基于红外光谱技术研究云南普朗斑岩铜矿的蚀变和矿化特征

近年来红外光谱技术作为一种绿色、快速、无损、精确探测矿物的技术手段而倍受关注,针对斑岩型矿床蚀变矿物高度叠加、蚀变分带界线不明显、细粒蚀变矿物多、黏土蚀变矿物多等特征,该技术在蚀变矿物识别和勘探信息解读等方面优势突出。本文应用红外光谱技术对云南普朗斑岩铜矿区钻孔ZK1801岩心进行矿物识别和蚀变分带划分的研究,识别出钾硅酸盐化带、绿帘石-绿泥石化带、绿泥石-伊利石化带、石英-伊利石化带和泥化带。研究表明:普朗铜矿整个钻孔的蚀变矿物主要有石英、钾长石、绢云母、绿泥石、绿帘石、高岭石、蒙脱石、伊利石等;根据矿化特征,发现铜矿体广泛赋存在钾硅酸盐化带和绿帘石-绿泥石化带中,与矿化关系密切的蚀变矿物"石英+钾长石+绢云母"和"绿帘石+绿泥石",可以作为普朗矿床勘查的标型蚀变矿物组合;研究区广泛发育的绢云母Al—OH波长随钻孔深度增加而逐渐从2210～2205nm减小到2202～2198nm, Al—OH波长2210～2205nm(长波绢云母)与矿化关系密切,可以作为普朗矿床勘查的指示信息。

The Infrared Spectroscopy Characteristics of Alteration and Mineralizationin the Porphyry Copper Deposit in Pulang, Yunnan Province

BACKGROUND: Infrared spectroscopy technology, as a green, fast, non-destructive and accurate mineral detection technology, has drawn widespread attention of geologists all over the world in recent years. In view of the high superposition of altered minerals in porphyry deposits, the inconspicuous alteration zone boundaries, many fine-grain altered minerals, and clay altered minerals, this technology has outstanding advantages in the identification of altered minerals and interpretation of exploration information.OBJECTIVES: To analyze the characteristics of alteration and mineralization of the porphyry copper deposit in Pulang, Yunnan Province, and to provide the basis theory for porphyry copper deposits (especially in the Pulang deposit) exploration.METHODS: The core samples in the drill ZK1801 were detected using HyLogger-3 through infrared spectroscopy technology, and the spectral data was processed and analyzed by TSG 8.0.RESULTS: K-silicate alteration, epidote-chlorite alteration, chlorite-illite alteration, quartz-illite alteration and clay alteration were identified in the Pulang porphyry copper deposit. The main altered minerals included quartz, potassium feldspar, sericite, chlorite, epidote, kaolinite, smectite and illite. According to the characteristics of mineralization, it was found that copper ore bodies were widely present in the potassium silicate zone and epidote-chlorite zone.CONCLUSIONS: Quartz+potash, feldspar+sericite and epdote+chlorite can be typical altered mineral assemblages for exploration of the Pulang porphyry copper deposit. The Al-OH wavelength from 2210nm to 2205nm of sericite (long-wave sericite) is closely related to mineralization, which can be used as an indicator for prospecting in the Pulang deposit.