Integrating seismic reflection profiles, well logs, and field evidence with GPS velocities from a network installed in Calabria, southern Italy, we have discovered that the Crotone basin is gliding toward the Ionian Sea over a buried viscous salt layer. This previously unknown megaslide (~1000 km2) is characterized by an onshore updip extensional domain and an offshore downdip toe‐thrust rim. The GPS velocity from the Crotone station is significantly higher than velocities from other stations in the region and differently oriented. We ascribe at least part of the anomalous GPS velocity from the Crotone station to the seaward motion of the megaslide or part of it. From the GPS velocity and other evidence, we obtain a viscosity of the buried salt layer within the known range of rock salt viscosity in nature.

[1] Data constraining the paleoenvironmental conditions during the Messinian evaporative drawdown of the Mediterranean basin are still conflicting. Here we present a comprehensive paleoclimatic reconstruction during Messinian halite deposition from several Italian sites. We performed fluid inclusion analyses to define better both the composition of the Mediterranean water body and the paleotemperatures of the Messinian brine during halite crystallization. We measured homogenization temperatures on 218 primary all-liquid fluid inclusions in Messinian halite from the Volterra, Crotone, and Caltanissetta evaporite basins. These measurements provided mean homogenization temperatures of 17-18 C, with a range between 10-11 C and 28-29 C, which should be close to the SST of the Mediterranean Sea during halite deposition. The occurrence of major elements such as Cl, Na, Mg, S, Ca, and K within the halite fluid inclusions, together with the presence of minerals such as pentahydrite, polyhalite, and Ca-, K-, and Mg-sulfates, indicates that these salt bodies originated from mainly marine water. Taking into account both the present-day annual SST of the Mediterranean Sea around the sampling sites, which ranges between 18 and 20 C, and the lower latitude of the Mediterranean Basin during the Messinian Salinity Crisis, our homogenization temperatures point to a colder climate during the Messinian halite deposition compared to the present interglacial climate stage. This conclusion is consistent with halite deposition during a Late Miocene glacial interval (TG12).

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The importance and economic interest of rocksalt as well as its influence on tectonics and applicative purposes such as mining, hydrocarbons extraction, and nuclear waste storage are well known. Careful characterization of physical and chemical properties of rocksalt is fundamental as the rocksalt behavior may influence its potential use for applicative purposes. Mechanical and rheological properties of rocksalt have been extensively studied in the past. However, the role of natural heterogeneities within rocksalt and their effect on salt rheology have not been investigated quantitatively. Here we present a comprehensive salt facies study on Messinian rocksalt from several Italian sites (Volterra Basin, Tuscany, Caltanissetta Basin, Sicily and Crotone Basin, Calabria). Four salt facies end members have been identified and analyzed by optical analyses. The main facies-defining characteristics resulted to be the primary salt crystal abundance, crystal size, roundness and orientation, as well as the clay inclusion contents. Three out of four facies were placed on an evolutionary path from an "immature," with respect to the deformation history, to a "mature," rocksalt. So we observed, with increasing rocksalt maturity, a progressive disappearing of primary crystal remnants, increasing crystals elongation and iso-orientation and decreasing in crystal size. This trend has been confirmed by differential stress calculation from subgrain size. Through seismic waves velocity measurements and uniaxial compressive runs, specific salt facies were tested. Results of the investigations demonstrate that the facies parameters have a distinct influence on the rocksalt petrophysical parameters like P-and S-waves velocity, dynamic and static Young Modulus, elastic limit, and strain at peak. Finally, this study allowed to suggest the subdivision of Volterra's salt sequence in three different units that have been subjected to variable deformation degree in response to the different salt characteristics.