Sedimentary record and sequence stratigraphy of the Middle Triassic carbonate ramp in Sardinia (Italy)

The Triassic succession of Sardinia (Italy) displays the typical “Germanic-like” facies tripartition (Buntsandstein-Muschelkalk-Keuper), which enables regional and interregional correlations with the Central Europe and the western Mediterranean sectors. This work explores the Middle Triassic (Muschelkalk) sedimentary record of this island, which has long been studied and recognized as a key-stratigraphic point for reconstructing the palaeogeographical evolution of the Western Tethys Sea during that time. 
We conducted a stratigraphic survey fieldwork on 12 sections representing the different formations, and integrated the new obtained palaeontological, geochemical, sedimentological and stratigraphical data with a comprehensive literature review. Moreover, a detailed facies analysis has been performed through field observation and petrographic analysis, following previous approaches to the regional sedimentology. As result, it has been possible to observe that the Sardinian Muschelkalk, interpreted as a carbonate ramp, comprises five main broad sedimentary environments: sabkha, carbonate tidal flat, shallow lagoon, shallow  calcarenitic shoals, and storm-dominated mid-ramp. 
The obtained data made possible to carry out a sequence stratigraphic analysis, which revealed a major transgressive-regressive cycle of about 5-6 million years (late Illyrian to latest Longobardian), comparable to a 2nd order cycle in the sense of Vail et al. (1991). This sequence is well developed and continuous in the north of the island (Nurra Region) and has its interregional equivalent in different basins of the Mediterranean and Levantine-Balearic domains of neighbouring Iberia (Mega-Depositional Sequence-II of Escudero-Mozo et al., 2015). However, we also noted the absence of outer ramp systems in Sardinia, unlike in other areas of the western Mediterranean.
The result of our study helps to better understand the paleogeography of the westernmost transgression of the Tethys Sea during the Middle Triassic, as well as the corridors available for the migration and distribution of the Alpine and Sephardic faunas during the time of the recovery after the Permian-Triassic transition crisis.
 
References:
Escudero-Mozo, M.J., Márquez-Aliaga, A., Goy, A., Martín-Chivelet, J., López-Gómez, J., Márquez, L., Arche, A., Plasencia, P., Pla, C., Marzo, M., Sánchez-Fernández, D., 2015. Middle Triassic carbonate platforms in eastern Iberia: Evolution of their fauna and palaeogeographic significance in the western Tethys, palaeogeography, Palaeoclimatology, Palaeoecology 417, 236–260.
Vail, P.R., Audemard, F., Bowman, S.A., Eisner, P.N., Perez-Cruz, C., 1991. The stratigraphic signatures of tectonics, eustasy and sedimentology–an overview. En: Einsele, G., Ricken, W., Seilacher, A. (Eds.), Cycles and Events in Stratigraphy. Berlin, Springer-Verlag, 617–659