Structural and thermal analysis of geothermal prospectivity in the Midyan Basin, NEOM, Saudi Arabia

Abstract

The Midyan Basin in the NEOM region of northwestern Saudi Arabia is a promising yet underexplored geothermal province situated within the tectonically active Red Sea Rift and Gulf of Aqaba transform system. Despite evidence of elevated regional heat flow and shallow Curie depths, the structural controls governing geothermal fluid circulation remain poorly constrained. This study identifies structurally controlled geothermal targets by integrating remote sensing, airborne geophysics, and field observations within a unified exploration framework. Multi-temporal Landsat-8 imagery acquired during six months of the year 2024 was used to derive land surface temperature (LST) through radiance-to-brightness temperature conversion and NDVI-based emissivity correction. Surface structural lineaments were interpreted from multidirectional hillshade models derived from a 30-m digital elevation model (DEM), while subsurface fault systems were delineated from airborne magnetic data using tilt-derivative analysis. Fault fracture density (FFD) mapping identified structurally enhanced permeability zones, which were integrated with persistent LST anomalies to delineate geothermal prospectivity. The analysis identified 5,809 surface lineaments and 1,262 basement-rooted magnetic lineaments, both dominated by NW–SE and NE–SW structural trends associated with the Red Sea Rift and Gulf of Aqaba transform system. Geothermal prospectivity is concentrated within discrete basement-rooted fault corridors rather than being uniformly distributed across the basin. The highest-confidence targets occur along the western and northwestern coastal escarpments, where high surface and subsurface fracture densities spatially coincide with persistent multi-season thermal anomalies, indicating enhanced permeability and structurally controlled heat transfer. Three priority geothermal target zones (Surface Zones A, B, and C and corresponding Subsurface Zones A′, B′, and C′) were identified, with Zone B/B′ representing the most prospective area owing to its strong structural continuity across surface and subsurface datasets. Field observations of dense fracture networks, fault-controlled granite–carbonate contacts, and subvertical dike swarms further corroborate the interpreted permeability pathways. Although direct geothermal manifestations and drilling data are not yet available, the integrated structural, thermal, and field evidence demonstrates that the Midyan Basin possesses favorable geological conditions for both hydrothermal resources and Enhanced Geothermal Systems (EGS). The proposed workflow provides a robust, cost-effective screening approach for reducing exploration uncertainty and prioritizing geothermal targets. It also guides future geothermal exploration and development within NEOM.