Palaeoclimatology of Central Asia and the northeastern Tibetan Plateau on basis of compound-specific isotope analysis of biomarkers.

该项目初始阶段的目的是通过主要应用有机地球化学代用指标，建立至少可追溯到末次盛冰期的干旱中亚和东北青藏高原（NE-TP）的水文气候记录。在本提案提出之时，已在三个湖泊（中亚帕米尔的卡拉库尔湖;东北TP的东吉科纳湖;东北TP的哈拉胡湖）取得成功。陆地生物标志物的氢同位素数据表明，在晚冰期的季风在两个研究区的异步加强。北方半球快速气候事件的影响似乎更强的中亚相比，两个研究的湖泊对东北-TP。来自同位素全球环流模型的数据的整合证明，降水季节性变化是晚冰期中亚卡拉库尔湖流域观测到的大规模水文和生态变化背后的主要驱动因素。我计划对已经处理过的样品中的其他水生化合物（烯酮、不饱和脂肪族化合物）进行额外的dD测量。目标是破译湖水同位素和盐度的过去变化，根据已经分析的有机和无机代理，这还不清楚。此外，我的目标是分析B）更多的样本，以增加时间分辨率在全新世部分的哈拉湖沉积物芯和c）额外的化合物指示生物质燃烧（左旋葡聚糖）和温度（长链二醇）。这种多代理的方法结合了几个温度敏感的代理（烯酮，长链二醇）和火灾指标的目的是促进正在进行的讨论，如果社会文化行为的东北-TP，特别是解决高海拔地区，全新世冷事件的影响。(Part A）。此外，我建议进行化合物特定的放射性碳分析（CSRA）的至少6个选定的样品从中亚卡拉库尔湖及其集水区，以更好地了解陆地有机化合物的命运和潜在的滞后时间在运输到沉积物中的超干旱环境（B部分）。

The aim of the initial phase of this project was to establish hydroclimatic records from both arid Central Asia and the northeaster Tibetan Plateau (NE-TP) which reach back at least to the last glacial maximum, by applying mainly organic geochemical proxies. At the timing of this proposal this has been progressed successfully at three lakes (Lake Karakul, Pamir, Central Asia; Lake Donggi Cona, NE-TP; Lake Hala Hu, NE-TP). Hydrogen isotopic data of terrestrial biomarkers show an asynchronous intensification of monsoons during the late glacial in the two study areas. Impacts of Northern Hemispheric rapid climate events appear stronger in Central Asia compared to the two studied lakes on the NE-TP. Integration of data derived from isotope enabled global circulation models give evidence for changes in precipitation seasonality as a major driving factor behind the observed large scale hydrological and ecological changes in the catchment of central Asian Lake Karakul during the late glacial.Within the extension phase of the project, I´m planning to do a) additional dD measurements on additional compounds of aquatic origin in already processed samples (alkenones, unsaturated aliphatic compounds). The goal is to decipher past changes of lake water isotopes and salinities, which is yet unclear based on already analysed organic and inorganic proxies. Further I aim to analyse b) more samples to increase time-resolution in the Holocene section of the lake Hala Hu sediment core and c) additional compounds indicative for biomass burning (levoglucosan) and temperature (long-chain diols). This multiproxy approach combining several temperature sensitive proxies (alkenones, long-chain diols) and fire indicators aims to contribute to the ongoing discussion if socio-cultural behaviour on the NE-TP, specifically the settling of higher altitudes, was influenced by Holocene cold-events. (Part A). Further, I propose to conduct compound-specific-radiocarbon analysis (CSRA) of a minimum of 6 selected samples from central Asian Lake Karakul and its catchment to better understand the fate of terrestrial organic compounds and potential lag-times during their transport into the sediment in a hyperarid environment (Part B).