Messinian Onset of Central Anatolian Plateau and Tauride Mountain Uplift as Evidenced by the Formation of an Orographic Barrier

Abstract:

The Central Anatolian Plateau (CAP) and the Tauride Mountains form part of the Anatolian plate. Westward escape of the Anatolian plate along large-scale strike-slip faults in response to Arabia-Eurasia collision is accommodated by extension and slab retreat in the Aegean domain. The CAP is currently characterized by NE-SW extension, which was suggested to have started in the latest Miocene, similarly timed to an acceleration of slab retreat in the Hellenic subduction zone.

Uplift of the CAP and its southern Tauride margin occurred within this context, and uplift of the Central Tauride Mountains occurred after ~7 Ma, as evidenced by marine deposits currently exposed at 1.5-2 km altitude. By the latest Miocene to Pliocene, the presence of an eroding topography is indicated by conglomeratic fluvial deposits in the Adana, Cilicia and Antalya basins.

Within the framework of the Continental Dynamics–Central Anatolian Tectonics project, we aim at further constraining the onset of CAP and Tauride uplift. Latest Oligocene to Pliocene lacustrine deposits on the CAP (i.e. N of the Tauride Mountains) were sampled for carbon and oxygen stable isotope analysis. The combination of δ¹³C and δ¹⁸O values forms a proxy for paleoenvironment, and δ¹⁸O values form a proxy for the development of an orographic barrier between the Mediterranean Sea and the CAP. Age constraints were obtained from magnetostratigraphy and ⁴⁰Ar/³⁹Ar dating, as well as published mammal associations. The δ¹⁸O values in combination with geologic observations suggest that the onset of uplift occurred after ~6.5 Ma. A 3-4‰ drop of δ¹⁸O values by 5 Ma indicates the presence of an orographic barrier and therefore the uplift of the Tauride Mountain belt. Based on our stable isotope data from well-dated sections, we conclude that a significant part of the uplift of the Tauride Mountains took place soon after their emersion.