Optical dating of stabilized parabolic dunes, Savary Island, British Columbia

Research has shown that the south coast of British Columbia (BC) has experienced changes in relative sea level and climate since deglaciation (~15 ka ago); however, there has been little study of the landscape’s response to these changes. On Savary Island, in the Strait of Georgia, there exist large parabolic dunes that are unique to the region. These dunes are stabilized, supporting mature forest growing in well-developed soil, and they contain eroded palaeosols indicating that their formation was punctuated by periods of episodic stabilization and soil formation. Optical ages from K-feldspar indicate that dune formation began prior to 7.69 ± 0.71 ka and stabilized by about 5.47 ± 0.36 ka ago when relative sea level lowering was slowing and climate was becoming cooler and moister. Periods of landscape stability during dune formation were brief, probably lasting only a few hundred years.