Has late Cenozoic climate change lead to enhanced erosion in the Kyrgyz and Chinese Tien Shan?

这项研究的一个基本问题和主要目的是破译气候和构造在山带演化中的相互作用，特别是晚新生代气候变化是否导致侵蚀加剧。我们建议用热年代学在吉尔吉斯和中国的天山验证这一假说。高温方法(磷灰石裂变径迹，锆石上的U-Th/He)将被用来确定几个范围的折返的开始和传播，然后将使用较低的温度方法(磷灰石上的U-Th/He)来测试这些地区在最后5 Ma是否经历了一次更强的折返事件。构造地质学和测绘将有助于确定掘尸的规模和机制。这将对晚新生代造山带的发展有一个全面的认识。确定这种年轻的构造运动脉冲在空间和时间上是同步的还是不同步的，并将这一记录与以前的历史进行比较，将有助于区分影响变形和隆升的构造和气候驱动因素。该项目的第二个目标是描述天山新生代构造生长的特征，天山是一个破碎的前陆，由基底隆起组成，分别类似于北美和南美的拉拉米德和Sierras Pampeas地貌构造省。目前，地震活动和缩短作用分布在整个造山带的宽度范围内，但缩短作用始于造山带南缘，并向北迁移。

A fundamental question and the primary goal of this study is deciphering the interplay of climate and tectonics in the evolution of mountain belts, in particular, whether late Cenozoic climate change has led to enhanced erosion. We propose to test this hypothesis in the Kyrgyz and Chinese Tien Shan using thermochronology. Higher temperature methods (apatite fission track, U-Th/He on zircon) will be used to establish the onset and propagation of exhumation of several ranges; lower temperature methods (U-Th/He on apatite) will then be used to test if these regions experienced an enhanced episode of exhumation in the last 5 Ma. Structural geology and mapping will aid in determining the magnitude and mechanisms of exhumation. This will provide a thorough understanding of the late Cenozoic development of the orogen. Determining whether such a young pulse of tectonism is spatially and temporally synchronous or asynchronous and comparing this record with the previous history will allow the differentiation between tectonic and climatic driving factors that influence deformation and uplift. The second goal of this project is to characterize the Cenozoic tectonic growth of the Tien Shan, a broken foreland comprised of basement uplifts akin to the North and South American Laramide and Sierras Pampeanas morphostructural provinces, respectively. At present, seismicity and shortening are distributed throughout the width of the orogen; however, shortening commenced on the southern margin of the mountain belt and migrated northwards.