THE PROBABILITY DISTRIBUTION OF URANIUM IN THE SINIAN AND CAMBRIAN AND POLYGENETIC COMPOUND URANIUM ORE DEPOSITS

Using the method of probability diagram, this paper has systematically studied in terms of probability distribution the uranium quantity value in every layer of Upper Sinian-Lower Cambrian age containing uranium ore bodies within the limits of some uranium ore deposits in the Southeast China diwa region. As a result, data on uranium contents (background values) of the rocks at the initial condition have been obtained within the limits of the ore deposits, It can be concluded that the uran- ium ore deposits of mica-siliceous mudstone type are not diagenetic in origin. A comparison of the uranium contents of the uranium-bearing bed and the underlying and overlying beds indicates that the uranium-bearing bed has a higher uranium content, being probably the source bed for the ore deposits. The uranium quantity value in every layer shows a mixed distribution of multimodal type and multipopulation. These facts demonstrate that the uranium ore deposits of this type in the region have been formed by superimposition, transformation or reconstruction in the late stage of metallogenesis on the base of uranium source bed.As exemplified by four ore deposits, this paper provides some information from the aspect of the probability distribution of ore-forming elements and indicates that the uranium ore deposits of dolomite-siliceous mudstone type belong to polygenetic compound uranium ore deposits.