Reconstructionof Asian monsoon using compound-specific isotope signals of terrestrial and aquativ biomarkers in Tibetan lake systems

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This project is part of a joint multiproxy research activity reconstructing the late Quaternary Monsoon dynamics on the Tibetan plateau. It uses stable isotopes (13C, 18O and D) to reconstruct the hydrology of individual lake systems and 14C to compare the timing of events in different lakes on the plateau. Latest compound-specific D and 14C technology using biomarkers are applied overcoming current limitations in palaeoclimate reconstruction. On the one hand δD values of aquatic and terrestrial biomarkers are applied to reconstruct monsoon intensity and climate, respectively. On the other hand compound-specific 14C values of terrestrial biomarkers will be used to establish an age sequence that is not affected by the variable reservoir effect of the lakes. Focal points of this proposal are reconstructions from the core Nam Co 08/01, which is the first core dates back to about 25 ka BP. We will firstly focus on the oldest and unknown part of the sequence followed by known events like 4k, 8k and the Younger Dryas. Secondly we will establish a valid age depth model that is not affected by the lake reservoir effect. Thirdly, we will participate in the retrieval of the new core at Tangra Yumco and collect necessary samples of plants, algae, soil and water for calibration studies. Based on all reconstructions of the joint research activity over the whole priority program for the first time the development of the monsoon extent over the Tibetan plateau can be reconstructed.