URANIUM METALLOGENESIS AND CHARACTERISTICS OF MOTIANLING MASSIF IN THE NORTH OF GUANGXI

Motianling Massif is located in the north of Guangxi, on the combining site of Yangtze Block and South China fold system. It is one of the oldest rockmass giving birth to uranium in granites in South China and its rockmass was formed in the Snow-peak Period. Through years of perambulation and research, it is found that there are a lot of uranium deposits, mineral occurrences and mineralized spots in Motianling region, the parts for uranium mieralization are various, and the types are rich. To research the uranium metallogenesis of those uranium deposits (mineral occurrence) in Motianling Massif, indoor comprehensive research and field investigation are made. Combining the previous research results, it is discovered that there are many periods and time of uranium metallogenesis in Motianling Massif and the major ones are Caledonian and Himalayan stagges. Meanwhile, the types of uranium mineralization in Motianling Massif are very rich. Till now, for the discovered uranium deposits, mineral occurrences and mineralized spots, they are either inner-granite type, contact type, silicified zone- pitch blende type, chlorite-pitch blende type, orAlkali replacement type. From the distribution of present uranium deposits or mineral occurrences, it can be seen that almost all deposits (mineral occurrences) are distributed not far from the three fault zones. For instance, Xincun Deposit is directly produced inside the Wuzhishan Fault and the neighboring branch faults and Daliang Deposit is produced on the south of Zishanping Fault, whose movement has certain effect on the superimposed mineralization of Dalian Deposit. Besides this, the northwestward fault also has certain effect on the mineralization, inside which some mineral occurrences are directly produced.