The Bukantau Mountains ring structures: Assessment of their role in gold ore mineralization prediction, based on remote sensing data interpretation

Abstract

The study assessed the significance of the Central and Western Bukantau Mountains ring structures for predicting gold ore mineralization, using remote sensing, geophysical, as well as geological and geochemical data. The paper is based on the 2018–2021 project for compiling a cosmo-geological structure diagram and a remote sensing map at a scale of 1 : 50,000 for an area of about 5,600 km2. Landsat-7 ETM+, Landsat-8 OLI, ASTER/Terra, Sentinel-2A, and QuickBird multi- spectral images were used together with aeromagnetic, gravity, and electrical survey data. The images were processed in ENVI, ERDAS IMAGINE, Geomatica PCI, ArcGIS, and LESSA software, involving color compositions, band ratios, PCA, IHS/ITS transforms, mineral and hydrothermal compositions, as well as computer-assisted lineament analysis. Visual and automated interpretation revealed a system of 21 ring structures different in terms of morphology. The most prospective sites were found to be peripheral and nodal parts of the ring structures associated with deep faults, intrusive exocontacts, and zones of hydrothermal alterations recognized by clay-mineral and iron indices. The comprehensive analysis of ring structures, lineaments, and spectral indicators of hydrothermal alteration proved to facilitate the Kokpatas-type gold ore mineralization prediction reliability. The identification of eight prospective sites with a total area of about 97 km 2 has become a practical outcome of the study performed.