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

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.