New chrono-stratigraphic data on the Boiano basin infilling (Molise, Italy)

The Boiano basin (ca. 500 m a.s.l.) is located between the carbonate Matese and Montagnola di Frosolone massifs and the adjacent Sannio hills (Fig. 1). It is a 4 km large tectonic intramountain depression, elongated 20 km in a NW-SE direction, and nowadays drained by the Biferno river. The deformation history of this basin is characterized by several compression phases occurred between Miocene and Pliocene, followed first by strike-slip tectonics and then, since Middle Pleistocene, by extensional tectonics (DI BUCCI et alii, 2002, with references). Main faults show a NW-SE trend and several of them are still active and responsible for the historical and present seismicity. Even if the tectonic evolution of the basin was investigated in detail, little is known about the stratigraphy and chronology of its Quaternary infilling. Only in the SE sector of the basin (Campochiaro area) it is ascertained that the infilling consists of at least 200 m of fluvial-lacustrine deposits of Middle Pleistocene to Holocene age (RUSSO & TERRIBILE, 1995). Other chrono-stratigraphical constraints come from S. Massimo (Fig.1), along the NW side of the Matese massif, where residual strips of fluvio-lacustrine sediments, cropping out at 300 m above the present plain, were 40Ar/39Ar dated to 0.6 Ma (DI BUCCI et alii, 2005).