摘要：

在大量的区域地质调研和野外露头观测资料基础上，详细研究了西藏羌塘盆地东部中生代不同构造单元的沉积充填序列、地层发育特征与接触关系、构造界面性质、沉积体系配置和沉积相分布等，阐述了盆地沉积与周缘构造带演化之间的耦合关系，重建了研究区中生代不同时期的构造古地理面貌。研究表明，羌塘盆地是一个大型叠复式盆地，盆地东部中生代有海相、海陆过渡相和陆相3个沉积体系组、9个沉积体系和多个沉积（亚）相。盆地内部包括南羌塘坳陷、北羌塘坳陷、唐古拉山隆起带，以及不同时期的次级凸起与断凹等构造单元。其中，多玛断凹是以前石炭纪构造片岩为基底的侏罗纪—早白垩世早期被动大陆边缘陆表海盆地，早白垩世晚期转换为前陆盆地，晚白垩世以来与索县—左贡断凹联合为一体，在陆内造山过程中经历了压陷型盆地充填演化阶段。索县—左贡断凹是在晚三叠世班公湖—怒江沟-弧-盆体系基础上发展起来的前陆盆地。北羌塘坳陷是以华力西期开心岭—杂多隆起带为基底，经过晚三叠世昌都前陆盆地沉积、早侏罗世断陷盆地火山—沉积作用之后，于中侏罗世与索县—左贡断凹联合为一体，形成北羌塘—昌都巨型坳陷型盆地。白垩纪北羌塘陆块和昌都陆块处于隆升剥蚀状态。

Abstract:

The Qiangtang Basin in Tibet is a largescaled multisuperimposed sedimentary basin. Based on the plentiful data of regional geology and field outcrop observations， detailed researches have been carried out on  the characteristics of different tectonic units of the Mesozoic in the Qiangtang Basin， such as sedimentary filling sequences， stratigraphic development and contacting relationship， properties of structural boundaries， sedimentary systems and facies distribution et al. The coupling relationship between  basin deposition and evolution of adjacent orogenic belts was investigated， and the tectonopalaeogeography in different periods of the Mesozoic were reconstructed in the study area. The researches show that the Mesozoic in the eastern Qiangtang Basin comprised of three sedimentary system sets， nine sedimentary systems and numerous sedimentary(subfacies)facies respectively belonging to marine facies, transitional facies from marine to continental facies and continental facies. There are many tectonic units， for example， North Qiangtang Depression， South Qiangtang Depression， Tanggula Mountains uplifting belt， and some subsalients， faulted sags and uplifts in different stages of the Mesozoic  in the eastern Qiangtang Basin. The Duoma Faulted Sag  is an epicontinental margin basin，located on the passive continental margin， which has a basement of the Precarboniferous tectonic schists， and was superimposed by the Jurassic Early Cretaceous sedimentationLater， during the Early Cretaceous， it transformed into a foreland basin， and since the Late Cretaceous， it has been connected with the SuoxianZuogong Faulted Sag. Totally， during the intracontinental orogenic processes， it experienced multiple compressiondepression evolution of sedimentary filling. The SuoxianZuogong Faulted Sag  is a foreland basin developed during the Late Triassic  based on the trougharcoceanic system. The North Qiangtang Depression was developed based on the Varician KaixinlingZaduo uplift， and followed by the Late Triassic Changdu foreland basin，as well as the Early Jurassic North Qiangtang Faulted Sag volcanicsedimentary basin. During the Middle Jurassic，the North Qiangtang and SuoxianZuogong depressions were combined as a multidepressional basin， and a huge Qiangtang Changdu Depression was formed. The North Qiangtang land block and Changdu land block were uplifted and experienced uplifting and exposure during the Cretaceous.