Cretaceous-Earliest Tertiary Basin Development, Deformation, and Magmatism in Southern Tibet: Implications for Pre-Indo-Asian Collision Lithospheric Structure

大陆碰撞造山带在碰撞事件之前是如何受到沿着会聚边缘作用的构造过程的预处理的？ 作为碰撞造山带原型的青藏高原是研究这一问题的理想天然实验室，因为它记录了碰撞前的安第斯式弧相关构造以及新生代的碰撞构造。 青藏高原演化的一般模型开始时，对影响模型结果的地壳厚度和地幔结构的初始条件作了假设。 然而，地质支持这些假设是稀缺的。 该研究整合了西藏南部拉萨地体广泛暴露的白垩纪和第三纪最早盆地充填物和火成岩的地质填图以及构造、地层、沉积学和地质年代学研究，为碰撞前的应变历史、盆地发展提供新的约束。古地理、剥蚀和岩浆活动。 我们希望，这些新的约束与以前的研究的整合将导致一个统一的构造模型，提供了现实的初始条件的岩石圈结构的藏南地区之前，印度-亚洲碰撞。 研究结果对中亚新生代造山作用模式以及碰撞造山作用具有广泛的意义。

How are continental collisional orogens preconditioned by tectonic processes that operate along convergent margins prior to the collisional events? The Tibetan plateau, which is generally accepted as the archetype of collisional orogens, is a perfect natural laboratory to study this question because it contains a record of pre-collisional, Andean-style arc-related tectonics as well as collisional tectonics during the Cenozoic. General models for Tibetan Plateau evolution begin with assumptions of initial conditions for crustal thickness and mantle structure that strongly influence the results of the models. However, geological support for these assumptions is scarce. This study is integrating geologic mapping and structural, stratigraphic, sedimentologic, and geochronologic studies of widely exposed Cretaceous and earliest Tertiary basin fill and igneous rocks in the Lhasa terrane of southern Tibet to provide new constraints on the pre-collisional history of strain, basin development, paleogeography, denudation, and magmatism. It is hoped that integration of these new constraints with previous studies will lead to a unified tectonic model that provides realistic initial conditions for the lithospheric structure of southern Tibet prior to the Indo-Asian collision. The results should have broad implications for models of Cenozoic orogeny in central Asia, as well as collisional orogenesis in general.