3 - La serie stratigrafica

The systematic exploration of the site of Guado San Nicola has allowed a two metres thick stratigraphic series to be highlighted, located at the distal part of the ancient conoid of the Torrente Lorda. From bottom to top the series in characterised by: S.U. E - coarse gravel deposits with sub- rounded and sub-angular edges deposited by a high energy stream; S.U. D - alternated layers and lenses of sands and silts with a low percentage of clays, with no archaeological content; S.U. C - gravely sands with sub-rounded and sub-angular clasts rich in pyroclastic sediments; the base of the unit is erosive; it is very rich in lithic artefacts and faunal remains; S.U. B*C - gravels with sands containing abundant lithic artefacts and faunal remains; S.U. S B - gravels with sub-rounded and sub-angular edges in a silty-sandy matrix, rich in lithic artefacts and faunal remains; S.U. A*B - lens of gravely-silty sands of brown colour, identified at the northern limit of the excavation area; presence of archaeological remains; S.U. A - limes and sands with a low presence of clay and gravels, with no archaeological content; S.U. TUFI - sands with gravels and limes, rich in pumice which constitute the coarser fraction, and other materials of pyroclastic origin, with rare and small limestone and chert clasts, sterile from an archaeological viewpoint; locally turned to red due to alteration processes. This sequence is buried under some metres of middle to coarse clays, enriched in cobbles of various dimensions at the top, with sub-angular to sub-rounded clasts in a sandy-gravel matrix with sporadic sandy and sandy-silty lenses. The deposit is altered by a palaeosoil more than 2.5 metres deep and characterised by a sequence of decarbonated horizons, rich in clays of a red-brownish colour with chert and deeply corroded limestone clasts.