A terminal Messinian flooding of the Mediterranean evidenced by contouritic deposits on Sicily

Abstract

The evolution of marine gateways and sea straits exerts major control on bottom current depositional systems. A well‐known interval in geological history characterized by frequent changes in marine connectivity is the Messinian Salinity Crisis (5.97 to 5.33 Ma) when the Mediterranean allegedly experienced major (>1 km) sea‐level drawdown followed by a catastrophic marine replenishment at the base of the Zanclean. Controversy exists around the timing and mode of this event as unambiguous flood deposits have so far never been drilled or recognized in outcrops. In the Sicilian Caltanissetta Basin (Italy), the Messinian/Zanclean boundary is directly underlain by the Arenazzolo Formation. This 5 to 7 m thick sandy sedimentary interval may reveal a genetic link with the abrupt refilling of the Mediterranean, but at present a detailed study to understand its origin is lacking. In this work, the Arenazzolo Formation at Eraclea Minoa has been studied by a multi‐method approach, employing detailed facies description, grain‐size analyses, petrographic analyses and palaeocurrent analyses. Palaeogeographical reconstructions and facies associations show that the Arenazzolo Formation sands were deposited on the northern flank of the Gela thrust front by persistent bottom currents, flowing parallel to the regional slope physiography, during a transgression. It is hypothesized that these currents are associated with the active circulation of surface and intermediate water masses coeval with a terminal Messinian flood, when basin margins overtopped and a reconnection between western and eastern Mediterranean was created. The Arenazzolo Formation is a unique example of a contouritic deposit formed by bottom currents that establish during the reconnection of major isolated water bodies.

New insights on the latest Messinian-to-Piacenzian stratigraphic series from the Dahra Massif (Lower Chelif Basin, Algeria): Lago Mare, reflooding and bio-events

“…marine conditions although they were ascribed to the basal Pliocene without paleontological argument (Rouchy et al, 2007). These data confirm the uppermost Messinian age of the Mediterranean reflooding (Cavazza and De Celles, 1998;Londeix et al, 2007;Carnevale et al, 2008;Bache et al, 2012;Do Couto et al, 2014;Clauzon et al, 2015;Suc et al, 2015;Popescu et al, 2021;Van Dijk et al, 2023).…”

“…The Messinian-Zanclean boundary, dated at 5.33 Ma, corresponds to the FAD of R. cisnerosii (Mazzola, 1971;Belkebir and Anglada, 1985;Backman et al, 2012;Popescu et al, 2017;Osman et al, 2021;Mansouri, 2021). It thus dates the marine reflooding before the early Zanclean (R. cisnerosii occurrence) (Mansouri, 2021;Cavazza and De Celles, 1998;Londeix et al, 2007;Carnevale et al, 2008;Bache et al, 2012;Do Couto et al, 2014;Clauzon et al, 2015;Suc et al, 2015;Popescu et al, 2021;Van Dijk et al, 2023).…”

Reconstructing the Evolutionary History of Pinna nobilis: New Genetic Signals from the Past of a Species on the Brink of Extinction

“…This discrepancy may be explained by the direction of the Zanclean flooding, initially involving the central part of the Mediterranean and excluding, at least in the initial phase, the Iberian Peninsula area [ 93 ]. The Zanclean flood also created a seabed incision (the Zanclean channel) through the erosion produced by the flooding waters [ 68 , 94 ], establishing a direct connection between the Atlantic and the central Mediterranean through the hydrographic constriction produced by the Strait of Gibraltar [ 93 , 95 ]. The areas laterally distant from this dashing flow were initially excluded [ 89 , 93 ].…”

New palaeocurrent analysis approach from two‐dimensional trough cross‐strata using photographs and anisotropy of magnetic susceptibility

“…Others have proposed that the Arenazzolo Formation is a transgressive sequence, linked to the Zanclean reflooding of the Mediterranean (Brolsma, 1978; Londeix et al., 2007; Bache et al., 2012; Popescu et al., 2021). Recently, it was interpreted as an along‐slope contouritic deposit, based on palaeocurrent directions among other criteria, related to a terminal Messinian flooding event (Van Dijk et al., 2023). Two trough cross‐stratified cosets of the Arenazzolo Formation that are exposed in two coastal outcrops with an 80° angle between them are analysed here (Figure 1).…”