Geological map of the eastern sector of the Gorgoglione Basin (southern Italy)

Paolo Giannandrea (*), Francesco Loiacono (**), Patrizia Maiorano (**), Fabrizio Lirer (***) & Diego Puglisi (****)
(*) Dipartimento di Scienze, Università della Basilicata, Campus Macchia Romana, Potenza, Italy. Cell.: 338 5906841; fax: 0971 205503; Corresponding author e-mail: aolo.giannandrea@unibas.it
(**) Dipartimento di Scienze della Terra e Geoambientali, Università di Bari Aldo Moro, Via Orabona, 4 - Bari, Italy.
(***) Istituto Ambiente Marino Costiero (IAMC) - Sede Napoli - CNR, Calata Porta di Massa, Interno Porto di Napoli, Napoli, Italy.
(****) Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università di Catania, Via A. Longo, 19 - Catania, Italy.

In this paper we report new stratigraphic data related to a new geological map of the Miocene Gorgoglione Basin of southern Italy, traditionally considered as a piggy-back or wedge-top basin filled by a turbidite-like succession. Well exposed outcrops in the study area (eastern sector of the basin) show four unconformities in the Castelmezzano-Pietrapertosa area. Two of these unconformities pass to paraconformities southeastward, in the Cirigliano-Gorgoglione area. Based on new stratigraphic data the "succession of the Gorgoglione Flysch" can be divided into different informal units: Val Miletta formation and Gorgoglione supersynthem. The latter can be subdivided into the Cirigliano and Castelmezzano synthems. The previously established Cirigliano synthem is here divided into three subsynthems. The lowermost sediments of the Gorgoglione Flysch on the eastern sectors correspond to a complex unit (Val Miletta formation) including Numidian-like quartzarenites, Gorgoglionelike sandstones, and, at the top of the formation, an olistostrome of varicoloured clays, belonging to the Argille Variegate Group. The stratigraphic analyses and the biostratigraphic results based on calcareous plankton assemblage, improve the reconstruction of the geometries of the sedimentary bodies and the time-space facies evolution of the synthems. Sedimentologic and petrographic characters of the upper part of the Castelmezzano synthem show a clear fining and thinning upward trend. Medium- and fine-grained arenites, varying in composition from quartz sandstones to siltstones and shales, are locally marked by abundant planktonic foraminifera and are interpreted as contourites. Moreover, the relationships between tectonics and sedimentation are analyzed. The data are used to propose a scheme of the Burdigalian to Tortonian tectono-stratigrafiphic evolution of the eastern sector of the basin.

Gorgoglione Flysch, Miocene turbidite thrust-top and foredeep basin, syntectonic sedimentation, southern Apennines (Italy).