The Western Tyrrhenian Sea revisited: New evidence for a rifted basin during the Messinian Salinity Crisis

Gael Lymer (1) , Johanna Lofi (2) , Virginie Gaullier (3) , Agnes Maillard (4) , Isabelle Thinon (5) , Francoise Sage (6) , Frank Chanier (3) , Bruno Claude Vendeville (3)

1 University of Birmingham
2 Géosciences Montpellier
3 LOG - Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187
4 GET - Géosciences Environnement Toulouse
5 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)
6 GEOAZUR 7329 - Géoazur

In the last fifty years, the Messinian Salinity Crisis (MSC) has been widely investigated in the Mediterranean Sea, but a major basin remains fewly explored in terms of MSC thematic: the Western Tyrrhenian Basin. The rifting of this back-arc basin is considered to occur between the Middle-Miocene and the Early-Pliocene, thus including the MSC, giving a unique opportunity to study the crisis in a context of active geodynamics. However the MSC seismic markers in the Western part of the Tyrrhenian Sea have only been investigated in the early eighties and the MSC event in the Western Tyrrhenian Basin remains poorly studied and unclear. In this study, we revisit the MSC in the Western Tyrrhenian Basin, i.e. along the Eastern Sardinian margin. We present results from the interpretation of a 2400 km long HR seismic-reflection dataset, acquired along the margin during the “METYSS” research cruises in 2009 and 2011. The maps of the MSC seismic markers reveal that the Eastern Sardinian margin was already dissected in structurals highs and lows during the MSC. We also demonstrate that the MSC markers constitute powerfull time-markers to refine the age of the rifting, which ended earlier than expected in the East-Sardinian Basin and the Cornaglia Terrace. These results allow us to discuss the palaeo water-depth of the Western Tyrrhenian Basin during the MSC, as well as implications for possibles scenarios of the Messinian Salinity Crisis across the Eastern Sardinian margin

Domaines: Interfaces continentales, environnement

Gael Lymer, Johanna Lofi, Virginie Gaullier, Agnes Maillard, Isabelle Thinon, et al.. The Western Tyrrhenian Sea revisited: New evidence for a rifted basin during the Messinian Salinity Crisis. Marine Geology, 2018, 398, pp.1-21. ⟨10.1016/j.margeo.2017.12.009⟩. ⟨hal-01884968⟩