Ostracod‐based reconstruction of Late Quaternary lake level changes within the Tangra Yumco lake system (southern Tibetan Plateau)
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Date
2018-08
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Publisher
Journal of Quaternary Science
Abstract
Tangra Yumco, a large saline lake located in the central–southern part of the Tibetan Plateau, liesin a hydrologically closed basin and is part of a cascade lake system including Tangqung Co, Tangra Yumco andXuru Co. The extension and position of this lake system makes it valuable for reconstructing palaeoclimaticvariations through the lake history and to compare both with the adjacent lake systems. We reconstructed LateQuaternary lake level changes based on data from two lacustrine sediment cores. A micropalaeontologicalanalysis focusing on Ostracoda was carried out combined with dating (14C,210Pb,137Cs), sedimentology andstable isotope data from bulk sediment. Ostracod analysis involves the quantitative documentation ofassociations. An ostracod-based transfer function for specific conductivity was applied to assess and refine lakelevel changes and to compare the results with other lake level reconstructions from the Tibetan Plateau forevaluating inter-regional climatic patterns. Seven ostracod species were detected, withLeucocytherella sinensisdominating the associations followed byLeucocythere?dorsotuberosa,Limnocythere inopinataandTonnacyprisgyirongensis.Fabaeformiscandona gyirongensis,Candona candidaandCandona xizangensiswere found in onlya few samples and at low percentages. The synthesis of ostracod-based environmental reconstruction andchronology for samples from Tangra Yumco reveals the evolution of the lake system during the past 17 ka. A lowlake level around 17 cal kaBPis followed by a recovering until the reaching of a high stand around 8–9 cal kaBP.Subsequently, between 7.7 and 2.5 cal kaBP, it remained relatively stable with a subsequent short-livinglowstand–highstand cycle at around 2 ka. Thereafter, the ostracod-based conductivity transfer function shows anincrease of conductivity corresponding to a lake level rising phase at around 0.4 ka. The recorded changes areindicators of past climatic conditions and refine the palaeoclimatic models in this area.Copyright#2018 John Wiley & Sons, Ltd.