Fluctuation history of the interior East Antarctic Ice Sheet since mid-Pliocene.

Cosmogenic Be-10 and Al-26 measurements from bedrock exposures in East Antarctica provide indications of how long the rock surface has been free from glacial cover. Samples from the crests of Zakharoff Ridge and Mount Harding, two typical nunataks in the Grove Mountains, show minimum Be-10 ages of 2...

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Bibliographic Details
Published in:Antarctic Science
Main Authors: Huang, F, Liu, XH, Kong, P, Fink, D, Ju, Y, Fang, A, Yu, L, Li, X, Na, C
Format: Article in Journal/Newspaper
Language:English
Published: Cambridge University Press 2008
Subjects:
Fluctuations
Antarctic Regions
Ice
Pliocene Epoch
Rock Beds
Mountains
Antarctic
East Antarctic Ice Sheet
East Antarctica
Grove Mountains
Harding
Mount Harding
Zakharoff Ridge
Antarc*
Antarctic Science
Antarctica
Ice Sheet
Online Access:http://apo.ansto.gov.au/dspace/handle/10238/1256
https://doi.org/10.1017/S0954102007000910
Description
Summary:Cosmogenic Be-10 and Al-26 measurements from bedrock exposures in East Antarctica provide indications of how long the rock surface has been free from glacial cover. Samples from the crests of Zakharoff Ridge and Mount Harding, two typical nunataks in the Grove Mountains, show minimum Be-10 ages of 2.00 +/- 0.22 and 2.30 +/- 0.26 Ma, respectively. These ages suggest that the crests were above the ice sheet at least since the Plio -Pleistocene boundary. Adopting a 'reasonable' erosion rate of 5-10 cm Ma(-1) increases the exposure ages of these two samples to extend into the mid-Pliocene. The bedrock exposure ages steadily decrease with decreasing elevation on the two nunataks, which indicates similar to 200 m decrease of the ice sheet in the Grove Mountains since mid-Pliocene time. Seven higher elevation samples exhibit a simple exposure history, which indicates that the ice sheet in the Grove Mountains decreased only similar to 100 in over a period as long as 1-2 Ma. This suggests that the East Antarctic Ice Sheet (EAIS) was relatively stable during the Pliocene warm interval. Five lower elevation samples suggest a complex exposure history, and indicate that the maximum subsequent increase of the EAIS was only 100 in higher than the present ice surface. Considering the uncertainties, their total initial exposure and subsequent burial time could be later than mid-Pliocene, which may not conflict with the stable mid-Pliocene scenario. © 2008, Cambridge University Press

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