Yankuang ceshi (Sep 2021)
The Infrared Spectroscopy Characteristics of Alteration and Mineralizationin the Porphyry Copper Deposit in Pulang, Yunnan Province
Abstract
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.
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