Mineral mapping and ore prospecting using Landsat TM and Hyperion data, Wushitala, Xinjiang, northwestern China

The Southern Tianshan area, situated in central Asia, is one of the most important gold belts identified by many world-class, superlarge and large gold deposits. The Wushitala area, located in the eastern part of Southern Tianshan, Xinjiang (China), has a strong potential for gold and other metallic mineral deposits. However, no metallic mineral deposit or occurrence has been reported in detail for the Wushitala area in the past, apparently due to poor exploration. This study attempts to map alteration zones and acquire ore prospecting targets in the Wushitala area by integrating Landsat TM and Hyperion data with the ASTER spectral library mineral spectra. The Crosta technique and the anomaly-overlaying selection method were combined to process four temporal Landsat TM data (acquired in the same season in different years) so as to eliminate the random interference-caused false anomalies of alteration minerals (iron oxides and hydroxyl-bearing minerals and carbonates) while retaining the real anomalies. The matched filtering method was applied on Hyperion data for the detailed identification of hydrothermally altered minerals surrounding the granites in the north. The results of Hyperion data are spatially consistent with those of Landsat TM data. Furthermore, the results of Hyperion data show that the alteration minerals associated with the potash feldspar granite are dominated by muscovite and goethite. In our field campaign, fourteen sites (eleven acid intrusion-related and three structure-associated) distributed throughout the study area were inspected, all of which proved to be of geological genesis. Our study led to the discovery of three mineralization sites associated with acid intrusions and structures that were not previously documented. Due to the extensively distributed acid intrusions and structures along the southern Tianshan Belt, several other gold-iron-copper mineralized locations could be found with more detailed investigations. Our mineral prospecting methodology proved effective in the study area and is hereby suggested for application in similar geological settings.