Holocene environmental changes and development of Figurnoye Lake in the southern Bunger Hills, East Antarctica |
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| Authors: | Sergey R Verkulich Martin Melles Hans-Wolfgang Hubberten Zinaida V Pushina |
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| Institution: | (1) Arctic and Antarctic Research Institute, The State Scientific Center, 199397 St. Petersburg, Russia;(2) Research Unit Potsdam, Alfred Wegener Institute for Polar and Marine Research, D-14473 Potsdam, Germany;(3) Russian Research Institute for Oceanology and Mineral Resources, 190121 St. Petersburg, Russia |
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| Abstract: | The lithology, radiocarbon chronology, granulometry, geochemistry and distribution of diatoms were investigated in three sediment cores from fresh-water Figurnoye Lake in the southern Bunger Hills, East Antarctica. Our paleolimnological data provide a record of Holocene environmental changes for this region. In the early Holocene (prior to 9.0 ± 0.5 kyr BP), warm climate conditions caused intensive melting of either the floating glacier ice mass or glaciers in the immediate lake surroundings, leading to the accumulation of terrigenous clastic sediments and limiting biogenic production in the lake. From ca. 9.0 ± 0.5 to 5.5 ± 0.5 kyr BP, highly biogenic sediments dominated by benthic mosses formed, indicating more distal glaciers or snowfields. A relatively cold and dry climate during this period caused weaker lake-water circulation and, likely, occurrence of lake ice conditions were more severe than present. The distribution of marine diatoms in the cores shows that, sometime between 8 and 5 kyr BP, limited amounts of marine water episodically penetrated to the lake, requiring a relative sea-level rise exceeding 10–11 m. During the last ca. 5.5 ± 0.5 kyr BP, sedimentation of mainly biogenic matter with a dominance of laminated microbial mats occurred in the lake under warm climatic conditions, interrupted by relative coolings: the first one around 2 kyr BP and then shortly before recent time. Between ca. 5.5 and 4 kyr BP, the drainage of numerous ice-dammed lakes took place in the southern Bunger Hills and, as a result, drier landscapes have existed here from about 4 kyr BP. |
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| Keywords: | Antarctic oasis Diatoms Holocene paleoenvironments Lake sediments Radiocarbon dating Sediment composition |
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