Enrichment rules and sedimentary environment characteristics of associated gallium in bauxite deposit in Dazhuyuan of Wuchuan in Guizhou Province

Through the study of Dazhuyuan bauxite deposit, we found that the content of associated gallium in bauxite deposit generally exceeds the minimum index of industrial utilization. Gallium has a different distribution in ore-bearing rock series and was moderately positively correlated with TiO₂, Cr, Zr, Sn, meaning that gallium may occur in minerals containing Cr, Zr, Sn. Gallium and Al₂O₃ has weakly positive correlation, indicating that gallium is possible to isomorphism exists in the form of aluminum. Also the Sr/Ba is 1.09-19.69, more than 1,showing that bauxite ore formed in marine environment. The Th/U is 1.72-12.31,showing the incomplete bauxite weathering. And Ga/Al is 0.45-1.84, showing that the pH of mineralization medium varies lightly, and mineral assemblages in acidic medium can be inferred by containing pyrite, kaolinite and other minerals in the ore-bearing rocks. The evidences that chondrite-normalized curve of rare earth element (REE) tilted to the right, light rare earth element (LREE) shows enrichment, heavy rare earth element (HREE) shows loss, δCe shows weak positive anomalies and Ce/Ce^* is 1.17-10.17, indicate that the ore-bearing rock series were formed in an oxygen-rich sedimentary environment. Besides δEu appear as negative anomalies, which further indicates that mineralization is in oxide-based environment. Dazhuyuan bauxite deposit is concluded to be formed in marine oxygen-rich sedimentary environment through comprehensive analysis.