The inner parts of the prism were affected by HP-LT recrystallization up to the eclogite facies in the deepest slices. During the second, subaerial stage, a thick tectonic prism composed of continental cover and basement rocks formed under the thrust slab.
At the end of this submarine stage, the oceanic slab moved onto the continental margin while bulldozing volcanic and sedimentary formations into a nappe complex. Such phenomenon might have occurred at a recently active mid-ocean ridge. By contrast, we argue that the magmatism must be ascribed to the fusion of an hydrated, thin mantle wedge at shallow depth during the lithospheric duplication,with partial anatexis in the HT-LP metamorphic sole at the base of the ophiolite.
The first stage was accompanied in the upper plate by a differentiated magmatism that has previously been ascribed to subduction. This lithosphere shortening is a process distinct from subduction and collision. It involved two main stages of thrusting of oceanic lithosphere: i) onto the adjacent oceanic crust and lower continental margin, without emergence ii) onto the upper continental margin, with emergence of the ophiolite. The Oman obduction can be considered as the type-obduction.
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