Characteristics And Genesis Of The Taibai Uranium Deposit In Guizhou Province

Limestone type uranium deposit as a subtype of the silicon carbon mudstone type uranium deposits, in the important position in the domestic uranium deposit is increasingly highlighted. Experienced in the1970s about ten years to the wide range of exploration and evaluation, to suck in carbonate rock type uranium deposit is affected by nuclear industry geological department to halt production adjustment, followed by30years at a standstill, basic work less. In recent years, suck to restart regional uranium geology research and exploration, and achieved better prospecting effect. This article relying on taibai uranium reconnaissance project, on the basis of predecessors’ work, through to the white uranium in-depth investigation and study, summed up the metallogenic conditions and formation mechanism, to improve the level of the metallogenic theory and further prospecting has important significance.Based on the geological exploration and analysis of fluid inclusions testing, combined with mathematical statistics method and the analysis of metallogenic environment and age causes, draw the research conclusion is as follows:(1) through the analysis of geological exploration data, Cambrian, ordovician loushanguan group mae tam, Permian MAO group of uranium content relatively high, which the formation of loushanguan group and mae tam group Th/U>3, low leaching rate of uranium, contribute to the enrichment of uranium in the area of small, Permian limestone MAO mouth group Th/U=0.5～1.0, the leaching rate of uranium is high, and the set of limestone of the Permian MAO had relatively higher content of Pb, zinc, Ni, Mo and other elements, consistent with the enrichment of the elements in the ore, should be the white uranium in the uranium source layer.(2) based on the relation and paragenetic association of minerals interspersed with each other of the two deposits mineralization are divided into diagenetic period, metallogenic stage and supergene stage. Among them, the metallogenic period in taibai uranium deposits are further divided into quartz and pyrite-needle nickel ore, quartz-uraninite-metal sulfide phase (the main metallogenic stage) and uraninite-pyrite-calcite phase.(3) the fluid inclusion analysis results indicate that the ore-forming fluid of the two deposits are in the low temperature, low salinity, low density fluids, mineralization occurs near the surface. Among them,906ore deposits of main ore-forming phase fluid inclusions homogenization temperature about245℃, salinity is about7.34wt.%NaCl equiv, density of about0.87g/cm3, pressure is about36.0x105pa;908ore deposits of main ore-forming phase fluid inclusion homogenization temperature about170℃, the salinity of2.1wt.%NaCl equiv, density of about0.92g/cm3, pressure is about9.14x105pa. Oxygen isotope research shows that the two deposits for the same issue product of hydrothermal activity, ore-forming fluid mainly for atmospheric precipitation.(4) by summarizing the results of the work produced, combining previous analysis of the mining area of sedimentary facies and metallogenic age of the investigation, judgment of uranium deposits in the area around the formation process of first deposit again by the old strata shower set finally through the participation of hydrothermal enrichment.