Study On The Formation Of Siliceous Rock And The Construction Of Uranium In The Southern Piedmont Area Of ​​South

Diebu ore field is a typical carbonate-silicate-mudstone uranium ore field. And some uranium deposits and mineralization points was found in it. These uranium deposits which are major located in Silurian stratum are generally controlled by structure and stratum. On the basis of previous studies, author do field geological investigation and microscope, scanning electron microscope test, mineralogy analysis, geochemistry analysis of the carbonate-silicate-mudstone formation of Silurian. The dissertation from revealing siliceous genesis in formation and uranium minerals occurrence state in siliceous rock to discuss the formation mechanism of the carbonate-silicate-mudstone uranium rich formation.From the work of dissertation, five achievement are got which are showed in the following paragraph.(1) The petrological, mineralogical and geochemical studies show that the siliceous rocks of carbonate-silicate-mudstone formation in Silurian stratum are hydrothermal sedimentary origin. In Early Silurian study area was marginal sea environment that with deep fault(rift), in Middle Silurian the deep fault(rift) begin transforming to small ocean basin.(2) The geochemistry analysis show that some uranium come from underlying medium-acidic volcano, some uranium come from terrigenous material which in siliceous rocks that located in Silurian stratum.(3) The mineralogy and scanning electron microscopy analysis indicated that uranium mineral in siliceous rocks is pitchblende which is local symbiosis with metal sulfides. Uranium minerals are wrapped by carbon substance( maybe graphite), and they are filled in micro pores and cracks in quartz grains. The symbiotic elements of uranium minerals is Ni, Mo, V, As and other elements.(4) Under the constraints of siliceous rocks origin, combined with carbonate rock, clastic rock theory origin, tectonic theory research and the results of previous studies, author disscuss the formation mechanism of carbonate-silicate-mudstone uranium rich formation.