柴达木盆地西部新生代沉积特征及其对阿尔金断裂走滑活动的响应  

SEDIMENTARY FEATURES OF THE CENOZOIC IN THE WESTERN QAIDAM BASIN:RESPONSE TO STRIKE-SLIPPING OF THE ALTUN FAULT

作　　者：柳祖汉[1] 吴根耀[2] 杨孟达[1] 郭泽清[3] 温志峰[3] 

机构地区：[1]湖南科技大学地质研究所,湖南湘潭411201 [2]中国科学院地质与地球物理研究所,北京100029 [3]石油大学地球资源与信息学院,山东东营257061

出　　处：《地质科学》2006年第2期344-354,共11页Chinese Journal of Geology(Scientia Geologica Sinica)

摘　　要：柴达木盆地西部新生代沉积的发育受昆仑山(及青藏高原)崛起和阿尔金断裂的走滑活动控制。基于对该地新生界尤其是下油砂山组沉积环境的剖析,并与邻区的索尔库里北盆地进行对比,对阿尔金断裂的新生代的活动提出以下认识。1)古近纪为右行走滑,中新世起变为左行走滑,在盆地北缘伴随走滑发生的冲断作用,早期向北东扩展,晚期向南西扩展。2)阿尔金断裂的斜冲作用在始新世和上新世表现尤为明显,控制了下干柴沟组上段和狮子沟组异常高的沉积速率和沉积中心自西向东迁移。3)中新世是阿尔金断裂的松弛期,在次级北东向正断层的联合作用下可能在柴西形成拉分盆地,因而盆地发育特征明显不同于邻区的索尔库里北盆地。4)新近纪阿尔金断裂在左行走滑的大背景下经历了一个陆内的拉张—挤压旋回。The development of the Qaidam Basin in Cenozoic was coupled with two orogenic processes：the Neotethyan orogenics （the Kumlun mountain chains） and the shear-orogenics of the Altun fault. In the western part of Qaidam, the Altun fault played a more important role in the basin development. Based on a systematic description of the Cenozoic strata, an analysis of the carbonate-argillaceous rocks in the Xiayoushashan Formation and a comparison with the neighboring North Xorkol Basin, the following knowledges could be drawn. 1 ） The Altun fault was a dextral strike-slip fault in Paleogene, and become a sinistral one from Miocene. Correspondingly, the related thrusting of early generation （the latest Cretaceous-Eocene） in the northern margin of the basin expanded towards the northeast, and the thrusting of later generation （Pliocene-Pleistocene） expanded towards the southwest. 2）The oblique-thrusting occurred in Eocene and Pliocene respectively, which resulted in a high sedimentary ratio of the Upper Member of Xiaganchaigou Formation and the Shizigou Formation, and the sedimentary centers immigrating eastwards obviously during that time. 3 ）The Miocene might be a relaxation period of the Altun fault owing to collapse of the Neotethysides. Co-operated with the NE-striking normal faults, a pull-apart basin might be occurred in western Qaidam where the sediments were dominated by the carbonate-argillaceous rocks, obviously different from the sediments in the neighboring North Xorkol Basin. 4）The Altun fault experienced an intracontinental cycle of extension-compression during Neogene in a background of sinistral strike-slipping.

关 键 词：阿尔金断裂 右行走滑 左行走滑 沉积响应 柴达木盆地西部 新生代 

分 类 号：P548.2[天文地球—构造地质学] P542[天文地球—地质学]