Submarine glacial-landform distribution across the West Greenland margin: a fjord-shelf-slope transect through the Uummannaq system (70-71 N)

Today, the Greenland Ice Sheet reaches the sea via a number of fast-flowing outlet glaciers that are fed by ice draining from huge interior basins (Rignot & Kanagaratnam 2006). At the Last Glacial Maximum (LGM), the ice sheet expanded to reach the continental shelf break around much of Greenland (Ó Cofaigh et al. 2013a). In the Uummannaq area at c. 70–71° N (Fig. 1a) there is now a 400 km distance between the terminus of Rink Glacier, which drains about 30 000 km2 of the ice sheet, and the shelf edge. This provides a transect from the modern glacier front, through a deep fjord system and adjacent cross-shelf trough, to the continental slope in Baffin Bay. The seafloor is now exposed along this transect and the landforms produced by past glacial activity can be examined using marine-geophysical methods. Deglaciation from the LGM was underway at the shelf edge in Uummannaq Trough by 14.8 kyr ago and from the mid-shelf by 10.9 kyr, and ice had probably retreated back into the fjord system by 9.3 kyr ago (Ó Cofaigh et al. 2013a; Roberts et al. 2013)