DOI: 10.1016/j.quascirev.2018.09.002
Scopus记录号: 2-s2.0-85054065591
论文题名: Subglacial permafrost evidencing re-advance of the Greenland Ice Sheet over frozen ground
作者: Ruskeeniemi T. ; Engström J. ; Lehtimäki J. ; Vanhala H. ; Korhonen K. ; Kontula A. ; Claesson Liljedahl L. ; Näslund J.-O. ; Pettersson R.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2018
卷: 199 起始页码: 174
结束页码: 187
语种: 英语
英文关键词: Cryogenic structure
; Crystalline bedrock
; Deglaciation
; Electromagnetics
; Greenland ice sheet
; Holocene
; Permafrost
Scopus关键词: Climate change
; Cryogenics
; Glaciers
; Groundwater
; Hydrogeology
; Permafrost
; Sediments
; Cryogenic structures
; Crystalline bedrocks
; Deglaciations
; Electromagnetics
; Greenland Ice Sheet
; Holocenes
; Ice
英文摘要: Greenland Ice Sheet (GrIS) covers an area of 1.7 km2. It has been an important source of climate information and the air temperature history of Greenland is well known. However, the thermal history and temperature conditions of the Greenland bedrock are poorly known. There are only few records on the temperature of the proglacial bedrock and no records on bedrock temperature underneath the ice sheet. The Greenland Analogue Project (GAP) recently investigated hydrological, hydrogeological and geochemical processes in Kangerlussuaq, West Greenland. Because permafrost has a major hydrological impact in Arctic regions, the cryogenic structure of the bedrock was an important research topic. From previous studies it was already known that Kangerlussuaq is located within the zone of continuous permafrost. Temperature profiling in a new research borehole, extending horizontally 30 m underneath the ice sheet, revealed that permafrost is 350 m deep at the ice margin. This result raised the question how far the permafrost extends under the ice sheet? In order to investigate the thermal properties, we made a series of electromagnetic (EM) soundings at the ice margin area – on proglacial area and on the ice sheet – and detected, that subglacial permafrost extends at least 2 km from the ice margin to inland. We also observed a patchy unfrozen sediment layer between the ice and the frozen bedrock. Possible existence of subglacial sediments and their role in ice dynamics has been debated in many recent papers. Our successful campaign shows that geophysics can be used for bedrock investigations through thick ice, which is known to be challenging for electromagnetic methods. Our results provide the first direct evidence supporting the proposed Holocene ice re-advance over frozen ground, and contribute to the discussion on the rapid climate changes in past, to the future of the ice sheet under warming climate and hydrogeology at the ice margin. © 2018 Elsevier Ltd Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/112040
Appears in Collections: 气候减缓与适应
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作者单位: Geological Survey of Finland, Espoo, FI-02150, Finland; Posiva Oy, Eurajoki, FI-27160, Finland; Swedish Nuclear Fuel and Waste Management Company, Box 3091, Solna, SE-16903, Sweden; Department of Earth Sciences, Uppsala University, Uppsala, SE-75236, Sweden
Recommended Citation:
Ruskeeniemi T.,Engström J.,Lehtimäki J.,et al. Subglacial permafrost evidencing re-advance of the Greenland Ice Sheet over frozen ground[J]. Quaternary Science Reviews,2018-01-01,199