Dating Late-Cenozoic erosional surfaces in Victoria Land, Antarctica, with cosmogenic Neon in Pyroxenes

• Published in: Antarctic Science
• Main Authors: OBERHOLZER P, BAUR H, WIELER R., BARONI, CARLO, SALVATORE, MARIA CRISTINA
• Other Authors: Oberholzer, P, Baroni, Carlo, Salvatore, MARIA CRISTINA, Baur, H, Wieler, R.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2008
• Subjects: Antarctic tor; Antarctic Gargoyl; East Antarctic Ice Sheet; EAIS; surface exposure dating; Noble gase; Mesa Range; Prince Albert Mountain; Victoria Land; Antarctica; Antarctic; Victoria; Polar Plateau; Prince Albert Mountains; Antarc*; Ice Sheet; Ice Shelf
• Online Access: http://hdl.handle.net/11568/204643; https://doi.org/10.1017/S095410200700079X

We present 21Ne exposure ages of erosional glaciogenic rock surfaces on nunataks in northern Victoria Land, Antarctica: i) in the Prince Albert Mountains and ii) near Mesa Range. These nunataks are located directly at the margin of the polar plateau and therefore provide an immediate record of ice volume changes of the East Antarctic Ice Sheet, not biased by ice shelf grounding or narrow valley sections downstream the outlet glaciers. The sampling locations overlook the present ice surface by less than 200 m, but were last covered by ice 3.5 Ma BP (minimum age, not corrected for erosion). This strongly indicates that the ice sheet has not been substantially thicker than today since at least the early Pliocene, which supports the hypothesis of a stable East Antarctic Ice Sheet. First absolute ages are reported for the alpine topography above the erosive trimline that typically marks the upper limit of glacial activity in northern Victoria Land. Unexpectedly low nuclide concentrations suggest that erosion rates on the alpine topography are considerably higher due to the steep slopes than those affecting flat erosional surfaces carrying Antarctic tors.