The Triassic and Jurassic sedimentary cycles in Central Sardinia: stratigraphy, depositional environment and relationship between tectonics and sedimentation

This field trip presents a general overview of the stratigraphical, sedimentological and paleogeographic evolution of the Middle Triassic and Middle Jurassic successions in che Central Sardinia Tacchi area (Gerrei, Sarcidano, Barbagia, Ogliastra). These successions are divided by an unconformity and are both laid down under active extensional tectonics conditions.
The Triassic Eastern Sardinia succession belongs to the Germanic Triassic Domain (Buntsandstein and Muschelkalk facies group), so showing strict affinites with the Iberian and Mid-European successions.
It is featured by transgressive siliciclastic to carbonate deposits not more than few tens of meters thick: they represent the evolution from a continental, middle to low-energy environment to a restricted shallow marine one. This succession deposited along the stretching southern margin of the Paleo-European Plate under a hot-arid climate: it represents the last remain of the first Mesozoic depositional cycle in the area.
The Middle Triassic deposits pass upward through a disconformity to the Middle Jurassic transgressive siliciclastic to carbonate succession that is some hundreds of meters thick. The represented depositional environments are all those comprised between high-energy fluvial deposits (fluvial fan) and carbonate shelf margin ones. These sediments deposited under a hot-humid climate and correspond to the second Mesozoic depositional cycle of Central Sardinia. They are directly linked to the opening of the Alpine Tethys that triggered in the Eastern Sardinia area the uplift of a wide tectonic high leading to the dismantling of the main part of the previous Mesozoic (Triassic-lowermost Jurassic) to Permian successions.

DOI 10.3301/GFT.2016.01

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