Deciphering the Dynamics of Continental Deformation in the Arabia-Eurasia Collision Zone

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Scientists from the Massachusetts Institute of Technology in collaboration with scientists from Turkmenistan, Azerbaijan, and France are carrying out a GPS investigation in the Caspian Sea region in order to determine the motion of the South Caspian Basin. The plate motion of this portion of the Arabian-Eurasian collision zone is poorly known yet key to understanding the active deformation with the collision zone. Existing data indicate that motions of the westward moving, counter-clockwise rotating Anatolia plate and the counter-clockwise rotating Lesser Caucasus-East Turkey Plateau are inconsistent with current models. This study is exploring the idea that processes associated with subduction of the African lithosphere are fundamentally responsible for the observed motion of Anatolia and the Lesser Caucasus-East Turkey Plateau. Specifically, two hypotheses are being tested: 1) A north-dipping slab is actively sinking beneath the Greater Caucasus, pulling the Lesser Caucasus-East Turkey Plateau northward; 2) The northward motion of the west side of the Lesser Caucasus-East Turkey Plateau is retarded by the rigid oceanic lithosphere of the East Black Sea, while the east side is dragged northward by the northward translating South Caspian block. A network of survey and continuous GPS instruments is being deployed in Turkmenistan and Azerbaijan for four years in order constrain the plate motions in this region.Results from this project will provide a complete kinematic picture of active deformation within the Arabia-Eurasia collision zone and allow determination of the character of strain accumulation along the South Caspian boundary faults, including faults along the west side of the Sea, the Baku-Ashkhabad seismic zone, and the fault systems along the SouthCaspian (Elborz Mountains). This new information will lead to advances in understanding the processes of early continental collision, the consumption of isolated ocean lithosphere within continental collision zones, and the factors that influence the initiation of subduction, slab pull, and lithospheric delamination. A new GPS network will be established and a significant international collaboration will be initiated and will involve training of Turkmenistan and Azerbaijan scientists in GPS techniques and analysis. This project is supported by the Tectonics Program in the Earth Sciences Division and the Europe and Eurasia Program in the Office of International Science and Engineering.