LIU He1,2, MA Yu1, REN Hong1, LIU Bihong1
(1. China Railway Resources Exploration Company Limited, Beijing 100161, China;
2. Dept. of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China)
Abstract: In recent years, short-wave infrared (SWIR) spectroscopy analysis has been developed and is gradually becoming a mature research method for the study of wallrock alteration of hydrothermal deposits. The wallrock alteration of the Tiemaoshan porphyry molybdenum deposit is intense. The dominant forms of alteration include potassic alteration, silicification, illitization, smectitization, showing obvious zoning characteristics. The illite-smectite alteration is highly associated with molybdenum mineralization. Through systematic measuring of short-wave infrared spectra, the alteration minerals were accurately identified. In addition, illite crystallinity (SWIR-IC) was calculated according to the profile of the short-wave infrared spectra, which can represent the quantitative intensity of illitization. The results show that within the illite-smectite alteration zones, the higher the SWIR-IC value is, the stronger is the molybdenum mineralization that will occur. However, within the silicification zone, the content of illites decreases dramatically. Within the potassic alteration zone, the SWIR-IC is unrelated with mineralization. During the exploration program, systematic measurement of short-wave infrared spectra can help the identify alteration minerals and can also indicate the ore-forming hydrothermal center based on the SWIR-IC value.
Keywords: short-wave infrared spectroscopy; illite crystallinity; porphyry molybdenum deposit; wallrock alteration
Email: liuhe1983@126.com
ACTA MINERALOGICA SINICA Vol. 35, No. 2, 2015, Page 221-228
