The nature and timing of early postglacial landscape change, central coast, British Columbia

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The history of landscape change along coastal British Columbia (BC) since the end of the last ice age (glaciation), about 15,000 years ago, is complex and poorly understood. This is because of several factors, including a relative sea level (RSL) that varied considerably from region to region during postglacial time, due to complex relationships between the depression of the earth's crust as a result of differential loading by glacial ice; the presence of a high-energy and variable wind and wave regimes that bring, or erode, sediment from the coast in a complex fashion; the sensitivity of coastal sedimentary landforms, such as modern and relict beaches and dunes, to short term changes in climate; and access many of the areas of interest are remote and can only be accessed by boat, helicopter, or by small amphibious aircraft. Gaining insight into the character of how the coastal landscape evolved since the last glaciation is important if predictions about how it will adjust as a result of predicted future climate change (e.g., rising global temperature and sea level, and increased coastal storm activity) are to be made. The BC coast has also been identified as a possible early migration route for the peopling of the Americas. There is new information that suggests that regions of the central coast where RSL change since the end of the last glaciation was minimal were areas of early and prolonged human settlement. There is also evidence that suggests that parts of the BC central coast were ice-free during the last and preceding glaciations. These regions would have served as places of refuge for plants and animals, and they would have spread from these places each time glaciation ended. It is therefore important to confirm the presence (in both time and space) of these refugia, and what survived in them, if the evolution of the landscape and the pattern of human migration and settlement is to be understood. Understanding the nature and timing of landscape change along the BC central coast is therefore not only of interest to geoscientists, but also to archaeologists and anthropologists, and the general public. This research program will investigate short and long-term changes to the coastal geomorphology of regions of the BC central coast, building on preliminary work done by others and by us on Calvert Island, with the aim of providing a more constrained (in time and space) record of landscape change. Landforms to be investigated are relict (raised) beaches dunes, and deltas that represent periods of transitory landscape stability and instability; special attention will be given to landforms that have been identified as having archaeological significance. Haida Gwaii will be revisited with the goal of gaining further evidence for the presence of biological refugia during the penultimate glaciation, which has so far been found at only one site.