Geological map of the eastern sector of the Pliocene-Quaternary Ofanto Basin: an upgrade
The mapped area is located west of Monte Vulture volcano on the fold-and-thrust belt front of the southern Apennines chain and includes Pliocene to Quaternary marine and continental sediments of the Ofanto Basin. This basin, showing an E-W trend, traces a marked bend in the NW-SE regular orientation of the South-Apennines morphostructures. The geological map here presented was drawn on a topographic base of IGM at 1:25,000 scale, using CorelDRAW® Graphics Suite software. It contains a large portion of the field survey performed in the CARG Project (geological cartography of Italy) for the mapping of the Sheet 451 "Melfi" at the scale 1:50,000. The Ofanto Basin is one of the best example of intra-chain basin with a rich record of tectonics-sedimentation interplay. The stratigraphic techniques here adopted vary in relation to the type of rocks, i.e. as a function of the presence of bedrock units, clastic covers, alluvial terraced deposits, or volcanic products. As a matter of fact, in the study area the bedrock is represented by tectonic units formed of continuous and concordant stratigraphic successions of different lithology, whereas the Pliocene-Quaternary deposits have been mapped using Unconformity-Boundary Stratigraphic Units (UBSU), in turn composed by several lithofacies. The need of an upgrade of the geological map of the Ofanto Basin, edited in 2014, has been stimulated by a new stratigraphic pattern concerning a relevant issue of the sedimentary succession, i.e. the further subdivision of an original unconformity-bounded unit. In particular, sedimentological and biostratigraphic analyses performed on many stratigraphic logs have revealed local unconformities which allowed subdividing the Ruvo del Monte synthem in five new subsynthems. The ages of such subsynthems and their arrangement along the axis of the basin display a peculiar tectonically-controlled west to east migration pattern of sedimentation, driven by left-lateral transpression.
DOI: 10.3301/GFT.2019.05