How does/did the Tibetan Plateau grow? Geologic-geophysical research in NE-Tibet

印度-亚洲大陆-大陆碰撞形成了地球上最高的山脉(喜马拉雅)和最大的高原(帕米尔-西藏)，并使中亚和东亚的大片地区(如天山)变形。高原东北段是研究大型断裂/剪切带(如昆仑、阿尔金)的活动碰撞构造、地壳增厚和侧向挤压的原型，这些带容纳了最近的8.1级地震。作为对地壳增厚的反应，高原的表面隆起影响了欧亚大陆的气候。结合地质-构造-热年代学和主动、被动地震观测手段，详细阐明了藏东北地区的地壳和上地幔结构。我们的目的是评估沿哪些大型变形带完成了地壳增厚，沿着东北-西藏原有的缝合带是否发生了活动的陆内俯冲，以及下地壳流是否是高原显著的增厚和抬升机制。该项目将与美国和中国的科学家密切合作执行。结合其他地球物理(如美国大地电磁)和地质调查，我们的工作将推动对碰撞构造的整体理解。

The India-Asia continent-continent collision is responsible for the highest mountain range (Himalaya) and the largest plateau (Pamir-Tibet) on Earth and deforms large regions of Central and Eastern Asia (e.g. Tien Shan). The NE part of the plateau is the archetype for studies of active collisional tectonics, crustal thickening, and lateral extrusion along large-scale fault/shear zones (e.g. Kunlun, Altyn Tagh); these zones accommodated Recent Ms <8.1 earthquakes. Surface uplift of the plateau as a response to crustal thickening influences the climate of Eurasia. Combining geologic-tectonic-thermochronologic and active and passive seismic observation tools, we will elucidate in detail the structure of the crust and upper mantle in NE-Tibet. Our aim is to evaluate along which of the large-scale deformation zones crustal thickening was/is accomplished, whether active intra-continental subduction occurs along the pre-existing sutures in NE-Tibet, and whether lower crustal flow is a significant thickening and uplift mechanism for the plateau. The project will be executed in close cooperation with US and Chinese scientists. Integrating other geophysical (e.g. US magnetotellurics) and geologic investigations, our work will push ahead the overall understanding of collisional tectonics.