湖南沃溪Au-Sb-W矿床中黑钨矿族矿物特征及其对矿床成因的指示
摘要
Through field observations in the Yu er shan and Hong yan xi ore section of the Woxi Au-Sb-W deposit in Hunan Province, we find that the ore structure of wolframite series occurs mainly as bands and veinlet, and is disseminated in less abundance. The texture is mainly subhedral-allotriomorphic lath. The results of x ray diffraction show that their phases are ferberite and their cell parameters are a0: 4.7454Ao , b0: 5.7160Ao , c0: 4.9753Ao , β: 90°13′. The results of EPMA show that the content of MnO is in the range of 0.97%~11%, with FeO in the range of 13.65%~23.36% and WO3 in the range of 71.39%~76.87%, including both high content and low content of MnO that varies continuously. From the deep to the shallow ore section, the content of MnO increases and forms the “reverse zone”. Crystalline formula is calculated to be (Fe0.57~1.02Mn0.46~0.04 ) W0.98~1.00O4. Correlation analysis of FeO and MnO shows that the correlation coefficient is -0.98; WO3 and MnO correlation 0.47; WO3 and FeO correlation coefficient is -4.10. The content of Nb and Ta of wolframite mineral series is low, suggesting possible sedimentary reworked hydrothermal genesis of theWoxi Au-Sb-Wdeposit.