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

麻省理工学院的科学家与土库曼斯坦、阿塞拜疆和法国的科学家合作，正在里海地区进行GPS调查，以确定南里海盆地的运动。阿拉伯-欧亚碰撞带的这一部分板块运动鲜为人知，但这是理解碰撞带活动变形的关键。现有资料表明，向西移动、逆时针旋转的安纳托利亚板块和逆时针旋转的小高加索-东土耳其高原的运动与目前的模式不一致。这项研究正在探索这样一种观点，即与非洲岩石圈俯冲有关的过程是观察到的安纳托利亚和小高加索-东土耳其高原运动的根本原因。具体来说，有两种假设正在得到验证：1)一个北倾的板块正在大高加索地区下方积极下沉，将小高加索-东土耳其高原向北拉；2)小高加索-东土耳其高原西侧的北移受到东黑海刚性海洋岩石圈的阻碍，而东侧则受到南里海地块向北平移的牵引。目前正在土库曼斯坦和阿塞拜疆部署一个调查网和连续GPS仪器，为期四年，以便限制该区域的板块运动。该项目的结果将提供阿拉伯-欧亚碰撞区内活动变形的完整运动学图像，并允许确定沿南里海边界断层的应力积累特征，包括沿海西侧的断层，巴库-阿什哈巴德地震带和沿南里海（埃尔博兹山脉）的断层系统。这一新的信息将有助于了解早期大陆碰撞的过程，大陆碰撞带内孤立的海洋岩石圈的消耗，以及影响俯冲、板块拉动和岩石圈剥离的因素。将建立一个新的全球定位系统网络，并将开始一项重要的国际合作，其中将包括培训土库曼斯坦和阿塞拜疆的科学家进行全球定位系统技术和分析。本项目由地球科学部构造学项目和国际科学与工程办公室欧洲和欧亚项目资助。

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.