Salt tectonics off northern Israel

The Messinian evaporites in the Eastern Mediterranean represent a world class site to study thin-skinned salt tectonic processes like gravity gliding or gravity spreading. In contrast to the Mesozoic evaporites in the Atlantic the related structures are just slightly overprinted by additional tectonic events. New high-resolution reflection seismic data image for the first time the entire lateral succession of gravity gliding-related features as they were suggested by analog models and demonstrate therewith the validity of those models for the Messinian evaporites. All three regimes of extension, translation and compression are present within the range of the seismic profiles. However, additional observations lead to an adapted and improved model. The generation of a critical slope angle caused by subsidence of the Levantine Basin is considered to be the main driving force for the thin-skinned salt tectonics and the lateral basinward creep of the basinal Messinian evaporites. In the extensional section beneath or near to the continental slope, where the basinal evaporites have been withdrawn, listric and antithetic listric growth faults, rollovers and keystone grabens form asymmetric turtleback structures above salt welds and salt rollers. Further basinwards an area with little or no deformation of the evaporites defines the translational segment. In the compressional region the lower and thickest part of the evapofites show ductile deformation (buckle folds), and the upper evaporites reveal brittle deformation (reverse faults and pop-up structures). Here the basinal evaporites have a maximum thickness of about 1500 m. The extensional zone shows continuous synsedimentary tectonic activity until recent times, whereas the compressional structures have developed later in a rather sudden event. There is clear evidence for neotectonics off the Israeli coast which is not related to salt dynamics. Faults cut through the entire pile of evaporites and the Post-Messinian overburden. Where the faults pierce the sea floor, mud escape structures have been observed. Deep rooted faults have been interpreted at the base of the Messinian paleo-slope, suggesting a shear zone off Israel and parallel to the Dead Sea Transform. (c) 2005 Elsevier Ltd. All fights reserved.