ON ORIGIN OF KARST BAUXITE IN CHINA AND BIO ORGANIC METALLOGENESIS
LIU Chang ling,QIN Zhi an (Tianjin Geological Academy,Tianjin 300061,China)
Bauxie in China is dominated by Carboniferous Karst diaspore type which account for 90% of this type in the world.In ancient hot and wet tropic zone, strong weathering of silicate rock (including clay and shale intracalasts) generated clayey material and alumina gel which were washed by water and shortly transported,then deposited to form bauxite in ajacent basin,such as lake, marsh, bay or lagoon. Organism and the derived materials played roles in different stages of the bauxite metallogenesis, such as transportation, organic material protected gel, the absorption, resolution and purification of large amount of orgrnic matter in water of sedimentary basin in which syngenetic and diagenetic stages were under reduction and diaspore and pyrite formed. In the supergenetic stage the oxidation of organic matter and pyrite made ore lose Si, S and Fe, become rough and porous ores rich in alumina.
【CateGory Index】： P618.45