Radiocarbon dating of active faulting in the Agri high valley, southern Italy

The high valley of the Agri River is a wide intermontane basin located in t he Lucanian Apennine, southern Italy. This basin was formed during Quaterna ry times in the hinterland of the Neogene fold-and-thrust belt. Tectonics h as strongly controlled shape, morphology and sedimentary evolution of the b asin up to the present. The Agri Valley, in fact, has been hit by recurrent and large earthquakes such as the 1857 Basilicata earthquake. Pleistocene extensional tectonics is commonly envisaged as responsible for the basin ev olution. On the grounds of new structural studies, indeed, the valley appea rs to be a more complex structure than a simple extensional graben, as;trad itionally assumed in the literature, or than a pull-apart basin, as suggest ed by some workers. The basin floor is filled by middle Pleistocene faulted alluvial deposits. A new survey has shown evidence of deformation also in younger sediments. A t Viggiano, located along the eastern flank of the basin, recent slope depo sits still attached to their source area display fault-controlled sedimenta tion. In this arsa,different climate-sedimentary cycles represented by:coar se:breccia talus alternated with palaeosoils are involved in the recent def ormation. At Pergola, located a few kilometres northwest of the Agri high v alley, the most recent fan deposits found at the foot of a major slope, inc luding evenly bedded breccia and intercalated palaeosoils, are strongly fau lted and tilted. In order to establish precise chronological constraints, palaeosoils have b een sampled in several sites and at different stratigraphic levels. Radioca rbon dating supports the: field evidence of very recent deformation associa ted to relevant displacements, yielding ages;between 40 and 20 ka. (C) 1999 Elsevier Science Ltd. All rights reserved.