Changes in paleo-erosion rates, and interactions between erosion, deposition and deformation in the Issyk Kul basin, Kyrgyzstan

• Applicants: Professor Dr. Stuart Alan Gilder; Professor Edward Sobel, Ph.D.
• Subject Area: Palaeontology
• Term: from 2015 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 273969534

Issyk Kul (literally 'Hot Lake') is a large, presently internally-drained lake in the heart of Central Asia. The structural position between mountain ranges belonging to the Kyrgyz Tien Shan, the Terskey Alatau (up to 5216 m) on the south and the Kungey and Zaili Alatau (up to 4973 m) on the north, explains the abundant accommodation space which has lead to the accumulation of ca. 4 km of strata during the late Cenozoic. The combination of glaciated ranges exceeding 4000m, a deep, presently underfilled basin hosting an ~670m deep lake, geodetic GPS-derived shortening rates of 5 mm/yr between the northern and southern ranges, and active deformation which has propagated into the basin during the past several Ma make this is an ideal location to study relationships between the strong erosional, depositional and tectonic signals in Central Asia. At the same time its position in the path of Westerly moisture transport, outside the monsoon influence, makes Issyk Kul an important target for climatic research. Indeed, the 2011 ICDP Workshop held in Kyrgyzstan noted that deciphering the timing and mechanism of formation of the Issyk Kul basin is important for understanding the evolution of Lake Issyk. This proposal focuses on quantifying how erosion rates have changed over time. Our goals are as follows: (1) Determine depositional ages and paleo-erosion and sediment accumulation rates using cosmogenic nuclide and paleomagnetic methods on stratigraphic sections. (2) Reconstruct paleo-precipitation and -vegetation patterns using stable isotopic analyses from dated stratigraphic sequences. (3) Compile existing well logs from the Issyk Kul basin to quantify basin subsidence as a proxy for the tectonic record of the region. With this combined database, we will be able to address changes in erosion rates over time, the evolution of the lake basin over the million year time scale, and examine interactions between the forces responsible for erosion, deposition, and the migration of deformation within the basin.

• DFG Programme: Research Grants