Early to mid-Holocene lake high-stand sediments at Lake Donggi Cona, northeastern Tibetan Plateau, China

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• 作者：Elisabeth Dietze^a ; ^{edietze@gfz-potsdam.de} ; Bernd Wü ; nnemann^a ; ^b ; Kai Hartmann^a ; Bernhard Diekmann^c ; Huijun Jin^e ; Georg Stauch^d ; Sizhong Yang^e ; Frank Lehmkuhl^d
• 关键词：Lake level fluctuations ; Lake high-stand sediment ; End-member modeling (EMMA) ; Grain size distributions ; Tibetan Plateau ; Asian monsoon
• 刊名：Quaternary Research
• 出版年：2013
• 出版时间：May, 2013
• 年：2013
• 卷：79
• 期：3
• 页码：325-336
• 全文大小：3464 K

文摘

Lake high-stand sediments are found in three onshore terraces at Lake Donggi Cona, northeastern Tibetan Plateau, and reveal characteristics of hydrological changes on lake shorelines triggered by climate change, geomorphological processes, and neo-tectonic movements. The terraces consist of fluvial-alluvial to littoral-lacustrine facies. End-member modeling of grain-size distributions allowed quantification of sediment transport processes and relative lake levels during times of deposition. Radiocarbon dating revealed higher than modern lake levels during the early and mid Holocene. Lake levels follow the trend of Asian monsoon dynamics, and are modified by local non-climatic drivers. Site-specific impacts explain fluctuations during the initial lake-level rise ~ 11 cal ka BP. Maximum lake extension reached ~ 9.2 cal ka BP, at ~ 16.5 m above present lake level (a.p.l.l.). Littoral and lacustrine sediment deposition paused during a phase of fluvial activity and post-depositional cryoturbations at ~ 8.5 cal ka BP, when the lake level fell to ~ 8 m a.p.l.l. After a second maximum at ~ 7.5 cal ka BP, lake level declined slightly at ~ 6.8 cal ka BP, probably due to a non-climatic pulse that caused lake opening. The level remained high until a transition towards drier conditions ~ 4.7 cal ka BP. Though discontinuous, high-stand sediments provide a unique, high-resolution archive.