10Be and 26Al exposure ages for the sirius group at Mount Fleming, Mount Feather and Table Mountain and the plateau surface at Table Mountain (original) (raw)
Citation
Ivy-Ochs, S., Schlüchter, C., Prentice, M., Kubik, P. W., & Beer, J. (1997). 10Be and 26Al exposure ages for the sirius group at Mount Fleming, Mount Feather and Table Mountain and the plateau surface at Table Mountain. In C. A. Ricci (Ed.), The Antarctic region. Geological evolution and processes. Proceedings of the 7th international symposium on Antarctic earth sciences, Siena, 1995 (pp. 1153-1158). Terra Antarctica.
We have measured 10Be and 26Al concentrations in rock surfaces from several landscape elements in the Dry Valleys of Antarctica. These data have allowed us to determine minimum exposure ages and maximum erosion (down-wearing) rates for the surfaces investigated. Exposure ages are considered to be minimum ages because of the difficulty in constraining absolute erosion rates, boulder weathering out, shifting or splitting. The plateau surface carved into the Beacon Sandstone at Table Mountain formed prior to the early Pliocene, based on the exposure ages greater than 5.5 Ma. This bedrock surface has experienced down-wearing at a rate of no more than 30 cm/Ma since at least the Miocene/Pliocene boundary. Clasts on top of the Sirius Group deposit at Table Mountain indicate a minimum age of 2.9 Ma for this deposit. We have determined exposure ages for two other Sirius Group deposits in the Dry Valleys, at Mount Fleming two clasts yielded minimum exposure ages of 4.8 and 5 .8 Ma. A single embedded boulder from Mount Feather had a minimum age of 2.3 Ma. The low erosion rates combined with the old exposure ages from the Dry Valleys surfaces indicate a climate similar to today's in the Dry Valleys since or prior to the beginning of the Pliocene. Rapid uplift rates during the Quaternary must be discounted because of the high measured 10Be concentrations.
Details
Publication Type
Title
10Be and 26Al exposure ages for the sirius group at Mount Fleming, Mount Feather and Table Mountain and the plateau surface at Table Mountain
Author(s)
Ivy-Ochs, S.
Schlüchter, C.
Prentice, M.
Kubik, P.W.
Conference Proceedings
The Antarctic region. Geological evolution and processes. Proceedings of the 7th international symposium on Antarctic earth sciences, Siena, 1995
Editor(s)
Ricci, Carlo Alberto (editor)
Publisher
Terra Antarctica
Publication Place
Siena
Start Page
1153
End Page
1158
Publication Year
1997
Conference
7th international symposium on Antacrtic earth sciences
Conference Place
Siena
Conference Date
1995
Keywords
cosmogenic isotopes 10Be
26Al
Sirius Group
Dry Valleys
Antarctica