How a carbonate platform drowns: Facies changesat the transition between shallow-water carbonates and Ammonitico Rosso facies (Trento Platform, N Italy)

Detailed sedimentological and stratigraphic analyses of the Trento Platform succession provide new insights into the processes leading to its drowning. The study of facies developed immediately below and above the main unconformity indicates the presence of dissolution cavities related to subaerial exposure, marking a the interruption of carbonate sediment production. After this exposure event, the platform underwent rapid subsidence, resulting in its permanent drowning and the transition from shallow-water carbonate sedimentation to pelagic deposition below the photic zone. The evolution of facies and depositional geometries suggests that the shift from a productive carbonate platform to a deeper-water setting occurred abruptly, likely driven by the combined effects of eustatic sea-level rise and tectonic subsidence. This study emphasizes the importance of integrating facies analysis with stratigraphic and structural data to better understand the interplay between sea-level fluctuations, tectonics, and carbonate platform evolution.