Interpretation of hydrothermal alteration and structural framework of the Huize Pb-Zn deposit, SW China, using Sentinel-2, ASTER, and Gaofen-5 satellite data: Implications for Pb-Zn exploration

The Huize Pb-Zn deposit is one of the largest and high-grade Pb-Zn deposits in the world, containing more than 7 Mt Pb and Zn reserves at an ore grade of similar to 30-35 % Pb + Zn. Therefore, brownfield exploration of additional Pb and Zn orebodies at Huize Pb-Zn deposit is of high priority. Hydrothermal alteration minerals and structural features are typically associated with Pb-Zn mineralization, which can be identified quickly and economically using a multi-source remote sensing satellite dataset. In this study, Sentinel-2, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), and Gaofen-5 (GF-5) satellite remote sensing imagery were employed for brownfield exploration of additional Pb-Zn orebodies in the Huize Pb-Zn deposit. The Sentinel-2 satellite remote sensing imagery was used to interpret the structure and map oxides/hydroxides by implementing the band ratio (BR) and principal components analysis (PCA) method; the ASTER satellite data were applied to map argillic, quartz, and carbonate hydrothermal alteration minerals using the PCA method; the GF-5 satellite data were utilized to map hematite, kaolinite, calcite, and dolomite minerals by the mixture tuned matched filtering (MTMF) method; and the mapped hydrothermal alteration information was verified by field reconnaissance and laboratory analysis. Finally, remote sensing geological exploration characteristics of the Huize Pb-Zn deposit were summarized by comprehensively analyzing the hydrothermal alteration minerals and structural characteristics, and three new brownfield exploration target zones of Pb-Zn mineralization were delineated. The study can provide a reference for the brownfields exploration in the vicinity of an existing Pb-Zn deposit around the world.