广东石人嶂钨矿床中的晶质铀矿研究

Study on the Uraninite in Shirenzhang Tungsten Deposit,Guangdong Province

石人嶂钨矿床含钨石英脉、花岗岩、云英岩中均发育有晶质铀矿。岩矿鉴定及EDS分析研究发现，铀矿与钍石构成类质同象系列（包括晶质铀矿、含钍晶质铀矿、铀钍石、含铀钍石、钍石、方钍石），它们常常与黄铁矿、磷钇矿、锆石、独居石等矿物共生。晶质铀矿成分在不同矿脉、不同中段均有变化，矿物内部成分也不稳定，可发育生长环带。XRD分析确认晶质铀矿的存在，主要成分是 UO2。随着热液活动的增强，矿物颗粒的增大，晶质铀矿成分变纯，UO2含量增加；晶质铀矿常常形成黄铁矿边，次生变化在边部析出富含杂质的铀矿微粒。电子探针测试晶质铀矿的年龄为151～157 Ma，与本区钨矿化年龄相吻合，跟华南地区铀矿化构成同一成矿系列，同属于燕山期成矿大爆发阶段同一成矿热液活动的产物，这对于在该地区钨矿床及外围寻找铀矿资源具有重要意义。

Uraninite has been found in tungsten-bearing quartz veins, granite and greisen in Shirenzhang Tungsten Deposit.It is shown by identification of rock-mineral and Scanning electron microscopy,energy spectrum analysis （EDS）that uraninite and thorite （including thorium-containing uraninite,uranothorites, uranium-containing thorite and thorianite ）usually form the isomorphous series,and have paragenetic relation with pyrite,xenotime,zircon,monazite and so on.The uraninite’s composition have variations along with different veins and levels,can form the growth zoning result from instability inside minerals;The UO2 content of uraninite is increase from the greisen to the quartz vein and higher in relatively big particles of uraninite than tiny ones.There is higher of nad lower of in the marginal of uraninite mineral, but it is exactly the opposite in the centre of uraninite mineral.Xray diffraction （XRD）analysis and electron probe confirms the presence of uraninite,and its main component is UO2 .Along with the enhancement of hydrothermal activity and the growing of mineral particles,uraninite compositions become pure and uranium dioxide has an increasing trend;during epigenetic change of the uranium particle rich in impurities can be dissolved out and formed pyrite’s rim formation at the edge of uraninite.The uraninite age tested by electron microprobe is approximately from 151 to 157 Ma,which are consistent with the age of tungsten mineralization in this area and uranium mineralization in southern China.They are belong to the occurrence of the same oreforming hydrothermal activity of metallogenic outbreak stage during Yanshan epoch,and it is important significance on searching for uranium resources inside and around tungsten deposit in the region.