The journey of the Band-e-Zeyarat ophiolite (Makran Accretionary Wedge, SE Iran) from the mid-ocean ridge to the accretionary complex: new insights from its sedimentary cover and associated basaltic dykes and sills

The sedimentary cover of the Band-e-Zeyarat ophiolite (BEZO) in the Makran Accretionary Prism (SE Iran) records a complex tectono-sedimentary evolution, extending from its formation at a mid-ocean ridge setting to deformation in an accretionary prism. Stratigraphic and biostratigraphic data indicate the occurrence of a Valanginian transition zone sequence separating the volcanic rock types and pelagic sedimentary cover. The latter consists of lower Hauterivian cherty limestone passing upwards to upper Hauterivian – Barremian marl and limestone. The pelagic sedimentary cover continues with post-Barremian – Cenomanian (?) marls. Arenites are interlayered in the sequence of the sedimentary cover; they are composed of rock fragments derived from volcanic arc and continental margin settings. The sedimentary cover of the BEZO is intruded by dykes and sills showing enriched mid-ocean ridge basalt chemical affinity. Structural analysis indicates a polyphase deformation history that involved faulting and folding. The results of our multidisciplinary study indicates that the BEZO formed in a mid-oceanic ridge (MOR) setting and that it was subsequently overprinted by off-axis and within-plate magmatism as it spread away from this MOR. The Band-e-Zeyarat oceanic crust was incorporated into the Makran accretionary prism in the latest Late Cretaceous – Paleocene, and was further deformed via strike-slip faulting along the dextral Minab-Sabzevaran fault during the Miocene - Pliocene.