Lithospheric Thinning of the Northeastern Arabian Margin Revealed by Matrix‐Free Teleseismic Traveltime Tomography

Abstract The obduction of the Tethys oceanic lithosphere is documented by the Semail ophiolite along the northeastern Arabian continental margin. Although the ophiolite is continuous and of similar age across the region, the eastern and western segments display distinct geological contrasts. To investigate the deep structural mechanisms underlying these surface variations, we applied teleseismic traveltime tomography using an advanced eikonal solver and a matrix‐free adjoint‐state approach on data from a dense seismic array. Our 3D upper mantle P‐wave model reveals a significant velocity contrast, with positive anomalies in the west and negative anomalies in the east, separated by a prominent fault zone. We propose that the continental lithosphere beneath northeastern Arabia underwent thinning during the Permian breakup of Pangaea. This pre‐obduction lithospheric segmentation likely influenced the subduction dynamics associated with the ophiolite obduction process. Additionally, early Cenozoic thermal activity may have further amplified lithospheric thinning, contributing to the observed structural variations.