The different Late Quaternary morphotectonic evolution of the two main peri-Tyrrhenian grabens: Campania and Sele river coastal plains (southern Italy)

The Campania sector of the southern Apennines is characterised by two wide coastal basins, namely Campania, in the north, and Sele plains, in the south. Both represent peri-Tyrrhenian half-grabens sharing common features such as i) NE-SW trending master fault systems in the NW border; ii) thousands of meters thick basin infilling and, iii) carbonatic bedrock downthrown up to 3-4 km b.s.l. The formation of such half-grabens is due to the Late Miocene extension, still active, that caused the opening of the Tyrrhenian back-arc basin. Even if during the Early Pleistocene the stratigraphic and structural setting, that led to the shaping of the Campania and Sele coastal plains is similar, their Late Quaternary evolution is quite different. In fact, while the Campania Plain records subsidence since Early Pleistocene and the formation of volcanic complexes during the Late Pleistocene, on the other hand, the trend of vertical motion, from subsidence to uplift, changes along the Sele Plain during the Late Pleistocene as testified by i) incision and terracing of the alluvial fill at the mountain foothills and, ii) presence of raised marine deposits on the coast. In order to better constrain the Late Quaternary morphotectonic evolution of both plains, an integrated morphotectonic and morphostratigraphic work was carried out by geomorphological analysis of high-precision topographic data (1:5.000 scale maps and 5-m DEM resolution), field work and analysis of subsurface data from former and new shallow borehole logs. New data provide a better definition of vertical movements during the Late Quaternary in the Campania and Sele plains by a detailed definition of the coastline changes as a consequence of the tricky interaction between sedimentary infill and sea level fluctuations. 1214