Subduction termination through progressive slab deformation across eastern Mediterranean subduction zones from updated P-wave tomography beneath Anatolia

• Published in: Geosphere (Boulder, Colo.) Vol. 14; no. 3; pp. 907 - 925
• Main Authors: Portner, Daniel Evan, Delph, Jonathan R, Biryol, C. Berk, Beck, Susan L, Zandt, George, Ozacar, A. Arda, Sandvol, Eric, Turkelli, Niyazi
• Format: Journal Article
• Language: English
• Published: Geological Society of America 01.06.2018
• Subjects: Anatolia; applied (geophysical surveys & methods); Asia; body waves; elastic waves; geophysical methods; geophysical surveys; Geophysics; lithosphere; mantle; Middle East; P-waves; passive methods; plate tectonics; seismic methods; seismic waves; slabs; solid Earth (tectonophysics); subduction; surveys; teleseismic signals; three-dimensional models; tomography; traveltime residuals; Turkey; velocity structure
• ISSN: 1553-040X; 1553-040X
• DOI: 10.1130/GES01617.1

Using finite-frequency teleseismic P-wave tomography, we developed a new three-dimensional (3-D) velocity model of the mantle beneath Anatolia down to 900 km depth that reveals the structure and behavior of the subducting African lithosphere beneath three convergent domains of Anatolia: the Aegean, Cyprean, and Bitlis-Zagros domains. The Aegean slab has a relatively simple structure and extends into the lower mantle; the Cyprean slab has a more complex structure, with a western section that extends to the lower mantle with a consistent dip and an eastern section that is broken up into several pieces; and the Bitlis slab appears severely deformed, with only fragments visible in the mantle transition zone and uppermost lower mantle. In addition to the subducting slabs, high-amplitude slow velocity anomalies are imaged in the shallow mantle beneath recently active volcanic centers, and a prominent fast velocity anomaly dominates the shallow mantle beneath northern Anatolia and the southern Black Sea. As a whole, our model confirms the presence of well-established slow and fast velocity anomalies in the upper mantle beneath Anatolia and motivates two major findings about Eastern Mediterranean subduction: (1) Each of the slabs penetrates into the lower mantle, making the Eastern Mediterranean unique within the Mediterranean system, and (2) the distinct character of each slab segment represents different stages of subduction termination through progressive slab deformation. Our findings on the destructive processes of subduction termination and slab detachment have significant implications for understanding of the post-detachment behavior of subducted lithosphere.