Luminescence dating of shoreline sediments indicates a late deglacial lake-level rise of Selin Co on the central Tibetan Plateau |
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| Institution: | 1. State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences (NIGLAS), Nanjing, 210008, China;2. School of Geography, Nanjing Normal University, Key Laboratory of Virtual Geographic Environment, Ministry of Education, Nanjing, 210046, China;3. Qinghai Province Key Laboratory of Physical Geography and Environmental Process, College of Geographical Science, Qinghai Normal University, Xining, 810008, China;4. Academy of Plateau Science and Sustainability, People''s Government of Qinghai Province and Beijing Normal University, Xining, 810016, China;5. University of Chinese Academy of Sciences, Beijing, 100049, China;6. State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China;7. School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China |
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| Abstract: | The palaeo-shorelines around the lakes on the Tibetan Plateau can be used to reconstruct water level variations, which serve as sensitive indicators of hydroclimate change. Extensive studies have been carried out to constrain the Holocene lake level fluctuations by dating shorelines with a variety of methods (e.g., luminescence, 14C, 10Be and U–Th series). In comparison, the timing of the lake level variations during the last glacial and subsequent deglaciation periods has been rarely studied. The driving factors of such changes, therefore, remain elusive. In this study, we performed a detailed luminescence dating investigation on six samples taken from a nearshore sedimentary outcrop in the south of Selin Co basin. The post-IR IRSL signals measured at 225 °C (pIRIR225) on sand-sized K-feldspar grains demonstrated a generally good behavior and yielded reliable chronologies, while the optically stimulated luminescence (OSL) signals of quartz showed systematical age underestimation, which was attributed to anomalous fading. Six pIRIR225 ages ranging from 15 to 10 ka suggested that the lake level of Selin Co during the last deglaciation reached up to 40–45 m high above the modern lake level. In view of the regional precipitation and temperature proxy records, we consider that the glacier meltwater supply has likely been the primary contributor to the lake highstands during the last deglaciation. |
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| Keywords: | Luminescence dating Selin Co Last deglaciation Lake highstand Glacier meltwater |
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