TY  - JOUR
A1  - Mischke, Steffen
A1  - Lai, Zhongping
A1  - Aichner, Bernhard
A1  - Heinecke, Liv
A1  - Mahmoudov, Zafar
A1  - Kuessner, Marie
A1  - Herzschuh, Ulrike
T1  - Radiocarbon and optically stimulated luminescence dating of sediments from Lake Karakul, Tajikistan
JF  - Quaternary geochronology : the international research and review journal on advances in quaternary dating techniques
N2  - Lake Karakul in the eastern Pamirs is a large and closed-basin lake in a partly glaciated catchment. Two parallel sediment cores were collected from 12 m water depth. The cores were correlated using XRF analysis and dated using radiocarbon and OSL techniques. The age results of the two dating methods are generally in agreement. The correlated composite core of 12.26 m length represents continuous accumulation of sediments in the lake basin since 31 ka. The lake reservoir effect (LRE) remained relatively constant over this period. High sediment accumulation rates (SedARs) were recorded before 23 ka and after 6.5 ka. The relatively close position of the coring location near the eastern shore of the lake implies that high SedARs resulted from low lake levels. Thus, high SedARs and lower lake levels before 23 ka probably reflect cold and dry climate conditions that inhibited the arrival of moist air at high elevation in the eastern Pamirs. Low lake levels after 6.5 ka were probably caused by declining temperatures after the warmer early Holocene, which had caused a reduction in water resources stored as snow, ice and frozen ground in the catchment. Low SedARs during 23-6.5 ka suggest increased lake levels in Lake Karakul. A short-lived increase of SedARs at 15 ka probably corresponds to the rapid melting of glaciers in the Karakul catchment during the Greenland Interstadial le, shortly after glaciers in the catchment had reached their maximum extents. The sediment cores from Lake Karakul represent an important climate archive with robust chronology for the last glacial interglacial cycle from Central Asia. (C) 2017 Elsevier B.V. All rights reserved.
KW  - Radiocarbon and OSL dating
KW  - Lake sediments
KW  - Pamir mountains
KW  - Late pleistocene
KW  - Holocene
Y1  - 2017
U6  - https://doi.org/10.1016/j.quageo.2017.05.008
SN  - 1871-1014
SN  - 1878-0350
VL  - 41
SP  - 51
EP  - 61
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Heinecke, Liv
A1  - Mischke, Steffen
A1  - Adler, Karsten
A1  - Barth, Anja
A1  - Biskaborn, Boris
A1  - Plessen, Birgit
A1  - Nitze, Ingmar
A1  - Kuhn, Gerhard
A1  - Rajabov, Ilhomjon
A1  - Herzschuh, Ulrike
T1  - Climatic and limnological changes at Lake Karakul (Tajikistan) during the last similar to 29 cal ka
JF  - Journal of paleolimnolog
N2  - We present results of analyses on a sediment core from Lake Karakul, located in the eastern Pamir Mountains, Tajikistan. The core spans the last similar to 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 TiO2 (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, TOCBr), redox potential (Fe/Mn) and changes in the endogenic carbonate precipitation (TIC, delta(18) OCarb) indicate changes within the lake. Low productivity characterised the lake from the late Pleistocene until 6.6 cal ka BP, and 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.
KW  - Arid Central Asia
KW  - Pamir Mountains
KW  - Lake sediments
KW  - XRF data
KW  - Grain-size end-member modelling
KW  - Geochemistry
Y1  - 2017
U6  - https://doi.org/10.1007/s10933-017-9980-0
SN  - 0921-2728
SN  - 1573-0417
VL  - 58
SP  - 317
EP  - 334
PB  - Springer
CY  - Dordrecht
ER  -