Crust Shortening of the Daliangshan Tectonic Zone in the Cenozoic Era and Its Implications

The Daliangshan tectonic zone is a rhombic area to the east of the Anninghe and Zemuhe fault zones in the middle segment of the Xianshuihe-Xiaojiang fault system along the southeast margin of the Qinghai-Xizang (Tibet) Plateau. Since the Cenozoic era, the neotectonic deformation in the Daliangshan tectonic zone has presented not only sinistral slip and reverse faulting along the Daliangshan fault zone, but also proximate SN-trending crust shortening. It is estimated that the average crust shortening in the Daliangshan tectonic zone is 10.9±1.6 km, with a shortening rate of 17.8±2.2% using the method of balanced cross-sections. The crust shortening from folding occurred mainly in the Miocene and the Pliocene periods, lasting no more than 8.6 Ma. Based on this, a crust shortening velocity of 1.3±0.2 mm/a can be estimated. Compared with the left offset along the Daliangshan fault zone, it is recognized that crust shortening by folding plays an important part in transferring crustal deformation southeastward along the Xianshuihe-Xiaojiang fault system.

作 者： Chen Changyun He Honglin   作者單位： Chen Changyun(First Crust Monitoring and Application Center, CEA, Tianjin 300180, China;Institute of Geology, China Earthquake Administration, Beijing 100029, China)

He Honglin(Institute of Geology, China Earthquake Administration, Beijing 100029, China) 

刊 名： 中國地震研究(英文版)  英文刊名： EARTHQUAKE RESEARCH IN CHINA  年，卷(期)： 2009 23(1)  分類號： P3  關(guān)鍵詞： Daliangshan tectonic zone   Crust shortening   Tectonic deformation   Qinghai-Xizang (Tibet) Plateau