globalchange  > 过去全球变化的重建
DOI: 10.1016/j.quascirev.2016.01.018
Scopus记录号: 2-s2.0-84957662249
论文题名:
Deglaciation of a major palaeo-ice stream in Disko Trough, West Greenland
作者: Hogan K.A.; Ó Cofaigh C.; Jennings A.E.; Dowdeswell J.A.; Hiemstra J.F.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2016
卷: 147
起始页码: 5
结束页码: 26
语种: 英语
英文关键词: Calving bay ; Deglacial lithofacies ; Greenland ice sheet ; Grounding-zone wedge ; Ice-sheet retreat ; Last glacial maximum ; Marine sediment cores ; Submarine landforms ; West Greenland
Scopus关键词: Deposition ; Glacial geology ; Glaciers ; Ice control ; Melting ; Sea ice ; Sediments ; Submarine geology ; Calving bay ; Greenland Ice Sheet ; Grounding-zone wedges ; Ice-sheet retreat ; Last Glacial Maximum ; Lithofacies ; Marine sediments ; Submarine landforms ; West Greenland ; Ice
英文摘要: Recent work has confirmed that grounded ice reached the shelf break in central West Greenland during the Last Glacial Maximum (LGM). Here we use a combination of marine sediment-core data, including glacimarine lithofacies and IRD proxy records, and geomorphological and acoustic facies evidence to examine the nature of and controls on the retreat of a major outlet of the western sector of the Greenland Ice Sheet (GrIS) across the shelf. Retreat of this outlet, which contained the ancestral Jakobshavns Isbræ ice stream, from the outer shelf in Disko Trough was rapid and progressed predominantly through iceberg calving, however, minor pauses in retreat (tens of years) occurred on the middle shelf at a trough narrowing forming subtle grounding-zone wedges. By 12.1 cal kyr BP ice had retreated to a basalt escarpment and shallow banks on the inner continental shelf, where it was pinned and stabilised for at least 100 years. During this time the ice margin appears to have formed a calving bay over the trough and melting became an important mechanism of ice-mass loss. Fine-grained sediments (muds) were deposited alternately with IRD-rich sediments (diamictons) forming a characteristic deglacial lithofacies that may be related to seasonal climatic cycles. High influxes of subglacial meltwater, emanating from the nearby ice margins, deposited muddy sediments during the warmer summer months whereas winters were dominated by iceberg calving leading to the deposition of the diamictons. This is the first example of this glacimarine lithofacies from a continental-shelf setting and we suggest that the calving-bay configuration of the ice margin, plus the switching between calving and melting as ablation mechanisms, facilitated its deposition by channelling meltwater and icebergs through the inner trough. The occurrence of a major stillstand on the inner shelf in Disko Trough demonstrates that the ice-dynamical response to local topography was a crucial control on the behaviour of a major outlet in this sector of the GrIS during retreat. © 2016 The Authors
资助项目: The data for this study were collected during cruise JR175 of the RSS James Clark Ross to West Greenland in 2009 and was funded by Natural Environment Research Council (NERC) grant NE/D001951/1 to C.Ó.C. Funding for this research was also provided by the Unites States National Science Foundation awards: NSF OPP-0713755 and NSF P2C2-1203492 to the University of Colorado to A.J. We also thank the officers, crew technical support staff and other scientists on board during JR175 for their assistance with data acquisition. The vibrocorer used on JCR was loaned and operated by staff from the British Geological Survey Marine Operations Group. This work forms part of the British Antarctic Survey program “Polar Science for Planet Earth” funded by the NERC. Lastly, we thank Sam Kelley and one anonymous reviewer for helpful comments on the manuscript.
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/59501
Appears in Collections:过去全球变化的重建

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作者单位: British Antarctic Survey, Natural Environmental Research Council, High Cross, Madingley Road, Cambridge, United Kingdom; Department of Geography, Durham University, Science Laboratories, South Road, Durham, United Kingdom; INSTAAR and Department of Geological Sciences, University of Colorado, Boulder, CO, United States; Scott Polar Research Institute, University of Cambridge, Lensfield Road, Cambridge, United Kingdom; Department of Geography, College of Science, Swansea University, Singleton Park, Swansea, United Kingdom

Recommended Citation:
Hogan K.A.,Ó Cofaigh C.,Jennings A.E.,et al. Deglaciation of a major palaeo-ice stream in Disko Trough, West Greenland[J]. Quaternary Science Reviews,2016-01-01,147
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