The Mediterranean Salt-Tectonic Supergiant: Salt Distribution and Its Tectonokinematic History

Our research aims at studying the Mediterranean salt-tectonic supergiant. Its geological history includes two noncoeval peaks of salt accumulation: the Triassic and the most known Late Miocene–Messinian. Both peaks are associated with the main tectonic events in the history of the Neo-Tethys and its frame. The Triassic peak is associated with the rift-related emplacement of the Neo-Tethys, while the Messinian peak is associated with the terminal phases of its closure during collision. The author has attempted to substantiate the presence of more ancient buried salt strata in the substrate and at the margins of the Messinian salt basins. The processes of intensive folding of these strata during the collision of paleocontinents and paleomicrocontinents were accompanied by the removal of salt upward from its original location and could have contributed to the accumulation of salts at the Messinian level. This article is based on the results of the author’s long-term integrated lithological and tectonic studies within salt-bearing sedimentary basins in Russia and around the world, as well as a broad generalization of the data available on the Mediterranean region. The article summarizes and analyzes geological and tectonic information on the current distribution of Miocene and Triassic salts in the Mediterranean, as well as their relationships. In addition, the study reveals the spatial relationships between salt deposits, identifies the main morphokinetic types of salt bodies, and characterizes their features in different areas of the Mediterranean. Currently, the pattern of the initial distribution of largely residual Triassic salts has been reconstructed. A key feature of this pattern is the maximum salt deposition along paleorift systems that preceded the formation of passive margins of paleocontinents and paleomicrocontinents. Possible changes in the salt bodies during tectonokinematic transformations in the region and their distribution pattern by the beginning of the Messinian are considered. It has been concluded that the Messinian salt accumulation basins were mainly located within the inner parts of zones of the pre-Messinian distribution of Triassic salts. The collision of paleocontinents and paleomicrocontinents, which intensified at the end of the Miocene, led to a significant increase in the intensity of compression, shearing and disruption of brine-salt sedimentary complexes, widespread along their passive paleomargins. These processes were also accompanied by large-scale tectonokinematic removal of Triassic salt-bearing deposits from these complexes. All this created material prerequisites for their involvement in the allochthonous and neoautochthonous accumulation of salts at the Messinian level and served as one of the probable causes of the Messinian Salinity Crisis.