Stratigraphic-paleogeographic evolution of Eastern Sardinia Jurassic passive margin carbonates: synthesis and future developments

Abstract

It is presented a synthetic reconstruction of the Eastern Sardinia Middle-Upper Jurassic stratigraphic setting, focusing the most important tectono-sedimentary events and the regional paleogeographic reconstruction, evolution of the carbonate depositional systems. This synthesis is based on data collected during 20 years of studies carried out in collaboration with several students and colleagues of the Carbonate Sedimentology and Stratigraphy research team of Milan University. The most original results refer to the lithostratigraphic revision and depositional architecture of the Kimmeridgian-Tithonian carbonate succession: Tului, Lower Bardia shallow water ramp and shelf margin depositional systems, coeval to the Baunei-S’adde Limestone Pedra Longa open to restricted intraplatform basins and peculiar inner platform carbonates and breccias of the Urzulei Fm. Thick, lenticular intercalations of tithonian poligenic carbonate breccias at the base of the Mt. Bardia Fm. are interpreted as mass transport events associated to large collapses of the platform margin. The breccia bodies are probably related to a tithonian tectonic activity with the reactivation of jurassic growth faults and a local flexuring. To improve our understanding of the detailed biological-sedimentological response of the Middle-Upper Jurassic shallow-water carbonates charactering the evolution of the Sardinia passive margin, new high-resolution ages are required and correlations with the coeval Tacchi and Nurra successions.