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Our research focuses on the reconstruction of turbidity paleocurrents of the Cilento Group in the Cilento area (southern Apennines, Italy). These deposits were formed in the wedge-top basin above the oceanic Ligurian Accretionary Complex, the early orogenic wedge of the southern Apennines. The Cilento Group succession, whose age ranges between the uppermost Burdigalian and lowermost Tortonian, consists of a thick pile of sandstones, conglomerates, marls and pelites grouped in two formations (Pollica and San Mauro Fms). We retrieved information on the turbidity current directions through sedimentary features such as flute and groove casts, flame structures and ripple marks. The aim of this study is to shed light on the early tectonic evolution of the southern Apennines by reconstructing the geometry of this basin, the source areas that fed it and the paleogeography of the central Mediterranean area in the Miocene. We analyzed 74 sites in both formations and collected 338 measurements of paleocurrent indicators. Because the succession was affected by severe thrusting and folding, every paleocurrent measurement was restored, reinstating the bedding in the horizontal attitude. Results indicate a complex pattern of turbidity current flow directions consistent with a basin model fed by a spectrum of sources, including recycled clasts from the Ligurian Accretionary Complex, Calabria–Peloritani Terrane and the Apennine Platform units and volcaniclastics from the synorogenic volcanoes located in the Sardinia block. [ABSTRACT FROM AUTHOR]

We report the occurrence of several sand liquefaction structures, such as sand dikes, in the stratigraphic record of the Campi Flegrei volcano, located both inside and outside the caldera. Five sites were analyzed within the caldera and two outside. The grain size analysis of the sand fillings indicates that these deposits are very fine-to-coarse sands generally poorly sorted. All of the granulometry curves fall within the field of the liquefiable, loose sediments. Frequently, dikes are characterized by two fillings: a rim showing poorly sorted finer sands and a core with extremely poorly sorted coarser sediments. We suggest that seismic-related liquefaction processes triggered the injection of these sand dikes during unrest episodes in the last 15 kyr. In particular, the sand dikes located outside the caldera, characterized by larger thicknesses and lengths, mark an important extensional episode, probably associated with the caldera formation during the Neapolitan Yellow Tuff eruption at 15 ka. Furthermore, liquefaction structures within the caldera are related to the seismic activity, probably occurring during the Agnano–Monte Spina caldera formation and the volcano-tectonic ground deformation, predating Epoch 3b (4.3 ka) and the Monte Nuovo (1538 CE) eruptions. This study highlights that these seismic-related liquefaction structures are common within the volcanic record of the Campi Flegrei, suggesting that the sand source can be both the widespread marine succession underlying the Epoch 3 deposits in the caldera central sector and the primary ash layers extensively present in the volcanic record. [ABSTRACT FROM AUTHOR]

We present a structural study on late Miocene-early Pliocene out-of-sequence thrusts affecting the southern Apennine orogenic belt. The analyzed structures are exposed in the Campania region (southern Italy). Here, thrusts bound the N-NE side of the carbonate ridges that form the regional mountain backbone. In several outcrops, the Mesozoic carbonates are superposed onto the unconformable wedge-top basin deposits of the upper Miocene Castelvetere Group, providing constraints to the age of the activity of this thrusting event. Moreover, a 4-km-long N-S oriented electrical resistivity tomography profile, carried out along the Caserta mountains, sheds light on the structure of this thrust system in an area where it is not exposed. Further information was carried out from a tunnel excavation that allowed us to study some secondary fault splays. The kinematic analysis of out-of-sequence major and minor structures hosted both in the hanging wall (Apennine Platform carbonates) and footwall (Castelvetere Group deposits and Lagonegro-Molise Basin units) indicates the occurrence of two superposed shortening directions, about E-W and N-S, respectively. We associated these compressive structures to an out-of-sequence thrusting event defined by frontal thrusts verging to the east and lateral ramp thrusts verging to the north and south. We related the out-of-sequence thrusting episode to the positive inversion of inherited normal faults located in the Paleozoic basement. These envelopments thrust upward to crosscut the allochthonous wedge, including, in the western zone of the chain, the upper Miocene wedge-top basin deposits. [ABSTRACT FROM AUTHOR]