Varve and radiocarbon dating support the rapid advance of Jakobshavn Isbr? during the Little Ice Age

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• 作者：J.P.  ; Briner^a ;   ; ^{jbriner@buffalo.edu} ; N.E.  ; Young^a ; E.K.  ; Thomas^b ; H.A.M.  ; Stewart^a ; S.  ; Losee^a ; S.  ; Truex^a
• 关键词：Jakobshavn Isbræ ; Varve ; Radiocarbon dating ; Lake sediments ; Little Ice Age
• 刊名：Quaternary Science Reviews
• 出版年：2011
• 出版时间：September 2011
• 年：2011
• 卷：30
• 期：19-20
• 页码：2476-2486
• 全文大小：1906 K

文摘

Large outlet glaciers draining the Greenland Ice Sheet significantly influence overall ice sheet mass balance. Considerable short term (years to decades) retreat and fluctuations in velocity of Jakobshavn Isbr?, western Greenland, illustrate the complex nature by which large outlet glaciers respond to climate change, making predictions of future ice sheet change challenging. To provide a longer-term view (centuries), we investigate the geological record of Jakobshavn Isbr? change. We use continuous sediment records from lakes that were influenced by the recent advance of Jakobshavn Isbr?, which took place during the Little Ice Age. In particular, we explore the use of annually laminated lake sediments (varves) to precisely constrain the advance of the ice margin as it approached its late Holocene maximum extent. We find that the ice margin advanced recently, at least after ?650 to ?700 AD, and more likely ?800 AD. We suggest that during this period Jakobshavn Isbr? advanced at a rate that was similar to its historically documented average retreat since ?850 AD. Our results indicate that Jakobshavn Isbr?, and presumably other large marine calving glaciers, have the ability to advance quickly in response to climate forcing.