拉拉铁氧化物-铜-金-钼-钴-稀土矿床辉钼矿的多型及标型特征

POLYTYPE AND TYPOMORPHIC CHARACTERISTICS OF MOLYBDENITE FROM LALA Fe-OXIDE-Cu-Au-Mo-Co-REE DEPOSIT IN SICHUAN PROVINCE, CHINA

用X射线衍射和电子探针等方法,研究了拉拉铁氧化物 铜 金 钼 钴 稀土矿床辉钼矿的标型特征。结果表明,辉钼矿有2H+3R和2H两种多型。2H+3R型辉钼矿中Se,Te,Cu质量分数较高,平均分别为0.16%,0.06%和0.39%;2H型的Se,Te,Cu质量分数较低,分别为0.05%,0.03%和0.24%。2H+3R型辉钼矿中的w(Re)较高,平均为112×10-6。辉钼矿的铅同位素放射成因铅极高,w(206Pb)/w(204Pb),w(207Pb)/w(204Pb),w(208Pb)/w(204Pb)比值分别为50.622～70.573,17.719～19.100,43.013～46.324;硫同位素具陨石硫特征。辉钼矿与黄铜矿等硫化物具有相同的物质来源和成因机制。

So far Lala is the exclusivel Fe-Oxide-Cu-Au-Mo-Co-REE deposit reported in China. Molybdenum mineralization is very strong in the deposit. Lala deposit contains about 20 Mt ore of average Mo, 0.03%. It has been determined by X-ray that molibdenite from the deposit is 2H+3R and 2H types (see to Fig.1 and Table 1). The averages content of Se, Te, and Cu in 2H+3R molybdenite is 0.16%, 0.06%, and 0.39%, respectively. The average content of these elements in 2H molybdenite is 0.05%, 0.03%, and 0.24%, respectively. The content of Re in the 2H+3R molybdenite ranges from 111.88×10^(-6) to (121.50)×10^(-6). The lead isotope ratios of molybdenite from the deposit vary considerably, ^(206)Pb/(^(204))Pb?^(207)Pb/^(204)Pb?^(208)Pb/^(204)Pb are 0.622～70.573, 17.719～19.100, and 43.013～46.324, respectively. The sulfur isotope composition, δ^(34)S‰, range from 1.82 to 2.25.It is suggested that molybdenite and chalcopyrite and other sulfides are of the same source and genesis.