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

伊塞克湖（字面意思是“热湖”）是一个位于中亚中心的大型内排湖泊。南部的吉尔吉斯天山和Terskey Alatau（海拔5216米）以及北部的Kungey和Zaili Alatau（海拔4973米）山脉之间的构造位置解释了丰富的容纳空间，导致晚新生代沉积了约4公里的地层。超过4000米的冰川山脉、一个深约670米深的未填满盆地、南北山脉之间由gps测量得出的5毫米/年的缩短速度，以及在过去几个世纪中传播到盆地的活动变形，这些因素的结合使这里成为研究中亚强烈侵蚀、沉积和构造信号之间关系的理想地点。同时，它位于西风水汽输送路径上，不受季风影响，使伊塞克库成为气候研究的重要目标。事实上，2011年在吉尔吉斯斯坦举行的ICDP研讨会指出，破译伊塞克库尔盆地形成的时间和机制对于理解伊塞克湖的演化非常重要。这个建议的重点是量化侵蚀率如何随时间变化。我们的目标是：(1)利用宇宙核素和古地磁方法在地层剖面上确定沉积年龄和古侵蚀沉积速率。(2)利用年代地层序列的稳定同位素分析重建古降水和植被格局。(3)编制Issyk Kul盆地现有测井资料，量化盆地沉降，作为该地区构造记录的代表。有了这个综合数据库，我们将能够解决随着时间的推移侵蚀率的变化，湖盆在百万年时间尺度上的演变，并检查负责侵蚀，沉积和盆地内变形迁移的力量之间的相互作用。

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.