Development of a litho-structural map for the Upper Mereb area, Eritrea, using multi-source remote sensing data and machine learning models

The Upper Mereb catchment area, located on the Southern zone of Eritrea, is a geologically complex region within the Arabian-Nubian Shield (ANS). The area's intricate litho-structural framework presents significant challenges for mineral exploration and groundwater investigations. Traditional geological mapping techniques often struggle to capture the fine-scale structural details necessary for resource assessments in such complex terrains. This study introduces a novel, high-resolution litho-structural mapping approach, integrating Landsat 9 (L9) multispectral data and gravity data with advanced machine learning algorithms, specifically Artificial Neural Networks (ANN) and Support Vector Machines (SVM). The classification results indicate that ANN outperforms SVM, achieving an accuracy exceeding 79 %, demonstrating the effectiveness of machine learning in distinguishing lithological units. Furthermore, detailed field investigations validate the accuracy of the litho-structural map, showing strong correlations with ground-truth data. A key component of this study is the structural analysis of lineament orientations, which provides critical insights into the tectonic evolution of the region. The Pan-African orogeny has significantly influenced the structural framework, with dominant NE-SW compressional forces creations the fracture patterns. The identified lineaments fall into three primary sets: NW-SE extensional fractures, indicative of crustal stretching; NE-SW release fractures, reflecting zones of stress relaxation; and N-S shear fractures, formed under oblique stress conditions. These structural features highlight the region's complex deformation history and provide essential information for understanding subsurface fluid flow and resource potential. This study represents the first comprehensive application of an integrated remote sensing and geophysical machine learning approach to geological mapping in the Upper Mereb area. The results emphasize the potential of hybrid remote sensing and geophysical data fusion for enhancing structural interpretations, offering a powerful tool for mineral exploration, groundwater assessments, and tectonic studies in the Arabian-Nubian Shield.