Daxigou-Yindongzi orefield consists of two neighboring large deposits. The Daxigou siderite deposit is located in the western part of the orefield and the Yindongzi silver-lead polymetallic deposit is located in the eastern part of the orefield. Typical slump structure was found in orebody No, 11 at the juncture of the two deposits. The deformed bed is marked by a thin siderite bed and the nondeformed bed is represented by beded barite rock, both being hot-water sedimentary rocks.Discovery of the slump structure indicates that there would be an underwater highland in the juncture between the two deposits, which divides the sedimentary basin into two depressions and controls the sediemntary environments and mineralization conditions of the two depressions. Theeastern depression is possibly deeper, in which hot brine may be divided into two parts-theupper and lower brine layers. The upper brine layer probably belongs to weaker oxidation-reduction sedimentary environment, forming barite-siderite orebodiee formed. The lower brine layer belongs to strong reduction sedimentary environment, in which silver-lead polymetallic sulfide orebodies formed. The depth of the western depression is believed to be comparatively shallow and the sedimentary environment may be similar to that of the upper brine layer in eastern depression , in which barite-siderite/magnetite orebodies are formed, Shaanxi Province.