Internal seismic stratigraphy of the Messinian evaporites across the northern sector of the eastern Mediterranean Sea

Abstract

A dense grid of high-resolutions multichannel seismic reflection profiles from the northern basins of the eastern Mediterranean (Rhodes, Finike, Antalya, Cilicia, Adana and Latakia basin) allow documenting a Messinian evaporite succession of variable thickness, bounded at its base and top by two strong seismic reflectors named respectively BS/BES (or the N-reflector) and TS/TES (or the M-reflector). Messinian evaporite succession is thickest in the deep Antalya Basin (2000–2400 ms twt), but is notably thinner in across the Rhodes and Finike basins in the west and the Adana, Cilicia, Latakia basins in the east. Five acoustically distinctive Messinian subunits are identified in the Antalya Basin (2e–2a): three of these subunits (2e, 2c, 2a) are acoustically stratified with strong laterally continuous reflections while two (2d, 2b) are acoustically transparent with few coherent reflections. Interval velocities and the internal acoustic character of subunits are used in conjunction with correlations with borehole data to suggest the lithological composition of the subunits. Subunit 2e is possibly composed of detrital sediment and resedimented primary lower gypsum, associated with the intensive subaerial erosion immediately after the onset of the Messinian drawdown. Correlations with the DSDP Sites 375 and 376 suggest that the acoustically transparent subunits 2d and 2b are likely composed of massive halite with interbeds of anhydrite, magnesium and potassium salts and minor siliciclastics. Subunit 2c is probably composed of interbedded siliciclastic and evaporites and/or trapped fluids. Subunit 2a probably corresponds to the gypsum horizons interbedded with carbonates and siliciclastics. Comparison between the Messinian subunits in the eastern and western Mediterranean shows remarkable acoustic similarities. In both regions there is a stratified lower subunit (2e), sequentially overlain by a thick transparent subunit (2d), thin stratified subunit (2c) and thick transparent subunit (2b), which are all capped by a mainly stratified subunit (2a). These similarities strongly suggest similarities in the sedimentary evolution of basins in the eastern and western Mediterranean.