Analisi di facies dei depositi tirreniani (Duna Rossa) affioranti nell'area di Castel Ponziano-Pomezia (Roma). Una versione ambientale

Abstract

New stratigraphic-sedimentologic studies on the Tyrrhenian deposits known in Latium as "Duna Antica" (Old.Dune) or "Duna Rossa" (Red Dune), have shown different environmental characters from those so far known. Particularly in the outcrop A (Cava Tacconi) three stratigraphic-depositional units (CT1, CT2and CT3) were identified; these are separated by erosion surfaces connected with a relative lowering of sea level. The lowest of these units (CT1revealed a progradational beach fades assodation, while the upper units (CT2and CT3) are the fluvio-lacustrine and marshy fades filling little incised valleys. The outcrop B constitutes a unit with fades related to a braided fluvial environment, in which the sediments were partially elaborated by the winds. From a palaeogeographic point of view it is possible to figure out a coastal plain where the landward part of which represents a braidplain, while seaward, during the sedimentation of CT1Unit the coastline was located near the outcrop A, in a position roughly parallel to the present coastline.