Dumak ophiolitic mélange, west of Zahedan (Eastern Iranian Range) Special focus on petrographic and geochemical properties of pillow lavas and sheeted dikes

The Dumak ophiolitic mélange in the Baluchistan region is one of the ophiolitic mélanges that contains all of the components of a complete ophiolite, located in the middle parts of the western margin of the Eastern Iranian range. Field studies indicate the presence of a large volume of pillow lavas in different parts of the Dumak mélange. The outcrop of sheeted dikes associated with the Dumak mélange is limited to the Shuru region. These dikes present below the pillow lava and Cretaceous pelagic sediments. Compositionaly, most of pillow lavas and sheeted dikes are basalt. Variations in SiO2 to FeOt/MgO in the pillow lavas and sheeted dikes indicates a tholeiitic trend for their productive magma. The pattern of REE elements and amounts of (La/Sm)N in these rocks are similar to E-MORB. The study of pillow lavas and sheeted dykes of Dumak ophiolitic mélange shows that the MORB ophiolitic body in Dumak has been gradually and continuously evolved in a supra-subduction zone environment and beginning of intra-oceanic subduction. Considering structural evidence of the region, after adding the Dumak ophiolite to the Lut block, during the continuation of tectonic movements related to orocline bending, a new mélange has formed with the presence of Eocene carbonate blocks.