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在阐述区域地质基础上,开展了研究区始新世—中新世事件地层学的研究,并建立了其事件地层系统,识别出5种事件面、8种事件带、6种事件组合和1个事件集群。事件面有隆升事件面、岩相转换事件面、洪泛事件面、生物灭绝事件面、气候转换(波动)事件面;根据地质事件的纵向发育特征,建立了暖热事件带、温凉事件带、δ18O高值事件带、δ18O低值事件带、挤压断陷事件带、走滑断陷事件带、湖盆扩张事件带和湖盆收缩事件带等,其中,暖热事件与δ18O低值事件、温凉事件与δ18O高值事件、地壳隆升与不整合事件、气候波动与生物灭绝事件均具有成因联系,它们分别构成了一个事件组合;所有事件组合构成了该时期的事件集群。上述事件带中,挤压断陷事件带、走滑断陷与湖盆扩张事件带以及湖泊收缩事件带体现了柴达木盆地西部的演化过程,而且这个演化过程与青藏高原的隆升密不可分。由于印度大陆与欧亚大陆的碰撞、拼合与俯冲挤压,促使青藏高原不断隆升和一系列喜山运动(共四幕)的产生,同时导致了研究区始新世—中新世事件集群的发生。
On the basis of expatiating on regional geology, the study on stratigraphy of Eocene-Miocene events in the study area was carried out and its event stratigraphic system was established. Five kinds of event surface, eight event bands, six event combinations and 1 Cluster of events There are uplift event surface, lithofacies conversion event surface, flood event surface, biological extinction event surface and climate change (fluctuation) event surface. According to the longitudinal development characteristics of geological events, warm event zone, warm event Δ18O high value event belt, δ18O low value event belt, squeezed faulting event belt, strike-slip faulting belt, lacustrine basin expansion event belt and lake basin shrinkage event zone. Among them, the warm event is associated with a low δ18O value Events, warm-cold events and δ18O high events, uplift and unconformity events of the earth’s crust, climate fluctuations and biological extinction events are all causally related to each other, and they constitute an event combination; all event combinations constitute the event cluster during this period. In the above events, the evolution of crustal fault zone, strike-slip faulting zone and lacustrine expansion event zone as well as the shrinkage zone of lakes reflect the western Qaidam basin, and the evolution is inextricably linked with the uplift of the Qinghai-Tibet Plateau . Due to the collisions, subduction and subduction of the Indian continent with Eurasia, the continuous uplift of the Tibetan Plateau and the occurrence of a series of Himalayan movements (a total of four scenes) resulted in the production of the Eocene-Miocene event cluster happened.