青藏高原递进式隆升的力学模式

根据青藏高原现代构造变形的GPS速度场、高原区喜马拉雅山等五大山脉之间的几何关系,及其在地貌构造上的褶皱结构特点、岩石圈的分层特征,提出在印度板块的推挤作用下,青藏高原具有递进式隆升特征的观点。在此基础上,建立了地壳层递进式弯曲隆升的力学模型,并利用FLAC有限差分法数值模拟软件,近似采用平面应变条件,模拟了在水平推力作用下,地壳层递进式挤压弯曲隆升的过程。根据所建立的力学模型和数值模拟结果认为,青藏高原隆升的主要动力源是印度板块北北东方向的推挤力,地壳层依照自南而北的次序逐步产生一系列弯曲隆起,从平面、剖面上均具有密切的时序因果关系;高原隆升与活动构造的发育、分布具有密切关系,断裂活动强度自南向北递进式扩展。

MECHANICS MODEL OF PROGRESSIVE UPLIFT OF QINGHAI- TIBET PLATEAU

On the basis of GPS velocity field of contemporary tectonic deformation, geometric correlation between Mt. Himalaya, Gangdese- Nyainqentanglha Range, Tanggula Shan, Kunlun Shan and Qilian Shan, morphostructure features of these mountains and layered structures of lithosphere in Qinghai - Tibet Plateau, a new point of view has been put forward, holding that the uplift of Qinghai - Tibet Plateau is progressive under the Indian Plate, which serves to push Qinghai - Xizang Plate northwards. Based on this cognition, the mechanics model of progressive bending and uplifting of crust has been established. Based on approximate plane strain conditions and by using the finite difference numerical analysis software - FLAC -2D, the process of sequential compressing, bending, folding and uplifting of crust under horizontal force was simulated. The result suggests that the main power - source for the plateau uplift is the driving and compressing of Indian plate toward NNE, and, a series of folding and uplifting of the crust successively appears from the south to the north, demonstrating a kind of sequence and consequence on the plane and section of Qinghai - Tibet Plateau. The uplift of Qinghai - Tibet Plateau resulted from the development and distribution of active tectonic zones.