ANALISI SEDIMENTOLOGICA DEL SINTEMA DI MONTE. SIRICO (PARTE ALTA DELLA SUCCESSIONE DEL BACINO DELL’OFANTO), APPENNINO MERIDIONALE, BASILICATA

Abstract

Sedimentologic analysis of the Monte Sirico Synthem (uppermost unit of the Ofanto Basin succession), Southern Apennine, Basilicata -
The tectonic evolution of the Southern Apennine chain, during Pliocene and Pleistocene allowed to develop satellite basins, testified by
thick terrigenous succession, locally well exposed. The Ofanto basin is Pliocene to Pleistocene east-west elongated satellite basin,
belonging to the outer Apennine chain domain. The basin fill is previously subdivided in UBSU. They testify the tectonic control during
the sedimentary infill. From the oldest to the youngest three supersynthems are distinguished: Aquilonia, Ariano Irpino - Calitri and
Atella.
The Atella Supersyntem is subdivided in the Difesa and M. Sirico Synthems, composed of transitional and continental facies respectively. The M. Sirico Synthem represent the separation phase of the Ofanto basin by foredeep basin; its sedimentation followed the uplift of the outer part of the chain. This unit, upper Pliocene-lower Pleistocene in age, overlies unconformably both the marine Pliocene units of Ofanto basin, and pre-Pliocene Apennine units. It underlies the middle Pleistocene M. Vulture volcanic units (674±7 ka and 132±12 ka).
The M. Sirico succession, a few hundred meters thick, consists of coarse-grained alluvial facies, outcropping near the marginal areas;
the south-western ones received detritus from pliocenic formation and mesozoic and tertiary units (Lagonegrese Units of S. Fele area).
The north-eastern ones received mainly arenaceous tertiary detritus. Paleocurrent data suggest a centripetal dispersal. In fact fine-grained marsh deposits with interfingering channelized conglomerates characterize the depocenter area of the basin.