Late Quaternary sea-level variations and geomorphic coastal responses in southern Italy: the Punta Licosa case study (Campania region)

The Punta Licosa promontory is located in the northern part of Cilento coast in the southern Tyrrhenian basin. In this attractive landscape, depositional and erosional landforms, located both above and below sea level, can be considered a challenge of scientific interest to reconstruct the geomorphological evolution under the control of sea-level changes occurred during the late Quaternary period. The geomorphological study of this area took into account data provided by literature, aerial photo interpretation, GPS measurements, geological surveys, GIS elaborations of high-resolution DTMs, bathymetric data and high-resolution orthophotos taken by unmanned aerial vehicles. The detected landforms were grouped based on morphogenetic and morphoevolutive criteria, paying particular attention to several orders of shore platforms recognized both in the emerged and submerged sectors. Thanks to their analysis, the response of this coastal system to sea-level stands and changes since MIS 7 was detailed reconstructed. According to our reconstructions, three different phases of sea-level stand were identified along the emerged coastal sector. The first sea-level stand is documented by the inner margins of shore platform remnants detected at 9.5 m MSL, ascribed to the MIS5e highstand, according to several authors. The second sea-level stand is poorly testified in our study area but is chronologically well-constrained at Cala Infreschi (southern part of Cilento promontory) thanks to aeolian sands located at 2.7 ± 0.1 MSL and dated by Bini et al. (2020) to 109.1 ± 0.8 ka BP (MIS5d). The third sea-level stand was extensively mapped along the entire coastal sector at about 4.5 m a.s.l. and dated by Iannace et al. (2001) to 102 ± 4 ka BP (MIS5c). The heights at which the above-mentioned sea-level stands are located suggest that the study area gained substantial tectonic stability since MIS 7. This deduction was the starting point of the second research phase in which the morphometric analysis of bathymetric data, coupled with a reinterpretation of literature data, provided clear evidence of sea-level stands occurred since the post-glacial sea-level rise and recognized at depths of about -43/-56 m, -16/-20 m and -8/-10 m MSL. Particular attention was paid to the wide platform formed after the Holocene slowdown in sea-level rise positioned between - 6 m MSL and the present MSL. By comparing our spatial analysis of this landform and the GIA models calculated for the southern Tyrrhenian area, we established that this platform was shaped during the last 6500 years, experiencing retreating rates of 0.030 m/yr, 0.046 m/yr, and 0.039 m/yr in the northern, central, and southern sector of Cilento promontory, respectively. In conclusion, our approach demonstrates the effectiveness of a multi-temporal geomorphological analysis, in order to reconstruct the coastal response to RSL variations in stable contexts along high rocky sectors.

References

Bini, M., et al. "An end to the Last Interglacial highstand before 120 ka: Relative sea-level evidence from Infreschi Cave (Southern Italy)." Quaternary Science Reviews 250 (2020): 106658.

Iannace, A., et al. "The OIS 5c along Licosa cape promontory (Campania region, southern Italy): morphostratigraphy and U/Th dating." Zeitschrift fur Geomorphologie 45.3 (2001): 307-320.