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三峡地区处于扬子板块北缘,北部与秦岭造山带相连,西部和四川盆地相邻,东北及东南部分别为华北板块及华南褶皱带,其在历史上各种地质构造运动频繁、复杂.本文利用三维重力成像方法,得到了三峡地区中上地壳三维密度分布,结果显示黄陵背斜为高密度异常区域,其最深处大约15km;黄陵背斜周围的主要区域性断裂构造呈菱形分布,这些断裂深度大约10～15km,一般切割至中地壳上部,控制着该区域的构造演化过程以及大部分的地震分布;黄陵背斜中部沿长江一线有大面积低密度地层分布,推测主要为低密度物质沿雾渡河断裂侵入有关.此外,西部的秭归盆地为低密度沉积区域,其沉积厚度明显不均,自巴东向秭归方向沉积厚度明显加深.
The Three Gorges area is located in the northern margin of the Yangtze Plate, connected to the Qinling orogenic belt in the north, adjacent to the Sichuan Basin in the west, and the North China Plate and South China fold belt in the northeast and southeast, respectively. Historically, various geological tectonic movements have been frequent and complicated. Three-dimensional gravimetric imaging method was used to obtain the three-dimensional density distribution of the upper and middle crust in the Three Gorges area. The results show that the Huangling anticline is a high-density anomaly area, the deepest of which is about 15km. The main regional faults around the Huangling anticline are rhombic. The fault depth is about 10-15 km. It is generally cut to the upper part of the middle crust and controls the tectonic evolution and most of the seismic distribution in the area. The middle part of the Huangling anticline has large area and low density stratigraphic distribution along the Yangtze River, In addition, the Zigui basin in the west is a low-density sedimentary area, and its sedimentary thickness is obviously uneven, and the sedimentary thickness is significantly deepened from Badong to Zigui.