青藏高原现今岩石圈的三维应变

Present three-dimension deformation of the lithosphere in Qinghai-Tibet Plateau

根据质量守恒原理,建立恒定体积条件下青藏高原岩石圈三维应变计算模型,模型以GPS资料提供的水平位移速率作为地表的边界约束。计算结果表明,青藏高原现今岩石圈的变形仍以南北向挤压缩短增厚为主,东西向伸展吸收的南北缩短量<30%。高原岩石圈深部的变形总体遵循粘滞性应变模型。综合层析成像资料和钾质、过碱性钾质火山作用的时空分布规律,提出岩石圈脉动增厚-减薄的高原隆升机制。

Based on the mass conversation law the model for the constant volume is setup to simulate the three-dimension deformation of lithosphere in Qinghai-Tibet Plateau. The horizontal displacements provided by GPS data act as boundary constraints on the earth surface in the model. The simulant results show that the main part of tectonic deformations in the plateau are shortening in N-S direction and vertical thickening of the lithosphere, and the shortened magnitude in N-S direction compensated by E-W direction stretch is less than 30%. The deformations of the lithosphere of the plateau followed a viscidity strain model. According to tomography data and the spatio-temporal distribution regularities of the potassic and peralkalic potassic volcanism, a model is proposed that the plateau uplift maybe derive from pulsed thickening-thinning of the lithosphere.