LE SUCCESSIONI ALLUVIONALI E LACUSTRI QUATERNARIE AFFIORANTI NELLA MEDIA VALLE DEL FIUME SINNI (APPENNINO MERIDIONALE, BASILICATA)

Abstract

Alluvial and lacustrine Quaternary successions in the middle Valley of Sinni River (Southern Apennine, Basilicata) – Thick terrigenous
successions, mainly Quaternary in age, crop out in the middle valley of Sinni River (Southern Apennines). Two main successions are
distinguished: the lower one, Pliocene to Middle Pleistocene in age, belongs to the southern part of BSA and shows a general regressive trend (marine to continental). The upper one, Middle Pleistocene to Holocene in age, consists of alluvial deposits referred to terraced stages of fluvial overcutting.
The BSA succession, was divided in the following three supersynthems:
- The oldest Monte Cotugno Supersynthem (SMC, Upper Pliocene), overlies unconformably the pre-pliocene substratum; it is mainly
composed of fine-grained shelf sediment.
- The Sinni Supersynthem (SS, Late Pliocene – Lower Pleistocene) consists of thick marine delta sandstone lobes passing upward to
alluvial-lacustrine deposits well cropping out in the south-western part of the area.
- The uppermost Serrapotamo Supersynthem (SSP, Lower-Middle Pleistocene) consists of alluvial and lacustrine systems underlying a
tabular coarse-grained body, a few ten meters thick and widely extended, interpreted as a braid plain system.
An erosional surface divides the BSA succession from the terraced units. In these units two different supersynthems are distinguished.
The first one (Bosco Farneta Supersynthem, SBF), located in the highest terraces, consists of alluvial deposits showing a northward
palaeoflow. The second one (Fosso Manga Ramelle Supersynthem, SMR), at different heights, consists of alluvial terraced deposits,
referred to the drainage basins of Sinni and Sarmento Rivers.
The stratigraphic setting results from the interaction of eustatic changes and tectonic uplift of the eastern sector of southern Apennines during Pleistocene.