Integrated multispectral remote sensing and field investigations for delineating ophiolitic complexes of Wadi Ghadir southeastern desert Egypt

Abstract

Abstract This study addresses the long-standing challenge of accurately distinguishing ophiolitic rock units in the structurally complex terrains South Eastern Desert of Egypt’s. By integrating multispectral satellite data from Sentinel 2 and Landsat 9 (OLI 2) with substantial field investigation and petrographic analyses, this research proposes an enhanced methodological framework for precise lithological mapping of the Wadi Ghadir ophiolitic complex. Advanced enhanced digital image processing methods for False Color Composites (FCC), Band Ratios (BR), Minimum Noise Fraction (MNF), Principal Component Analysis (PCA), and Maximum Likelihood (ML) classification were systematically applied and evaluated. A newly proposed band ratio combination of Landsat-9 (6/7, 6/5, 6/3) proved highly effective in differentiating serpentinite, talc-carbonate, metagabbro, sheeted dykes, and pillow lavas, while PCA and MNF transforms improved separation of granitic, metasedimentary, and volcanic units. The resulting 1:25,000 scale geological map demonstrates the innovation of integrating complementary satellite sensors with ground validation to overcome spectral confusion and mapping limitations typical of Neoproterozoic ophiolitic terranes. This integrated workflow enhances geological interpretation accuracy and provides a cost effective, reproducible approach for regional mineral exploration and mapping in similar environments.