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”）是位于中亚中心的一个大型内排水湖。吉尔吉斯斯坦天山山脉、南边的特尔斯基阿拉套山脉（海拔 5216 m）和北边的贡吉阿拉套山脉和扎伊里阿拉套山脉（海拔 4973 m）之间的构造位置，解释了丰富的住宿空间，导致了约 100 亿人口的聚集。新生代晚期地层4公里。冰川范围超过 4000m，一个深且目前未充满的盆地内有一个约 670m 深的湖泊，GPS 测得的北部和南部山脉之间每年 5 毫米的缩短率，以及过去几 Ma 期间传播到盆地的活动变形，使这里成为研究中亚强侵蚀、沉积和构造信号之间关系的理想地点。同时，伊塞克湖位于西风水汽输送路径上，不受季风影响，因此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，破译伊塞克湖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。 该提案的重点是量化侵蚀率随时间的变化。我们的目标如下：（1）利用宇宙成因核素和古地磁方法在地层剖面上确定沉积年龄以及古侵蚀和沉积物积累速率。 (2) 使用已定年地层序列的稳定同位素分析重建古降水和植被模式。 (3) 编制伊塞克湖盆地的现有测井曲线，以量化盆地沉降，作为该地区构造记录的代理。借助这个综合数据库，我们将能够解决侵蚀率随时间的变化、湖盆在百万年时间尺度上的演变，并研究导致盆地内侵蚀、沉积和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.