Relationship of Land Terminating and Fjord Glaciers to Holocene Climatic Change, South Georgia, Antarctica

Abstract

This paper uses ELA and mass balance gradient reconstructions to understand the climatic significance of Holocene glacier fluctuations in South Georgia. The position of the island between mid-latitude southern South America and coastal Antarctica makes it an important link in the chain of Holocene glacier histories in the Southern Hemisphere. A Neoglacial cooling of 1°C and a Little Ice Age cooling of 0.5°C reflect the increased frequency of southern air masses from the Weddell Sea which lowered temperatures but modified precipitation only slightly. Radiocarbon dating the most extensive Neoglacial advance is problematic because most data have been obtained only for the moraine of a calving fjord glacier. This, the Moraine Fjord glacier, is believed to have advanced 450–650 years later than land-terminating glaciers, since its progress down-fjord depended on the construction of a pinning moraine bank. The scale of late Holocene-Little Ice Age glacier advances in South Georgia was small by mid-latitude standards, possibly because of the relatively arid environment in the lee side of the island.