Geochronological constraints on the evolution of the Periadriatic Fault System (Alps)

Fault rocks from various segments of the Periadriatic fault system (PAF; Alps) have been directly dated using texturally controlled Rb-Sr microsampling dating applied to mylonites, and both stepwise-heating and laser-ablation 40Ar/39Ar dating applied to pseudotachylytes. The new fault ages place better constraints on tectonic models proposed for the PAF, particularly in its central sector. Along the North Giudicarie fault, Oligocene (E)SE-directed thrusting (29-32Ma) is currently best explained as accommodation across a cogenetic restraining bend within the Oligocene dextral Tonale-Pustertal fault system. In this case, the limited jump in metamorphic grade observed across the North Giudicarie fault restricts the dextral displacement along the kinematically linked Tonale fault to ~30km. Dextral displacement between the Tonale and Pustertal faults cannot be transferred via the Peio fault because of both Late Cretaceous fault ages (74-67Ma) and sinistral transtensive fault kinematics. In combination with other pseudotachylyte ages (62-58Ma), widespread Late Cretaceous-Paleocene extension is established within the Austroalpine unit, coeval with sedimentation of Gosau Group sediments. Early Miocene pseudotachylyte ages (22-16Ma) from the Tonale, Pustertal, Jaufen and Passeier faults argue for a period of enhanced fault activity contemporaneous with lateral extrusion of the Eastern Alps. This event coincides with exhumation of the Penninic units and contemporaneous sedimentation within fault-bound basin

3D-Kernel Based Imaging of an Improved Estimation of (Qc) in the Northern Apulia (Southern Italy)

We investigate crustal seismic attenuation by the coda quality parameter (Qc) in the Gargano area (Southern Italy), using a recently released dataset composed of 191 small earthquakes (1.0 ≤ ML ≤ 2.8) recorded by the local OTRIONS and the Italian INGV seismic networks, over three years of seismic monitoring. Following the single back-scattering theoretical assumption, Qc was computed using different frequencies (in the range of 2–16 Hz) and different lapse times (from 10 to 40 s). The trend of Qc vs. frequency is the same as that observed in the adjacent Umbria-Marche region. Qc at 1 Hz varies between 11 and 63, indicating that the area is characterized by active tectonics, despite the absence of high-magnitude earthquakes in recent decades. The 3D mapping procedure, based on sensitivity kernels, revealed that the Gargano Promontory is characterized by very low and homogeneous Qc at low frequencies, and by high and heterogeneous Qc at high frequencies. The lateral variations of Qc at 12 Hz follow the trend of the Moho in this region and are in good agreement with other geophysical observations

Seismic Envelopes of Coda Decay for Q-coda Attenuation Studies of the Gargano Promontory (Southern Italy) and Surrounding Regions

Here, we describe the dataset of seismic envelopes used to study the S-wave Q-coda attenuation quality factor Qc of the Gargano Promontory (Southern Italy). With this dataset, we investigated the crustal seismic attenuation by the Qc parameter. We collected this dataset starting from two different earthquake catalogues: the first regarding the period from April 2013 to July 2014; the second regarding the period from July 2015 to August 2018. Visual inspection of the envelopes was carried out on recordings filtered with a Butterworth two-poles filter with central frequency fc = 6 Hz. The obtained seismic envelopes of coda decay can be linearly fitted in a bilogarithmic diagram in order to obtain a series of single source-receiver measures of Qc for each seismogram component at different frequency fc. The analysis of the trend Qc(fc) gives important insights into the heterogeneity and the anelasticity of the sampled Earth medium

Landslides and predisposing factors of the Southern Apennines, Italy

The FiumarelladiCorletodrainagebasinisanemblematicsectorofthesouthernApennine thrust beltintheBasilicataregion(SouthernItaly),whichisstronglyaffected bylandslides. Landslides bothaffect theurbanareaandthefacilitiesrelatedtohydrocarbonexploitation, such asthepipelinesandoilwellsconnectedwiththeoilcentrelocatedjustoutsidethe eastern borderofthestudyarea.Basedonadetailed field survey,supportedby stereoscopic analysis,alandslideinventorymaphasbeenrealized,whichalsoreportsthe associated processesandlandforms.Therelationshipsbetweenthedifferent typesof landslides andthevariouspredisposingfactorslikeoutcroppinglithologies,slopes steepness, slopeexpositionandlandusehavebeenalsoinvestigated.Theacquireddata relate toageologicallycomplexareaofthesouthernApenninessubjecttorecentupliftand represent afundamentalcontributionusefulforthecorrectmanagementoftheterritory

Structural and Mineralogical Characterization of a Fossil Hydrothermal System Located at the Outermost Front of the Southern Apennines Fold-and-Thrust Belt

Aiming at investigating the hydrothermal circulation along the eastern flank of the Vulture volcano, along the outermost edge of the southern Apennine fold-and-thrust belt (ftb), we studied the fossil hydrothermal alteration that mineralized a transtensional fault that crosscuts volcanoclastic rocks in the Rapolla area. On the basis of structural, mineralogical, and fluid inclusion data, three main stages of activity of the hydrothermal system are documented. Stage 1 was produced by the circulation of fluids having low-pH conditions (pH ≈ 3-4) and relatively high-SO42- activity, as testified by the hydrothermal alteration mainly carried out by the alunite group minerals (particularly jarosite), which is typical of an advanced argillic alteration facies. Hydrothermal fluids were characterized by a high temperature of about 200°-210°C. These hot fluids altered and mineralized the matrices of pyroclastic rocks and sealed both burial-related and fault-related fracture networks. Later hydrothermal circulation (Stage 2) was recorded by opal A-rich veins present both within and outside the fault zone. The fluids responsible of opal A precipitation were characterized by lower temperature conditions, probably lower than 100°C. Current goethite mineralization takes place along the main slip surfaces of the study high-angle fault zone due to low temperature (<30°C) underground water circulation. This study highlights that a high-temperature hydrothermal system developed in the past within the transtensional fault zone of the Rapolla area when a high thermal anomaly was present. If we take into account that this area is still affected by a heat flux positive anomaly (90 mW/m2), we may infer that it has the potentiality to be considered an interesting site for future exploration devoted to the finding of medium-enthalpy geothermal resources at depth

Reconstruction of tectonically disrupted carbonates through quantitative microfacies analyses: an example from the Middle Triassic of Southern Italy

AbstractThe main goal of the paper is the reconstruction of a Middle Triassic buildup cropping out in the central part of the Southern Apennines. Middle Triassic reefs of the western Tethys realm are well known in the Northern and Southern Alps. In contrast, few studies of the Anisian–Ladinian carbonate platforms of the southern Apennines are available, due to the diagenetic alteration and tectonic disruption that hinder their paleoenvironmental and stratigraphic reconstruction. In an attempt to fill this gap, and to improve the knowledge on the Anisian–Ladinian carbonates of central Mediterranean area, this research is focused on a carbonate buildup cropping out in the "La Cerchiara" area, Sasso di Castalda (Basilicata, Southern Italy). The buildup, affected by intense tectonic deformation associated with the development of the Apennine thrust and fold belt, was studied using a statistical evaluation of the quantitative microfacies data. The research enabled a reconstruction of the original stratigraphic relationships of the various buildup fragments. A positive linear regression between the sample positions vs the percentage of autochthonous carbonates indicates an increase of the autochthons carbonate toward the top of the succession. The allochthonous fabrics (packstone/wackestone) at the base of the section (Unit IIIa) pass gradually upward into autochthonous (boundstones) facies (Units IIIb, I), consisting of microbialites (clotted peloidal micrite, microbial-derived laminae, and aphanitic micrite), microproblematica and cyanobacterial crusts, with few encrusting skeletal organisms. Statistical data suggest that units IIIa, IIIb, and I are in stratigraphic order while unit II appears to have been moved by tectonic dislocation from its original position at the base of the succession. The absence of metazoan reef framework, and the richness of micro-encrusters, autochthonous micrite and synsedimentary cements, suggest a mud-mound style of growth for the carbonate bodies of the Southern Apennine during the Anisian

Application of field surveys and multitemporal in-SAR interferometry analysis in the recognition of deep-seated gravitational slope deformation of an urban area of Southern Italy

The analysis of 4 year In-SAR Interferometry images and a detailed geomorphological survey have been carried out to detect a large Deep-Seated Gravitational Slopes (DSGSD) affecting the urban area of the Episcopia village, in Southern Italy. The DSGSD largely develops within phyllites of the Liguride Units and, in the upper slope, within Pleistocene sand and conglomerate deposits of the Sant'Arcangelo Basin. Field survey has shown trenches at the top and an evident bulge at the base of the DSGSD, corresponding to the Talweg of the Sinni River. Geological and geomorphological field surveys allowed us to hypothesize a listric geometry of the DSGSD subsurface plane reaching about 700 m of depth. Furthermore, the multi-temporal In-SAR Interferometry analysis collected from November 2014 to May 2017 revealed that a ground deformation of ±30 mm was occurred, and the process is still active in the whole area

A Geological Itinerary Through the Southern Apennine Thrust-Belt (Basilicata—Southern Italy)

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