A glacial origin of Sable Island: ice and sea-level fluctuations from seismic stratigraphy on Sable Island Bank, Scotian Shelf, offshore Nova Scotia

Abstract

A database of interpreted geological cross-sections assembled from analogue high-resolution seismic-reflection profiles from Sable Island Bank has been compiled. A preliminary seismostratigraphy has enhanced understand- ing of the mid-late Pleistocene section. Numerous units and their bounding unconformities indicate a complex his- tory of glaciogenic and sand-sheet deposition and associated sea-level fluctuations. A near-shelf-break ice-maximum position is interpreted for the Late Wisconsinan and inferred for earlier stades and/or glaciations. A late readvance sometime between 16 ka and 14 ka deposited a thick sand body over the transgressed bank, form- ing ancestral Sable Island. Modification and transport of sands accompanied a subsequent transgression. The database will provide the basis for compilation of a lithological and geotechnical zonation and a suite of maps depicting unit thickness and distribution, unconformities, and subsurface features, including geohazards, as well as large-scale (>1.5 m high) surficial bedforms.