Surface uplift and sea level change: constraints from Late Pleistocene paleoshorelines

The aims of this PhD research project are both a reconstruction of the surface uplift of the Tyrrhenian coastal side of the southern Apennines in the Middle-Late Pleistocene time span and a field data acquisition on Relative Sea Level (RSL) indicators in order to better constrain the sea level change for the western sector of the Mediterranean. The field study has been based on detail scale morphotectonic and stratigraphic analyses, which have been carried out by geomorphological analyses on topographic maps and Digital Elevation Models (DEM), on two key areas of the Tyrrhenian coast: the Campania Plain margin and the Basilicatanorthern Calabria area. The morphostratigraphical analyses have been integrated by new U-series dating of calcite deposits (speleothems and a calcite vein) and coral C. caespitosa samples. The main topics and results can be summarised as follows: A study of formerly known and new outcrops of marine terraces has been carried out in the NE margin of the Campania Plain (Fellino Mt.), a Quaternary coastal graben located in the Tyrrhenian side of the southern Apennines; • Raised paleoshorelines assigned to two raised paleoshorelines (labelled T1 and T2) were detected along Fellino Mt. at variable elevation; • The synchronous correlation method, based on U-series dating on a calcite vein post-dating the age of T2 terrace, allow relating the T2 and T1 identified paleoshoreline to MIS 9 and MIS 7 respectively; • Structural data collection allow defining the geometry and kinematics of the main Quaternary structures filling, hence, the existing gap along the borders of the Campania plain. The study reports the first field evidence of Quaternary extensional tectonics affecting the Campania Plain borders. The identified paleoshorelines are displaced by a major extensional fault zone c. E-W oriented (namely Polvica Fault), and several faults c. N-S and NW-SE oriented with less displacements; • The uplift fault-related rate of the Polvica Fault, the throw rate and the Earthquake Recurrence Interval (ERI) have been estimated in c. 02-06 mm/y range, 0.4 mm/y and c. 1100 y respectively. The uplift rate is characterised by a spatially variation along the strike of the Polvica Fault; A flight of paleoshorelines up to c. 60 m a.s.l. located along the Tyrrhenian sector of the Basilicata - northern Calabria has been investigated by detailed geomorphological-stratigraphical analyses. The flight of paleoshorelines has been constrained in the early 1990s with AAR and U-series dating but the new U-series dating provided in this study has allowed the reconstruction of a chronological framework for the analysed sea level markers. The U- series dating have been performed on C. caespitosa corals and calcite concretions, either predating or postdating the paleoshorelines. In particular, the U-series dating allow correlating the T1 terrace at 5 m a.s.l. to the MIS 6e, the T2 at c. 16 m to MIS 5c, the T3 terrace at c 22 m a.s.l. to MIS 5a, the T4 terrace at 35 m .s.l. to the MIS 5e and the higher T5 terrace to MIS 7. The new findings shed light on the Quaternary evolution of the Basilicata area – northern Calabria; • A Relative sea level (RSL) curve during the Middle-Late Pleistocene time span for the northern Calabria-Basilicata Tyrrhenian sector has been constructed; A mean uplift rate of 0.235 ± 0.01 mm/y since the Last Interglacial has been evaluated. The uplift rate is one order of magnitude larger than estimation based on former dating; • The new data provide new constraints to both the long term evolution of the Tyrrhenian margin of the southern Apennines and the late Quaternary sea level fluctuations in the western Mediterranean. The elevation of MIS 5a, 5c and 6e peaks and the time span of 5a have been evaluated. Such elevations may better constrain ice sheets volume variation during the late Quaternary. • The geomorphological reconstruction has demonstrated that a mere sequential correlation may be misleading in the interpretation of flights of marine terraces, and indicates that multiple age controls are crucial to unravelling the complex interaction between uplift and sea level fluctuations in uplifted coastal areas; A review of MIS 5 paleoshorelines along the western Mediterranean (Spain, France, Italy, Istria, Kvarner and Dalmatia, Algeria and Morocco) has been compiled in the framework of the Word Atlas of Last Interglacial Shorelines (WALIS).