The complex tectonic regime of the Cyprus Arc: A short review

The tectonic regime of the Cyprus Arc is commonly considered to be that of a compressional zone between the northward-moving African Plate and the southward- moving Eurasian Plate, a tectonic compression that is bound to close the eastern Mediterranean in the foreseeable geological future. The Cyprus Arc is therefore presumed to be the product of that compression. The site where the Tethyan oceanic lithosphere off NE Africa is being subducted northward under the Anatolian Plate. Characteristic of this process was the apparent subduction of Eratosthenes Seamount, which seems to be thrusting northwards under the Cyprus Arc, and also to be pushing up and uplifting the Troodos massif. It was presumed further that the concurrent converging motion of Africa and Anatolia, the subsidence of Eratosthenes Seamount, and the uplift of Troodos would lead to the obduction of the Troodos ophiolite on top of the continental lithosphere of Eratosthenes Seamount. However, this interpretation is incompatible with recently acquired evidence that Anatolia is not moving southwards. Abundant GPS evidence shows that Anatolia is moving westwards, and the rate of that displacement increases westwards as well, from east Anatolia to the Aegean Sea. Furthermore, the structural layout of the eastern segment of the Cyprus Arc, from Hecataeus Plateau to western Syria, is not compressional but transtensional. Salt diapirs that were reported from Cilicia basin suggest normal faulting and extension there. The structural evidence of compressional strain and thrust faulting is discernible in a few locations, such as the southern flank of the arc, between Cyprus and Eratosthenes Seamount, and southward-verging thrust faults, dated to the Plio-Quaternary, are known in the Kyrenia Range in northern Cyprus. Recent earthquakes show sinistral transpressional motions along the Cyprus Arc off SW Cyprus and the Florence Rise, while extensional earthquakes are abundant in the region of southern Anatolia off Cyprus. These GPS and earthquake measurements suggest that the westward Anatolian motion can be attributed to the rollback of the Ionian subduction and the subsequent growth of the Aegean Sea. Therefore, the composite tectonic regime of the Cyprus Arc shows fingerprints primarily of the extensional growth of the Aegean Sea, but also of the motion of Africa toward Anatolia.