Geochemical characteristics of W-Sn-Mo-Bi-Cu-bearing Manganoan skarn and petrogenesis and mineralization of the Xinshan tungsten polymetallic deposit in Gejiu, Yunnan Province, China

Geochemical anomalies of W-Sn-Mo-Bi-Cu -bearing skarn in Xinshan ore block of Gejiu were studied with the idea of mineral geochemical petrography. The W-Sn-Mo-Bi-(Au)-Cu-(Ag)-Mn comprehensive geochemical anomaly in the tungsten polymetallic ore of Xinshan ore block is closely related to the manganoan skarn which is developed in the contact zone of Yanshanian biotite granite. The orebody delineated by comprehensive economic index of tungsten polymetallic ore will improve the utilization of low-grade tungsten orebody. The sorosilicates such as grossularite, andradite, salite, hedenbergite and hastingsite, which are rich in manganese, formed the manganoan skarn. The wide spread isomorphic replacement of Mo³⁺→W³⁺ in scheelite and Mn²⁺→Fe²⁺ in wolframite included in skarn and the mineral assemblage of molybdenite formed manganoan W-Mo-Mn indicator elements. Chalcopyrite, bismuthinite, joseite and bismuth can also be recovered.