Rheological Regime of the Upper Mantle beneath the Taiwan Strait and Its Tectonic Significance

作     者：H.W.GreenⅡ 

作者机构：U яivetsity of CaliforniaRiuersideC A 92521U.S.A. 

出 版 物：《Acta Geologica Sinica(English Edition)》 (地质学报（英文版）)

年 卷 期：1995年第69卷第3期

页      面：259-271,340页

核心收录：

学科分类：070704[理学-海洋地质] 0709[理学-地质学] 07[理学] 0707[理学-海洋科学] 

基　　金：This study was supported mainly by China National Natural Science Foundation Grant No.4880126 partly by U.S. National Science Foundation Grant INT-8612713 

主　　题：mantle-derived xenolith high-temperature creep rheology of the upper mantle rifting Penghu Islands 

摘      要：This paper deals with deformation textures and fabrics of mantle-derived xenoliths and dislocation microstructures of olivine in the upper mantle in the Penghu Islands, Taiwan. According to the calculation of the chemical composition of xenolith minerals (pyroxene), the equilibrium temperatures and pressures were 986-1116@ and 1.50-2.60 GPa, respectively. Deformation events in the upper mantle may fall into three sequences (1) uniform steady-state flow deformation with high temperatures and low stresses, (2) shear flow deformation with high temperatures and relatively high stresses on diapiric margins of the upper mantle, and (3) extraction deformation of {110} glide bands with low temperatures and high strain rates. Deformation events and thermal structure of the upper mantle in the study area show that eastern Fujian and the Penghu Islands are characterized by very similar rheological properties of the upper mantle. Volcanism of basalts in the Penghu Islands is related to hot spots of the upper mantle under neath the Taiwan Strait, and diapirism and upwelling of the upper mantle are the dominant factors responsible for rifting of the continental margins in eastern China.