Probable root structures and associated trace fossils from the Lower Pleistocene calcarenites of Favignana Island, southern Italy : dilemmas of interpretation

Two types of large, branched structures from the Lower Pleistocene (Calabrian) high-energy calcarenites of Favignana Island are described: Faviradixus robustus gen. et sp. nov. and Egadiradixus rectibrachiatus gen. et sp. nov. They may be interpreted as root structures of large plants, trees and trees or shrubs, respectively. The former taxon co-occurs with the marine animal trace fossils Ophiomorpha nodosa, Ophiomorpha isp., Thalassinoides isp. and Beaconites isp. The interpretation as root structures although tentative is probable and can be related to short emergence episodes for the formation of E. rectibrachiatus or to longer emergence, responsible for the discontinuity at the base of the overlying Tyrrhenian deposits, for F. robustus. Calcified root mats of smaller plants associated with the Tyrrhenian or younger emergence surfaces are common

Tectonic evolution of the Sicilian Thrust System (central Mediterranean)

The Sicilian Thrust System (STS) is a south-verging (Africa-verging) fold-and-thrust belt including a Mesozoic-Paleogene sedimentary sequence. This thrust stack owes its origin to the deformation of pre-orogenic strata deposited in different palaeogeographic domains belonging to passive margins of the African plate. The STS was deformed during the Neogene, following the closure of the Tethys Ocean and the continental collision between the Sardo-Corso Block and the North Africa margins. The thrust pile was detached from the underlying basement during the Miocene-Pleistocene. The regional-scale structural setting recognized allows us to reconstruct the tectonic evolution of the STS as follows: I - piggy-back thrusting from the Late Oligocene to the Langhian, inducing the building of the Inner Sicilian Chain (ISC); II - piggy-back thrusting from the Langhian to the Tortonian, inducing the formation of the Middle Sicilian Chain (MSC); III - generalized extensional deformation in the chain-foredeep-foreland system from the Tortonian to the Early Pliocene; IV - a new onset of piggy-back thrusting after the Early Pliocene allowed the building of the Outer Sicilian Chain and out-of sequence thrusting in the previously developed ISC and MSC

Integration of HVSR measures and stratigraphic constraints for seismic microzonation studies: the case of Oliveri (ME)

Because of its high seismic hazard the urban area of Oliveri has been subject of first level seismic microzonation. The town develops on a large coastal plain made of mixed fluvial/marine sediments, overlapping a complexly deformed substrate. In order to identify points on the area probably suffering relevant site effects and define a preliminary Vs subsurface model for the first level of microzonation, we performed 23 HVSR measurements. A clustering technique of continuous signals has been used to optimize the calculation of the HVSR curves. 42 reliable peaks of the H/V spectra in the frequency range 0.6–10 Hz have been identified. A second clustering technique has been applied to the set of 42 vectors, containing Cartesian coordinates, central frequency and amplitude of each peak to identify subsets which can be attributed to continuous spatial phenomena. The algorithm has identified three main clusters that cover significant parts of the territory of Oliveri. The HVSR data inversion has been constrained by stratigraphic data of a borehole. To map the trend of the roof of the seismic bedrock, from the complete set of model parameters only the depth of the seismic interface that generates peaks fitting those belonging to two clusters characterized by lower frequency has been extracted

SÉDIMENTOLOGIE ET BIOSTRATIGRAPHIE DE LA FORMATION TRIASIQUE MUFARA (SICILE OCCIDENTALE): FORAMINIFÈRES, CONODONTES, PALYNOMORPHES

Nella parte nord-occidentale della Sicilia, la Formazione Mufara costituisce la base comune delle successioni appartenenti ai domini paleogeografici Panormide e Imerese. Questa formazione, costiruita da un'alternanza di marne gialle e di calcari marnosi, calcareniti e calciruditi, affiora in modo discontinuo in tutta la regione presa in esame. Inclusi nelle marne si osservano anche blocchi esotici di calcari grigi recifali d'affinità Panormide. Lo studio micropaleontologico (Conodonti, Palinomorfi) dei calcari marnosi e marne ha permesso di attribuire a questa successione un'età carnica (Tuvaliano, con esclusione del Tuvaliano terminale). L'analisi sedimentologica dei livelli calcarenitici e calciruditici, che contengono una microfauna a Foraminiferi d'età ladino-carnica e d'affinità Panormide, induce a ritenere un'origine torbiditica per le intercalazioni calcaree della Formazione Mufara ed anche ad attribuire un'età ante-norica all'individuazione della piattaforma Panormide