The Pretare-Piedilama Clastic Deposit: New Evidence of a Quaternary Rock Avalanche Event in Central Apennines (Italy)

This paper deals with the origin of the Pretare clastic deposit (PRA), which crops out along the Morricone fluvial valley in the Central Apennines of Italy. With the aim of deciphering the genesis of the PRA deposit, geological s.l. and geomorphological analyses were carried out allowing for the interpretation of the PRA deposit as a rock avalanche. Furthermore, geological cross sections constrained by well-log and field survey data, together with stratigraphic, sedimentologic, and morphometric analyses, allowed us to assign the deposit to a catastrophic rock slope failure, which occurred during a cold climate of the Late Pleistocene. Several issues concerning the propagation mechanisms were inferred from the mapping of 350 boulders over the entire accumulation area and from the measure of the morphometric parameters of the landslide body. We also performed a restoration of the potential source area by comparing the reconstructed pre- and post-failure DEMs. A missing volume of 8.41 x 10(6) m(3) was estimated on the south-eastern side of the Vettore Mt., which is consistent with the deposit volume computed from the geological interpretation (10.56 x 10(6) m(3)). The outcomes of this study provide useful insights for a better understanding of the Quaternary morpho-evolution of the Central Apennines area where analogous rock avalanche events marked the recent evolution of the belt.

Automated summary

This paper investigates the origin of the Pretare clastic deposit (PRA) in the Morricone fluvial valley in the Central Apennines of Italy. Through geological and geomorphological analyses, the PRA deposit is interpreted as a rock avalanche. The study also identifies the deposit as a catastrophic rock slope failure during the Late Pleistocene cold climate, using geological cross sections, stratigraphic, sedimentologic, and morphometric analyses. The findings provide insights into the Quaternary morpho-evolution of the Central Apennines area.