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

中亚大陆在新生代期间荒漠化加剧，并形成季风气候。这些大陆尺度的气候变化与青藏高原等山脉的隆起、帕拉提斯山脉的最终撤退和南中国海的扩张有关。这种气候变化相对于全球气候演变的时间，以及这一过程中区域和全球因素之间的相互作用，目前还知之甚少。该项目旨在根据哈萨克斯坦东南部湖泊序列的异常暴露，从轨道到构造的时间尺度重建中亚中中新世的气候动力学。作为第一个成果，我们将建立两个区段(阿克陶丘陵和金字塔山谷)的轨道和磁性地层学，并将它们与地磁极性时间尺度相关联。这将为作为第二个主要成果进行的古环境和古气候重建提供所需的年龄控制。特别是，我们打算研究中亚在中中新世期间相对于天山抬升和东太平洋海平面变化而增加水分供应的来源和时间。

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.