THE CARBON AND OXYGEN ISOTOPIC CHARACTERISTICS AND TRACE ELEMENT GEOCHEMISTRY IN ZOIGE 510-1 URANIUM DEPOSIT

510-1 uranium deposit is in the southwest of China ,Sichuan Province . The author studied detailedly the Carbon and Oxygen isotopic Characteristics and trace elements and rare earth elements of hydrothermal minerals such as calcite, quartz and pyrite which are intensely related with mineralization. The innovative achievements and views are as follows:

1.The author found for the first time that the vertical zoning of gangue minerals (quartz and calcite) in 510-1 uranium ore deposit showed an “acid top and alkaline bottom” rule. The research indicated that there existed an “acid and alkali isolation” geochemical interface nearby No.5 level of 510-1 uranium deposit (200m or so below present earth surface), which is also a high concentration position for uranium outburst of mineralization.

2.The results suggest that the δ¹³C value changes of limestoneAsilliceous limestone and calcite veins generated in the strata are between -1.48‰ and 3.18‰, and the average value is 1.51‰; the δ¹⁸O values are from -12.81‰ to -3.71‰, and the average value is -9.92‰,which is the highest in the uranium ore field. The δ¹³C value of the ore-bearing calcite veins ranges from -2.78‰ to -4.81‰, with an average of -3.93‰; the δ¹⁸O value ranges from -13.14‰ to -15.05‰, and the average value is -13.87‰, the range of δ¹³C value is from -3.53‰ to -6.35‰, with an average of -4.93‰, which have same range to the carbon isotope of ore-bearing calcite veins,showing that it is also the product of mineralization; and the range of δ¹⁸O value is from -16.00‰ to -24.75‰,with an average of -19.36‰,which is the lowest in the uranium ore field and showing the characteristic of deep sources. overall, carbon and oxygen isotopic compositions of the Zoige uranium ore field indicated that its ore-forming fluids should be derived from the mantle.

3.The author studied the geochemical characteristics of trace elements and rare earth elements of hydrothermal minerals such as calcite,quartz and pyrite which are intensely related with mineralization, the results showed that calcite,quartz and pyrite possess similar trace elements composing, they concentrated comparatively elements such as Sr, Zr, Ba, Zn, U, Ni, and Cr.