Latest Miocene to Quaternary horizontal and vertical displacement rates during simultaneous contraction and extension in the Southern Apennines orogen, Italy

Foreland contraction and hinterland extension in the Southern Apennines orogen of Italy produced a complex spatial and temporal pattern of vertical and horizontal displacement. Remarkably, Late Miocene to mid-Pleistocene foreland migration of the contractional front at ∼16 mm yr⁻¹ was not accompanied by uplift and the frontal thrust belt remained at or below sea level. Only following a mid-Pleistocene reduction in horizontal displacement did the frontal thrust belt and foreland begin uplift at ∼0.5 mm yr⁻¹, a rate that increased to ∼1 mm yr⁻¹ after 125 ka. Although the extensional hinterland experienced net subsidence during formation of the Tyrrhenian basin, an extensional transition zone adjacent to the frontal thrust belt records sustained uplift at ∼0.3 mm yr⁻¹. The interaction of preexisting crustal structure and deep tectonic processes resulted in time-integrated displacement rates suggesting steady-state deformation for periods of 10⁶ years. Displacement rate changes were abrupt and occurred over intervals of 10⁵ years or less.     

Active thrust tectonics in western Sicily (southern Italy): the 1968 Belice earthquake sequence

The 1968 Belice earthquake sequence, characterized by six main shocks with 5 < M < 5.4, represents the strongest seismic event recorded in western Sicily in historical times. The epicentral area is located in the Belice Valley, a region lacking any topographic lineament likely to result from a fault with significant offsets of any kind. Instrumental data show that hypocentres of the major shocks are distributed along a roughly N-dipping plane extending from about 36 km to 1 km depth. Fault plane solutions show pure thrusting mechanisms on N-dipping, ENE-trending planes, or oblique slip with a right-lateral component of motion along steep WSW-dipping planes, both as a result of approximate N-S shortening. The observed destruction indicates that isoseismal areas are elongated in an ENE direction. Similarly, the epiccntral distribution of events with M ≥ 4 outlines a roughly elliptical ENE-elongated area located 20 km NW of the Sciacca-Rocca Ficuzza thrust front. This ENE-striking structure, representing the regional morphotectonic feature closest to the epicentral area, consists of two main imbricate fan systems. In the southernmost system, Quaternary deposits (tentatively dated as 1.0–0.7 Myr old) are involved in a large ramp anticline uplifting them to a maximum altitude of 346 m. The occurrence of Holocene lacustrine piggy-back basins on the rear of this structure also indicates late Quaternary activity of the underlying thrust. Seismological, structural and morphotectonic observations suggest that multiple ruptures might have occurred during the 1968 sequence on a blind crustal thrust ramp located beneath the epicentral area. Slip propagated southwards along the shallow ramp-flat system characterizing the thin-skinned foreland fold and thrust belt of southwestern Sicily, being dispersed in flexural folding processes and diffuse strain along this path.     

A possible solar-wind cause of the segmented appearance and of the changes in orientation of the plasma-tail axis of Comet Austin 1982g

Several directional discontinuities in the plasma tail of Comet Austin 1982g are apparent on photographs obtained by different observers between 1982 Augut 17.84 and August 21.85. Furthermore, anomalous changes in the orientation of the inner tail axis with respect to the projection on the sky of the prolonged radius vector are noticed. An analysis based on the wind-sock theory of plasma comet tail orientations shows that changes in the azimuthal component of the solar-wind velocity would have produced the observed anomalies. No satellite data on interplanetary conditions were available to check the existence of such a solar-wind event. A type II–IV solar radio event observed on August 17.64, followed by a geomagnetic storm in August 20.67, might denote, however, the existence of a solar flare-generated interplanetary disturbance.     

Intracontinental tectonic melange in Southern Apennines

On the axial zone of the Southern Apennines the major tectonic boundary between the inner platform (Western platform unit) and the pelagic (Lagonegro units) domains is represented by a thick level of highly deformed rock‐assemblage. Structural analysis reveals that this tectonic unit represents an intracontinental melange complex characterized by a block‐in‐matrix fabric that contains blocks from both hangingwall platform and footwall basin units. This unit comprises different sets of structures that, caused by shearing processes, developed at depths ranging from about 8–9 km to the surface. These tectonites represent the product of a crustal shear zone developed at the major boundary between platform‐basin domains of Adria during the thick‐skinned tectonic processes controlling the Southern Apennines mountain building.     

A model for the calculation of the seismic properties of geologic units

A model for the calculation of a representative complete elastic tensor of a geologic body is presented here, in order to fill the gap between the small scale sample and the complex structural and lithological association of a geologic body, which may be of the same large scale as the wavelength used on the seismic survey. The major problems arising during the modelling are discussed, namely the representativity of a suite of hand samples and the evaluation of the volume fraction of the different lithologies comprising a formation. An application example is presented of a metapelitic sequence spanning the tectonic boundary of the Ivrea-Verbano zone with the Serie dei Laghi in Valle Cannobina (N. Italy). It is shown that the effective formation anisotropy is drastically reduced relative to that of hand samples when the structure is averaged over a large area, except for the sheared and mylonitic sub-areas comprising the tectonic contact zone (the Cossato-Mergozzo-Brissago- and Pogallo lines). In these subareas the effective anisotropy is slightly reduced (a few points of a percent) from the hand sample scale to that of the geologic formation. Moreover, because the polarization of the fastest shear wave and the plane of maximum shear wave splitting of the most common crustal rock types coincide with the foliation, there is an opportunity to infer the structure of deep rock formations from teleseismic shear waves.     

Rip current hazard assessment on a sandy beach in Liguria,NW Mediterranean

Natural Hazards - Rip currents are one of the most significant environmental hazards for beachgoers and are of interest to coastal scientists. Several studies have been conducted to understand rip...     

Prediction of the thermodynamic properties of metal–arsenate and metal–arsenite aqueous complexes to high temperatures and pressures and some geological consequences

The standard thermodynamic properties at 25°C, 1 bar (ΔG _f^o, ΔH _f^o, S ^o, C _P^o, V ^o, ω) and the coefficients of the revised Helgeson–Kirkham–Flowers equations of state were evaluated for several aqueous complexes formed by dissolved metals and either arsenate or arsenite ions. The guidelines of Shock and Helgeson (Geochim Cosmochim Acta 52:2009–2036, 1988) and Sverjensky et al. (Geochim Cosmochim Acta 61:1359–1412, 1997) were followed and corroborated with alternative approaches, whenever possible. The SUPCRT92 computer code was used to generate the log K of the destruction reactions of these metal–arsenate and metal–arsenite aqueous complexes at pressures and temperatures required by the EQ3/6 software package, version 7.2b. Apart from the AlAsO₄^o and FeAsO₄^o complexes, our log K at 25°C, 1 bar are in fair agreement with those of Whiting (MS Thesis, Colorado School of Mines, Golden, CO, 1992). Moreover, the equilibrium constants evaluated in this study are in good to fair agreement with those determined experimentally for the Ca–dihydroarsenate and Ca–hydroarsenate complexes at 40°C (Mironov et al., Russ J Inorg Chem 40:1690, 1995) and for Fe(III)–hydroarsenate complex at 25°C (Raposo et al., J Sol Chem 35:79–94, 2006), whereas the disagreement with the log K measured for the Ca–arsenate complex at 40°C (Mironov et al., Russ J Inorg Chem 40:1690, 1995) might be due to uncertainties in this measured value. The implications of aqueous complexing between dissolved metals and arsenate/arsenite ions were investigated for seawater, high-temperature geothermal liquids and acid mine drainage and aqueous solutions deriving from mixing of acid mine waters and surface waters. Electronic Supplementary Material The online version of this article () contains supplementary material, which is available to authorized users.     

Comparison between epiphyte assemblages of leaves and rhizomes of the seagrass Posidonia oceanica subjected to different levels of anthropogenic eutrophication

This paper aimed to compare epiphyte assemblages of leaves and rhizomes of Posidonia oceanica exposed to different levels of concentration of nutrients. The same design including a potentially impacted meadow and two reference meadows was used in each of two locations, characterized by the presence of a city or of suspended cages of a fish farm, respectively. This allowed to test for the consistency of responses of epiphytic assemblages to different sources of eutrophication. In both studies, results documented differences in patterns of composition and abundance of epiphytic assemblages on leaves between disturbed and reference meadows, while assemblages on rhizomes did not appear sensitive to this kind of disturbance. Moreover, in potentially impacted meadows, both assemblages showed different patterns of spatial variability compared to reference assemblages. Species composition and abundance of epiphyte assemblages seemed suitable for detecting moderate nutrient increases, even if adequate sampling designs are needed to separate patterns related to the large natural spatial variability of these systems from those related to changes in environmental conditions.     

Mantle and crustal processes in the magmatism of the Campania region: inferences from mineralogy, geochemistry, and Sr–Nd–O isotopes of young hybrid volcanics of the Ischia island (South Italy)

Ischia, one active volcano of the Phlegraean Volcanic District, prone to very high risk, is dominated by a caldera formed 55 ka BP, followed by resurgence of the collapsed area. Over the past 3 ka, the activity extruded evolved potassic magmas; only a few low-energy explosive events were fed by less evolved magmas. A geochemical and Sr–Nd–O isotope investigation has been performed on minerals and glass from products of three of such eruptions, Molara, Vateliero, and Cava Nocelle (<2.6 ka BP). Data document strong mineralogical, geochemical, and isotopic heterogeneities likely resulting from mingling/mixing processes among mafic and felsic magmas that already fed the Ischia volcanism in the past. Detailed study on the most mafic magma has permitted to investigate its origin. The mantle sector below Ischia underwent subduction processes that modified its pristine chemical, isotopic, and redox conditions by addition of ≤1 % of sediment fluids/melts. Similar processes occurred from Southeast to Northwest along the Apennine compressive margin, with addition of up to 2.5 % of sediment-derived material. This is shown by volcanics with poorly variable, typical δ¹⁸O mantle values, and ⁸⁷Sr/⁸⁶Sr progressively increasing toward typical continental crust values. Multiple partial melting of this modified mantle generated distinct primary magmas that occasionally assimilated continental crust, acquiring more ¹⁸O than ⁸⁷Sr. At Ischia, 7 % of Hercynian granodiorite assimilation produced isotopically distinct, K-basaltic to latitic magmas. A SW–NE regional tectonic structure gave these magmas coming from large depth the opportunity to mingle/mix with felsic magmas stagnating in shallower reservoirs, eventually triggering explosive eruptions.     

Geophysical Survey and Archaeological Data at Masseria Grasso (Benevento,Italy)

The use of geophysical methods in metrology is a significant tool within the wide research topic of landscape archaeology context. Since 2011, the Ancient Appia Landscapes Project aims to recognize dynamics, shapes and layout of the ancient settlement located along the Appia road east of Benevento, and cyclical elements and human activities that influenced the choice of landscapes. The integration of geophysical data with an archaeological infra-site analysis allowed us to investigate the area of Masseria Grasso, about 6 km from Benevento (Campania region, Italy). In this framework, an archaeogeophysical approach (Geomagnetic and Ground Penetrating Radar) was adopted for detecting anomalies potentially correlated with buried archaeological evidences. The geomagnetic results have given a wide knowledge of buried features in a large survey highlighting significant anomalies associated with the presence of buildings, roads and open spaces. These geophysical results permitted us to define the first archaeological excavations and, successively, a detailed Ground Penetrating Radar approach has been provided highlighting the rooms and paved spaces. The overlap between archaeological dataset and geophysical surveys has also allowed recognizing the path of the ancient Appia road near the city of Benevento and hypothesize the settlement organization of the investigated area, which has been identified with the ancient Nuceriola.