<sup>10sup>Be surface exposure ages on the late-Pleistocene and Holocene history of Linn茅breen on Svalbard
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- 作者：Melissa Reusche<sup>asup> ; Kelsey Winsor<sup>asup> ; Anders E. Carlson<sup>bsup><sup> ; sup><sup>acarlson@coas.oregonstate.edu" class="auth_mailsup> ; Shaun A. Marcott<sup>bsup> ; Dylan H. Rood<sup>csup><sup> ; sup><sup>dsup> ; Anthony Novak<sup>bsup> ; Steven Roof<sup>esup> ; Michael Retelle<sup>fsup> ; Alan Werner<sup>gsup> ; Marc Caffee<sup>hsup> ; Peter U. Clark<sup>bsup>
- 关键词：Svalbard glaciers ; Late Pleistocene ; Holocene ; Neoglacial ; Little Ice Age
- 刊名：Quaternary Science Reviews
- 出版年：1 April, 2014
- 年：2014
- 卷：89
- 期：Complete
- 页码：5-12
- 全文大小：2284 K
文摘
Arctic glaciers were sensitive to past changes in high-latitude winter precipitation and summer temperature. Here we develop a late-Pleistocene to Holocene history for Linn茅breen (Linn茅 Glacier) in western Svalbard using <sup>10sup>Be surface exposure ages on isolated erratic and moraine boulders. We show that Linn茅breen had separated from the larger ice sheet over Svalbard and was retreating up valley around the start of the Younger Dryas cold period. We attribute this retreat during a cold period on Svalbard to moisture starvation of Linn茅breen from advanced sea ice and/or elevated shortwave boreal summer insolation that overwhelmed any reduction in sensible heat. After an ice-free period during the early to middle Holocene, Linn茅breen reformed sometime after 4.6聽卤聽0.2聽ka, and was at a position roughly equivalent to its Little Ice Age (LIA) maximum extent before it began to retreat at 1.6聽卤聽0.2聽ka. Comparison with calibrated <sup>14sup>C dates from three other glaciers could suggest that this period of ice retreat at 鈭?.6聽ka could be regional in extent. Linn茅breen occupied the pre-LIA moraine when there was an increased ratio of cold Arctic-sourced relative to warm Atlantic-sourced waters around Svalbard and advanced sea ice. The retreat of Linn茅breen at 鈭?.6聽ka was concurrent with the increased presence of warm Atlantic waters around Svalbard and attendant sea-ice retreat. These coincident changes in ocean temperatures, sea-ice extent, and Linn茅breen moraine age could imply a climatic forcing of the pre-LIA advance and retreat of Linn茅breen. Summer temperatures, rather than changes in precipitation, would then be dominant in driving ice retreat, although the possibility of stochastic glacier-margin variability cannot be excluded. Our data therefore suggest that Linn茅breen may have responded differently to past changes in sea-ice extent that could depend on the background climate state (deglacial climate vs. late-Holocene climate), which highlights the complexity in climatic controls on Arctic glaciers.