Stratigrafia sequenziale della formazione di Heiligkreug sul fianco meridionale del gruppo delle Tofane

During the Middle Triassic, the Western Tethys displayed a complex paleogeography, featuring isolated carbonate platforms and carbonate-siliciclastic deep basins. This morphology changed during the Carnian, when a global climatic event (Carnian Pluvial Event or CPE) increased significantly the terrigenous input to marginal basins and determined in many cases their infilling. With deposition of the Heiligkreuz Fm there is a levelling out of the paleogeography. The Carnian Pluvial Event marks a crisis of the M-type carbonate factories and depositional systems, that were able to build high-relief platforms during the Middle Triassic and the Early Carnian. This interval outcrops on the Southern walls of the Tofana di Rozes (Dolomites, Cortina d'Ampezzo). This work takes into account the outcrops from rifugio Dibona to Torri del Falzarego. Seven sections of the Heiligkreuz Fm. were measured in this area to understand lateral facies variations. The rifugio Dibona outcrop shows a complete succession of the Heiligkreuz Fm. This formation is divided in three members: Borca Member, Dibona Member and Lagazuoi Member. At rifugio Dibona, photogrammetric modeling and laser scanner data permitted to study and visualize geological features in 3D to create a sedimentological model for the basal part of the Heiligkreuz Fm. The aims of this work are the facies analysis and the understanding of depositional environments in specific portions of the Heiligkreuz Fm. and their significance for the sequence stratigraphic intepretation of the succession. The facies analysis shows how the Borca Member consists of numerous carbonate mounds, grown on a pre-existing inclined slope surface, and intercalated with an alternation of skeletal carbonates (grainstones and packstones) and siltitesarenites. Instead the studied portion of the Dibona Member record tidal structures deposited in a carbonate strait environment. Data collected in this work confirm the presence of a tidal influence on the deposition of the Heiligkreuz Fm. in the Tofane area, and the strong lateral continuity of facies is in agreement with deposition at the time of the maximum marine ingression (mfs)