Hydrothermal sedimentary manganese deposits associated to volcanic activities—Permian manganese deposit in Guizhou

Abstract：Manganese deposits, ferromanganese deposits and manganiferous siderite deposits occurring in the Second Member of the Middle Permian Maokou Formation in Guizhou are all distributed in platform gullies in central Guizhou. There are carbonate manganese deposits in the Zunyi area in the east and mainly manganese gossan-type secondary manganese oxidized deposits in the Xuanwei-Shuicheng area in the west. The purpose of this paper is to discuss the mineralization conditions of manganese deposits in order to extend ore prospects. Study shows that various manganese ore types and rocks of ore embryo layers formed by hydrothermal processes. The evidence is as follows：(1) there are many diagnostic minerals of hydrothermal deposition；(2) major and trace element and REE data all show characteristics of hydrothermal deposition；and (3) he homogenization temperatures of fluid inclusions range from 90 to 275℃. The formation of the manganese deposits is probably closely related to the middle and late stages of the evolution of the Emeishan mantel plume. The outpouring of Maokouan basalt was favorable to the formation of the silica-lime-mud-manganese association in the platform gullies of central Guizhou. Manganese deposits in the Zunyi area in the east are strictly confined in the area of siliceous breccia formed by hydrothermal eruption. Based on these, combined with other characteristics, it is thought that the formation of manganese deposits in the study area is related to strong hydrothermal eruption.