleistocene). Pollen and spore assemblages reveal climates generally dryer and colder than today, but punctuated by cold and dry or warm and relatively moist conditions. Dry stage assemblages indicate local presence of grasses (Poaceae) and sagebrush (Artemisia) similar to regional lower elevation valleys today. High abundance of Selaginella spores characterize tundra-like periods. Pine (Pinus) and spruce (Picea) intervals mark warm interglacial intervals. The Highland Valley Formation includes datable volcanic tephras and offers wide-ranging opportunities for the investigation of ecosystems and climatic changes during a key part of the Pleistocene.