The structure of the Africa‐Anatolia plate boundary in the eastern Mediterranean

Abstract

New marine deep seismic reflection data from south of Cyprus to the Syrian coast provide images of the upper crustal structure of the Cyprean Arc indicating that the deformation is partitioned along strike‐slip fault systems distributed over a wide zone, rather than forming a sharp plate boundary between African and Anatolian plates. Three major submarine strike‐slip fault systems, tens of kilometers in length, are mapped, which follow bathymetric features and merge together toward the east. These structures exhibit the three‐dimensional characteristics typical of strike‐slip deformation zones throughout the seven pre‐stack depth‐migrated sections, including several sets of positive flower structures forming bathymetric ridges, and the intervening contemporaneous subbasins. Beneath the Plio‐Quaternary sediments (500 m thick) that are blanketing the whole area and that reflect only the main surface traces of the fault systems, the subbasins are of varied dimensions and have rapid lateral changes in the thickness of the sedimentary fill. They include two major unconformities that have been correlated throughout the data marked by the M and K reflections. The M reflection is well imaged above varied thickness of Messinian evaporites, and the K reflection commonly appears at the base of syntectonic Tertiary age sediments. Within the eastern Cyprean Arc the K reflection corresponds to the basement‐cover contact, indicating that the strike‐slip tectonic scenario may have been active since the uppermost Cretaceous or lowermost Paleogene times to present. The active deformation front of the Alpine belt in the eastern Mediterranean corresponds to a strike‐slip fault system that forms a 110° arc and coincides at the southern slope of the Hecateaus Rise, continuing along the Latakia Ridge to the Syrian coast. The mapped structures fit within a general kinematic framework of left‐lateral transcurrent deformation that transfers slip from the subduction zone southwest of Cyprus into the Dead Sea transform system in the east. This change in the mode of deformation at the Africa‐Anatolia plate boundary occurs toward the junction between African, Anatolian, and Arabian plates.