Miocene paleoclimate evolution of Central Asia reconstructed from lacustrine successions in SE Kazakhstan

在新生代期间，中亚大陆的荒漠化加剧，季风气候形成。这些大陆尺度的气候变化与青藏高原等山脉的隆起、副特提斯的最终退缩和南中国海的扩张有关。人们对这种气候变化相对于全球气候演变的时间以及区域和全球因素在这一过程中的相互作用还知之甚少。该项目旨在根据哈萨克斯坦东南部湖泊演替的特殊暴露，从轨道到构造时间尺度重建中亚中中新世气候动态。作为第一个交付成果，我们将建立两个部分（阿克套山和金字塔谷）的轨道和磁性地层，并将它们与地磁极性时标相关联。这将为作为第二个主要交付成果进行的古环境和古气候重建提供所需的年代控制。特别是，我们打算研究的来源和时间增加的水分供应在中亚中中新世相对于天山的隆起和海平面变化在东副特提斯。

Continental settings of Central Asia witnessed increased desertification and the establishment of a monsoonal climate during the Cenozoic. These continental-scale climate shifts are connected to the uplift of mountain ranges such as the Tibetan plateau, the final retreat of the Paratethys and the expansion of the South China Sea. The timing of this climatic change relative to global climate evolution and the interplay between regional and global factors in this process are yet poorly understood. This project aims at reconstructing Middle Miocene climate dynamics in Central Asia from orbital to tectonic time scales based on exceptional exposures of lacustrine successions in SE-Kazakhstan. As a first deliverable, we will establish orbital and magnetic stratigraphies for two sections (Aktau Hills and Pyramid Valley) and correlate them to the Geomagnetic Polarity Time Scale. This will provide the age control required for paleoenvironmental and paleoclimatic reconstructions to be carried out as the second main deliverable. In particular, we intend to study the source and timing of increased moisture supply in Central Asia during the Middle Miocene relatively to the uplift of the Tien Shan and sea-level change in the Eastern Paratethys.