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

## TL;DR

This study improves geological mapping of ophiolitic rocks in Egypt's desert using satellite data and fieldwork.

## Contribution

A new band ratio combination for Landsat-9 enhances differentiation of ophiolitic rock units.

## Key findings

- The proposed band ratio (6/7, 6/5, 6/3) effectively distinguishes serpentinite and related rock types.
- PCA and MNF transforms improve separation of granitic and volcanic units.
- The integrated method produces a detailed 1:25,000 scale geological map of Wadi Ghadir.

## 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.