| Aigao area of GanNan is located in the southern tip of Dawang Shan-Yu Shan uranium polymetallic metallogenic belt,which is one of the important uranium metallogenic belts in south China.After years' efforts,the uranium bed,ore point and mineralization point are found with a good prospect of a large number of gamma anomaly points and belts for uranium mineralization.Based on previous research results of field and indoor work,this paper analyzes the genesis and metallogenic model of uranium mineralization by studying the tectonic background,regional geological characteristics,mineralized characteristics information,mineralized control factors,radioactive geophysical and geochemical characteristics.The following are the results of the study.1.There are many tectonic movements in Aigao rock mass of Yingtan – AnYuan and Zhongzhai-Jiangtou deep fracture.North east to regional deep fault is the uranium mineralization of master ore structure,the fault activity in the gorge determine the body to form the north west to subprime extensional faults,the tensile fracture is not only the diabasic dike assault on the positioning of the space,and by the superposition of the late tectonic activities many times,or deep thermal fluid rise extraction activated uranium in rock mass migration,main channels and precipitation of metallogenic.2.The uranium mineralization in this area is mainly produced in the diabase,fractured granites and alkali metasomatic granites.In a small amount,it is found in the laminates,and the mineralization in which the grade is more than 0.3 percent is produced in the diabase and the fractured granites.In the alkaline metasomatic granite and the small number of laminates,the mineralization is characterized by a large but low grade uranium mineralization.This indicates that the superimposed enrichment of ophiolite and cataclastic granite and the later uranium mineralization are closely related.The ore body is small,the continuity is poor,the ore body quantity is much,the ore body grade is low,the uranium ore body mainly exists in the "enter" type triangle belt,the double belt clamping area,the multi-group structure intersections.3.Gamma field in this region presents a general trend of low and low eastern and high west.Ascend higher the average strength of rock mass,the gamma,uranium content high,show that high pass complex massif is a rich uranium rock mass,the variation coefficient is larger,under the effect of later structure,the enrichment of radioactive elements,the formation of uranium mineralization phenomenon.Granite rock body in fai green dike is more development,more show north north west,north west direction,gamma high strength coefficient of variation(23.3%),showed that the region diabasic dike activities,with the migration of uranium.4.In the Late Yanshan period(90Ma),Aigao rock mass was affected by the deep fault of the north east of Yanshan,and the mantle source base was invaded along the fault line,forming a large amount of northern west to the pyrogreen lithosphere in the pass,and the thermal fluid that accompanied it carried on the alkali replacement of the lateral granite Aigao rock mass which occurred in the large scale of the granite-oriented uranium mineralization of the region,and then the northern east to the fracture extrusion was briefly relaxed,and the northern west was crushed by the extrusion of the dihui green rock veins,and formed the fractured granite belt in the north west.After a brief relaxation(70 ma),north east to regional deep fracture activity again,sinistral shearing compressive,accompanied by the torsional pressure,Aigao rock mass in the north west again tensile fracture structure,ore-forming fluid to early to initial concentration of alkali metasomatism type uranium mineralization superposed renovation,formation of diabase-type granite,diabase,reddening rupture-silicified fracture zone node type and purple fractured granite type uranium mineralization. |
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