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Low Strain Rate regions (LSRrs), i.e., areas undergoing tectonic deformation at rates of 1 mm/yr or less, often host important cities and highly vulnerable anthropogenic assets, and due to their subdued topography and relatively infrequent seismicity, are often considered low seismic hazard areas. Despite this, infrequent but high-magnitude earthquakes in such regions suggest that identifying active structures in the LSRr is one of the primary challenges for both the scientific community and modern societies. In such regions, one of the main issues in identifying active faults is the lack of valuable outcrop data due to erosional/sedimentation rates overwhelming the fault deformation, causing the hidden morphological signature of the tectonic structures. This work proposes a multidisciplinary approach designed to detect active geological structures and their related deformation in such areas. Our approach consists of quantitative morphotectonic, offshore and onshore tectonostratigraphic and GNSS joint analyses. To test this approach, we selected as a natural laboratory the partially offshore northern Sicilian LSRr (southern Italy) in the coastal sector located between the two major cities of Palermo and Termini Imerese. This area includes the compressional structures of the northern sector of the Apennine-Maghrebian fold and thrust belt, presently accommodating the slow Africa-Europe plate convergence. The main results we achieved are 1) new evidence of active tectonic deformation in this region; 2) the 3D modelling of two NNW-trending active faults; 3) the slip rate of a segment of the westernmost of the two detected faults; 4) a newly recorded relative GNSS velocity field; 5) a new morphotectonic map and morphotectonic evolution model of the study area. Our multidisciplinary approach allowed us to shed new light on the active tectonic framework of a slowly deforming area that crosses the physical limit of the coastline.

160 km long hill ranges in the Kachchh region (NW-India) form a major E-W oriented topographic break delimiting the marshy plain of Banni in the North from the more elevated area of the Katrol Hill Range (KHR) in the south. Such topographic break is considered as the superficial expression of a quaternary active fault labelled Kachchh Mainland Fault (KMF). Numerous rivers cross this hilly region flowing roughly from South to North. The majority of those rivers are characterized by extensive fan lobes pinching out from the 200–300-meter anticlines of the hilly range.Starting from archaeological evidence from the past 4000-5000 years, it has been inferred that an extremely fast coastal landscape evolution brought such a region to evolve from an initial gulf landform to the current setting, i.e., the marshy plains of Banni and the salt-encrusted Rann. The location of the fans lobes marked the boundary between the fluvial and marine environments.High sedimentation rates varying between 1.1-2 mm/yr reported for the Banni plains together with historical and recent earthquakes (1668 Indus Delta, 1819 Allah Bund, 1845 Lakhpat, 1956 Anjar and 2001 Bhuj) provide valuable constraints for inferring the climatic and tectonic forcing on the region's quick dynamics.In our ongoing work, we propose a multidisciplinary approach made by morphotectonic mapping, morphometric analyses, and geochronology to understand better how the interplay of tectonics and eustatic perturbations drove such an abrupt landscape evolution.

From 2017, an unknown rural settlement in Contrada Castro at Corleone (Palermo Province, western Sicily) was investigated as part of the `Harvesting Memories Project¿. The stratigraphic sequence, supported by radiocarbon dating, has demonstrated a reoccupation of a pre-Roman site during the transition between the Byzantine and Islamic periods. In particular, the main occupation occurred in the late 8th¿9th century when pottery kilns and a probable warehouse were constructed. During the 10th¿11th century, a new structure with different orientations replaced the previous buildings that had already collapsed. Specifically focusing on a perspective of the household production and its relationship to the surrounding landscapes of this site, this paper presents the results of a geological survey and petrographic analysis of ceramic finds and lithic samples to identify the source area of the geomaterials used in the studied settlement. The ceramic finds were divided into different Paste Groups based on the characteristics of a polarizing microscope study. The use of some locally available raw materials was recorded both for ceramic and lithic samples. Such an approach enables us to better understand ceramic craft technology, clay and lithic procurement strategies and, more broadly, the consumption of household pottery in the Early Medieval site in Contrada Castro. Furthermore, this study verifies the close relationship that this rural settlement had with the surrounding resources in the area and reveals a connection with the city of Palermo during the Early Middle Ages., Bona Furtuna LLC; Università degli Studi di Palermo, Funding information: Bona Furtuna LLC; Università degli Studi di Palermo

International audience; Thirteen seismic reflection profiles and field observations have been used to build a three-dimensional watertight geological model of the sub-surface architecture of the Trapanese carbonate platform unit of the Apennine-Maghrebian chain in the Mt. Kumeta and Mt. Rocca Busambra (NW Sicily, Italy). Either a single step or a two-step thrust-fault deformation model is acceptable on the basis of seismic interpretation but the integration of 3D model reconstruction and 3D geomechanical restoration, validates only the scenario with a single stage of deformation.The 3D model highlights along strike variations of the structural style for the Trapanese unit where pre-existing discontinuities (e.g. inherited Mesozoic normal faults) played an important role in the preferential occurrence of hinterland verging structures. In detail, backthrusts (N-verging) are dissected by tear faults along the Mt. Kumeta structure whereas an imbricate backthrust system evolves into thrust along the Mt. Rocca Busambra structure. Shortening estimate indicates low amount of internal deformation affecting the carbonate platform unit (

This study presents a world review as well as new additional data in form of submerged speleothems that are used for paleo sea level reconstructions. Speleothems significantly contributed to the understanding of the global and regional sea level variations during the Middle and Late Quaternary. The studied speleothems cover the last 1.4 Myr and are focused mainly on Marine Isotope Stages (MIS) 1, 2, 3, 5.1, 5.3, 5.5, 7.1, 7.2, 7.3 and 7.5. Results reveal that submerged speleothems represent extraordinary archives providing detailed information on former sea level changes. We present also new results from stalactites collected in central Mediterranean sea, at Favignana and Ustica islands (Sicily, Italy), both characterized by continental, phreatic or marine layers. The study and analysis of the latter speleothems provide results of great interest for relative sea level changes over the last 1000 years.

18 pages, 13 figures, 1 table, We present here for the first time a morpho-structural study of the submarine sector of the Ustica volcanic edifice, located in the south-western Tyrrhenian Sea, considered as an inactive volcanic system, middle Pleistocene in age. The main aim of this research study is to unravel the submarine dynamics along the slope sectors of the Ustica volcano, in order to provide new insights on one of the most tectonically active regions of the Central Mediterranean during the Quaternary. We analysed and interpreted an integrated seismo-acoustic data set consisting of multibeam swath-bathymetry, sub bottom profiles, single-channel seismic reflection records, all of them acquired during the last two decades. The seismostratigraphic analysis indicates that the Ustica volcano is composed by a sequence of lava flows and pyroclastic products, whose geometry can be interpreted as the consequence of combined upward growing and northward shifting of the volcanic centers. The mapped geomorphological elements distributed along the submerged slopes were classified based on their specific morphogenetic process. The achieved results reveal that volcanic, tectonic, oceanographic and gravity processes interacted in shaping the complex current physiography of the volcanic edifice, which is characterized by extremely uneven submarine flanks. The northern region is characterized by the widespread occurrence of well-preserved cones, probably linked to the last submarine volcanic activity of the area. Along the eastern sector, elongate gullies and linear furrows locally incise the shelf break and develop downward producing slope failures. Furrows and gullies represent the main conduits for flushing sediments through various types of flows and mass wasting, from the shallow sectors to the bathyal plain. Along the southern and eastern region slope failures processes carve almost totally of the shelf edge and mainly propagate through retrograding collapses. Further on, the southern region is mainly shaped by E-W and N-S trending fault escarpments that may have triggered the largest slope failures of the area. The main results of this study contribute to improve the understanding of the geological processes and geodynamic activity between the Northern Sicily Continental Margin and the Tyrrhenian Basin and represent a baseline for assessing the geo-hazard potential on the Ustica Island, We acknowledge the CARG Project (Geological Maps of Italy) funded by the ISPRA-Italian Geological Survey and the Italian National Research Projects MaGIC (Marine Geological Hazard along the Italian Coast) funded by the Italian Civil Protection Department.-- With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

This study presents a global overview of the submerged speleothems used to reconstruct paleo sea levels and reports new results from two stalactites collected in the Mediterranean Sea. Coastal cave deposits significantly contributed to the understanding of global and regional sea-level variations during the Middle and Late Quaternary. The studied speleothems cover the last 1.4 Myr and focused mainly on Marine Isotope Stages (MIS) 1, 2, 3, 5.1, 5.3, 5.5, 7.1, 7.2, 7.3 and 7.5. The results indicate that submerged speleothems represent extraordinary archives that can provide detailed information on former sea-level changes. The two stalactites collected in the central Mediterranean Sea, at Favignana and Ustica islands (Sicily, Italy), are both characterized by continental, phreatic or marine layers. The U-Th and 14C ages of the new speleothems provide results of great interest for relative sea-level changes over the last 1000 years.

A three-stage evolution has characterized the Sicilian Fold and Thrust Belt (SFTB) during the last 15 My: two main thin-skinned shortening events involving mainly Meso-Cenozoic carbonate units, followed by thick-skinned thrusting involving Plio-Pleistocene deposits in the frontal area as well as the crystalline basement in the inner and deeper sector of the chain. We investigated the northern Sicily continental margin, by using differently-penetrative seismic reflection data and new field surveys, which revealed, both offshore and onshore, north-vergent compressional structures that affected the tectonic edifice during Quaternary time. These structures, correlated with the kinematic setting pointed out by seismicity and GPS measurements, could disclose an important change in distribution and orientation of deformation in the frame of the Africa-Europe convergence. Our hypothesis is that the most recent tectonic processes in the northern Sicily continental margin are representative of a jump of the deformation from the frontal area of the SFTB in the Sicily Channel to the inner sector in the Southern Tyrrhenian Sea. This study is in agreement with recent interpretations about a change in the subduction polarity in the central Mediterranean orogenic system, as a consequence of the ongoing collision of the African promontory with the thinned continental to oceanic sectors (Algerian and Tyrrhenian basins) of the European plate. The seismic activity associated with the north-vergent thrust could have implication for the assessment of the seismic risk in the Central Mediterranean and understanding of active structures in marine areas that could be responsible for tsunami hazard.

We investigate the tectonically active Northern Sicily Continental margin focusing on the neotectonics affecting the Offshore of Termini (Southern Tyrrhenian Sea) by using high-resolution seismic and multibeam data. The sedimentary succession along the North Sicilian Continental Margin (NSCM) represents the marine prolongation of those outcropping along the Northern Sicily coastal belt. The NSCM has been originated as a consequence of a complex interaction of compressional events, crustal thinning, and strike-slip faulting. E–W, NW–SE, and NE–SW trending, both extensional and compressional faults, with a local strike-slip component, exerted control on the morphology of the present-day shelf and coastal areas during the Pleistocene. During the Quaternary, the tectonic as well as depositional events have strongly shaped the margin forming the actual complex geomorphic setting of the margin. We present the main results of a high resolution survey that allow to identify several features (e.g. Mass Transport Deposits and pockmarks) linked to gravitational mass movement and fluids escape processes strongly controlled by the tectonics affecting the NSCM. All over the study area, we mapped inside the Late Quaternary depositional sequence repeated and variously distributed MTDs, characterised by transparent/chaotic seismic facies, interbedded to hemipelagic deposits, with seismic facies showing subparallel seismic reflectors of the transgressive and high stand systems tracts. We infer that this MTDs have been seismically induced by earthquakes. We estimate the recurrence times of earthquakes, by using an elaborate age-model that considers a constant sedimentation rate for the last 11.5 My, between 680 and 2200 years.

The central Mediterranean is a very complex area constituted by a puzzle of different lithosphere segments, whose geological evolution is controlled by the interaction between the European and African plates. Within this geological domain, the northern Sicily continental margin and adjacent coastal belt represent a link between the Sicilian chain and the Tyrrhenian extensional (back-arc) area in the north-south direction, whereas in the east-west direction a transition from a subduction type B (Ionian-Tyrrhenian) to a continental collisional system, subduction type A, (Sicilian-Maghrebian Chain) is recognized.The structure of the lithosphere in this area is matter of a strong debate. Most uncertainties on the geologic evolution of the boundary between the European and African plate at depth rise from the lack, up to now, of constraints and clear evidence of geometry of the lithosphere down to the crust-mantle interface.In order to investigate the regional crust-mantle tectonics, here we discuss recent deep seismic reflection data, gravimetric modelling, the regional fluid geochemistry coupled to the seismicity that clearly indicate presence, along this sector of the Central Mediterranean, of a hot mantle-wedging at about 28 km of depth. This wedge lies just below a thick-skinned deformed belt cut by a dense system of faults down to the Mohorovicic discontinuity.We also discuss new geochemical data in mineralization (fluorite) of hydrothermal deposits along the main regional faults above the mantle wedge. The mineralization is strongly enriched in saline fluid inclusions that allowed high precision analyses of the trapped volatiles (H2O, CO2 and noble gases). Notwithstanding the region is far from any evidence of volcanism (Etna volcano and Aeolian Islands are in about 80km), the new geochemical data highlight the presence of mantle-derived volatiles that degas through the crust (e.g., He isotopes, up to 1.4Ra, Ra is the He isotopic ratio in atmosphere). An excess of heat sourced from the mantle characterizes the region. This is a rare case of occurrence of mantle volatiles together with heat in a collisional system.The active regional seismicity indicates that the mantle fluids move from the mantle wedge to the surface, hence across the ductile crust that could be thought as a barrier to the advective transfer of fluids because of its low permeability on long time scales. Here we reconstruct the deep faults by the deep seismic reflection data that works as a network of pathways that actively sustains the advective transfer of the mantle fluids through the entire continental crust. Finally, the new geochemical data strongly supports that 1) the mantle wedge and possible associated magmatic intrusions as the source of the mantle volatiles outgassing in the region. A comparison of the noble gases isotopic signature of fluids coming from the mantle wedge and those emitted from the Mt Etna volcano furnish new constrain on the mantle composition below the central Mediterranean getting new constrains to the processes that controlled the geodynamic evolution of the central Mediterranean (i.e., delamination processes).

Degassing of volatiles across the Earth crust towards the atmosphere is mainly controlled by long last diffusion. However, it can also be episodic. In fact, tectonic control of solid phase release of radiogenic helium (4He) due to, e.g. fracturing, may contribute to explain variance of the continental 4He degassing flux over multiple time and space scales. Rock rheology have a controlling influence on a wide range of crustal-scale processes including fluid flow, tectonic deformations and seismicity. Though faults comprise a small volume of the crust, they influence the mechanical and fluid flow properties of the crust, and are mechanisms for accommodating most of the elastic strain in the crust through a variety of slip-behaviours. Helium isotopes (3He,4He) are useful tracers for investigating many important geological processes because helium is a stable and conservative nuclide that does not take part in any chemical or biological process. Indeed, 4He released from rocks in the porefluid can be used to trace the deformation of rocks in a field of stress [Bauer 2017; Torgersen and O’Donnell 1991]. In fact, a volume of rock starts to be affected by micro-fractures from since it is subjected to stress conditions exceeding about half its yield strength [Bauer, 2017]. Hence, the network of fractures evolves in a volume of rock progressively increase as a function of the evolution of deformation, improving the release of 4He that is trapped since its production. Consequently, 4He in natural fluids that outgas in a region of active tectonic can record the evolution of the field of stress and this volatile component could be used to trace changes in stress and deformation field. For the purpose of quantifying the amount of 4He present in the geological traps that feed the mud volcanoes of Regnano-Nirano mud volcanoes systems (Bonini et al., 2007), in the north Italy, in our study we have reconstructed the 3D geological model of the reservoirs, and proceeded to estimate the gas contained in them. Fluids emitted from these systems are thermogenic-CH4 rich, which vertically migrates towards the surface. Helium is in traces and its isotopic signature (≈0.01-0.02Ra, Ra is the 3He/4He in air) shows that 4He is mainly produced in the crust by U-Th decay. We have found that the present 4He is greater than what should be available taking into account only the steady-state crustal production. Therefore, we compared the excess helium present in the reservoirs with the contribution coming from the seismic activity of the area, which is sufficient to explain this excess. Our study highlights that an intense fracturing of a volume of rock, due to the recent seismicity below the studied area, may explain the accumulation of helium in the reservoir higher than the steady-state condition. Therefore, the effective vertical rate of fluid transport in the Earth's continental crust can be characterized by episodic events controlled by fracturing.Bonini (2007) - JGRes Solid Earth Torgersen & O’Donnell (1991) - GRL, vol.18Bauer (2017) - SAND2017-9438

The paleomagnetic investigation of the western Sicily Maghrebian belt has revealed since the 1970s that large clockwise rotations up to 140° with respect to the Hyblean-African foreland occurred synchronous with Tertiary shortening of the chain. The observation that rotations decrease stepwise from internal to external tectono-stratigraphic units led in the 1990s to a widely accepted model postulating that rotational thrust-sheet emplaced during forward orogenic propagation. More recently, other authors suggested that clockwise rotations from Sicily are conversely the result of late orogenic dextral strike-slip tectonics. Here we report on a paleomagnetic investigation of 30 Jurassic-Eocene sedimentary sites sampled mainly across the WNW-ESE Mt. Kumeta and Rocca Busambra ridges (Trapanese Unit), both bounded to the north by high-angle reverse faults with dextral strike-slip components. We find rotations of 110°–120° at faults of northern ridge margins, which decrease to 80°–90° at ~200m to the south and rise again moving further south. Thus, an excess rotation of 20°–40° due to dextral-strike-slip shear is annulled to the regional rotational background of the Trapanese Unit at only 200m from fault traces, translating to paleomagnetically calculated strike-slip offsets not exceeding 600m. Further north, seven sites sampled in the Imerese Unit, tectonically stacked above the Trapanese Unit, yield a ~130° rotation. Thus, our data confirm that CW rotations in Sicily are predominantly related to thrust-sheet emplacement. Strike-slip tectonics has very limited relevance and gives local rotations that fade out at only 200m from fault planes.

The Sicilian Fold and Thrust Belt developed during Neogene-Quaternary times characterized by main African-wards tectonic transport direction. Recent investigations highlighted extensive hinterland-verging tectonic structures active during late Pliocene-Pleistocene time suggesting a late collisional stage of the Sicilian Fold and Thrust Belt that could be a precursor of a change in the subduction polarity in the central belt of Mediterranean.

In order to investigate the variability of helium degassing in continental regions, its release from rocks and emission into the atmosphere, here we studied the degassing of volatiles in a seismically active region of northern Italy (MwMAX = 6) at the Nirano-Regnano mud volcanic system. The emitted gases in the study area are CH4–dominated and it is the carrier for helium (He) transfer through the crust. Carbon and He isotopes unequivocally indicate that crustal-derived fluids dominate these systems. An high-resolution 3-dimensional reconstruction of the gas reservoirs feeding the observed gas emissions at the surface permits to estimate the amount of He stored in the natural reservoirs. Our study demonstrated that the in-situ production of 4He in the crust and a long-lasting diffusion through the crust are not the main processes that rule the He degassing in the region. Furthermore, we demonstrated that micro-fracturation due to the field of stress that generates the local seismicity increases the release of He from the rocks and can sustain the excess of He in the natural reservoirs respect to the steady-state diffusive degassing. These results prove that (1) the transport of volatiles through the crust can be episodic as function of rock deformation and seismicity and (2) He can be used to highlight changes in the stress field and related earthquakes.

Backthrusting, nappe refolding, and normal faulting frequently characterize late collisional stage of an orogen. Shortening driven by backthrusting is widely reported in the Alpine orogen, and it has been proposed to be responsible for the increase of subsidence (Roure et al., 1990). Moreover delamination and backthrusting has been considered as related to subcritical condition of a Coulomb-type accretional wedge (Torres Carbonell et al., 2011). The Sicilian Fold and Thrust Belt (SFTB) was characterized by a three-stage evolution during the last 15 My: two main shortening events generated and developed at different structural levels (shallow- and deep-seated thrusts in thin-skinned thrust-model) and at different time intervals, involving mainly the Meso-Cenozoic carbonate units of the ancient African passive continental margin, followed by a more recent thick-skinned thrust-model involving the Plio-Pleistiocene deposits in the frontal area as well as the crystalline basement in the internal sector of the chain. We investigated the northern Sicily continental margin by using differently-penetrative seismic reflection data, calibrated with field surveys and borehole data. The tectonic edifice appears to be interested, both offshore and onshore, by a structural style typical of a triangle zone bounded, on the southern side by N-dipping high-angle transpressional faults, mainly Early Pliocene to Early Pleistocene in age, and on its northern side, by high-angle S-dipping thrusts, deeply connected with a low-angle décollement layer. In the outer sector of the SFTB, double-verging structures (with NW and SE-tectonic transport) have been described for the Plio-Pleistocene evolution of the Gela Thrust System. The southern Tyrrhenian region is also interested by normal faulting and subsidence, delamination processes, and widespread deep seismicity. A late Miocene-Quaternary northern migration of the plate margin producing opposite-verging structures is reported in the northern Africa plate boundary (e.g. NW Algeria Neogene margin; Yelles et al., 2009; Mauffret, 2007). A plate boundary reorganization during the latest 0.8–0.5 My with the development of backthrusts have been documented in the Mediterranean region (Goes et al., 2004). Our hypothesis is that the most recent tectonic processes in the study region are representative of a late collisional stage in the northern Sicily mountain building and at a larger scale could be a precursor of a change in the subduction polarity in the central belt of Mediterranean, as a consequence of the ongoing collision of the African promontory with the thinned continental to oceanic sectors (Algerian and Tyrrhenian basins) of the European plate.

The flow of fluids into the Earth’s crust can produce large-scale heat and mass transport. The mechanisms and driving forces for this fluid-transport range from molecular diffusion, to grain boundary diffusion and to advective flow. Recent studies [Torgersen,2010 and references therein] suggest that largescale vertical transport of fluids in the continental crust is likely advective and episodic. So it is crucial to understand if the variability of the measured degassing flux is a reflection of this episodic and advective transport. Here we try to answer these questions by using the noble gases. In particularly He that is recognized as a powerful tracer in variousfields, such as hydrology, hydrocarbon exploration, mantle processes [Burnard, 2013]. Degassing of He produced in the crust mainly consists of two stages that act on different scales: (1) the release of volatiles from the mineral/rocks and (2) their transport toward the surface [Burnard, 2013]. Tectonic deformation of rocks can rupture mineral grains, cause pervasive fracturing, increase effective porosity, open new fault zone. These processes lead to a release of accumulated geogenic gases (e.g. He) trapped in immobile porosity and/or mineral grains to adjacent fracture networks, which allow transport through the system. We have developed our study in the central Apennines, which is a seismically active region. We investigate the outgassing of He from two mud volcanoes systems(Nirano and Regnano) since the geographical distance from active volcanic systems and the typical radiogenic He isotope signatureindicate the crustal origin of the outgassing volatiles.Furthermore in this area aseismic sequence (Mw 6.1) occurred on 2012 May at shallow depths (about 7–9 km). We have compared both in situ 4He production and 4He from an external crustal flux, with the helium contained in the Nirano-Regnano natural hydrocarbon reservoirs. Our model uses a high precision basin volume reconstruction based on the geological-map data and calibrated by using data from deep wells. Our results indicatea higher amount of helium in the reservoir than one could expect. So this studysupport that He that is released by rock fracturing contributes to the amount of He emitted from these mud volcanoes. This approach furnish new tools for the use of natural degassingas tool to monitor and investigate the state of stress and strain in Earth materials and the effect of deformation on material transport properties.

We describe soft-sediment deformation structures into the Upper Triassic cherty limestone outcropping in the Pizzo Lupo section (Central Sicily, Italy), pertaining to the deep-water palaeodomain of the Southern Tethyan margin. In the study section, mainly consisting of thin-bedded mudstone/marl alternations with bedded chert intercalations, some lithofacies have been separated on the basis of the abundance of the calcium carbonate/clay content and the overall textural features. The deformational structures, displaying different deformational styles as folded and faulted beds, disturbed layers, clastic dikes, and slumps occur mainly in the deformed horizons that involve marl-dominated lithofacies. Small-scale water-escape structures involve beds with nodular fabric. Synsedimentary faults affect the mud-limestone dominated lithofacies, which are characterized by fault-rotating blocks producing lateral thinning. These bodies appear to have moved coherently along an overall planar surface. We relate these soft-sediment deformations to slump sheets, associated with down-slope sliding of sedimentary masses. The deformation mechanism and driving force for these soft-sediment deformations are due essentially to gravitational instability and dewatering. Detailing, rotational (slump) and translational (glide) slides and water-escape are the main processes causing the distinguished deformational styles. The synsedimentary extensional tectonics that affected the Upper Triassic pelagic deposits was the triggering process responsible for the instability of the seafloor inducing loss of coherence of the unconsolidated sediments on the sea bottom, developing a large number of gravity-driven slides. The analysis of both of these SSDSs and their relationships with the structural scenario allow us to hypothesise that they are seismically-induced.

Temperature-dependent clay mineral assemblages, vitrinite reflectance, and one-dimensional (1-D) thermal and three-dimensional (3-D) geological modeling of a Neogene wedge-top basin in the Sicilian fold-and-thrust belt and its pre-orogenic substratum allowed us to: (1) define the burial history of the sedimentary succession filling the wedge-top basin and its substratum, (2) reconstruct the wedge-top basin geometry, depocenter migration, and sediment provenance through time in the framework of a source-to-sink system, and (3) shed new light into the kinematic evolution of the Apennine-Maghrebian fold-and-thrust belt.The pre-orogenic substratum of the Scillato basin shows an increase in levels of thermal maturity as a function of stratigraphic age that is consistent with maximum burial to 3.5 km in deep diagenetic conditions. In detail, Ro% values range from 0.40% to 0.94%, and random ordered illite-smectite (I-S) first converts to short-range ordered structures and then evolves to long-range ordered structures at the base of the Imerese unit. The wedge-top basin fill experienced shallow burial (∼2 km) and levels of thermal maturity in the immature stage of hydrocarbon generation and early diagenesis. Vitrinite reflectance and mixed-layer I-S values show two populations of authigenic and inherited phases. The indigenous population corresponds to macerals with Ro% values of 0.33%–0.45% and I-S with no preferred sequence in stacking of layers, whereas the reworked group corresponds to macerals with Ro% values of 0.42%–0.47% and short-range ordered I-S with no correlation as a function of depth.Authigenic and reworked components of the Scillato basin fill allowed us to unravel sediment provenance during the Neogene, identifying two main source areas feeding the wedge-top basin (crystalline units of the European domain and sedimentary units of the African domain), and to detect an early phase of exhumation driven by low-angle extensional faults that predated Neogene compression.

Neogene-Quaternary wedge-top-basins arose during the Sicilian fold and thrust belt (FTB) build-up. The infilling sedimentary successions are: i) middle-upper Miocene silicoclastics succession, accommodated on top of the accreted Sicilide and Numidian flysch nappes; ii) upper Miocene-lower Pliocene deepening-upwards sediments unconformably overlying the inner Meso-Cenozoic deep-water, Imerese and Sicanian thrust units; iii) Upper Pliocene-Quaternary coastal-open shelf deposits unconformably covering (in the outer sector of the FTB) a tectonic stack (Gela thrust system). These successions are characterized by a basal unconformity on the deformed substrate believed to be the depositional interface common both to the coeval wedge-top and foredeep basins. The tectono-sedimentary evolution of the syn-tectonic basins was controlled by the progressive deepening of the structural levels, which were active during the growing of the FTB. The palinspastic restoration of a crustal geological transect in central Sicily points to: i) the occurrence of two subsequent, basal main thrusts (MT1 and MT2) active during the Neogene-middle Pleistocene tectonic evolution, as well as ii) a decrease in slip- and shortening-rate, estimated for the later MT2 as compared to earlier MT1 basal main thrust. The foreland-basin system evolution recorded during these two steps suggests: – the regional lithofacies distribution, during late Tortonian-early Pliocene, accounted for a wide depozone including the Iblean plateau and its offshore;– a crucial change was recorded by the late Pliocene-Pleistocene wedge-top depozone, when the deeper basal main thrust (MT2) involved and thickened (in the inner sector of the FTB) the crystalline basement (thin- to thick-skinned thrust tectonics); this change influenced the depozones, progressively narrowing up to the present-day setting. As regards this general evolutionary framework, thin-skinned and thick-skinned thrust tectonics can be recognized in the Sicilian FTB evolution. The late Tortonian-early Pliocene, thin-skinned thrust tectonics include two main tectonic events, a “shallow-seated” Event 1 and a “deep-seated” Event 2, with the Pliocene-Pleistocene thick-skinned thrust tectonics representing a third tectonic event (Event 3).

The submerged sill in the Strait of Messina, which is located today at a minimum depth of 81 m below sea level (bsl), represents the only land connection between Sicily and mainland Italy (and thus Europe) during the last lowstand when the sea level locally stood at about 126 m bsl. Today, the sea crossing to Sicily, although it is less than 4 km at the narrowest point, faces hazardous sea conditions, made famous by the myth of Scylla and Charybdis. Through a multidisciplinary research project, we document the timing and mode of emergence of this land connection during the last 40 kyr. The integrated analysis takes into consideration morphobathymetric and lithological data, and relative sea-level change (both isostatic and tectonic), resulting in the hypothesis that a continental land bridge lasted for at least 500 years between 21.5 and 20 cal ka BP. The emergence may have occurred over an even longer time span if one allows for seafloor erosion by marine currents that have lowered the seabed since the Last Glacial Maximum (LGM). Modelling of palaeotidal velocities shows that sea crossings when sea level was lower than present would have faced even stronger and more hazardous sea currents than today, supporting the hypothesis that earliest human entry into Sicily most probably took place on foot during the period when the sill emerged as dry land. This hypothesis is compared with an analysis of Pleistocene vertebrate faunas in Sicily and mainland Italy, including a new radiocarbon date on bone collagen of an Equus hydruntinus specimen from Grotta di San Teodoro (23-21 cal ka BP), the dispersal abilities of the various animal species involved, particularly their swimming abilities, and the Palaeolithic archaeological record, all of which support the hypothesis of a relatively late land-based colonization of Sicily by Homo sapiens. © The Geological Society of London 2016.

In this paper we present and discuss data concerning the morphostructural evolution at Ustica Island (Tyrrhenian Sea, Italy) during Late Quaternary. New insights on the relative sea-level changes of Ustica are coming from data collected during a geomorphological field survey around the island, together with the bathymetric analysis of the surrounding seabed and 14C datings on samples of speleothems, flowstones and marine shells found inside three selected sea caves. The survey was mainly accomplished on June 2015 through the first complete snorkel investigation off the about 18 km-long volcanic coast of the island, which allowed to precisely define location, relationship and morphometric features of coastal landforms associated with modern sea level. This study highlights the occurrence, for the first time in the Mediterranean, of tidal notches in correspondence of carbonate inclusions in volcanic rocks. The elevation of the modern tidal notch suggests that no significant vertical deformations occurred in the southeastern and eastern sectors of Ustica in the last 100 years. However, the presence of pillow lavas along the coast demonstrates that Ustica was affected by a regional uplift since the Late Quaternary, as also confirmed by MIS5.5 deposits located at about 30 m a.s.l., which suggests an average uplift rate of 0.23 mm/y. Radiocarbon dating of fossil barnacles collected inside the Grotta Segreta cave indicate an age of 1823 ± 104 cal. BP. The difference in height with respect to living barnacles in the same site suggests that their present elevation could be related to stick-slip coseismic deformations caused by the four earthquake sequences (two of which with Mw = 4.63 ± 0.46) that strongly struck the island between 1906 and 1924. © 2017 Elsevier B.V.

The paleotectonic and volcanic features of the Jurassic–Cretaceous carbonate successions, outcropping in central-western Sicily, allow us to restore the tectono-sedimentary evolution of a sector of the African continental margin. These successions consist of shallow-to-deep-water Mesozoic deposits that have formed in the carbonate platform-to- pelagic plateau depositional setting of the so-called Trapanese paleogeographic domain. Fieldwork, including structural analyses, has indicated the occurrence of lateral facies changes, resedimented materials, volcanic products (pillow lavas and tuffitic deposits), unconformity surfaces and paleofaults of different trends and age. These data, combined with facies and a physical–stratigraphic analysis, allow one to distinguish between the different tectono-stratigraphic settings. A structural low, filled with thick pillow lavas and reworked deposits, appears bordered by two main structural highs: an articulate carbonate-pelagic platform with a stepped fault margin, and the flank of a structural high, where the volcanoclastic deposits are interlayered with reworked reef materials, suggest the occurrence of a submarine volcano, that evolved into an atoll-type carbonate shelf setting. Tectonic and magmatic events punctuated the sedimentary evolution during the Early Jurassic, Middle–Late Jurassic, Early and Late Cretaceous. The horst and graben structures connected by steeped margins and the occurrence of distinctive types of volcanic products suggest that the study areas could represent a sector of the Jurassic–Cretaceous southern Tethyan passive continental margin, situated at the edge of the continental platform bordering those basinal areas where rifting and possible spreading processes were active during the Mesozoic.

We illustrate the tectono-sedimentary evolution of a Jurassic–Cretaceous intraplatform basin in a fold and thrust belt present setting (Cala Rossa basin). Detailed stratigraphy and facies analysis of Upper Triassic–Eocene successions outcropping in the Palermo Mts (NW Sicily), integrated with structural analysis, restoration and basin analysis, led to recognize and describe into the intraplatform basin the proximal and distal depositional areas respect to the bordered carbonate platform sectors. Carbonate platform was characterized by a rimmed reef growing with progradational trends towards the basin, as suggested by the several reworked shallow-water materials interlayered into the deep-water succession. More, the occurrence of thick resedimented breccia levels into the deep-water succession suggests the time and the characters of synsedimentary tectonics occurred during the Late Jurassic. The study sections, involved in the building processes of the Sicilian fold and thrust belt, were restored in order to obtain the original width of the Cala Rossa basin, useful to reconstruct the original geometries and opening mechanisms of the basin. Basin analysis allowed reconstructing the subsidence history of three sectors with different paleobathymetry, evidencing the role exerted by tectonics in the evolution of the narrow Cala Rossa basin. In our interpretation, a transtensional dextral Lower Jurassic fault system, WNW–ESE (present-day) oriented, has activated a wedge shaped pull-apart basin. In the frame of the geodynamic evolution of the Southern Tethyan rifted continental margin, the Cala Rossa basin could have been affected by Jurassic transtensional faults related to the lateral westward motion of Africa relative to Europe.

The Pizzo Lupo section (Sicanian Mts, central Sicily) is an Upper Triassic–Lower Jurassic condensed deep-water succession, where the relationships among synsedimentary tectonic, soft-sediment deformations, volcanism and lithological changes reflect the evolution of a rift-basin. The morphostructural setting of the studied basin appears as a gently dipping slope where a fault-delimited area (graben to halfgraben) was developed. The instability of the sea floor, related to the seismic shocks, was the cause of the gravity-driven deformational sedimentary structures (slumping, breccia channelized bodies). The partly stratified basaltic rocks, with disorganized and chaotic stratification, suggest the occurrence of a volcanic complex located in neighbouring areas. A regional comparison with the tectono-sedimentary evolution of the pelagic drowning platform succession (i.e. Trapanese domain Auct.), outcropping in adjacent areas, suggests that these different domains were close to each other during the studied period forming a stepped margin platform-to-basin system. The environmental changes, synsedimentary tectonic activity and gravity-driven phenomena were the result of repeated events occurred during a long time interval, spanning from Late Triassic to Early Jurassic.

Sicily is a thick orogenic wedge formed by (1) the foreland (African) and its Sicilian orogen and (2) the thick-skinned, Calabrian–Peloritani wedge. The crust under central Sicily, from the Tyrrhenian margin to the coastline of the Sicily Channel, has been investigated by the multidisciplinary (SI.RI.PRO.) research project. The project dealt with the nature and thickness of the crust and depth and geometry of the Moho, which is essential in formulating subduction models and improving the knowledge of African and Tyrrhenian–European lithospheres. The results resolve features such as (1) the main orogenic wedge, (2) the very steep, NW–SE-trending regional monocline suggesting inflection of the foreland crust, (3) the deep Caltanissetta synform imaged, for the first time, to about 25 km, and (4) the top of the crystalline basement and the inferred crust–mantle boundary. The SI.RI.PRO. transect confirmed that the NNW-dipping, autochthonous Iblean platform of SE Sicily and its basement extends all the way into central Sicily. Further NW, towards the NNW end of the transect, a large uplift involves the Iblean platform and its underlying basement. The associated gravity anomaly is interpreted as the southern wedge edge of the Tyrrhenian mantle that splits the subducting Iblean–Pelagian (African) continental slab from an overlying synformal stack of allochthonous thrust sheets. Supplementary materials: Additional data are available at www.geolsoc.org.uk/SUP18594.

New data in the coastal area between Acquedolci and Patti (northeastern Sicily, Italy) have been collected to calculate vertical tectonic rates in a key sector between the Kabilian-Calabrian and the Sicilian-Maghrebian chain. The comparison among marine geology data (multibeam and seismic reflection profiles) on the continental shelf-slope system and the radiocarbon ages on geomorphological markers collected during a coastal survey, provided new stratigraphic, geomorphological and biological data, contributing to the knowledge of the geological evolution of this sector for the last 125 ky.This coastal area is framed between two main structural features active during the Pleistocene in northern Sicily: the Kabilian-Calabrian Thrust Front (west of Acquedolci) and the Vulcano-Tindari Fault (east of Patti). The occurrence of these structural features, the former compressive, the latter transcurrent, confirms that the study area is tectonically active and " moves" vertically in differential mode. Fault systems separate blocks with different uplift rates both in onland and offshore areas. In the Gulf of Patti, the offshore area is subsiding, while contemporaneously uplift of the mainland can be observed. The study sector records the same uplift rates both during MIS 5.5 and the Holocene, in contrast to the other areas of Sicily. © 2012 Elsevier Ltd and INQUA.

The fold and thrust belt in western Sicily is characterized by the presence and interference of shallow and deep-seated compressional structures, which were generated and developed at different structural levels. The shallow structures consist of imbricated thrusts and asymmetric folds, with a typical wavelength of 2 km, involving relatively thin deep-water units. These units are superimposed on thick platform carbonate units, along a wide and originally almost flat floor thrust. The axial trend of the folds is variable, as multi-phase folding often occurred, producing a characteristic interference pattern, reflecting continuous variations of the apparent transport direction during the emplacement (i.e. rotation of the allochthonous thrust sheets). The deep-seated structures consist of large, double-verging pop-up structures, with a typical wavelength of 5–10 km, involving thicker platform carbonate successions. The deep-seated structures are characterized by large folds, with vertical to overturned limbs, caused by high-angle, transpressive ramps that reactivated previous (i.e. Mesozoic) synsedimentary normal or transtensional faults. The floor thrust of the shallow structures was passively deformed by the subsequent growth of the underlying, younger deep-seated structures. Large clockwise rotations of the tectonic units occurred during the compressional deformation, and the amount of rotation is apparently related to the timing and amount of the tectonic transport.