柴达木盆地大柴旦地区盆地中新生代演化机制电性特征分析

柴达木盆地位于青海省西北部，是在昆仑山、阿尔金山和祁连山控制形成的山间断陷盆地，由于盆地中生代沉积了大范围的侏罗系地层，因此盆地内含有丰富的油气资源，众多学者对柴达木盆地的构造演化做了大量的研究，受限于盆地的山盆耦合模式，地形、地质条件复杂，山前地带大多是地震的空白区，仅在局部获得了地震勘探资料，但资料品质较差。由于缺乏详细资料，关于该区域构造演化的研究没能深入开展，盆地内部构造演化的研究主要在构造背景和构造格架上，对于构造的细节没有得到解析。本文通过音频大地电磁法探测大柴旦地区盆地地质特征，基于三维非线性共轭梯度(3D NLCG)反演算法，获得研究区三维电性模型，结合区域地质、地球物理资料研究盆地构造演化，结果表明：三维电性模型揭示了柴北缘地区盆地中生代以拉张为主形成一系列断陷盆地，新生代以喜山构造活动为主产生一系列挤压为主的冲断构造，造成早侏罗系-晚白垩系地层的局部缺失等地质活动的盆地演化动力学电性特征。

Electrical characteristics analysis of Mesozoic and Cenozoic evolution mechanisms of basins in the Dachaidan area, Qaidam Basin

The Qaidam Basin in the northwestern part of Qinghai provincet is an intermontane faulting basin controlled by the Kunlun Mountains, the Altun Mountains and the Qilian Mountains. Due to large- scale deposition of the Jurassic strata in the basin, the basin contains abundant oil and gas resources. Many scholars have done a lot of research on the tectonic evolution of the Qaidam Basin, but study was restricted by the basin- mountain coupling mode of the basin. Most of the basin lacks the seismic data due to complicated topography and geological conditions. Only local areas obtained some seismic data, but with poor quality. Lacking exploration data has restricted detailed study of the tectonic evolution of the region. The study focused mainly on the tectonic setting and structural framework of the basin. Based on the regional geology and geophysical data of the Qaidam Basin, this study obtained 3- D electrical model of the study area using three- dimensional nonprofilear conjugate gradient (3D- NLCG). The results show that the three- dimensional electrical model has revealed a seires of faulting basins in the northern margin of the Qaidam Basin, which were produced from the Mesozoic extension. A series of compression- dominated thrusting structures produced from the Himalayan tectonic activity during the Cenozoic resulted in the dynamic electrical characteristics of the basin, such as cal absence of early Jurassic- late Cretaceous strata.