The Hecataeus Rise, easternmost Mediterranean: A structural record of Miocene-Quaternary convergence and incipient continent-continent-collision at the African-Anatolian plate boundary

Abstract

The Hecataeus Rise represents a plateau-like structure, adjacent to the southern Cyprus margin and directly next to the Cyprus – Eratosthenes Seamount convergence zone, where incipient continent-continent-collision is believed to occur. Based on newly acquired seismic reflection and bathymetric data, we report on the Miocene to Quaternary structural evolution of this yet underexplored sector along the African-Anatolian plate boundary. A period of pre-Messinian compression has significantly deformed the western and southern part of the plateau area. Offshore continuation of onshore Cyprus lineaments attests the existence of a pre-Messinian structural link between Cyprus and the Hecataeus Rise. Owing to its relatively elevated position during the Messinian Salinity Crisis, the Hecataeus Rise experienced wide-spread Messinian erosion and only local deposition of evaporites which were precipitated within small, isolated sub-basins. Post-Messinian convergence was accommodated along the southeastern flank of the Hecataeus Rise, where NE–SW trending anticlinal structures experienced reactivation and significant growth. A prominent intra-Pliocene-Quaternary unconformity in the northwestern part of the plateau area may correlate with the Pliocene–Pleistocene transition and indicates the near synchronous occurrence of several tectonostratigraphic events. We suggest that these events represent a chain of structural and depositional changes initiated by incipient collision of Eratosthenes Seamount with Cyprus and the northwestern corner of the Hecataeus Rise. Collision-derived uplift of Cyprus resulted in vertical separation between Cyprus and the Hecataeus Rise and the development of a prominent unconformity in the northwestern part of the plateau area. Increasing the slopes adjacent to Cyprus facilitated more energetic downslope sediment transport, expressed by the development of sediment waves and the evolution of a prominent canyon structure at the northeastern limit of the plateau area.