气候变化领域集成服务门户(CCPortal): Bed erosion during fast ice streaming regulated the retreat dynamics of the Irish Sea Ice Stream

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DOI	10.1016/j.quascirev.2020.106526
	Bed erosion during fast ice streaming regulated the retreat dynamics of the Irish Sea Ice Stream
	Van Landeghem K.J.J.; Chiverrell R.C.
发表日期	2020
ISSN	0277-3791
卷号	245
英文摘要	Marine-terminating ice stream behaviour often defines the stability of ice sheets and is driven by a complex interplay of climatic, oceanic, topographic and glaciological factors. Here, we use new integrated high resolution, extensive (2100 km2) and continuous geophysical, sedimentological and geotechnical data to reconstruct past glacial environments during the Last Glacial Maximum from a well-preserved palaeo-landscape. The data is from the axial centre of the Irish Sea Ice Stream (ISIS), which drained > 17% of the former British-Irish Ice Sheet. Recent geochronological data of the palaeo-ISIS show a build-up and advance of ice to marine-terminating maximum limits in the southern Celtic Sea 27–25 ka BP, followed by rapid ice margin retreat into the northern Irish Sea Basin (ISB) by 20.8 ± 0.7 ka BP. However, the flow dynamics in the central and axial bed of the ISIS through this timeframe are not well understood. Here, we use our new glacial landscape reconstruction to identify the spatial and temporal patterns of flow re-organisation and re-activations for the marine-terminating ISIS. From this we infer how ice streaming was driven by a variety of factors through advance, deglaciation and towards a temporary lift-off of ice from its bed and an ultimate demise. Overprinted subglacial bedforms with differing ice flow directions indicate an on/off behaviour to the ice-streaming, an increasing topographical influence and substantial realignment of ice flows. Subsurface geophysical data reveal the erosive capability of the ice stream through time, with a first erosive component in the formation of mega-scale glacial lineations leaving bedrock exposed at the ice stream bed. The depositional component of MSGL crest building occurred in the same ice-flow phase. Whilst the ice stream was laterally constricted in two locations, likely contributing to changes in ice margin retreat rates, we also propose that changes in basal drag associated with exposed bedrock at the ice‒bed interface influenced the retreat dynamics, particularly when this exposure was near the grounding zone. The wider implications of this work are that episodic and highly erosive ice streaming during ice advance and early retreat can change ice‒bed conditions radically and in turn influence glacial dynamics during later retreat episode, thus constituting a feedback process to be considered in modelling the dynamics of marine-terminating ice streams. © 2020 Elsevier Ltd
英文关键词	British-Irish ice sheet; Deglaciation; Europe; Geomorphology; Geophysics; Glaciology (incl. palaeo-ice sheets); MSGL; Palaeo-ice streaming; Quaternary; Subglacial bedforms
语种	英语
scopus关键词	Data streams; Dynamics; Geochronology; Geophysics; Glaciers; Sea ice; British-Irish ice sheet; Geophysical data; Geotechnical data; Glacial environments; Glacial landscapes; Glacial lineation; Last Glacial Maximum; Spatial and temporal patterns; Glacial geology; bedrock; deglaciation; grounding line; ice flow; ice retreat; ice sheet; ice stream; Last Glacial Maximum; sea ice; spatiotemporal analysis; Atlantic Ocean; Celtic Sea; Irish Sea
来源期刊	Quaternary Science Reviews
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/151333
作者单位	School of Ocean Sciences, Bangor University, Menai BridgeLL59 5AB, United Kingdom; School of Environmental Sciences, University of Liverpool, Liverpool, L69 7ZT, United Kingdom
推荐引用方式 GB/T 7714	Van Landeghem K.J.J.,Chiverrell R.C.. Bed erosion during fast ice streaming regulated the retreat dynamics of the Irish Sea Ice Stream[J],2020,245.
APA	Van Landeghem K.J.J.,&Chiverrell R.C..(2020).Bed erosion during fast ice streaming regulated the retreat dynamics of the Irish Sea Ice Stream.Quaternary Science Reviews,245.
MLA	Van Landeghem K.J.J.,et al."Bed erosion during fast ice streaming regulated the retreat dynamics of the Irish Sea Ice Stream".Quaternary Science Reviews 245(2020).