Caucasus collisional history: Review of data from East Anatolia to West Iran

Abstract

This article summarizes the geodynamic evolution of the Caucasus mountain belt from the Paleozoic to Present based on a review of works from Eastern Anatolia, Greater and Lesser Caucasus and Western Iran. The geological history of crystalline basements provides evidence for their derivation from Gondwana, for their drift at 450–350Ma by roll-back of the South-dipping Rheic slab. Accretion to Eurasia of the Pontides-Transcaucasus block (PTB) occurred in the Carboniferous, and later an active continental margin was formed above a North-dipping subduction zone since at least the Early Jurassic. In the Mesozoic, the Neotethys ocean is separated into two domains, to the North and South of an E-W elongated block, the Taurides–Anatolides-South Armenian (ATA) Block. Two major subduction jumps are accounted for closure of the Tethys domain in Mesozoic to Cenozoic times: (i) jump at 90–80Ma from the Northern to the Southern branch of Tethys after the closure of the northern branch of Neotethys along the Southern Eurasian margin in the Lesser Caucasus following the accretion of the ATA block to the PTB, (ii) jump at c. 40Ma from the Southern branch of Neotethys to the Greater Caucasus back-arc basin (GCB), following the accretion of the ATA-Bitlis to the Arabian margin. The GCB will close completely during the Late Eocene to Pliocene and will give rise to the Greater Caucasus mountains. The Pliocene times mark an abrupt transition from a phase of convergence accommodated by subduction of marginal basins into a ‘hard’ collisional phase dominated by the reactivation of sutures and leading to a generalized uplift and diffuse deformation in the whole region.