凡口矿床闪锌矿和方铅矿的微量元素及其比值——一个对比性研究

Minor Elements in Sphalerites and Galena from Fankou Pb-Zn Deposit and Their Ratios-A Comparative Study

矿床的一般特征凡口矿床位于华南准地槽粤中海西坳陷带北段。该矿床主要赋存于中、晚泥盆世碳酸盐建造中,其次,赋存于早石炭世细碎屑岩-碳酸岩建造中。中、晚泥盆世碳酸盐建造以岩石中普遍含陆源碎屑石英、夹有黄铁矿页(板)岩或粉砂质页岩夹层、化石丰富、炭质和泥质含量较高为特征。

The representative sphalerite separates,galena separates and zinc concentrates from Fankou Pb-Zn deposit have been analysed.The analyses show that the Fankou sphalerites is rich in Ga,Ge and Ag,but poor in Se and Te-,the Fankou galena are rich in Ag,Hg,Sb and As,but poor in Se,Te and Tl.The average of Zn/Cd ratios for sphalerites from Fankou is 311.This average is similar to those from Gaobanhe deposit and Heqing deposit,which may be classified as the Mississippi Valley type(i.e.MV type)deposits,Accesa deposit(Alpine type)and Broken Hill deposit(sedimentary-metamorphic type),and is lower than those from Bleikvassil deposit(volcano-sedimentary type),Gorno deposit(Alpine type with some volcano-sedimentary features)and Pine Point deposit(MV type),but higher than those from all of the discussed skarn-hydrothermal and hydrothermal deposits.The Ga-Ge-Ag atomic ratios for sphalerites(especially light sphalerites)from Fankou are similar to those for the syngenetic sphalerites from the British Isles and ror sphalerites from Gorno deposit.The average of Sb/Ag ratios(0.74)in galena from Fankou is closed to that(0.8)in the syngenetic galena from the British Isles,but much lower than those from other deposits.The Sb-Bi-Ag atomic ratios in Fankou galena are closed to that in the syngenetic galena of the British Isles and not very different from that in Broken Hill galena.On the basis of the comparison of the minor elements and their ratios in Fankou and other deposits,the following conclutions can be reached:(1)Fankou deposit possesses some syngenetic features;(2)It is similar to MV type deposits,Alpine type deposits and sedimentary-metamorphic deposits,as well as different from them in minor element aspect;(3)ft evidently differs from skarn type,and volcano-hydrothermal type deposits in the characteristics of minor elements.