Cosmogenic nuclide exposure age constraints on the glacial history and biogeography of the Lake Wellman area, Darwin Mountains, Antarctica.

• Published in: Antarctic Science
• Main Authors: Storey, B. C., Fink, D., Hood, D., Joy, K., Shulmeister, J., Riger-Kusk, M., Stevens, M. I.
• Other Authors: Megan R. Balks, Ed Butler, Shulamit Gordon, Clive Howard-Williams
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press 2010
• Subjects: Cosmogenic Exposure Dating; Last Glacial Maximum; Latitudinal Gradient Project; Ice-sheet; 1105 Ecology; Evolution; Behavior and Systematics; 1907 Geology; 1910 Oceanography; Ross Ice Shelf; Transantarctic Mountains; Wellman; Darwin Mountains; Hatherton Glacier; Antarc*; Antarctica; Ice Sheet; Ice Shelf
• Online Access: https://espace.library.uq.edu.au/view/UQ:224075

We present direct terrestrial evidence of ice volume change of the Darwin and Hatherton glaciers which channel ice from the Transantarctic Mountains into the Ross Ice Shelf. Combining glacial geomorphology with cosmogenic exposure ages from 25 erratics indicates a pre-LGM ice volume at least 600m thicker than current Hatherton ice elevation was established at least 2.2 million years ago. In particular, five erratics spread across a drift deposit at intermediate elevations located below a prominent moraine feature mapped previously as demarcating the LGM ice advance limits, give a well-constrained single population with mean 10 Be age of 37.0 +/- 5.5 ka (1 sigma). At lower elevations of 50-100m above the surface of Lake Wellman, a further five samples from within a younger drift deposit range in exposure age from 1 to 19 ka. Our preferred age model interpretation, which is partly dependent on the selection of a minimum or maximum age-elevation model, suggests that LGM ice volume was not as large as previously estimated and constrains LGM ice elevation to be within +/-50 m of the modern Hatherton Glacier ice surface, effectively little different from what is observed today.