Role of the Allahyarlu ophiolite in the tectonic evolution of NW Iran and adjacent areas (Late Carboniferous — Recent)

Abstract

In this paper we reconstruct the tectonic evolution of Eastern Turkey, the Lesser Caucasus and NW-N Iran from the Late Carboniferous to Recent. NW Iran is one of the most complicated regions of the country, that with Turkey and the Lesser Caucasus is influenced by movements of the Arabian Plate. The Ahar Block, which is bounded by the Tabriz, Talysh, Araks, Myaneh and Allahyarlu-Hovai Faults, underwent compression and faulting. The block shows counterclockwise rotation through the confining faults and is being compressed by northward pressure from the Arabian Plate. The age and the nature of the Allahyarlu ophiolite, which is located at the northern boundary of the Ahar Block, are not known unequivocally. During the Late Carboniferous the Allahyarlu-Kaleybar-Northern Iran Basin opened, and Neotethys 1 was spreading. During the Permian the Allahyarlu-Kaleybar-Northern Iran Basin changed from a passive to a convergent environment and closed at Late Triassic to Early Jurassic time. In the Early Jurassic Neotethys 1 began to be subducted, causing the opening of the Sevan-Akera back-arc basin. Thereafter the Sevan-Akera Basin and the Neotethys 2 Basin were widening up to the Late Jurassic. The Black Sea-South Caspian Sea-Kopet Dagh Basin opened during the Jurassic. These basins were widening up to the Paleocene, but northward slider replacement of NW Iran caused the separation of the Caspian Sea Basin and the Black Sea Basin and the formation of the Kurdamir Uplift. In the Late Cretaceous the Central Iran basins were closed and the inner-Iran ophiolites were emplaced. Neotethys 1 closed in the Late Cretaceous and Neotethys 2 in the Late Miocene.