江西留龙金矿两类矿石成因的稀土与微量元素证据

留龙金矿产于赣南震旦系上施组变沉凝灰岩中,含金毒砂石英脉和含金铅锌硫化物石英脉均沿近南北向断裂产出。前者形成于低温条件,成矿流体以大气降水为主,铅同位素组成与变沉凝灰岩一致;后者形成于中一高温条件,成矿流体以岩浆水为主,铅同位素组成与加里东期花岗岩接近。含金毒砂石英脉与变沉凝灰岩具有相同的稀土参数和稀土模式,二者的微量元素呈现同步变化关系。含金铅锌硫化物石英脉与加里东期花岗岩稀土元素组成非常相似,微量元素曲线形态非常接近。表明矿石与所对应的岩石之间存在一定的成因联系。以上结论与矿床地质和地球化学特征吻合。

REE AND TRACE ELEMENT EVIDENCES OF TWO-TYPE ORE GENESIS IN LIULONG GOLD DEPOSIT, JiANGXI

Liulong gold deposit occurs in meta-sedimentary tuff (Shangshi Formation, Sinian System) in south Jiangxi. Both gold-bearing arsenopyrite quartz vein and gold-bearing Pb-Za sulfide vein occur along near-SN faults. The former is formed under the low temperature condition, its ore-forming fluid is dominated by meteoric water and lead isotopic compositions are consistant with these of metasedimentary tuff. The latter is formed under intermediate-high temperature condition, its ore-forming fluid is dominated by juvenile water and Pb isotopic compositions are very similar to these of Caledonian granite. Gold-bearing arsenopyrite quartz vein and meta-sedimentary tuff have the same REE parameters and same REE patterns. Trace elements of both reveal the same changing trend. REE compositions of gold-bearing Pb-Zn sulfide quartz vein are close to those of Caledonian granite. Trace element curves of both are very similar too. This indicates that there are some genetic relations. This conclusion completely tallies with geological and geochemical chaaracteristics of the ore deposit.