阿尔金断裂昌马大坝-宽滩山段全新世活动特征  

Study on the Activity of the Changmadaba-Kuangtanshan Segment of Eastern Altyn Tagh Fault During Holocene Epoch

作　　者：陈柏林[1] 刘建生[2] 王春宇[1] 张永双[1] 刘建民[1] 董诚[1] 吴乃芬[1] 

机构地区：[1]中国地质科学院地质力学研究所,北京100081 [2]中国地震局兰州地震研究所,兰州730000

出　　处：《地质学报》2008年第4期433-440,共8页Acta Geologica Sinica

基　　金：中国地质调查局地质调查项目(编号水[2003]018-02);国家重点基础研究发展计划项目(编号2007CB411305)资助的成果

摘　　要：阿尔金断裂是我国西部著名的巨型走滑断裂带之一，也是全新世活动断裂和发震断裂。该断裂昌马大坝一宽滩山段运动方式为以左行走滑占主导，伴有弱的垂直运动；在距今2．7ka以来发生过明显的新构造活动（和地震）。在沙坪-宽滩山段全新世左行走滑位移速率为0．9～2．2mm／a，明显低于阿尔金断裂东段昌马大坝以西地区4～5mm／a和中西段9～11mm／a的位移速率。阿尔金断裂东段在肃北和昌马大坝出现二次位移速率的锐减，锐减的部分分别转化为海原活动断裂西段（党河南山断裂）和祁连山北缘活动断裂西段的左行走滑和逆冲，且在位移速率数值上相互之间具有非常好的对应性。阿尔金断裂在肃北位移速率减少部分（4．6mm／a）与海原活动断裂西段（党河南山断裂）的位移速率（4～5mm／a）非常接近，同样阿尔金断裂在昌马大坝位移速率减少部分（3．2mm／a）与祁连山北缘活动断裂的位移速率（3．0mm／a）也非常接近。Altyn tagh fault, as one of large strike-slip faults in western China, is an active and causative fault during Holocene epoch. The Changmadaba-Kuantanshan segment of the Altyn tagh fault was dominated by sinistral slip accompanied a slightly vertical displacement, and no new, distinct tectonic activity or earthquake has taken place since 2. 7 ka. The displacement rate of the segment is 0. 9 - 2. 2mm/a, obviously lower than that （4-5mm/a） in the western section and that （9-11mm/a） in the central west section of the Changmadaba-kuantanshan segment, east of the Altyn tagh fault. The rate of the second displacement occurring in Subei and Changmadaba to the east of the fault decreased greatly; part of the decreased rate was transferred to sinistral slip and overthrusting in the west of the Haiyuan active fault, i. e. the Danghenanshan fault, and in the west segment of the active fault along the north margin of the Qilianshan, respectively; both rates correspond to each other perfectly. The reduced part （4.6mm/a） of the displacement rate in the Subei segment of the Altyn tagh fault is close to that （4~5mm/a） in the west Haiyuan active fault （Danghenanshan fault）. Similarly, the reduced part （3.2mm/a） of the displacement rate in the Changmadaba segment of the Altyn tagh fault is close to that （about 3.0mm/a ） in the northern margin fault of Qilianshan mountains.

关 键 词：全新世 位移转换 阿尔金断裂 昌马大坝-宽滩山段 甘肃 

分 类 号：P542[天文地球—构造地质学]