Late Quaternary Stratigraphy of the Baffin Island Slope

English Abstract:

The Baffin Island Slope (BIS) extends more than 1000 km from Davis Strait in the south to Lancaster Sound in the north. Relatively little is known about lateral variations in the late Quaternary stratigraphy and geological history of the BIS. The adjacent Baffin Island Shelf is incised by 11 transverse troughs that point to a complicated history of sediment supply to the BIS. In this study, 17 piston cores, multibeam bathymetry and high resolution sub-bottom profiler data were used to examine regional variations in the Late Quaternary stratigraphy of the BIS. The shallow seismic stratigraphy of the BIS can be broadly divided between the slope north of Home Bay, where acoustically transparent sediment overlies more reflective sediment, and the slope south of Home Bay, where acoustic penetration is greater and acoustically stratified and chaotic reflections (representing mass transport deposits) are present. Similarly, north of Home Bay, the shallow lithostratigraphy is consistant; cores typically stop in a basal, dark diamict that is overlain by turbidites, stratified ice-rafted deposits, IRD-rich detrital carbonates and hemipelagic sediments. Synthetic seismogram analysis shows that the basal, dark diamict coincides with the regional change to more acoustically reflective deposits on sub-bottom profiler data. South of Home Bay, core samples are generally finer-grained with less diamict but ice-rafted detritus layers are still present. This distinct lateral change in the shallow stratigraphy of the BIS represents differences in the style of proglacial and glacio-marine sedimentation along the slope which may provide important insight into the late Quaternary glacial history of the region. Ongoing research is focused on acquiring age control for the various lithostratigraphic facies; large dateable shell fragments are uncommon in core samples, so analysis of forams and lithostratigraphic correlation with published magnetostratigraphy results will hopefully better constrain the timing of major stratigraphic events.