Thrusting and veining under blueschist facies conditions: multi-technique and multiscalar study of the Little Snake Gorge Thrust, Jabal Akhdar Mountains (Oman)

The Oman Mountains are a complex orogenic system shaped by diverse tectonic events, serving as a natural observatory for studying subduction and obduction. Historically, the Jabal Akhdar Dome, a prominent tectonic window located in their central-eastern sector, was thought to have undergone only low-grade metamorphism, unaffected by deep subduction during the Cretaceous. However, recent discoveries challenge this view. Evidence of Cretaceous blueschist-facies metamorphism indicates high-pressure, low-temperature conditions typical of subduction channels. Studies in the “Little Snake Gorge” area have yielded new structural and metamorphic data, prompting a reassessment of the dome’s evolution. Deformation structures linked to the “Little Snake Gorge Thrust,” along with metamorphic aragonite in foliation-parallel veins, support a Cretaceous high-pressure overprint, likely tied to Late Cretaceous subduction of the Arabian margin beneath Eurasia. Subduction caused complex folding in Precambrian rocks, with alternating brittle and ductile phases. Structural data reveal deformation styles associated with high-pressure metamorphism. To define metamorphic conditions, Raman Spectroscopy on Carbonaceous Material (RSCM) was used, yielding peak conditions of ~348 ± 50 °C and 0.85 ± 0.12 GPa in the Mu’aydin Formation footwall. A model of progressive deformation, based on U-Pb geochronology, describes the evolution of the Little Snake Gorge Thrust, highlighting stress-axis rotation during Late Cretaceous subduction. The deformation history includes an initial SW-NE layer-parallel shortening, followed by folding and thrusting under blueschist conditions, and a final NNW-SSE folding phase linked to stress-field rotation, forming the interference structures observed today. These results enhance understanding of high-pressure metamorphism and support revising tectonometamorphic models for the Jabal Akhdar Dome.