柴达木盆地英雄岭地区新生代构造演化动力学特征

Cenozoic dynamics characteristics of tectonic evolution in Yingxiongling(YL) area in Qaidam basin

通过分析柴达木盆地英雄岭 (YL)地区地质、2D/ 3D地震、遥感、重磁电和钻探等资料 ,提出了喜马拉雅运动几个阶段在该区的构造动力学响应特征。研究认为喜马拉雅运动晚期 ,英雄岭地区西南侧的阿卡腾能山因近SN向的区域挤压作用 ,产生了顺时针方向的旋转及隆升作用 ,从而在干柴沟一带形成了强烈的SE向局部挤压应力场 ,基底大幅隆升 ,而在英雄岭隆起的南侧则产生了局部的拉张构造环境。喜马拉雅山中期运动在该区的主要表现形式就是使古近纪的张扭构造环境转变为新近纪的坳陷构造环境 ,英雄岭西南的阿尔金地区发生隆升作用 ,沉积中心发生向东和向北的迁移。通过分析主干断裂、构造块体和沉积凹陷的分布特征等 ,得出喜马拉雅早期英雄岭及邻区发育局部拉张环境 ,为较为稳定的断陷湖盆发育期 ,沉积了一套优质烃源岩。英雄岭地区潜在勘探领域主要有构造裂缝型圈闭、地层岩性圈闭及渐新世断凸构造圈闭等。

The authors summarize the dynamic features of Himalaya stages in Yingxiong Ling Uplift(YL), west of Qaidam Basin,from integration of geology, 2D/3D seismic, remote sensing, gravity, aeromagnetic and well data. During the later stage of Himalayan orogeny, Aktenen mountain, a part of Altin Zone, in the west of YL Uplift rotated clockwise and uplifted because of SN regional compression, while a SE local compression stress field developed in Ganchaigou zone(middle part of west YL Uplift), which resulted in the basement uplifted rapidly. In the near southern area of YL, local extension tectonic stress field developed, and a Neogene-Quaternary lake formed. The middle stage movement of Himalaya orogeny transformed the paleogene transtensional tectonic setting into down-warping in West Qaidam basin. The Altyn mountains rised, sediment center migrated toward east and north. By analyzing the major faults, tectonic blocks and sediment depression distribution, the authors realize that the local extension tectonic setting developed, the stable fault basin formed, and fine source rocks developed in the YL and adjacent area. The perspective exploration targets include fracturing traps, stratigraphic traps and Oligocene epoch raised fault blocks in the study area.