DOI: 10.1016/j.epsl.2020.116501
论文题名: Deglaciation of Pope Glacier implies widespread early Holocene ice sheet thinning in the Amundsen Sea sector of Antarctica
作者: Johnson J.S. ; Roberts S.J. ; Rood D.H. ; Pollard D. ; Schaefer J.M. ; Whitehouse P.L. ; Ireland L.C. ; Lamp J.L. ; Goehring B.M. ; Rand C. ; Smith J.A.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2020
卷: 548 语种: 英语
中文关键词: Amundsen Sea Embayment
; Antarctica
; cosmogenic isotopes
; geomorphology
; glaciation
; Holocene
英文关键词: Electric grounding
; Glacial geology
; Glaciers
; Sea level
; Amundsen Sea sectors
; Antarctic ice sheets
; Continental shelves
; Flow acceleration
; Glacial isostatic adjustment models
; Last Glacial Maximum
; Surface exposure dating
; Surface lowering
; Ice
; beryllium isotope
; coastal morphology
; deglaciation
; glacier retreat
; glacioisostasy
; Holocene
; ice stream
; Last Glacial Maximum
; sea level change
; Amundsen Sea
; Antarctica
; Pope Glacier
; Southern Ocean
; West Antarctica
英文摘要: The Amundsen Sea sector of the Antarctic ice sheet presently dominates the contribution from Antarctica to sea level rise. Several large ice streams that currently drain the sector have experienced rapid flow acceleration, grounding line retreat and thinning during the past few decades. However, little is known of their longer-term – millennial-scale – retreat history, despite the reliance of several ice sheet and glacial-isostatic adjustment models on such data for improving sea level prediction from this critical region. This study investigates the timing and extent of surface lowering of one of those ice streams, Pope Glacier, since the Last Glacial Maximum (LGM), using glacial-geological evidence for former ice cover. We present a new deglacial chronology for the glacier, derived from surface exposure dating of glacially-deposited cobbles and ice-scoured bedrock from Mount Murphy and its surrounding peaks. Cosmogenic 10Be exposure ages from 44 erratic cobbles and 5 bedrock samples, and in situ 14C exposure ages from one erratic and 8 bedrock samples are predominantly in the range 5.5-16 ka. Although 10Be inheritance from prior exposure is prevalent in some erratics and probably all bedrock samples, none of the ages pre-date the LGM. From these results we infer that the surface of Pope Glacier lowered by 560 m during the early- to mid-Holocene (9-6 ka), at an average rate of 0.13 ± 0.09/0.04 m yr−1. The lowering coincided with a period of enhanced upwelling of warm Circumpolar Deep Water onto the continental shelf in the region. A reduction in buttressing − facilitated by such upwelling − by an ice shelf that is thought to have spanned the embayment until 10.6 cal kyr BP could have triggered simultaneous early Holocene thinning of Pope Glacier and glaciers elsewhere in the Amundsen Sea Embayment. © 2020 The Author(s) Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165062
Appears in Collections: 气候变化与战略
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作者单位: British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, United Kingdom; Department of Earth Science & Engineering, Imperial College London, London, SW7 2AZ, United Kingdom; Earth and Environmental Systems Institute, Pennsylvania State University, University ParkPA 16802, United States; Lamont-Doherty Earth Observatory, Columbia University, Route 9W, PalisadesNY NY10964, United States; Department of Geography, Durham University, Durham, United Kingdom; Department of Earth & Environmental Sciences, Tulane University, New Orleans, LA 70118, United States
Recommended Citation:
Johnson J.S.,Roberts S.J.,Rood D.H.,et al. Deglaciation of Pope Glacier implies widespread early Holocene ice sheet thinning in the Amundsen Sea sector of Antarctica[J]. Earth and Planetary Science Letters,2020-01-01,548