Calvert Island sea-level reconstruction

The central British Columbia (BC) coast is host to several important archeological sites that hold key information on the post-glacial populating of North America via a west coast route. Remarkably, however, the relative sea-level history for the region - a key environmental control on migration and occupation potential during and after deglaciation - remains relatively unstudied. Over recent decades, new techniques in sedimentology for absolute dating (e.g., optically stimulated luminescence, OSL) and remote sensing technologies for terrain mapping and analysis (e.g., airborne Light Detection And Ranging, LiDAR) have emerged to allow for more detailed, landscape-scale examination of Holocene coastal landform development and sea-level trend reconstructions.

This presents a timely opportunity to use these methodological advances to explore a potentially significant geographical gap in knowledge of post-glacial landscape evolution. The Hakai Institute on Calvert Island, about 100 km north of Vancouver Island on the central coast of BC, has entered a partnership with our lab and geochronologist  Dr. Olav Lian from the University of the Fraser Valley to reconstruct the Holocene sea-level history and associated landscape development for the region.

Our component of this research involves three key objectives:

  1. Map and interpret the geomorphic and surficial geologic landscape of the northern half of Calvert Island using a high-resolution LiDAR-derived digital elevation model (DEM) and coincident digital orthophotography coupled with ground surveys;
  2. Locate distinct Holocene shoreline positions and geomorphic features that relate to periods of stable past sea levels and collect sediment and organic sampling sites for OSL and 14C dating; and
  3. Examine and interpret the results to reconstruct the sea-level history (from highstand to present) and related landscape responses during deglaciation and sea-level regression over the Holocene.

This project provides a unique opportunity to apply leading-edge remote-sensing technology and absolute dating methods to enrich our understanding of a key gap in understanding the palaeogeography and geoarchaeological history of understudied area of the BC coast. 

An ongoing component of this project is a geomorphic map of the region, which is available as a shapefile here and here (supporting data). Example screengrab: 

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