Major end moraines of Younger Dryas age on Wollaston Peninsula, Victoria Island, Canadian Arctic: implications for paleoclimate and for formation of hummocky moraine

Some of the most extensive and massive end moraines of Younger Dryas age (1 1-10 C-14 ka BP) yet recognized in North America occur on Wollaston Peninsu la of Victoria Island. On the western part of the peninsula, numerous close ly spaced end moraines formed in the interval starting 11 100 +/- 100 radio carbon years ago and ending about 10 500-10 200 years ago. Net recession wa s generally slow throughout and was punctuated by moraine-building and at l east two readvances. Recession is mapped with a resolution that is approxim ately decadal. The moraines form an orderly, nested succession and are cons istently associated with westward shedding of meltwater, which formed a seq uence of marine-limit deltas. We lack firm, independent proxy-climate evide nce needed to assess whether these moraines formed because of cold Younger Dryas climate, rather than because of controls such as topographic setting and water depth, but climatic control seems probable. The moraines evidentl y retain glacier ice cores, as do most similarly large moraines in the Cana dian Arctic Archipelago and northern mainland. They formed along active ice margins when the glacier mass balance on average was only slightly negativ e. Future melting of ice cores would produce regional hummocky moraine and much basal meltout till more than 10 000 years after deglaciation. Some sou thern areas of hummocky moraine may have originated as ice-cored moraines f ormed by active ice margins rather than from extensive regional stagnation.