Late Quaternary sediments and chronology of the northeast Labrador Shelf (Karlsefni Trough, Saglek Bank): Links to glacial history

摘要

Core HU87033-015, an 11-m-long giant piston core from the western end of Karlsefni Trough, was taken only 25 km from the coast of northernmost Labrador. The regional acoustic framework was established via a high-resolution, deep-towed (Huntec DTS) seismic survey. We recognized four acoustic facies that are associated with designated and recovered major lithologic units. The ages of these units were determined from 13 accelerator mass spectrometry 14C dates from marine biogenic carbonates. These results suggest that glacial ice was present on the shelf from at least the mid-Wisconsinan and that the basal sequence contains reworked glacial-marine diamicton. Furthermore, our data provide the first evidence that the northern Labrador inner shelf was ice free by ca. 11 14C ka. The bulk of the postglacial deposition was around 8.2 ka and consists of increased detrital carbonate deposition. The deposition of this detrital carbonate is age equivalent with DC-0 on the southeastern Baffin Shelf and in the North Atlantic.