Late Wisconsinan glaciation of southern Eureka Sound: evidence for extensive Innuitian ice in the Canadian High Arctic during the Last Glacial Maximum

Abstract

Southern Eureka Sound was originally proposed as the centre of an Innuitian Ice Sheet in the Canadian High Arctic at the Last Glacial Maximum (LGM) based largely on the pattern of Holocene emergence. This paper focuses on the glacial geological evidence for such an ice sheet in the region. Granite dispersal trains and ice-moulded bedrock record regional, westward flow of warm-based ice into Eureka Sound from SE Ellesmere Island. Regional ice was coalescent with local ice domes on inter-fiord peninsulas. Marine limit in the form of raised deltas, beaches and washing limits formed during deglaciation of the regional ice. Throughout southern Eureka Sound, marine limit dates ⩽9.2 ka BP, indicating that ice commenced retreat during the early Holocene. Ice-divides were located along the highlands of central Ellesmere and Axel Heiberg islands, from which ice inundated Eureka Sound, flowing north and south along the channel. Regional radiocarbon dates on marine limit show that deglaciation occurred in two steps. Initial break-up and radial retreat of ice from Eureka Sound to the inner fiords was rapid and preceded stabilisation along adjacent coastlines and at fiord heads. Two-step deglaciation is also reflected in differences in glacial geomorphology between the inner and outer parts of many fiords. A prominent belt of fiord-head glaciogenic landforms, long proposed to mark the last glacial limit, is re-interpreted to record initial, stabilisation of ice margins due predominantly to bathymetric control.