阿尔金山斜坡的深部电性结构及推覆构造

在柴达木盆地西部边缘的阿尔金山斜坡带上进行了16个测点的大地电磁测深工作。反演结果表明,测区的电性结掏具有明显的南北分区特征。南部表现为低阻特征,与盆地内部相似;北部具有明显的高阻特征。根据电性与地层的追溯对比,结合钻孔与地质资料推测,在柴达木盆地西部的阿尔金山斜坡带上存在由北向南的推覆构造,下古生界和元古界地层推覆在中、新生代地层之上。推覆体宽度和推覆距离均超过10km。

DEEP ELECTRIC CHARACTERISTICS AND NAPPE STRUCTURE OF ALTUN MOUNTAIN SLOPE

Magnetotelluric sounding has been made at sixteen sites on Altun Mountain slope along the western margin of Qaidam Basin. The result of data inversion shows that the electric structure beneath the slope has remarkoble different features in its northern and southern parts, Low electric resictivity is found in the southern part and is similar to that in the interior of Qaidam Basin. But high electric resistivity is remarkobly in the northern part near the outcrop area of Altun Mrs. Based on the tracing and comparison of stratigraphic units and their electric properties in combination with drilling data and geological information, it can be inferred that a nappe structure overthrusting from north to south exists on the Ahum Mountain slope in the western part of the Caidam Basin. Lower Palaeozoic and Proterozoic strata have been overthrust onto Cenozoic and Mesozoic deposits. The sounding data in the area indicate that the width of the nappe and its overthrusting distance are more than 10 kilometers. This discovery is important for study of the tectonic structure of this area and for development of the oil and gas prospecting in the Qaidam Basin.