HYDROTHERMAL ALTERATION AND MINERALOGICAL ZONATION AT THE BOZSHAKOL PORPHYRY COPPER DEPOSIT: INTEGRATION OF SPECTRAL, MAGNETIC, AND 3D MODELING DATA

This study investigates the mineralogical and spatial characteristics of hydrothermal alteration at the Bozshakol porphyry copper deposit within the Central Asian Orogenic Belt (CAOB) in Kazakhstan. Geological and geophysical exploration conducted from 2018 to 2024 provided an extensive dataset comprising approximately 24,000 meters of drill core samples collected at two-meter intervals. Analytical methods included short-wave infrared (SWIR) spectroscopy using Arcspectro FT-NIR Rocket (900–2600 nm) and TerraSpec4 spectrometer (350–2500 nm), complemented by magnetic susceptibility measurements utilizing a KT-10 kappameter. Spectral data interpretation employed The Spectral Geologist (TSG) software, integrating automated mineral identification (TSA algorithm) and manual validation (Aux Match). This integrated approach precisely mapped hydrothermal alteration zones, delineating potassic, phyllic, and propylitic facies, each defined by distinct mineral assemblages and magnetic signatures. Potassic alteration, located centrally, features secondary biotite and K-feldspar. This transitions outward into a phyllic halo characterized by pervasive sericitization and reduced magnetite content. The peripheral propylitic zone displays abundant chlorite, epidote, carbonate minerals, and elevated magnetic susceptibility due to magnetite preservation. A key outcome was identifying zones rich in chlorite and epidote, known to adversely affect flotation recovery rates, thus impacting ore-processing efficiency. Leapfrog Geo software facilitated 3D modeling, enhancing visualization and structural interpretation of alteration domains. This comprehensive characterization significantly improves geological understanding and supports optimized exploration and processing strategies, demonstrating best practices in applying modern spectroscopic and geophysical methods to porphyry copper deposits.