气候变化领域集成服务门户(CCPortal): Ice-stream flow switching by up-ice propagation of instabilities along glacial marginal troughs

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DOI	10.5194/tc-13-981-2019
	Ice-stream flow switching by up-ice propagation of instabilities along glacial marginal troughs
	Brouard E.; Lajeunesse P.
发表日期	2019
ISSN	19940416
EISSN	13
起始页码	981
结束页码	996
卷号	13 期号:3
英文摘要	Ice-stream networks constitute the arteries of ice sheets through which large volumes of glacial ice are rapidly delivered from the continent to the ocean. Modifications in ice-stream networks have a major impact on ice sheet mass balance and global sea level. Reorganizations in the drainage network of ice streams have been reported in both modern and paleo-ice sheets and usually result in ice streams switching their trajectory and/or shutting down. While some hypotheses for the reorganization of ice streams have been proposed, the mechanisms that control the switching of ice streams remain poorly understood and documented. Here, we interpret a flow switch in an ice-stream system that occurred prior to the last glaciation on the northeastern Baffin Island shelf (Arctic Canada) through glacial erosion of a marginal trough, i.e., deep parallel-to-coast bedrock moats located up-ice of a cross-shelf trough. Shelf geomorphology imaged by high-resolution swath bathymetry and seismo-stratigraphic data in the area indicate the extension of ice streams from Scott and Hecla & Griper troughs towards the interior of the Laurentide Ice Sheet. Up-ice propagation of ice streams through a marginal trough is interpreted to have led to the piracy of the neighboring ice catchment that in turn induced an adjacent ice-stream flow switch and shutdown. These results suggest that competition for ice discharge between the two ice streams, which implies piracy of ice drainage basins via marginal troughs, was the driving mechanism behind ice flow switching. In turn, the enlargement of the ice catchment by piracy increased the volume and discharge of Scott Ice Stream, allowing it to Erode deeper and flow farther on the continental shelf. Similar trough systems observed on many other glaciated continental shelves may be the product of such competition for ice discharge between catchments. © 2019 Copernicus GmbH. All rights reserved.
学科领域	catchment; continental shelf; drainage network; geomorphology; glacial erosion; glaciation; glacier mass balance; ice flow; ice sheet; ice stream; last glaciation; Laurentide Ice Sheet; sea level change; swath bathymetry; Arctic Ocean; Baffin Island; Canada; Nunavut; Saskatchewan; Scott
语种	英语
scopus关键词	catchment; continental shelf; drainage network; geomorphology; glacial erosion; glaciation; glacier mass balance; ice flow; ice sheet; ice stream; last glaciation; Laurentide Ice Sheet; sea level change; swath bathymetry; Arctic Ocean; Baffin Island; Canada; Nunavut; Saskatchewan; Scott
来源期刊	The Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/118905
作者单位	Centre d'Études Nordiques, Département de Géographie, Université Laval, Québec, QC, Canada
推荐引用方式 GB/T 7714	Brouard E.,Lajeunesse P.. Ice-stream flow switching by up-ice propagation of instabilities along glacial marginal troughs[J],2019,13(3).
APA	Brouard E.,&Lajeunesse P..(2019).Ice-stream flow switching by up-ice propagation of instabilities along glacial marginal troughs.The Cryosphere,13(3).
MLA	Brouard E.,et al."Ice-stream flow switching by up-ice propagation of instabilities along glacial marginal troughs".The Cryosphere 13.3(2019).