Geomorphologic and sedimentary evolution of a transgressive thermokarst coast, Mackenzie delta region, Canadian Beaufort Sea

Transgression of a thermokarst coastline results in the development of a di stinctive coastal morphology consisting of breached thermokarst lakes, sepa rated by narrow headlands fringed by barrier-spit complexes and sandflats. A detailed description of the geomorphology and sediment facies of one such area east of North Head in the Canadian Beaufort Sea is combined with seis mic and core analysis fi om the adjacent inner shelf to develop a sedimento logic model for use in interpolating geotechnical conditions in the region. The model proposes the sedimentary successions that develop during transgr ession in a number of sub-environments related to the thermokarst morpholog y. It differs from conventional shoreface evolution models in that thermoka rst processes create additional accommodation space at the coastline. This extra space, formerly occupied by ground ice, is rapidly filled by coastal and shelf lithosomes, the latter consisting principally of mud from the nea rby Mackenzie River.