气候变化领域集成服务门户(CCPortal): Age determination and bulk geochemistry of sediment core KK12-1, Lake Karakul, Tajikistan in 2012

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DOI	https://doi.org/10.1594/PANGAEA.876024
	Age determination and bulk geochemistry of sediment core KK12-1, Lake Karakul, Tajikistan in 2012
	Heinecke; Liv; Mischke; Steffen; Adler; Karsten; Barth; Anja; Biskaborn; Boris K; Plessen; Birgit; Nitze; Ingmar; Kuhn; Gerhard; Rajabov; Ilhomjon; Herzschuh; Ulrike
发布日期	2017-06-08
数据集类型	dataset
英文简介	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.
空间范围	Latitude: 39.017600 * Longitude: 73.532750
时间范围	2012-04-22T00:00:00 - 2012-04-22T00:00:00
语种	英语
国家	国际
学科大类	气候变化
学科子类	气候变化
文献类型	数据集
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/215322
推荐引用方式 GB/T 7714	Heinecke,Liv,Mischke,et al. Age determination and bulk geochemistry of sediment core KK12-1, Lake Karakul, Tajikistan in 2012.2017-06-08.https://doi.org/10.1594/PANGAEA.876024.