Age determination and bulk geochemistry of sediment core KK12-1, Lake Karakul, Tajikistan in 2012

DOI

We present results of analyses on a sediment core from Lake Karakul, located in the eastern Pamir Mountains, Tajikistan. The core spans the last ~29 cal ka. We investigated and assessed processes internal and external to the lake to infer changes in past moisture availability. Among the variables used to infer lake-external processes, high values of grain-size end-member (EM) 3 (wide grain-size distribution that reflects fluvial input) and high Sr/Rb and Zr/Rb ratios (coinciding with coarse grain sizes), are indicative of moister conditions. High values in EM1, EM2 (peaks of small grain sizes that reflect long-distance dust transport or fine, glacially derived clastic input) and TiO 2 (terrigenous input) are thought to reflect greater influence of dry air masses, most likely of Westerly origin. High input of dust from distant sources, beginning before the Last Glacial Maximum (LGM) and continuing to the late glacial, reflects the influence of dry Westerlies, whereas peaks in fluvial input suggest increased moisture availability. The early to early-middle Holocene is characterised by coarse mean grain sizes, indicating constant, high fluvial input and moister conditions in the region. A steady increase in terrigenous dust and a decrease in fluvial input from 6.6 cal ka BP onwards points to the Westerlies as the predominant atmospheric circulation through to present, and marks a return to drier and even arid conditions in the area. Proxies for productivity (TOC, TOC/TN, TOC Br ), redox potential (Fe/Mn) and changes in the endogenic carbonate precipitation (TIC, d18 O) indicate changes within the lake. Low productivity characterised the lake from the late Pleistocene until 6.6 cal ka BP, but productivity increased rapidly afterwards. Lake level remained low until the LGM, but water depth increased to a maximum during the late glacial and remained high into the early Holocene. Subsequently, the water level decreased to its present stage. Today the lake system is mainly climatically controlled, but the depositional regime is also driven by internal limnogeological processes.

Supplement to: Heinecke, Liv; Mischke, Steffen; Adler, Karsten; Barth, Anja; Biskaborn, Boris K; Plessen, Birgit; Nitze, Ingmar; Kuhn, Gerhard; Rajabov, Ilhomjon; Herzschuh, Ulrike (2017): Climatic and limnological changes at Lake Karakul (Tajikistan) during the last ~29 cal ka. Journal of Paleolimnology, 58(3), 317-334

Identifier
DOI https://doi.org/10.1594/PANGAEA.876024
Related Identifier IsSupplementTo https://doi.org/10.1007/s10933-017-9980-0
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.876024
Provenance
Creator Heinecke, Liv ORCID logo; Mischke, Steffen ORCID logo; Adler, Karsten; Barth, Anja; Biskaborn, Boris K ORCID logo; Plessen, Birgit ORCID logo; Nitze, Ingmar ORCID logo; Kuhn, Gerhard ORCID logo; Rajabov, Ilhomjon; Herzschuh, Ulrike ORCID logo
Publisher PANGAEA
Publication Year 2017
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Resource Type Supplementary Publication Series of Datasets; Collection
Format application/zip
Size 2 datasets
Discipline Earth System Research
Spatial Coverage (73.533 LON, 39.018 LAT)