The sedimentary environment and formation mechanism of bauxite-bearing rock series in Dazhuyuan area, northern Guizhou Province

The lithostratigraphy of the bauxite-bearing rock series of Dazhuyuan area in northern Guizhou is the upper Carboniferous Dazhuyuan Formation, which was deposited in Zhuoshui Lake in the late Carboniferous Maping stage. The lake was one of the offshore lakes in the southwest of Yu'e Bay. In the period of the early Dazhuyuan Formation, the high water lake with the area of 480 km2 was close to the coastline of Yu'e Bay. Sediments were mainly derived from the chemical deposition in the permanent low-energy shallow lake. It deposited amounts of chlorite rock, chlorite clay rock, ferruginous clay rock and a small amount of chamosite iron, hematite. In the period of the late Dazhuyuan Formation, the lake with the area of 288 km2 became shallow and small because of the augmenting of the distance between the lake and the coastline of Yu'e Bay. Then the lake became an intermittent flood control high-energy shallow lake. Huge areas of bauxite (bauxite rock) was deposited from the physical deposition.