Geomorphological evidence and cosmogenic 10Be/26Al exposure ages for the Last Glacial Maximum and deglaciation of the Antarctic Peninsula Ice Sheet

2006 ◽  
Vol 118 (9-10) ◽  
pp. 1149-1159 ◽  
Author(s):  
M. J. Bentley ◽  
C. J. Fogwill ◽  
P. W. Kubik ◽  
D. E. Sugden
Keyword(s):  
Last Glacial Maximum ◽  
Antarctic Peninsula ◽  
Ice Sheet ◽  
Glacial Maximum ◽  
Last Glacial ◽  
Cosmogenic 10Be ◽  
The Antarctic ◽  
Exposure Ages ◽  
The Last Glacial Maximum ◽  
The Last Glacial

scholarly journals Reconstruction of ice-sheet changes in the Antarctic Peninsula since the Last Glacial Maximum

2014 ◽  
Vol 100 ◽  
pp. 87-110 ◽  
Author(s):  
Colm Ó Cofaigh ◽  
Bethan J. Davies ◽  
Stephen J. Livingstone ◽  
James A. Smith ◽  
Joanne S. Johnson ◽  
...  
Keyword(s):  
Last Glacial Maximum ◽  
Antarctic Peninsula ◽  
Ice Sheet ◽  
Glacial Maximum ◽  
Last Glacial ◽  
The Antarctic ◽  
The Last Glacial Maximum ◽  
The Last Glacial

The deglacial history of NW Alexander Island, Antarctica, from surface exposure dating

2012 ◽  
Vol 77 (2) ◽  
pp. 273-280 ◽  
Author(s):  
Joanne S. Johnson ◽  
Jeremy D. Everest ◽  
Philip T. Leat ◽  
Nicholas R. Golledge ◽  
Dylan H. Rood ◽  
...  
Keyword(s):  
Last Glacial Maximum ◽  
Antarctic Peninsula ◽  
Ice Sheet ◽  
Glacial Maximum ◽  
Ice Shelf ◽  
Last Glacial ◽  
Ice Cap ◽  
The Antarctic ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Recent changes along the margins of the Antarctic Peninsula, such as the collapse of the Wilkins Ice Shelf, have highlighted the effects of climatic warming on the Antarctic Peninsula Ice Sheet (APIS). However, such changes must be viewed in a long-term (millennial-scale) context if we are to understand their significance for future stability of the Antarctic ice sheets. To address this, we present nine new cosmogenic 10Be exposure ages from sites on NW Alexander Island and Rothschild Island (adjacent to the Wilkins Ice Shelf) that provide constraints on the timing of thinning of the Alexander Island ice cap since the last glacial maximum. All but one of the 10Be ages are in the range 10.2–21.7 ka, showing a general trend of progressive ice-sheet thinning since at least 22 ka until 10 ka. The data also provide a minimum estimate (490 m) for ice-cap thickness on NW Alexander Island at the last glacial maximum. Cosmogenic 3He ages from a rare occurrence of mantle xenoliths on Rothschild Island yield variable ages up to 46 ka, probably reflecting exhumation by periglacial processes.

scholarly journals Reconstruction of changes in the Weddell Sea sector of the Antarctic Ice Sheet since the Last Glacial Maximum

2014 ◽  
Vol 100 ◽  
pp. 111-136 ◽  
Author(s):  
Claus-Dieter Hillenbrand ◽  
Michael J. Bentley ◽  
Travis D. Stolldorf ◽  
Andrew S. Hein ◽  
Gerhard Kuhn ◽  
...  
Keyword(s):  
Last Glacial Maximum ◽  
Ice Sheet ◽  
Glacial Maximum ◽  
Weddell Sea ◽  
Antarctic Ice Sheet ◽  
Last Glacial ◽  
The Antarctic ◽  
The Last Glacial Maximum ◽  
The Last Glacial

scholarly journals Glacial geomorphology and cosmogenic 10Be and 26Al exposure ages in the northern Dufek Massif, Weddell Sea embayment, Antarctica

2012 ◽  
Vol 24 (4) ◽  
pp. 377-394 ◽  
Author(s):  
Dominic A. Hodgson ◽  
Michael J. Bentley ◽  
Christoph Schnabel ◽  
Andreas Cziferszky ◽  
Peter Fretwell ◽  
...  
Keyword(s):  
Last Glacial Maximum ◽  
Ice Sheet ◽  
Glacial Maximum ◽  
Weddell Sea ◽  
Glacial Geomorphology ◽  
Last Glacial ◽  
Exposure Dating ◽  
Exposure Ages ◽  
The Last Glacial Maximum ◽  
The Last Glacial

AbstractWe studied the glacial geomorphology and geochronology of two ice-free valleys in the Dufek Massif (Antarctic Specially Protected Area 119) providing new constraints on past ice sheet thickness in the Weddell Sea embayment. 10Be and 26Al cosmogenic surface exposure dating provided chronological control. Seven glacial stages are proposed. These include an alpine glaciation, with subsequent (mid-Miocene?) over-riding by a warm-based ice sheet. Subsequent advances are marked by a series of minor drift deposits at 760 m altitude at > 1 Ma, followed by at least two later ice sheet advances that are characterized by extensive drift sheet deposition. An advance of plateau ice field outlet glaciers from the south postdated these drift sheets. The most recent advance involved the cold-based expansion of the ice sheet from the north at the Last Glacial Maximum, or earlier, which deposited a series of bouldery moraines during its retreat. This suggests at most a relatively modest expansion of the ice sheet and outlet glaciers dominated by a lateral ice expansion of just 2–3 km and maintaining a thickness similar to that of the northern ice sheet front. These observations are consistent with other reports of modest ice sheet thickening around the Weddell Sea embayment during the Last Glacial Maximum.

The Antarctic Ice Sheet during the Last Glacial Maximum and its subsequent retreat history: a review

2002 ◽  
Vol 21 (1-3) ◽  
pp. 49-70 ◽  
Author(s):  
John B Anderson ◽  
Stephanie S Shipp ◽  
Ashley L Lowe ◽  
Julia Smith Wellner ◽  
Amanda B Mosola
Keyword(s):  
Last Glacial Maximum ◽  
Ice Sheet ◽  
Glacial Maximum ◽  
Antarctic Ice Sheet ◽  
Last Glacial ◽  
The Antarctic ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Glacial and marine geological evidence for the ice sheet configuration in the Weddell Sea–Antarctic Peninsula region during the Last Glacial Maximum

1998 ◽  
Vol 10 (3) ◽  
pp. 309-325 ◽  
Author(s):  
Michael J. Bentley ◽  
John B. Anderson
Keyword(s):  
Last Glacial Maximum ◽  
Antarctic Peninsula ◽  
Ice Sheet ◽  
Weddell Sea ◽  
Antarctic Ice Sheet ◽  
Geological Evidence ◽  
Last Glacial ◽  
The Antarctic ◽  
The Last Glacial Maximum ◽  
The Last Glacial

The Weddell Sea region arguably represents the largest unknown in quantifying the Antarctic contribution to the global water balance following the Last Glacial Maximum (LGM). This paper reviews the available onshore and offshore geological evidence constraining the volume of formerly expanded ice in the Weddell Sea embayment, focusing on the West Antarctic Ice Sheet (WAIS) and provides a preliminary reconstruction of the WAIS during the LGM. Dating control is generally poor and so our WAIS reconstruction is based on the assumption that the evidence of most recent ice sheet expansion dates to the LGM. Our reconstruction is intended to provide initial constraints with which glaciological models can be compared and shows grounded ice extent, flow directions, and ice surface elevations. Both marine and terrestrial geological evidence imply a substantial expansion of ice in the Weddell Sea embayment. Marine evidence shows that ice sheets were grounded in Crary Trough in the southern Weddell Sea and on the Antarctic Peninsula continental shelf during the LGM. Inland, the ice thickened by between 400 m (Ellsworth and Palmer Land) and 1900 m (Ellsworth Mountains). Ice core evidence suggests that the interior of the ice sheet remained the same or even thinned relative to present. The main unknowns now concern the exact location of the grounding line on some sectors of the shelf and the timing of ice sheet grounding and retreat. The limited radiocarbon data that exist on the eastern shelf indicates that the East Antarctic Ice Sheet retreated from the shelf prior to the LGM.

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