Comprehensive geophysical and remote sensing studies of orogenic and intrusion-related gold systems in the Zalm-Ad Duwayhi Dhalhat Shahbab belt of the Saudi Arabian shield

Abstract

This study presents an integrated geological and geophysical investigation of the Zalm-Ad Duwayhi-Dhalhat Shahbab gold belt within the Saudi Arabian Shield, combining remote sensing (Landsat-8 OLI), aeromagnetic data, and field observations to map lithological units, structural fabrics, and hydrothermal alteration zones across the Zalm, Zalm-As Suq, and Ad Duwayhi regions. Advanced spectral analysis, including band ratios and Principal Component Analysis, was used to identify alteration minerals and assess their spatial relationship to major fault networks and gold mineralization. Aeromagnetic data, processed with reduced-to-pole (RTP), upward continuation, and Logsigm Function (LSF) filtering at multiple depths, reveal persistent NW-trending structures that become more continuous and dominant with depth, while locally significant subsidiary trends appear at shallower levels. The close association of gold deposits with these major structures and intrusive complexes underscores the importance of fault systems, magmatic events, and hydrothermal processes in ore localization. The study characterizes both orogenic (OGS) and intrusion-related (IRGS) gold systems, highlighting the Ad Duwayhi deposit as a major Neoproterozoic IRGS with over one million ounces of confirmed resources. Overall, the multi-scale integration of geological and geophysical methods provides new insights into the structural, lithological, and mineralization controls in this mineral-rich segment of the Arabian Shield, offering valuable guidance for future exploration and resource assessment in Precambrian terranes.