洞庭拗陷位于湖南北部,东西两侧为幕阜—九岭隆起、武陵隆起,南北与雪峰、华容隆起为邻,是在古老构造的基础上,由燕山运动形成的白垩—第三纪断陷盆地。盆地内又可分成几个次级凹陷和凸起。喜山运动使整个盆地抬升,下第三系普遍遭受剥蚀。下第三系、白垩系及其更老地层,直接被第四系覆盖。(图1) Dongting depression is located in northern Hunan, east and west sides of the Mufu - Jiuling uplift, Wuling uplift, north and south and Xuefeng, adjacent to Huarong uplift, is based on the ancient structure, the Yanshan movement formed by the chalk - Tertiary Period Subsidence basin. The basin can be divided into several secondary depression and bulge. Himalayan movement uplift the entire basin, under the Tertiary generally suffered erosion. The Lower Tertiary, Cretaceous and its older strata are directly covered by the Quaternary. (figure 1)