Inversion structures across the crest of the Larnaka Ridge associated with strike-slip faulting during the uppermost Messinian–Quaternary, eastern Mediterranean

Abstract The structural evolution of the Larnaka Ridge is studied using high-resolution multichannel seismic reflection profiles and multibeam mosaics of the seafloor. Multibeam maps revealed the presence of two families of en-echelon tension cracks (young and old) on the seafloor north of the ridge. Rose diagram on the young tension cracks revealed that most lineations are oriented NW–SE, where the instantaneous tensile σ3 is oriented NE–SW. The old tension cracks are oriented N-S, here the instantaneous tensile σ3 is oriented E–W. In addition, the seafloor in the Latakia Basin and over the crest of the Latakia Ridge includes by several prominent ridges and their intervening valleys, forming four groups of seafloor lineations, each having a distinctive orientation, including ENE–WSW, ESE–WNW, NE–SW and NNW–SSE. The multichannel seismic reflection profiles revealed that (a) the ridges and valleys are developed exclusively within the uppermost Messinian–Quaternary Unit 1, bounded at their tops by the seafloor and bases by the top erosional surface (TES), (b) there is a reciprocal relationship between the seafloor and the TES, such that when the seafloor goes up, the TES goes down, (c) there is a prominent mid–Unit 1 unconformity (γ-reflector), which separates the convex-up reflectors of the upper subunit 1a from the convex-down reflectors of the lower subunit 1b. These sedimentary structures are developed as a series of positive and negative flower structures along the Amanos–Larnaka fault zone, a prominent sinistral strike-slip system in the eastern Mediterranean. The data show evidence of a switch during the Quaternary of the direction of the principal maximum compressive stress from N-S to NW–SE, probably associated with the docking of the Eratosthenes Seamount which must have fixed the northwestern margin of the Sinai Block, allowing the northeastern sector to freely rotate counterclockwise.