Mineral chemistry of the ophiolitic peridotites and gabbros from the Serow area: Implications for tectonic setting and locating the Neotethys suture in NW Iran

摘要

The Serow ophiolite in NW Iran, located at the Iran-Turkey border, is composed of mantle sequence peridotites, predominantly lherzolitic-harzburgite with subordinate amounts of lherzolite and dunite, and a crustal sequence made from gabbros, diabases, pillow lavas and deep marine carbonates and radiolarite sediments. The rocks appear as a tectonic mélange. This ophiolitic complex forms part of the ophiolites marking a branch of Neotethys oceanic crust in NW Iran. The chemistry of olivine, orthopyroxene and clinopyroxene in the lherzolitic-harzburgite and clinopyroxene in the gabbros suggests a supra-subduction setting for the ophiolite. The Serow ophiolite is similar to other ophiolites in NW Iran such as the Piranshahr, Naghadeh and Khoy and NE Turkey ophiolites in terms of the rock units, tectonic setting and age. The Serow ophiolite links the Iranian ophiolites from Baft in the SE through the South Azerbaijan suture to the Izmir-Ankara-Erzincan suture in the NW.