Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hambrey, M. J. Articles by Krissek, L. A. Search for Related Content GeoRef GeoRef Citation

Neogene glacial record from the Sirius Group of the Shackleton Glacier region, central Transantarctic Mountains, Antarctica

Michael J. Hambrey^,1, Peter-Noel Webb^,2, David M. Harwood^,3 and Lawrence A. Krissek^,4

¹ Centre for Glaciology, Institute of Geography and Earth Sciences, University of Wales, Aberystwyth SY23 3DB, UK
² Department of Geological Sciences and Byrd Polar Research Center, Ohio State University, Columbus, Ohio 43210, USA
³ Department of Geosciences, University of Nebraska, Lincoln, Nebraska 68588-0340, USA
⁴ Department of Geological Sciences and Byrd Polar Research Center, Ohio State University, Columbus, Ohio 43210, USA

Neogene glacigenic strata, collectively referred to as the Sirius Group, are widely distributed throughout the Transantarctic Mountains. The group is particularly well exposed near the head of Shackleton Glacier (85°10' to 85°40'S) on Roberts Massif and at Bennett Platform. These deposits are critical for examining the nature of former ice flow from the East Antarctic Ice Sheet into the Ross Embayment. The Sirius Group rests on a glacially grooved and striated pavement named herein the "Shackleton erosion surface." The sub–Sirius Group surface on Roberts Massif was of low relief, and glaciogenic sediment was deposited on it as a sheet of uniform thickness. At Bennett Platform, stratigraphic sections attain a thickness of 110 m thick and are subdivided into the Shackleton Glacier Formation (maximum thickness 98 m) and the overlying Bennett Platform Formation (44 m), separated by an unconformity. A third, older, lithified diamictite containing wood fragments occurs as clasts within these formations and as boulders in the modern lateral moraines of Shackleton Glacier. The dominant facies, massive diamict, is interpreted primarily as lodgement till. Other facies indicate glaciofluvial and glaciolacustrine deposition. Facies associations suggest deposition either by sliding temperate or by polythermal glaciers, under much warmer conditions than those of today. Widespread large- and small-scale faulting has affected the Sirius Group and underlying rocks to the extent that inland exposures are over 500 m higher than those to the north, over a distance of 30 km. Thus, at the time of deposition of the Sirius Group, the mountains were probably lower, and the ice sheet was much thinner.

Key Words: Neogene • glacial record • Sirius Group • Antarctica • Shackleton Glacier • Transantarctic Mountains

This article has been cited by other articles:

				M. J. Hambrey and J. L. Smellie Distribution, lithofacies and environmental context of Neogene glacial sequences on James Ross and Vega islands, Antarctic Peninsula Geological Society, London, Special Publications, January 1, 2006; 258(1): 187 - 200. [Abstract] [PDF]

				D. J.A. Evans Glaciers Progress in Physical Geography, June 1, 2004; 28(2): 294 - 305. [PDF]