Glaciation history of Queen Maud Land (Antarctica) using in situ produced cosmogenic 10Be, 26Al and 21Ne


Glaciation history of Queen Maud Land (Antarctica) using in situ produced cosmogenic 10Be, 26Al and 21Ne

Altmaier, M.; Herpers, U.; Delisle, G.; Merchel, S.; Ott, U.

We have determined exposure ages of more than 50 quartz rich samples primarily from the Wohlthat Massiv / Queen Maud Land, Antarctica, via in situ produced 10Be (T1/2 = 1.51 Ma) and 26Al (T1/2 = 0.7 Ma) using accelerator mass spectrometry (AMS). Measured radionuclide concentrations vary from extremely low values up to saturation. For a scenario with extremely low erosion and minimal tectonic uplift 10Be and 26Al surface exposure ages are generally in good agreement. Long exposure ages up to >8 Ma were confirmed by measurement of stable 21Ne using noble gas mass spectrometry.
Our data call for a decisively higher ice stand in the Wohlthat Massiv / Queen Maud Land about 0.3 Ma ago, the ice level being 200 400 m higher than today. The following successive reduction of the glaciation down to the present level was essentially completed 0.1 Ma ago. Low level changes during the last glacial maximum occurred about 0.02 Ma ago and did affect only a region located close to the present shelf ice. As the extremely low erosion rates (<5 cm Ma-1) inferred for several samples can only exist under extremely cold and hyperarid conditions, we exclude a scenario featuring a prolonged period with warm and humid climatic conditions within the last 8 Ma.

Keywords: Antarctica; Queen Maud Land; landscape evolution; glaciation history; cosmogenic nuclides; AMS

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Publ.-Id: 12750