GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 1.1 GNGTS 2023 The central transect (Strakhov-8) is located south of Cyprus. From south to north, this profile shows the Eratosthenes Continental Block, the Cyprus Trench, and its accretionary wedge. The Eratosthenes Continental Block is faulted by active extensional faults due to the weight of the upper plate that is overriding the lower one. As this block has a thicker crust than the surrounding Levant Basin (thinned continental crust) and the Herodotus Basin (oceanic crust), it now acts as an inhibitor to the propagation of the Cypriot accretionary wedge. This inhibitory behaviour is also witnessed by the uppermost reflectors in the Cyprus Trench. The lower part of the Plio-Quaternary succession is characterised by growth strata that flatten in the upper part. This effect is related to a minor propagation of the Cyprus Arc in this sector. In fact, from the Pleistocene onwards, the island of Cyprus experienced a strong uplift due to the docking of this thick continental block, which stopped the horizontal spreading and triggered the vertical movements (Fig.2b). The eastern transect (MS56) crosses the Latakia Ridge, i.e., the northern boundary of the Levant Basin. The seismic line continues north into the Cyprus-Latakia Basin, crosses the Kyrenia Ridge and reaches the Turkish coast. On the seismic section we interpreted the Mesozoic subduction front, which is now hindered by strike-slip motions on the Latakia Ridge. Another prominent transpressive structure is the Kyrenia Ridge, which is interpreted as an active structure with a well-imaged thrust system in front of it (Fig.2c). DISCUSSION AND CONCLUSION Our data allowed an accurate reconstruction of the evolution of these convergent margins from the Messinian to the Quaternary in the western and central transects and from the Paleogene in the eastern transect (Fig.2). Moving from west to east with respect to Cyprus, it was possible to analyse the evolution of this convergent margin from oceanic subduction to continent-continent collision. The characteristic features are a thinner accretionary wedge to the west and a thicker and more deformed wedge towards the east. The trenches also vary along strike: the Herodotus Basin has a poorly developed trench due to the small amount of sediment that can reach it as the Florence Rise is a structural barrier. South of Cyprus, the trench is well developed and records the recent evolution of this system, and on the eastern transect, there is no trench as strike-slip movements dominate today. This interpretation is also supported by the earthquake location, which becomes shallower from west to east (Güvercin et al., 2021) and is in good agreement with the gravimetric (Ergün et al., 2005) and magnetic studies (Rybakov et al., 2011). REFERENCES Brew, G., Barazangi, M., Al-Maleh, A. K., & Sawaf, T. (2001). Tectonic and geologic evolution of Syria. GeoArabia , 6 (4), 573-616. Calon, T. J., Aksu, A. E., & Hall, J. (2005). The Neogene evolution of the outer Latakia Basin and its extension into the eastern Mesaoria Basin (Cyprus), eastern Mediterranean. Marine Geology , 221 (1-4), 61-94. Ergün, M., Okay, S., Sari, C., Oral, E. Z., Ash, M., Hall, J., & Miller, H. (2005). Gravity anomalies of the Cyprus Arc and their tectonic implications. Marine Geology , 221 (1-4), 349-358.