Geomorphological Evidence of Holocene Climatic Change from Northwest Ellesmere Island, Canadian High Arctic

Abstract

Proxy data from the northern coast of Ellesmere Island are used to reconstruct Holocene palaeoclimate and appear to corroborate the ice core record from the Canadian and Greenland high arctic despite some regional variation. Geomorphological evidence indicates that deglaciation was associated with a marked climatic amelioration in the late Pleistocene/early Holocene (≥10 ka BP). This contrasts with glaciers on the south side of Grant Land Mountains which started to retreat at 7.5 ka BP perhaps due to significant differences in glacioclimatic regime and the influence of the Arctic Ocean. Indicators of sea ice conditions on northern Ellesmere Island suggest that the early Holocene was a period of considerable open water. Radiocarbon dates on driftwood collected from behind the north coast ice shelves suggest that the ice shelves formed during a mid-Holocene climatic deterioration. Geomorphic evidence shows that the ice shelves are presently breaking up and melting in response to recent warming. Glaciers have responded to Holocene climate change at varying rates which are related to drainage basin size. Many large glaciers are still advancing in response to the mid-Holocene climatic deterioration. Some glaciers display evidence of dual advances which may reflect mid-Holocene and ‘Little Ice Age’ accumulation. Other evidence of ‘Little Ice Age’ cold and recent warmth is perennial snowbank retreat and fluvially eroded ice wedge polygons near sea level. Different cryogenic systems on northern Ellesmere Island have responded to Holocene climate change at various rates: 103 a for glaciers with drainage basin areas >5 km2; 102 a for ice shelves and glaciers <5 km2; and 101 a for sea ice.