TY - JOUR
T1 - Meteoric Be-10 from Sirius Group suggests high elevation McMurdo Dry Valleys permanently frozen since 6 Ma
AU - Dickinson, Warren W.
AU - Schiller, Martin
AU - Ditchburn, Bob G.
AU - Graham, Ian J.
AU - Zondervan, Albert
PY - 2012/1/1
Y1 - 2012/1/1
N2 - A long-standing debate concerning Neogene Antarctic climate in the McMurdo Dry Valleys relies largely on evidence from landscape evolution, glacial modeling and stratigraphy. We provide new evidence from meteoric 10Be for the onset of frozen, hyper-arid conditions on a high elevation (1840m) interfluve at Table Mountain. A simple decay model for the co-occurrence of meteoric 10Be and illuviated clay in cores of ice-cemented glacial sediments indicates that the clays were actively migrating down from the surface in a warm climate until the system froze between 6 and 9Ma. Although this age range may be sensitive to possible interference by in situ produced 10Be, the implied minimum age of 6Ma for the Sirius Group indicates that the Dry Valleys were permanently frozen down to this elevation at this time. The model also suggests denudation rates of 1-6cmMyr-1 since freezing. These data provide an independent test of glacial-stratigraphic evidence used to determine Antarctic paleoclimate.
AB - A long-standing debate concerning Neogene Antarctic climate in the McMurdo Dry Valleys relies largely on evidence from landscape evolution, glacial modeling and stratigraphy. We provide new evidence from meteoric 10Be for the onset of frozen, hyper-arid conditions on a high elevation (1840m) interfluve at Table Mountain. A simple decay model for the co-occurrence of meteoric 10Be and illuviated clay in cores of ice-cemented glacial sediments indicates that the clays were actively migrating down from the surface in a warm climate until the system froze between 6 and 9Ma. Although this age range may be sensitive to possible interference by in situ produced 10Be, the implied minimum age of 6Ma for the Sirius Group indicates that the Dry Valleys were permanently frozen down to this elevation at this time. The model also suggests denudation rates of 1-6cmMyr-1 since freezing. These data provide an independent test of glacial-stratigraphic evidence used to determine Antarctic paleoclimate.
UR - http://www.scopus.com/inward/record.url?scp=84867127335&partnerID=8YFLogxK
U2 - 10.1016/j.epsl.2012.09.003
DO - 10.1016/j.epsl.2012.09.003
M3 - Journal article
AN - SCOPUS:84867127335
SN - 0012-821X
VL - 355-356
SP - 13
EP - 19
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
ER -