Revealing prospective locations of hydrothermal alteration zones (HAZs) is an important technique for mineral prospecting. In this study, we used multiple criteria inferred from Landsat-8 OLI, Sentinel-2, and ASTER data using a GIS-based weighted overlay multi-criteria decision analysis approach to build a model for the delineating of hydrothermal mineral deposits in the Khnaiguiyah district, Saudi Arabia. The utilized algorithms revealed argillic, phyllic, and propylitic alteration characteristics. The HAZs map resulted in the identification of six zones based on their mineralization potential, providing a basis for potential hydrothermal mineral deposit assessment exploration, which was created by the fusion of mineral bands indicators designated very low, low, moderate, good, very good, and excellent and covers 31.36, 28.22, 20.49, 10.99, 6.35, and 2.59%. Based on their potential for hydrothermal mineral potentiality, the discovered zones match gossans related to sulfide mineral alteration zones, as demonstrated by previous studies.

Situated along the Yanbu Suture Zone, the Al-Wask ophiolite is one of the largest and best-preserved ophiolite sequences in the Proterozoic Arabian shield. A mantle section of serpentinized ultramafics is structurally overlain by a crustal section of gabbros and pillow lavas. The whole ophiolite sequence is capped by pelagic sedimentary cover, and tectonically emplaced over a metamorphosed island-arc volcano-sedimentary succession. The Al-Wask ultramafic rocks are strongly deformed, metamorphosed, and altered by carbonatization and silicification. Samples dominated by antigorite indicate upper greenschist to lower amphibolite facies peak metamorphic grade, whereas samples dominated by lizardite and magnesite preserve lower grade conditions that we interpret as a cooling path buffered to low CO₂ activity by the increasing stability of magnesite with decreasing temperature. Nearly all the primary silicate minerals have been replaced by serpentine minerals, leaving only relics of primary olivine and chromian spinel. Petrographic observation of relict olivine and spinel and of mesh and bastite textures in the serpentines suggest that the peridotite protoliths were mainly harzburgite with minor dunite. Whole-rock compositions of serpentinites show low CaO (<0.1 wt.%), Al₂O₃ (<1.5 wt.%), and Y ( 60) and low TiO₂ (≤0.2 wt. %) of spinel and high forsterite contents (90–92) of associated olivine indicate residual mantle that underwent extensive partial melt extraction. The whole-rock and mineral chemistry of the serpentinized ultramafic rocks are both consistent with extracted melt fractions from ∼32 to 38 percent. This extent of melting is typical of fore-arc supra-subduction zone settings, which is the most likely tectonic environment for formation and preservation of the Al-Wask ophiolite.