Alteration mineral mapping and thermal anomaly reconstruction based on GF-5 data: A case study of the Ga’erqiong–Galale Cu–Au mining district, Tibet

• GF-5 data extracted 29 alteration minerals and restored thermal distribution. • Propose a mineralization system coupled with “intrusions and structures”. • Deep understanding of regional mineralization laws by applying multi-source data. To elucidate the deep metallogenic mechanisms of porphyry–skarn systems and to establish a remote sensing exploration model for high-altitude, cold regions, this study focuses on the Ga’erqiong–Galale Cu–Au mining district in Tibet. We integrated GF-5 hyperspectral data with Landsat-8, Sentinel-2, and GF-2 imagery to conduct mineral-scale alteration mapping, structural analysis, and multi-source data fusion. Employing a Minimum Noise Fraction (MNF)–Pixel Purity Inde (PPI)–n-Dimensional Visualizer (n-D Visualizer) workflow enhanced by geology-guided endmember optimization, the Spectral Angle Mapper method successfully identified 29 hydrothermal alteration minerals. Based on their diagnostic formation temperatures, we reconstructed the thermal zonation of the hydrothermal system. By synthesizing multiple lines of evidence, this study reveals, for the first time, the internal architecture of the mineralizing system: (Ⅰ) the high-temperature alteration core, circular structures, and aeromagnetic highs are spatially coincident, collectively indicating a concealed intrusion acting as the central heat and metal source; (Ⅱ) linear structures serve as preferential pathways for hydrothermal fluid transport, controlling a bead-like distribution of high-temperature minerals along ENE-WSW fault zones; and (Ⅲ) structural intersections and the margins of circular structures represent favorable nodes for ore precipitation. Consequently, we propose a coupled metallogenic system of “concealed intrusion (heat source) — throughgoing faults (fluid pathways) — structural intersections (precipitation nodes) ”. This study demonstrates the powerful capability of GF-5 hyperspectral data to delineate the core and architecture of hydrothermal systems finely. When integrated with geophysical and other multi-source datasets, it provides a robust technical framework for enhancing the understanding of regional metallogeny and defining exploration targets in analogous Tibetan terrains.