Mapping alteration minerals in the Pulang porphyry copper ore district, SW China, using ASTER and WorldView-3 data: Implications for exploration targeting

Abstract

• The PCA + S-A method with WorldView-3 data has good potential for alteration minerals extraction. • New potential porphyry mineral alteration zonings were found. • The results ars helpful for understanding the Pulang mineralization system. Identifying alteration minerals of porphyry Cu deposits by using multispectral remote sensing data is a significant approach for ore prospecting. However, obtaining refined alteration information related to a porphyry Cu system is still challenging, especially in an area with complex geological background. In this study, the effectiveness of spectroscopic techniques for mapping alteration minerals associated with the Pulang porphyry copper deposit, SW China, which is located in high altitude and with tough terrain, were discussed by using ASTER and WorldView-3 data. The method of Principal Component Analysis (PCA) + Spectrum-Area (S-A) was developed to enhance the remote sensing information extraction of the alteration zones with quartz, sericite, chlorite and epidote. The results suggested that the extraction accuracy of porphyry alteration minerals based on WorldView-3 data with the method of PCA + S-A is significantly improved comparing with that of ASTER data. Using the method, we identified a new alteration zone caused by sericite anomalies in the Pulang deposit, which was afterward confirmed by field investigation. Hence, the PCA + S-A method based on WorldView-3 data is an effective approach for mapping alteration zones and ore prospecting in the porphyry copper system.