L'Unita Caotica Composita messiniana del Bacino Terziario Piemontese: interazione di processi tettonici, sedimentari e diapirici.

The origin of chaotic rock bodies is commonly attributed to tectonic disruption and mixing of originally coherent sequences, gravitational submarine downslope movements and shale diapirism, caused by the rising towards the sea floor of overpressured, fluid-permeated fine grained sediments. The recognition of the role played by each of these processes in the geologic record is problematic, due to the strong facies convergence of their products and to the fact that these mechanisms can coexist and interact in a complex way. The study of the Messinian chaotic sediments of the Tertiary Piedmont Basin allows to evaluate the relative contribution, the time relationships and causative links among tectonic, sedimentary and diapiric processes in their genesis. It appears that these mechanisms, triggered by regional tectonic deformation, impacted on each other and operated sequentially in a short time span.