EARLY PLIOCENE EXPANSION OF THE EAST ANTARCTIC ICE SHEET, UPPER WRIGHT VALLEY, ANTARCTICA
Whereas the glacial geomorphology of lower and central Wright Valley is reasonably well understood, the upper valley region, including the North and South Forks and the Dais, has received little attention. Our studies suggest that a wet-based glacier overrode the area and deposited what has been mapped elsewhere as the Peleus till. While we did not observe this silt-rich till in the Labyrinth, it occurs on the Dais and in protected areas of the North and South Forks. Most importantly, our findings imply that the Wright Upper Glacier, an outlet glacier of the East Antarctic Ice Sheet, deposited lateral moraines and lateral-moraine segments along the north and south walls of both the North and South Forks following deposition of the Peleus till. We argue that this drift is correlative with Taylor IVa drift in central Taylor Valley and Alpine III drift in central Wright Valley, based on landscape features, surface-boulder weathering, soil development, and stratigraphy. The presence of meltwater channels, outwash, kame moraines, esker-like features, and kames suggests that ice-marginal or supraglacial water may have accompanied this glaciation.
Document Type: Research Article
Affiliations: 1: Department of Soil Science and Gaylord Nelson Institute for Environmental Studies, University of Wisconsin, USA, Email: [email protected] 2: Landcare Research, Hamilton, New Zealand, Email: [email protected]
Publication date: 2008-09-01