Minimum Bedrock Exposure Ages and Their Implications: Larsemann Hills and Neighboring Bolingen Islands, East Antarctica |
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| Authors: | HUANG Feixin LI Guangwei LIU Xiaohan KONG Ping JU Yitai David FINK FANG Aimin YU Liangjun |
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| Institution: | [1]Institute of Mineral Resources Research, China Metallurgical Geology Bureau, Beijing 100025, China [2]Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China [3]Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China [4]Australian Nuclear Science and Technology Organization, Menai, NSW 2234, Australia [5]Graduate University of the Chinese Academy of Sciences, Beijing 100049, China |
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| Abstract: | Considerable controversy exists over whether or not extensive glaciation occurred during the global Last Glacial Maximum (LGM) in the Larsemann Hills. In this study we use the in situ produced cosmogenic nuclide 10Be (half life 1.51 Ma) to provide minimum exposure ages for six bedrock samples and one erratic boulder in order to determine the last period of deglaciation in the Larsemann Hills and on the neighboring Bolingen Islands. Three bedrock samples taken from Friendship Mountain (the highest peak on the Mirror Peninsula, Larsemann Hills; -2 km from the ice sheet) have minimum exposure ages ranging from 40.0 to 44.7 ka. The erratic boulder from Peak 106 (just at the edge of the ice sheet) has a younger minimum exposure age of only 8.8 ka. The minimum exposure ages for two bedrock samples from Blundell Peak (the highest peak on Stornes Peninsula, Larsemann Hills; ～2 km from the ice sheet) are about 17 and 18 ka. On the Bolingen Islands (southwest to the Larsemann Hills; ～10 km from the ice sheet), the minimum exposure age for one bedrock sample is similar to that at Friendship Mountain (i.e., 44 ka). Our results indicate that the bedrock exposure in the Larsemann Hills and on the neighboring Bolingen Islands commenced obviously before the global LGM (i.e., 20-22 ka), and the bedrock erosion rates at the Antarctic coast areas may be obviously higher than in the interior land. |
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| Keywords: | east Antarctica Larsemann Hills Bolingen Islands 10Be exposure age erosion rate |
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