Mineral mapping using spaceborne Tiangong‐1 hyperspectral imagery and ASTER data: A case study of alteration detection in support of regional geological survey at Jintanzi‐Malianquan area, Beishan, Gansu Province, China

Abstract

This is an extension of our previous study and an applicability test on the mapping capability of Tiangong‐1 data with more complicated geological conditions over large areas. The Jintanzi‐Malianquan area is located in a major Au‐Cu‐Ni‐Cr resource belts in China. In order to support the 1:50,000 regional geological survey, this study presents the mapping results of using spectral angle mapper method and image endmembers from spaceborne Tiangong‐1 Hyperspectral Imager (HSI) shortwave infrared and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data. Six alteration minerals (muscovite, kaolinite, chlorite, epidote, calcite, and dolomite) related to hydrothermal ore deposits are used in the analysis. By comparing the results from both datasets, it is confirmed Tiangong‐1 HSI data can detect six major minerals (muscovite, kaolinite, chlorite, epidote, calcite, and dolomite), while ASTER can only discriminate the first five minerals in this study area. Fifteen targets for mineral exploration are mapped from the remote sensing results. Eleven targets have been verified by existing geologic maps and field validation for muscovite and epidote alteration. The results of this study suggest that the Tiangong‐1 HSI data are well suited for quick spaceborne reconnaissance of alteration minerals to support routine geological survey in large areas at 20‐m resolution, which provides continuous mapping products for all terrains at an accuracy of better than 1:50,000 scale map.