Trezze San Pietro e Bardelli - Italy

The rocky outcrops known locally as trezze are characterized by substrates of various origins (clastic sedimentary, sedimentary sediments, organogenic) and with extensions ranging from a few to several hundred meters. The geological nature of the outcrops reveals that not all of them can be assimilated to bioconstructions, but there are also slabs deriving from the cementation of sand or rocks by methane gas. From recent investigations about 250 outcrops have been identified only in the Gulf of Trieste between Punta Sdobba and Punta Tagliamento; the most widespread range of these outcrops is on the seabed in front of the lagoons of Grado and Marano at a distance from the coastline of between 2 and 17 km, and a depth varying between 8.3 and 21.5 m. From the bibliography it emerges that the areas involved in rocky outcrops extend from the Gulf of Trieste to the coast of Ancona, along the entire northwestern and western coast of the North Adriatic. The calcareous concretions are attributable to Corallinaceous algae and secondly to Briozoa, Molluscs (Arca noae, Chama gryphoides), Anthozoans (Cladocora caespitosa), Serpulids (Serpula concharum, Serpula vermicularis, Pomatoceros triqueter, Rotula sp.plur.). The typology of the San Pietro and Bardelli trezze is of the Tabular type consisting of a fractioned set of many outcrops of the same type, however there are some major elements of larger dimensions.