DOI: 10.1016/j.quascirev.2014.11.001
Scopus记录号: 2-s2.0-84911208991
论文题名: Early break-up of the Norwegian Channel Ice Stream during the Last Glacial Maximum
作者: Svendsen J.I. ; Briner J.P. ; Mangerud J. ; Young N.E.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2015
卷: 107 起始页码: 231
结束页码: 242
语种: 英语
英文关键词: 10Be dating
; Last Glacial Maximum
; Lateglacial
; Norwegian Channel Ice Stream
; Scandinavian Ice Sheet
; Western Norway
Scopus关键词: Glacial geology
; Glaciers
; Submarine geology
; <sup>10</sup>Be dating
; Ice sheet
; Ice streams
; Last Glacial Maximum
; Lateglacial
; Western Norway
; Ice
; beryllium isotope
; foraminifera
; ice cover
; ice free corridor
; ice retreat
; Last Glacial Maximum
; late glacial
; marine sediment
; mollusc
; Scandinavian Ice Sheet
; sediment core
; Atlantic Ocean
; North Sea
; Norwegian Channel
英文摘要: We present 18 new cosmogenic 10Be exposure ages that constrain the breakup time of the Norwegian Channel Ice Stream (NCIS) and the initial retreat of the Scandinavian Ice Sheet from the Southwest coast of Norway following the Last Glacial Maximum (LGM). Seven samples from glacially transported erratics on the island Utsira, located in the path of the NCIS about 400km up-flow from the LGM ice front position, yielded an average 10Be age of 22.0±2.0ka. The distribution of the ages is skewed with the 4 youngest all within the range 20.2-20.8ka. We place most confidence on this cluster of ages to constrain the timing of ice sheet retreat as we suspect the 3 oldest ages have some inheritance from a previous ice free period. Three additional ages from the adjacent island Karmøy provided an average age of 20.9±0.7ka, further supporting the new timing of retreat for the NCIS. The 10Be ages from Utsira and Karmøy suggest that the ice stream broke up about 2000 years earlier than the age assignment based on 14C ages on foraminifera and molluscs from marine sediment cores. We postulate that the Scandinavian Ice Sheet flowed across the Norwegian Channel to Denmark and onto the North Sea plateau during early phases of the LGM. When the NCIS started to operate this ice supply to the North Sea was cut off and the fast flow of the NCIS also led to a lowering of the ice surface along the Norwegian Channel and thereby drawdown of the entire ice sheet. This facilitated rapid calving of the ice front in the North Sea and we reconstruct a large open bay across the entire northern North Sea by ~20ka based on our 10Be ages in the east and radiocarbon ages from marine cores in the west. Additional 10Be ages show that the mainland slightly east of the islands Utsira and Karmøy remained ice covered until about 16ka, indicating almost no net ice-margin retreat for the 4000 years between 20 and 16ka. After 16ka the ice margin retreated quickly up-fjord. © 2014 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/60077
Appears in Collections: 过去全球变化的重建
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作者单位: Department of Earth Science, University of Bergen and Bjerknes Centre for Climate Research, Postbox 7803, Bergen, Norway; Department of Geology, University at Buffalo, Buffalo, NY, United States; Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, United States
Recommended Citation:
Svendsen J.I.,Briner J.P.,Mangerud J.,et al. Early break-up of the Norwegian Channel Ice Stream during the Last Glacial Maximum[J]. Quaternary Science Reviews,2015-01-01,107