Mapping hydrothermal alteration of the Pulang porphyry copper deposit, SW China, using ASTER and ZY1-02D satellite data

Abstract

Alteration minerals are important prospecting indicators, and multispectral and hyperspectral remote sensing technologies are important prospecting tools. Multispectral remote sensing data such as ASTER have been widely used for extracting alteration mineral information. The dataset is easy to access, cost-effective to use, and rich in rock and ore spectrum information. Recently, the use of alteration mineral identification technology and hyperspectral satellite data for fine prospecting has become feasible in China, considering the development of hyperspectral remote sensing technology, especially the launch of the ZY1-02D satellite in China. Pulang porphyry copper deposit, Southwest China, is a largescale, explored deposit with unclear peripheral prospecting. Therefore, principal component analysis (PCA) and mixed tuned matched filtering (MTMF) methods were used in this study to extract the mineralized alteration minerals of the Pulang porphyry copper deposit area from the ASTER multispectral data and ZY1-02D hyperspectral data. Then, Al-OH and Fe-Mg-OH alteration information was obtained from the ASTER data using the PCA method. Meanwhile, sericite, chlorite, and epidote alteration information was extracted using the MTMF method and ASTER data. With the ZY1-02D data, the alterations of sericite, chlorite, and epidote were extracted by the PCA and MTMF methods. A field verification showed that the overall accuracy of the ASTER-based alteration extraction was up to 0.57, and the overall accuracy of the ZY1-02D-based alteration extraction was up to 0.88. And circled six favorable areas of copper deposit based on alteration mapping. Therefore, the ZY1-02D data can be regarded as a reliable and promising tool for delineating potential prospecting areas according to the mapping of hydrothermal alteration information, which can be explored further in the prospecting field in the future. The eastern and northern parts of the first mining area should be further explored for potential prospecting.