Evidence for late Pleistocene and Holocene bottom current activity in Baffin Bay

Baffin Bay forms an elongated ocean basin that connects the Arctic Ocean to the Labrador Sea and the North Atlantic via several Canadian Arctic Channels and Davis Strait. The modern ocean circulation in Baffin Bay is cyclonic; the West Greenland Current enters the bay in the southeast and flows northward along the east Baffin Bay margin, eventually turning westward and combining with Arctic Ocean outflow to become the south-flowing Baffin Current that exits the bay in the southwest. The present-day general oceanographic pattern likely existed during the Late Miocene and Pliocene; in fact, large Pliocene contourite drifts are recognized in the eastern and western margin of the bay. Throughout the Quaternary, however, it is thought that the circulation pattern was temporarily interrupted by ice sheet extension in the Canadian Arctic Archipelago that prevented Arctic Ocean inflow to Baffin Bay. The purpose of this study is to examine the geological evidence for Late Quaternary bottom current activity in Baffin Bay, a time when sedimentation within the bay was largely controlled by glacigenic processes.

During the Quaternary, ice sheets carved several transverse troughs across the Baffin Bay continental shelves. Seaward of the troughs, extensive trough mouth fans form the dominant depositional feature along the Baffin Bay slope. Superimposed on the glaciomarine deposits is evidence for contour current processes. The most apparent features are along-slope furrows and moats that mark the east Baffin Bay slope, between Disko and Melville bays, in water depths to 1400 m. A sediment core from a contouritic levee shows that the sediments have a higher silt content than non-levee sediments. Furrows are also present on the southwest Baffin Bay slope off Home Bay; they occur in 1300 m water depth and coincide with elongate pockmarks, however, they are less continuous than the eastern bay examples. Farther south, linear to curvilinear bedforms are present in 500 m water depth on the southwest Baffin Bay slope and likely formed by enhancement of the south-flowing Baffin Current as it encountered Davis Strait. These results show that despite the predominance of glaciomarine processes in Baffin Bay during the Late Pleistocene, bottom currents were sufficiently active to be preserved in the geological record.