Hajar Mountains

The Hajar Mountains run about 700 kilometers across northern Oman and the United Arab Emirates, roughly 100 kilometers wide, sitting on the northeast corner of the Arabian Plate some 50 to 100 kilometers inland from the Gulf of Oman. Their highest peak, Jabal Shams, reaches 3,009 meters. The range is built from four major rock groups: pre-Permian basement clastics, carbonates and evaporites; middle Permian to Late Cretaceous shelf carbonates; transported nappes including the Semail Ophiolite, a slab of oceanic crust thrust onto the continent; and late Cretaceous to Miocene sedimentary rock, with eclogite exposed at Saih Hatat that had been subducted to about 80 kilometers depth into the mantle before being pushed back to the surface. Mountain building came in phases: initial uplift during the Late Cretaceous as the African-Arabian Plate was overridden by oceanic crust, a second deformation episode in the Eocene around 45 to 40 million years ago, and the range's modern topography taking shape sometime between the late Eocene and the Miocene, with the exact timing still debated among geologists. This entity documents the Hajar Mountains specifically as a geological formation built by ophiolite obduction and multi-phase continental mountain building.