Evidence for Wisconsinan Glaciations in the Verrill Canyon Area, Scotian Slope

Abstract

AbstractA composite thickness of about 25 m of sediment has been cored from the Verrill Canyon on the Scotian Slope. It is interpreted that the majority of this sequence was deposited in a glaciomarine environment during oxygen isotopic stage 2 and the top of stage 3. These sediments, as seen in high-resolution seismic reflection profiles, are well stratified, become thicker upslope, are laterally variable in thickness, and pass upslope into possible outer shelf tills. Three wedge-shaped units of incoherent reflections interfinger with the parallel reflections and terminate in water depths greater than 700 m. These wedge-shaped units are interpreted as slumped diamict and outwash deposits. The age of the uppermost wedge-shaped unit is 26,000–21,000 yr based on extrapolation of radiocarbon dates. This unit documents a late Wisconsinan glacier readvance on the outer Scotian Shelf. The underlying wedge-shaped unit, estimated to be 70,000 yrs old, extends further west along the continental slope, and may represent a more extensive early Wisconsinan ice advance. A third wedge-shaped unit, inferred to have formed during isotopic stage 6, is possibly a remnant of the first glaciation in the study area.