Obduction versus subduction and collision in the Oman case and other Tethyan settings

Abstract

The Oman obduction can be considered as the type-obduction. It involved two main stages of thrusting of oceanic lithosphere: 1) onto the adjacent oceanic crust and lower continental margin, without emergence; 2) onto the upper continental margin, with emergence of the ophiolite. This lithosphere shortening is a process distinct from subduction and collision. The first stage was accompanied in the upper plate by a differentiated magmatism that has previously been ascribed to subduction. 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. -from Authors