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Climate variability in the past ∼19,000 yr in NE Tibetan Plateau inferred from biomarker and stable isotope records of Lake Donggi Cona

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dc.contributor Háskóli Íslands
dc.contributor University of Iceland
dc.contributor.author Saini, Jeetendra
dc.contributor.author Günther, Franziska
dc.contributor.author Aichner, Bernhard
dc.contributor.author Mischke, Steffen
dc.contributor.author Herzschuh, Ulrike
dc.contributor.author Zhang, Chengjun
dc.contributor.author Mäusbacher, Roland
dc.contributor.author Gleixner, Gerd
dc.date.accessioned 2018-03-12T13:45:20Z
dc.date.available 2018-03-12T13:45:20Z
dc.date.issued 2017-02
dc.identifier.citation Saini, J., Günther, F., Aichner, B., Mischke, S., Herzschuh, U., Zhang, C., . . . Gleixner, G. (2017). Climate variability in the past ∼19,000 yr in NE Tibetan Plateau inferred from biomarker and stable isotope records of Lake Donggi Cona. Quaternary Science Reviews, 157, 129-140. doi:https://doi.org/10.1016/j.quascirev.2016.12.023
dc.identifier.issn 0277-3791
dc.identifier.uri https://hdl.handle.net/20.500.11815/622
dc.description.abstract We investigated 4.84-m-long sediment record spanning over the Late Glacial and Holocene from Lake Donggi Cona to be able to reconstruct circulation pattern on the Tibetan Plateau (TP). Presently, Lake Donggi Cona is located at the boundaries of Westerlies and Asian monsoon circulations in the northeastern TP. However, the exact timing and stimulating mechanisms for climatic changes and monsoon shifts in this region are still debated. We used a 19-ka-long stable isotope record of sedimentary n-alkanes to address this discrepancy by providing insights into paleohydrological conditions. The δD of nC23 is influenced by lake water evaporation; the δD values of sedimentary nC29 are mainly controlled by moisture source and temperature changes. Long-chain n-alkanes dominate over the core whereas three mean clusters (i.e. microbial, aquatic and terrestrial) can be inferred. Multi-proxies suggest five major episodes in the history of Lake Donggi Cona. The Lake Donggi Cona record indicates that the Late Glacial (18.4–14.8 cal ka BP) was dominated by low productivity of mainly microbial and aquatic organisms. Relatively low δD values suggest low temperatures and moist conditions eventually caused by stronger Westerlies, winter monsoon and melt-water influence. Likely, the shift (∼17.9 cal ka BP) from microbial to enhanced aquatic input suggests either a change from deep to shallow water lake or a break in local stratification. Between 14.8 and 13.0 cal ka BP, variable climatic conditions prevailed. Although the Westerlies weekend, the increase in temperature enhanced the permafrost and snow melting (displayed by a high sedimentary accumulation rate). Higher δD values indicate increasingly arid conditions with higher temperatures which eventually lead to high evaporative conditions and lowest lake levels. Low vegetation cover and high erosion rates led to high sediment accumulation resulting in stratification followed by anoxia in the terminal lake. From 13.0 to 9.2 cal ka BP, lowered values of δD along with high contents of terrestrial organic matter marked the early-Holocene warming indicating a further strengthening of summer precipitation and higher lake levels. A cooling trend was observed in the mid-Holocene between 9.2 and 3.0 cal ka BP accompanied by higher moisture availability (displayed by lowered δD values) caused by reduced evaporative conditions due to a drop in temperature and recovering Westerlies. After 3.0 cal ka BP, a decrease in lake productivity and cold and semi-arid conditions prevailed suggesting lower lake levels and reduced moisture from recycled air masses and Westerlies. We propose that the summer monsoon was the predominant moisture source during the Bølling-Allerød warm complex and early-Holocene followed by Westerlies in mid-to-late Holocene period. Stable carbon isotope values ∼ - 32‰ indicate the absence of C4-type vegetation in the region contradicting with their presence in the Lake Qinghai record. The δD record from lake Donggi Cona highlights the importance of the interplay between Westerlies and summer monsoon circulation at this location, which is highly dynamic in northeastern plateau compared to the North Atlantic circulation and insolation changes. Consequently lake Donggi Cona might be an important anchor point for environmental reconstructions on the Tibetan Plateau.
dc.description.sponsorship We would like to thank German Research Foundation (DFG) for funding within the priority program 1372 “Tibetan Plateau: Formation – Climate – Ecosystems (TiP)” and of project Ai 134/2–1, GL 262/16. This study is a joint cooperation with the Institute of Tibetan Plateau Research. We also want to thank Roman Witt, Steffen Rühlow and Elisabeth Dietze for assistance, MPI for Biogeochemistry, IMPRS gBGC and Institute of Geography, FSU-Jena for additional project funding in the framework of the TiP.
dc.format.extent 129-140
dc.language.iso en
dc.publisher Elsevier BV
dc.relation.ispartofseries Quaternary Science Reviews;157
dc.rights info:eu-repo/semantics/openAccess
dc.subject n-alkanes
dc.subject Hydrogen isotopes (δD)
dc.subject Carbon isotopes (δ13C)
dc.subject Carbon preference index (CPI)
dc.subject Westerlies
dc.subject Continental air masses
dc.subject Precipitation
dc.subject Late Glacial and Holocene
dc.subject Jarðefni
dc.subject Loftslag
dc.subject Ísöld
dc.subject Nýlífsöld
dc.title Climate variability in the past ∼19,000 yr in NE Tibetan Plateau inferred from biomarker and stable isotope records of Lake Donggi Cona
dc.type info:eu-repo/semantics/article
dcterms.license This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
dc.description.version Peer Reviewed
dc.identifier.journal Quaternary Science Reviews
dc.identifier.doi 10.1016/j.quascirev.2016.12.023
dc.contributor.department Jarðvísindadeild (HÍ)
dc.contributor.department Faculty of Earth Sciences (UI)
dc.contributor.school Verkfræði- og náttúruvísindasvið (HÍ)
dc.contributor.school School of Engineering and Natural Sciences (UI)

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