CURRENT FINDINGS IN BC: Archaeological Prospection on the Pacific Northwest Coast (Quadra Island)

July 7, 2016

By Alex Lausanne

Archaeological prospecting is inhibited by many factors on the Pacific Northwest coast. Changing sea levels, the dense rainforest canopy and thick sediment layers obscure the buried archaeological record and reduce site discovery rate. Recent theories show the earliest peopling of North America likely occurred between 13,000 and 11,500 years ago via a coastal route, along the Pacific coast, as opposed to via an “ice-free corridor” through interior North America, as previously thought. Due to environmental restrictions and insufficient discovery methods, only a handful of these “early period” sites are known. Traditionally, sites are often found by chance discovery or through surveys restricted to the modern coastline. To combat these issues, the key objective of this study (for my M.Sc.) is to use an integrated methodology to identify locations of highest potential for evidence of the archaeological record on Quadra Island, B.C. Through a combination of sea level history, remote sensing technology and GIS (Geographic Information Systems) archaeological prospection can be greatly improved.

On Quadra Island, the land dramatically rebounded after the last glaciation. As a result, the sea level has dropped 160 m relative to the land over the past 14,000 years. Therefore, the oldest shorelines are inland and represent key targets for archaeological prospection, as past peoples frequently lived very close to the shoreline. Using a form of remote sensing, called LIDAR (Light Detection and Ranging), vegetation can be removed and high-resolution visualizations can reveal hidden topographic features, such as old shorelines. Through combining environmental variables commonly associated with archaeological site locations, such as distance to old shorelines, an GIS-based archeological potential model/map can be created to guide prospection. New inland archaeology sites have since been unearthed this way. This study shows how LIDAR, in conjunction with sea level history, is an invaluable tool for archaeological prospecting on the Pacific Northwest coast. It can decrease the time and effort spent doing fieldwork, and increase site identification rate.

Understanding these research questions by using an integrated methodology is the focus of my M.Sc.(geoarchaeology, UVic), which is in partnership with the Hakai research institute. This research is part of a five-year project entitled the Discovery Islands Landscape Archaeology (DILA), and is currently entering its third field season.

For more informtion, and 3D visuals, check out the Hakai blog article “Flooding the Map:” https://www.hakai.org/blog/science-coastal-margin/flooding-map