CGRG Bibliography of Canadian Geomorphology
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Author : Antoniades, D.; Francus, P.; Pienitz, R.; St-Onge, G.; and Vincent, W.
Date : 2008.
Title : Northern ice shelves were stable for millennia before recent abrupt breakup.
Publication : International Arctic Change 2008 Conference. December 9-12, 2008. Quebec City, Quebec.
Issue : Conference Programme and Abstracts
Page(s) : 171.
Abstract
Northern Ellesmere Island (Nunavut, Canada) is home to several rare ecosystem types that are currently threatened by recent climate warming, including ice shelves and epishelf lakes. Ice shelves fringed much of northern Ellesmere Island in the early 20th century, but have since shrunk by over 90% due to climate warming. During the last decade, several ice shelves have either fractured or detached from the Ellesmere coast and floated away entirely. Although estimates of their age range from 5,500 and 3,000 calendar years before present, there is no direct evidence for the establishment of these ice shelves and their dynamics since formation remain unknown. In order to place the significance of recent breakup in a long-term context, a better understanding is required of the history and evolution of these northern ice shelves. Epishelf lakes (ice-dammed fiords with stratified water columns) depend on ice shelves for their existence, and sedimentary records from these fiords can yield insights into past ice shelf dynamics. Here we report on two radiocarbon-dated sediment cores collected with a percussion corer that document several thousand years of the history of Disraeli Fiord (just south of the Ward Hunt Ice Shelf), using sedimentary pigment (HPLC) and geochemical (XRF) analyses. Changes in elemental concentrations, including Ca, Fe and Mn, are interpreted to reflect variation in runoff and catchment influence related to the formation of the Disraeli epishelf lake, while pigment ratios and concentrations record climatemediated changes in freshwater/marine conditions and past productivity, respectively. These data indicate that, prior to its disintegration, the Ward Hunt Ice Shelf was stable for millennia, and therefore that recent changes are significant in a long-term climate context.
Bibliography of Canadian Geomorphology