Altered Rock Characteristics and Gold Prospecting of Gangcha-Kemo Area in Gansu Province

doi:10.19657/j.geoscience.1000-8527.2020.070

Abstract

Abstract:

The Gangcha-Kemo gold deposit in the Xiahe-Hezuo region is located on the northern margin of the west Qinling orogen. The deposit is of epithermal type with possible occurrence of deeper porphyry mineralization system. We studied the rock alteration features of the gold deposit with the short-wave infrared spectral (SWIR) mineral analysis technique. The results indicate that local alteration minerals include mainly muscovite, illite, montmorillonite, kaolinite, dickite, chlorite, epidote and quartz. Phyllic alteration is developed mainly around the orebody. The central phyllic zone, transitional argillic zone, and the peripheral propylitic zone are developed successively away from the Xiajiamengoukou area. Besides, illite crystallinity has shown obvious decreasing trend outward from Xiajiamengoukou. This shows that Xiajiamengoukou likely represents the hydrothermal center.

Key words: short-wave infrared spectroscopy (SWIR), alteration mineral, illite crystallinity, prospecting, Gangcha-Kemo gold deposit

CLC Number:

P618.51

WANG Shuhao, SHEN Junfeng, PENG Zidong, XU Liwei, NIU Gang, LIU Haiming, LI Jinchun, DU Baisong, LIU Jiajun. Altered Rock Characteristics and Gold Prospecting of Gangcha-Kemo Area in Gansu Province[J]. Geoscience, 2021, 35(02): 579-588.

Figures/Tables 9

Fig.1 Geological sketch map of the Gangcha-Kemo mining area

Fig.2 Histograms of alteration minerals identified by SWIR in the study area

Fig.3 SWIR spectra of major alteration minerals

Fig.4 Distribution isograms of major alteration minerals along exploration line ZK-07

Fig.5 Spatial distribution maps of alteration minerals in the main study area

Fig.6 Alteration zonation profile along exploration line ZK-07

Fig.7 Surficial zonation map of alteration minerals in the main study area

Fig.8 Distribution isogram of the illite crystallinity index (SWIR-IC) along exploration line ZK-07

Fig.9 Spatial variation of the illite crystallinity (SWIR-IC) index on the ground surface of the main study area

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