The Triassic (251 – 200 Mya) is the most important period in the geological history of western Trentino. The limit between Permian and Triassic is marked by a large mass extinction that leads to the disappearance of 95% of living species. In this period the continents unite to form the Pangea supercontinent. In this context, the Geopark area is located along the eastern coast of the great Tethys ocean, at intertropical latitudes.
The Pangea is immediately unstable, the continents are again dividing. The opening of the Neotetide ocean causes, in the current Southern Alps, the formation of high and depressed areas (platforms and basins). In this period, the area of the Geopark is located between the Trento platform (to the east) and the Lombard basin (to the west). This structural and morphological diversity leads to the birth of the first carbonate platforms. In other words, sediment layers deriving from organisms with a calcareous skeleton (e.g. corals). Contemporary with the atolls of the eastern Dolomites. These were born in the lower depth areas of Neotetide (Dolomia del Serla, Formation of Contrin, Dolomia dello Sciliar, Calcare di Esino). Meanwhile calcareous and dolomite formations are deposited in the basins and lagoons (Calcare d’Angolo). Some with volcanic intercalations (Calcare di Prezzo, Buchenstein Formation).
In the more recent Upper Triassic, the basins are filled. While, in the Southern Alps, a tidal plain environment is formed. Here the Main Dolomia is deposited, the most representative of the Brenta Dolomites. It also constitutes the summit of many other eastern Dolomite mountain groups (Tre Cime di Lavaredo, Antelao, Civetta, Tofane). Above the Main Dolomia, there are the formations of Zorzino and Zu limestone. Proof of the deposition of other sediments during a gradual sinking of the seabed in the Western Trentino area.