Central Calabria Research Articles

Modern Approaches for Historical Seismograms: Moment Tensor Inversion of the 1947 Squillace Basin, South Italy, Earthquake

Abstract The scientific community has become increasingly aware of the importance of preserving and recovering historical seismic data, also because of their possible use in combination with modern techniques of analysis. Seismograms coming from the analog recording era cover more than 100 yr of seismic activity and may have a great relevance, especially for seismic risk evaluations in regions struck by destructive events in the past centuries but characterized by minor activity in the last decades. In this study we used analog seismograms to investigate an earthquake of presumed magnitude 5.7 that occurred in 1947 in central Calabria, south Italy, a high-seismic risk region framed in a complex geodynamic setting led by northwest-trending Nubia–Eurasia convergence and southeastward Ionian slab rollback. According to seismic catalogs, the 1947 is the only M > 5.5 earthquake instrumentally recorded in an area where the presence of the lateral edge of the Ionian slab has been suggested and an intense debate is still open concerning possible existence, and proper location, of a subduction-transform edge propagator (STEP) fault zone. To study this earthquake, we selected 15 medium- to long-period analog seismograms with related instrumental parameters, and we proceeded with vectorization process and proper waveform corrections. A technique specifically developed for time-domain moment tensor computation through waveform inversion of analog seismograms has been applied to the digitized recordings. The moment tensor solution estimated for the 1947 earthquake indicates strike-slip mechanism, focal depth of 28 km and Mw 5.1. The obtained hypocentral depth and left-lateral kinematics on about west-northwest–east-southeast-oriented fault fit well with the local seismotectonic framework and are compatible with STEP fault activity in central Calabria, furnishing a new seismological constraint to the debate concerning slab edge kinematics. Moreover, the presented analysis is useful for sharing with the scientific community new data and methodological issues related to historical seismogram management.

Phenomena of Contact and Mixing in the Arbëresh Dialects of San Marzano di San Giuseppe in Salento and Vena di Maida in Calabria

In this work, we will investigate hybridization, borrowing, and grammatical reorganization phenomena in the Arbëresh dialects of San Marzano (Apulia) and Vena di Maida (central Calabria). The data from the Arbëresh of S. Benedetto Ullano (northern Calabria) will be useful to provide a comparative frame. Arbëresh is the name of the Albanian varieties spoken in the villages/cities generally formed in the late fifteenth century by communities fleeing from Albania as a consequence of the Ottoman occupation. The long-time contact with neighboring Romance varieties is reflected in the extended mixing phenomena which characterize the lexicon and the morphosyntactic organization of Arbëresh as a heritage language. This is particularly evident in the two dialects that we investigate in this contribution, where relexification and grammatical reorganization phenomena provide us with an interesting testing ground to explain language variation.

Size characteristics of asbestiform fibers in lung tissue of animals that grazed in areas rich in ophiolitic outcrops in Central Calabria (Southern Italy)

In Calabria (Southern Italy) naturally occurring asbestos (NOA) mainly occurs in the ophiolitic sequences cropping in the Mount Reventino area. The most common type of asbestos detected was the amphibole tremolite; fibrous antigorite and minor chrysotile were also found. The development of asbestos-related diseases depends on, among other things, the morphological characteristics of fibers, length and width, affecting the durability of asbestos fibers in the lung.In this work fifteen lung samples of sheep, goats and wild boars, grazing around the Mount Reventino area were collected and asbestos fibers analysed. Observed fibers (357), of which 97 % were tremolite and 3 % antigorite fibers, were grouped according to species, grazing area and age of the animals. The aim of this work was to highlight any differences among the groupings and to compare our size results with data in literature related to exposed populations.Principal Component Analysis (PCA) highlighted a positive correlation between tremolite fiber length and width and revealed groupings in terms of animal age. The Kruskal-Wallis test showed statistically significant differences between fiber mean widths in young and old animals. 63 % observed asbestiform fibers were longer than 5 μm and 7 % of the fibers were longer than 20 μm (critical fiber length connected to the frustrated phagocytosis by the macrophage). Fibers conforming to the Stanton Hypothesis size (predictor of the carcinogenic potency of fibers) were 1 %.Our size parameters of fibers detected in the animal lungs were in fairly good agreement with literature data for human asbestos exposure to tremolite.These results confirmed that an animal-sentinel system could be used to monitor the natural background of the airborne breathable fibers exposure. In addition, the size correlation of animal-human breathed fibers could be useful to study their potential toxicity.Additional data are necessary for improving the agreement with human exposure data.

Fabric Analysis in Upper Crustal Post-Collisional Granitoids from the Serre Batholith (Southern Italy): Results from Microstructural and AMS Investigations

The Serre Batholith in Central Calabria (southern Italy) represents the intermediate portion of a continuous cross-section of late Variscan continental crust. The various granitoid units of the batholith were emplaced at depths between 23 and 6 km through an overaccretion mechanism that, at its upper levels, was marked by the emplacement of two-mica granodiorites and granites (MBG) at c. 295 Ma, followed by weakly peraluminous granodiorites (BAG) at c. 292 Ma. These upper crustal granitoid rocks have recorded tectonic stresses, which affected the batholith during cooling of the magmatic bodies, exhibiting a range of deformation microstructures from submagmatic to low-temperature subsolidus conditions, but without developing an evident meso/micro-structural fabric. Anisotropy of magnetic susceptibility (AMS) was employed to identify a possible “internal” fabric of the Serre upper crustal granitoids, revealing a magnetic foliation represented by a mainly oblate AMS ellipsoid. Magnetic foliations and lineations are consistent with a stress field characterized by a shortening axis roughly oriented NW–SE. Further studies are in progress to investigate more in depth the relationships between regional tectonic structures and the emplacement of the late-Variscan Serre Batholith granitoids.

Recent Activity and Kinematics of the Bounding Faults of the Catanzaro Trough (Central Calabria, Italy): New Morphotectonic, Geodetic and Seismological Data

A multidisciplinary work integrating structural, geodetic and seismological data was performed in the Catanzaro Trough (central Calabria, Italy) to define the seismotectonic setting of this area. The Catanzaro Trough is a structural depression transversal to the Calabrian Arc, lying in-between two longitudinal grabens: the Crati Basin to the north and the Mesima Basin to the south. The investigated area experienced some of the strongest historical earthquakes of Italy, whose seismogenic sources are still not well defined. We investigated and mapped the major WSW–ENE to WNW–ESE trending normal-oblique Lamezia-Catanzaro Fault System, bounding to the north the Catanzaro Trough. Morphotectonic data reveal that some fault segments have recently been reactivated since they have displaced upper Pleistocene deposits showing typical geomorphic features associated with active normal fault scarps such as triangular and trapezoidal facets, and displaced alluvial fans. The analysis of instrumental seismicity indicates that some clusters of earthquakes have nucleated on the Lamezia-Catanzaro Fault System. In addition, focal mechanisms indicate the prevalence of left-lateral kinematics on E–W roughly oriented fault plains. GPS data confirm that slow left-lateral motion occurs along this fault system. Minor north-dipping normal faults were also mapped in the southern side of the Catanzaro Trough. They show eroded fault scarps along which weak seismic activity and negligible geodetic motion occur. Our study highlights that the Catanzaro Trough is a poliphased Plio-Quaternary extensional basin developed early as a half-graben in the frame of the tear-faulting occurring at the northern edge of the subducting Ionian slab. In this context, the strike-slip motion contributes to the longitudinal segmentation of the Calabrian Arc. In addition, the high number of seismic events evidenced by the instrumental seismicity, the macroseismic intensity distribution of the historical earthquakes and the scaling laws relating to earthquakes and seismogenic faults support the hypothesis that the Lamezia-Catanzaro Fault System may have been responsible for the historical earthquakes since it is capable of triggering earthquakes with magnitude up to 6.9.

The Curinga\u2013Girifalco Line in the framework of the tectonic evolution of the remnant Alpine chain in Calabria (southern Italy)

In the peri-Mediterranean metamorphic belts, the tectonic evolution of the Calabria–Peloritani terrane during the dominant compressive tectonics of the Eocene represents one of the most problematic points in palinspastic restorations. A matter of particular debate is its shortening, which could have occurred during the Alpine or the Apennine subduction. In this regard, a crucial joint is provided by the kinematics of one of the most relevant shear zones such as the Curinga–Girifalco Line, cropping out in central Calabria. This shear zone juxtaposed a nearly complete Hercynian crustal section (i.e. the Sila and Serre Unit) onto the remnants of the Castagna Unit. The data in the available literature on ductile kinematics from the south-eastern branch of the Curinga–Girifalco Line indicate a downward movement of the hanging wall. In the present paper we show new, ductile kinematic data and petrographic evidence from outcrops in the north-western and south-eastern branches of the Curinga–Girifalco Line. Our results highlight the coherent kinematics of the Eocene shortening during the Alpine subduction system, followed by (late Eocene?)Oligocene to early Miocene, dominantly ductile extensional reworking, relating to the Apennines subduction system.

Geochemical modelling of granitoid magma diversity at Capo Vaticano Promontory (Serre Batholith, southern Italy)

Late-Variscan metaluminous/weakly peraluminous (quartz-diorites and tonalites) and strongly peraluminous (two mica porphyritic granodiorites and granites) granitoids represent two magmatic associations making up the Capo Vaticano Promontory (central Calabria, Italy). They characterize a portion of a complete continental crustal section exposed in continuity from NW to SE in the adjacent Serre Batholith. In this paper, we deal with geochemical modelling trying to understand the evolutionary processes responsible for the CVP granitoid genesis. We have investigated the main processes such as fractional crystallization, variable entrainment of peritectic mineral phases in the melt (Stevens et al., 2007; Clemens and Stevens, 2012), restite-unmixing (White and Chappell, 1977) and magma mixing to explain the geochemical variability in major and trace elements of these magmatic suites. The quartz-diorites and tonalites, representing the deepest seated rocks, are constituted by various amount of Pl + Bt + Amph + Qtz. Bt-rich and Pl-rich quartz-diorite are characterized by cumulus of Bt and Pl, respectively. A multi-step articulated fractional crystallization process was able to reproduce the quartz-diorite/tonalitic trends. Starting from a tonalitic parental magma, three different cumulates were produced: a mafic (Bt-rich) cumulate (75 % Bt, 10 % Pl and 5 % Ap) after F = 10 %, a second cumulate composed by Pl (45 %), Bt (30 %) and Amph (5 %) after F = 20 % and Pl-rich quartz-diorite (60 % Pl, 20 % Bt and 20 % Amph) as the third cumulates, after F = 30 %. Among the source-related models, restitic unmixing could have played a minor role in the quartz-diorite and tonalite genesis, defining them as products derived from partial melting of I-type sources. Pl + Kfs + Qtz + Bt + Ms are the main phases constituting the porphyritic granodiorites and granites. A simple fractional crystallization from less evolved granodiorites sample (KA2) has reproduced the more evolved liquid composition (PA27), after F = 27 %. In addition, PAE modelling is consistent with partial melting of a metapelitic source with entrainment of 20 to 5 % vol. of a peritectic assemblage made of orthopyroxene and garnet.Magma mixing modelling with mafic end-members (a basalt, a basaltic andesite and the MME of CVP) excluded any additional contribution from the mantle.Finally, geochemical modelling highlights the fractional crystallization as the main responsible process in the CVP granitoids differentiation, whereas PAE and restite unmixing processes do not provide evidence about source contributions. This study supports the idea that granitoid rocks represent recycled crustal material in the Capo Vaticano Promontory.

Latest observations on the nesting of the black stork Ciconia nigra Linnaeus, 1758 (Aves Ciconiidae) in valle del Vitravo (Calabria, Italia)

This work contains the latest observations on the Black Stork nesting in the Site of National Importance, Vitravo Valley, in central and eastern Calabria. The data acquired relates to the 2019 breeding season during which a monitoring was conducted on the nesting site and throughout the area of highest frequency of the species. The research allowed to ascertain the couple in the reproductive phase, with the failed hatching of the laid eggs and to record the constant presence of a sub-adult specimen in the nesting area.

Quick analysis of the characteristic hydrogeological parameters of an aquifer, using empirical formulas and the implementation of the clay substrate map: the case study of the shallow aquifer of the S. Eufemia Lamezia plain (Central Calabria - Italy).

In Calabria, there are few works of quantitative hydrogeology. Therefore, the present study aims to provide a contribution to the hydrogeological knowledge of the region and, in particular, of the shallow aquifer of the S. E. Lamezia plain, characterized by a multi-layer aquifer. The study area is located in the Tyrrhenian sector of the “Graben of Catanzaro, an important tectonic structure in the wider context of the Calabrian Peloritano Arc. The acquisition of new lithostratigraphic and hydrogeological data, related to drillings for water research, has allowed expanding the knowledge of the phreatic aquifer of S. E. Lamezia plain. In the study area, there is a high number of abusive wells without data, not declared and are made without a basic hydrogeological study. Therefore, they are free of flow rate tests and information about the drilling depth, stratigraphy and construction methods. However, a certain numbers of wells is authorized and the available data are: Stratigraphy, static and dynamic level, critical flow rare (Qc) and, in some cases, also the specific lowering (Δs). Therefore with these data, using empirical formulas, a quick analysis of the hydrogeological parameters characteristic of the aquifer it was done. Moreover, interpolating the stratigraphic data with a geostatistic method the map of the clay substrate was returned. In particular, the Transmissivity [T] and the Storage coefficient [S] were calculate with empirical formulas using well data. From the Transmissivity. the Hydraulic conductivity [K] is derived. The hydraulic gradient from the piezometric map graphically is calculated. The thickness of the saturated layer (b) of the aquifer was obtained directly from the stratigraphy of the wells surveyed or, in those cases in which stratigraphy was not known, from the differences between the values obtained from the isopiezometric map and the map of the clay substrate. In conclusion, this study, with the implementation of the clay substrate map and a quick analysis of the main hydrodynamic parameters, aims to provide a contribution to the definition of the hydrogeological model of the shallow aquifer of the Plain that represents a fundamental tool for the protection and the correct management of the water resource.

IG-Mapper: A new ArcGIS® toolbox for the geostatistics-based automated geochemical mapping of igneous rocks

This work introduces a user-friendly, fast and effective tool for the automated geochemical mapping of igneous rocks, to provide a geospatial representation of petrological parameters through the application of either deterministic or stochastic interpolation techniques. The geostatistical approach allows mapping to be extended to areas where igneous rocks are hidden under sedimentary cover, also introducing an estimate of the interpolation reliability. This new GIS-based automated procedure, which is mostly constructed with the ArcGIS® Model-Builder as a graphical code designer, can generate three main types of outputs: 1) interpolation maps of major and trace elements, isotopic compositions, and derived parameters, to provide valuable geospatial information regarding the genetic and structural relationships between magmatic bodies; 2) lithological maps, that are based on the geostatistical interpolation of major element data and mirror the main geochemical classification diagrams of plutonic rocks; and 3) interpolation checking maps, which provide an estimate of the geostatistical interpolability for one specific parameter at a time. This last output is expressed in the form of an empirical index (Stochastic Interpolation Index), which highlights the randomness level of a specific value distribution. This automated lithological mapping function is an entirely new tool based on five original python scripts, which makes it possible to interpolate on a georeferenced map the compositions deriving from the most used geochemical classification diagrams. This new tool package is presented here by using a portion of the Serre Batholith in central Calabria (southern Italy), to illustrate the potential of this method to open new research perspectives in igneous petrology.

Reconstructed seismic and tsunami scenarios of the 1905 Calabria earthquake (SE Tyrrhenian sea) as a tool for geohazard assessment

Italy is one of the most seismically active regions in the central Mediterranean and one of the countries with the longest record of historical earthquakes in the world. Over the last decades the scientific community has recognised the value of historical data when used to constrain modelling tools in hazard analyses. This is the case of the destructive 1905 Calabria (South Italy) earthquake, followed by a tsunami and by many secondary effects on the environment observed both inland and offshore. Recently acquired geophysical data allowed to identify an active normal fault, named Sant'Eufemia Fault, located nearshore in the Sant'Eufemia Gulf (SE Tyrrhenian sea), considered the most probable seismogenic source of the 1905 earthquake and capable to trigger future events.In this paper we perform a scenario-based deterministic analysis for an earthquake resulting from the rupture of the Sant'Eufemia fault (SEF) and a preliminary potential risk analysis. After defining source parameters compatible with the 1905 earthquake (ca. 40km fault length and ca. 2.3m slip, Mw 6.9), KF-analysis and tsunami simulations are carried out and modelling results are compared against historical available data. The obtained results allow one to border areas in central Calabria that are most exposed to geohazard deriving from the analyzed fault. Some of these areas happen to be zones with intense economic/touristic and urban development, which calls for the need to integrate the ongoing development plans with adequate programs of risk mitigation and prevention.

The Neogene-Quaternary geodynamic evolution of the central Calabrian Arc: A case study from the western Catanzaro Trough basin

The Catanzaro Trough is a Neogene-Quaternary basin developed in the central Calabrian Arc, between the Serre and the Sila Massifs, and filled by up to 2000m of continental to marine deposits. It extends from the Sant’Eufemia Basin (SE Tyrrhenian Sea), offshore, to the Catanzaro Basin, onshore. Here, onshore structural data have been integrated with structural features interpreted using marine geophysical data to infer the main tectonic processes that have controlled the geodynamic evolution of the western portion of the Catanzaro Trough, since Upper Miocene to present.The data show a complex tectonostratigraphic architecture of the basin, which is mainly controlled by the activity of NW–SE and NE–SW trending fault systems. In particular, during late Miocene, the NW-SE oriented faults system was characterized by left lateral kinematics. The same structural regime produces secondary fault systems represented by E-W and NE-SW oriented faults. The ca. E-W lineaments show extensional kinematics, which may have played an important role during the opening of the WNW–ESE paleo-strait; whereas the NE-SW oriented system represents the conjugate faults of the NW-SE oriented structural system, showing a right lateral component of motion. During the Piacenzian-Lower Pleistocene, structural field and geophysical data show a switch from left-lateral to right-lateral kinematics of the NW-SE oriented faults, due to a change of the stress field. This new structural regime influenced the kinematics of the NE-SW faults system, which registered left lateral movement. Since Middle Pleistocene, the study area experienced an extensional phase, WNW-ESE oriented, controlled mainly by NE-SW and, subordinately, N-S oriented normal faults. This type of faulting splits obliquely the western Catanzaro Trough, producing up-faulted and down-faulted blocks, arranged as graben-type system (i.e Lamezia Basin).The multidisciplinary approach adopted, allowed us to constrain the structural setting of the central Calabria segment. The joined onshore with offshore structural data analysis allowed us to image a more faithful geodynamic evolution of the Calabrian Arc, included in the wider geodynamic framework of the Mediterranean regionMoreover, our results show the close correlation between the NE-SW and N-S normal fault systems and evidence of deformed Quaternary deposits. These findings are relevant to seismic hazard understanding in an area which is historically considered at the highest risk of earthquake and tsunami and where are present important infrastructures and cities.

Nothocasis rosariae sp. n., a new sylvicolous, montane species from southern Europe (Lepidoptera: Geometridae, Larentiinae).

In this paper, we describe Nothocasis rosariae sp. n. as the second European species belonging to the genus Nothocasis Prout, 1937. Differential features from its allopatric sibling species N. sertata (Hübner, 1817) are presented basing on wing pattern, morphology of male and female genitalia, and molecular data (COI barcode region). The type series is designated from southern Italy, but one examined specimen was collected in Epirus, Greece. The largest phenotypic and genetic variation was observed in the Pollino Massif, northern Calabria, whilst the population of the locus typicus in the Sila Massif, central Calabria, appears to be more homogeneous. 128 individuals were collected in mountainous beech forests from late August to mid-November. We hypothesize that larvae of N. rosariae sp. n. feed on Fagus sylvatica whilst those of its sibling species, N. sertata, feed on Acer.

Timescales and mechanisms of batholith construction: Constraints from zircon oxygen isotopes and geochronology of the late Variscan Serre Batholith (Calabria, southern Italy)

The late Variscan Serre Batholith in central Calabria represents the middle portion, c. 13-km-thick, of a tilted crustal section continuously exposed from lower-crustal granulites to upper-crustal phyllites. The batholith is zoned, consisting of several granitoid types that were emplaced at depths ranging from c. 23 to c. 6km. Deep, strongly foliated quartz diorites and tonalites were emplaced into migmatitic metapelites, the intermediate level granitoids are weakly foliated to unfoliated porphyritic granodiorites and monzogranites, and the shallowest bodies are two-mica granodiorites and granites, grading upward to biotite ± amphibole granodiorites, emplaced into paragneisses and phyllites. Five samples, representative of the main granitoid types in terms of both composition and emplacement depth, have been dated by SHRIMP. Zircon from a lower-crustal quartz diorite gave an emplacement age of 297.3±3.1Ma; two middle-crustal strongly peraluminous K-feldspar megacrystic granites were emplaced at 296.1±1.9Ma and 294.9±2.7Ma; a middle- to upper-crustal two-mica monzogranite was emplaced at 294.2±2.6Ma and finally, an upper-crustal weakly peraluminous granodiorite from the batholith roof was emplaced at 292.2±2.6Ma. These results are consistent with the development of the batholith by incremental multipulse overaccretion, each granitoid body being in a dominantly rigid state before intrusion of the next, with little or no possibility of magma mixing. The difference in age between the oldest and youngest granitoids, from the batholith floor and roof, respectively, is 5.1±4.0Ma, providing an upper limit of about 9Ma on the time taken for batholith construction. The presence in the c. 296–294Ma granitoids of c. 305–302Ma anatectic zircon with varied Th/U and oxygen isotope compositions indicates a time interval of 8–9Ma between incipient partial melting in the lower crust and magma emplacement in the middle crust. The emplacement of the first granitoid bodies into the top of the lower crust was controlled tectonically by the activation of a deep-seated shear zone. The shallowest granodiorites were emplaced during the waning stages of the shear zone activity, producing late- to post-tectonic contact metamorphism in the upper-crustal phyllites and mylonitic paragneisses.

Plagioclase microstructures and compositions as tracers of mixing processes in weakly to strongly peraluminous granodiorites and granites from the Serre Batholith (southern Italy)

The granitoids of the Serre Batholith make up the middle portion of an entire section of late Variscan continental crust exposed in the central Calabria. The most felsic rock types consist of two-mica K-feldspar megacrystic granodiorites and granites (BMPG), passing southward to two-mica granodiorites and granites (BMG), that grade further south to Bt±Am granodiorites (BAG). Microstructural features of plagioclase from the three granitoid units were studied in detail and An contents profiles were obtained for selected crystals from representative samples. Large (4-7 mm), medium (1-3 mm) and small (

Transition from strike-slip to extensional tectonics in the Plio-Pleistocene Catanzaro Trough (Calabria, south Italy)

The Catanzaro Trough (South Italy) is a Neogene-Quaternary sedimentary basin developed between the Serre and the Sila Massif, located in the central Calabrian Arc. Since Miocene, the study area experienced different tectonic phases, resulting confined by both longitudinal and transversal faults systems.Combining of land geo-structural with marine geophysical data was performed a detailed analysis of processes that during last 5 My have controlled the evolution of western portion of the Catanzaro Trough.Sedimentary basin hosted by the Catanzaro Trough is controlled, mainly, by NW–SE and NE–SW oriented fault systems. The data analysis allowed us to state the activity of NW-SE oriented faults with strike slip and oblique kinematics related to the opening of a WNW–ESE-oriented paleo-strait connecting the Tyrrhenian area to the Ionian Sea. The NW-SE trending faults have acted since Miocene as edges of a transfer zone, and represent elements of tectonic accommodation between northern and southern Calabrian Arc.The structural framework is further complicated by the activation of the NE-SW striking normal faults, arranged as a graben-type system, which since Middle Pleistocene segment the western Catanzaro Trough.Thanks to this multidisciplinary approach we are able to provide a more reliable and detailed structural frame of the central Calabria segment, providing new elements about recent activity of faults, and giving a further contribution for the seismogenetic potential assessment of an area historically considered with the highest earthquake and tsunami risk throughout Italy.

Remarks on the hydrogeological setting of S. Eufemia Lamezia plain through the development of the top surface of the intermediate confined aquifer (central Calabria)

The S. Eufemia Lamezia plain, located in central Calabria, is characterized by the presence of a multi-layered aquifer. In particular, it was studied the intermediate artesian aquifer, content in the Pliocene sands and sandstones. The collection of new lithostratigraphic data, related to drilling for water supplies, allowed to draw the map of the top of intermediate artesian aquifer underlying in the study area. The top surface of sands and sandstones map, presented here, seems to confirm the structural-geological data of the surface showing, also in depth, the conditioning of tectonics on the study area and on the groundwater flow. The analysis of the selected stratigraphic data shows that the studied aquifer is constituted by Pliocene deposits of sand and sandstones, confined to the top by Pliocene clay. Therefore locally hydraulic connections with the shallow aquifer for leackage phenomena are possible. The supply of the studied aquifer happens mainly for lateral recharge because the clay horizon that borders with the top of the aquifer prevents direct transfer of rainfall recharge. However, a reduced recharge rate is due to the meteoric recharge, which is possible in limited parts of the territory to the east of the study area and over. Therefore, this study aims to implement the knowledge of the groundwater flow of S. Eufemia plain by returning the top intermediate confined aquifer map which, is little studied but strongly exploited because, respect to the shallow aquifer, is more productive and more protected by potential contamination due to the presence of the aquiclude/aquitard which isolates it by the top.

The Calabria-Peloritani Orogen, a composite terrane in Central Mediterranean; its overall architecture and geodynamic significance for a pre-Alpine scenario around the Tethyan basin

The Calabria-Peloritani Orogen is an arcuate segment of the peri-Mediterranean orogenic Alpine nappe system that comprises the whole Calabria and the north-eastern sector of Sicily. It comprises the Sila and Catena Costiera Massifs in northern Calabria, the Serre and Aspromonte Massifs in central and southern Calabria, and the Peloritani Mountains in Sicily. In Sila and Catena Costiera Massifs, three tectonic complexes are recognisable: a) the basal Apennine Complex, which consists of carbonate platform sequences of passive continental margin; b) the intermediate Liguride Complex, made of oceanic-derived units, affected by HP/LT metamorphism; and c) the upper Calabride Complex, which represents a nearly entire section of continental crust. The Catanzaro Line separates the northern sector from the Serre Massif that also represents a nearly entire segment of Variscan continental crust unaffected by Alpine metamorphism. Further to the south, the Palmi Line separates the Serre from the Aspromonte Massif and the Peloritani Mountains. These two latter nappe edifices consist of either Variscan metamorphic units, Variscan units with Alpine overprint and units of continental derivation that are exclusively affected by Alpine metamorphism. The comparison between the geological evolutions of the various chain sectors, as well as their structural setting and their direction of tectonic transport, indicates that the Calabria-Peloritani Orogen is a composite terrane derived from the amalgamation of crustal blocks of different continental provenance. Northern Calabria represents a fragment of the Adria palaeomargin, whereas southern Calabria and northeastern Sicily are relics of an accretionary wedge resulting from the deformation of the European continental margin. As a consequence, nowadays a segment of the Europe-Adria collisional suture crops out in central Calabria.

Source-inherited compositional diversity in granite batholiths: The geochemical message of Late Paleozoic intrusive magmatism in central Calabria (southern Italy)

The Serre Batholith, in central Calabria, is a Late Paleozoic granitoid complex that makes up the middle portion, ca. 13km thick, of a continuous and nearly complete section of the continental crust. The batholith displays a large compositional variety, with granitoid rocks ranging with continuity from quartz diorite to syenogranite, a distinct group of leucotonalites also occur. The granitoids are on the whole magnesian and calcic to calc-alkalic, with only some of the more evolved rocks showing a ferroan calc-alkalic to alkali-calcic composition. Quartz diorites and tonalites are metaluminous to weakly peraluminous, while granodiorites and granites are weakly to strongly peraluminous, with two-mica porphyritic types being the only population with a genuine strongly peraluminous character. Fe*-number, MALI and ASI features highlight a strong affinity of the Serre Batholith rocks with Cordilleran granitoids, inherited from the compositions of the source rocks rather than reflecting the real tectonic environment of the magmas. Major trace element and existing Sr-Nd data are consistent with an origin of the Serre Batholith from the assembling of several batches of magmas with specific original compositions derived by fluid-absent melting of different crustal sources.Quartz diorites and tonalites originated from a metabasaltic magma source, whereas metagraywackes with various mafic and pelitic contents appear the most likely sources of weakly peraluminous granodiorites and strongly peraluminous granodiorites and granites. Biotite±amphibole granodiorites could also have been derived from mafic-intermediate metaigneous sources. Two-mica porphyritic leucogranites are the only rock types representing pure crustal melts, resulting from melting of mafic pelitic sources. The other granitoid compositions are too silica-poor and MgO+FeOt rich to represent pure melts, so they need to include other components, such as solid restitic/peritectic material entrained from the magma source.Mantle-derived magmas do not appear to have played a role in the geochemical diversity of the Serre Batholith granitoids; their inherited arc signature resulted from partial melting of crustal material of magmatic arc derivation, such as magnesian igneous rocks and sediments derived from their rapid erosion. This study suggests that post-collisional granitoid magmatism is likely not to be associated with the direct generation of new continental crust; all the granitoid rock types appear to represent recycled and reworked crustal material.

Investigating slab edge kinematics through seismological data: The northern boundary of the Ionian subduction system (south Italy)

An integrated analysis of seismotomography models, earthquake spatial distribution and focal mechanism solutions has been performed in the still poorly constrained region marking the northern boundary of the Ionian subducting slab (south Italy). In this area, research findings related to the continuous- vs detached-slab transition are diffused on a wide sector running from central Calabria to the southern Apennines tip and different locations of a subduction-transform edge propagator (STEP) have also been proposed in the recent literature. We present seismic data and analyses aimed to investigate the location of the northern edge of the in-depth continuous slab and the present-day kinematics of the concerned boundary region by also focusing on the possible clues of STEP fault activity. We used both standard linearized and non-linear probabilistic methods to locate, in a recently developed shallow-to-intermediate 3D velocity model, the seismicity that occurred between 1997 and 2012 at the Ionian slab northern boundary. Earthquake kinematics have also been investigated by integrating high-quality focal mechanisms selected from the literature with 70 waveform inversion solutions obtained in the present study.The results allow to identify in central Calabria the northern edge of the in-depth continuous slab and just north of it a ca. 100km-wide deformation zone reflecting lateral STEP migration in the slab edge area. The migration likely indicates an alternation of tear propagation along a slab edge and slab break-off progressively reducing the lateral extension of the subduction zone. In this framework, the recent seismicity seems also to suggest the possible location of an incipient shallow slab break-off beneath central Calabria.