Characteristics of marine deposits of the bauxite-bearing rock series in central Guizhou-southern Chongqing area

The central Guizhou-southern Chongqing area had experienced peneplanation at the beginning of Ziyun Movement before the end of the Devonian. In the deposition process of the Carboniferous bauxite-bearing rock series, the lower bauxitebearing rock series (iron-clay rock) was mostly offshore lake facies, and the upper bauxite-bearing rock series(aluminous rock)was mostly offshore plain facies. In this environment, the influence and reformation of ingression and strong storm surge were frequent. Thus, there exsited a few marine plant fossils (brachiopoda) and marine microfossils (acritarch and conodont) in the bauxite-bearing rock series, which mostly deposited in a continental environment. And there were less marine carbonate lens in the lower (iron-clay rock segment) and the upper (aluminiferous rock segment) bauxite-bearing rock series, suggesting obvious characteristics of marine deposition. All these phenomena indicate that the formation environment of the bauxite-bearing rock seriesin central Guizhou-southern Chongqing area was very diverse and complex. It was affected not only by continental sedimentary environment but also by other factors.