Geosciences

Geoscience disciplines play a pivotal role in the assessment of the conservation state of Cultural Heritage to orient the subsequent restoration interventions. In this report, we exemplify the potential of petrographic and thermographic analyses for the evaluation of the conservation state of a unique symbol of the architectural heritage in the challenging lagoon environment of Comacchio city (Ferrara Province, northeastern Italy). This study focuses on the Loggiato dei Cappuccini, starting from the historical analysis of the maintenance and restorations that this simple and pleasant monument has undergone over time. The degradation morphologies and the related triggering causes, characterized by macroscopic observations, were contextualized based on the recent restoration interventions. The current state of conservation has been evaluated quali-quantitatively, combining optical petrographic analyses of the main construction materials with thermographic analyses of the structures. The results of this study highlight the detrimental effects of previous restoration interventions on the long-term conservation state of the monument, emphasizing the need for a general environmental evaluation preliminarily to any conservative action. In particular, geoscience can contribute to a knowledge-based choice of materials that minimize the risk for alveolization and detachments. Full article

Although the principal aim of the rockfall management is to prevent rock boulders from reaching the buildings instead of the buildings resisting the boulder impacts, there usually exists a residual risk that has to be assessed, even when structural protection measurements are taken. The evaluation of the expected damage of buildings due to rockfalls using empirical data from past events is not always possible, as transferring and applying damage observations from one area to another can be unrealistic. In order to simulate potential rockfall scenarios and their damage on buildings, numerical methods can be an alternative. However due to their increased requirements in expertise and computational costs, their integration into the risk analysis is limited, and simpler tools to assess the rockfall vulnerability of buildings are needed. This paper focuses on the application of artificial intelligence AI methods for providing the expected damage of masonry walls which are subjected to rockfall impacts. First, a damage database with 672 datasets was created numerically using the particle finite element method and the finite element method. The input variables are the rock volume (VR), the rock velocity (RV), the masonry wall (t) and the masonry tensile strength ${\mathrm{f}}_{\mathrm{m}}$. The output variable is a damage index (DI) equal to the percentage of the damaged wall area. Different AI algorithms were investigated and the ANN LM 4-21-1 model was selected to optimally assess the expected wall damage. The optimum model is provided here (a) as an analytical equation and (b) in the form of contour graphs, mapping the DI value. Known the VR and the RV, the DI can be directly used as an input for the vulnerability of masonry walls into the quantitative rockfall risk assessment equation. Full article

Due to their genesis, volcanic rocks present some singularities that make their geotechnical characteristics significantly different from other more common types of massifs, such as sedimentary and metamorphic rocks. The formation mechanisms of volcanic rocks are varied, rapid, and, in general, of high energy. These processes give this type of rock a geotechnical behaviour and geomechanical properties that are totally different from those of other nonvolcanic materials, derived from their high heterogeneity and anisotropy. There are voids and cavities due to the alternation of strata of different competences and resistances, or susceptibility to erosion, and discontinuities and joints of very different genesis (of thermal origin, by mechanical forces, by erosive processes or by shrinkage—recrystallization). The phenomenology of the instability of blocks and stones is variable, which makes it very difficult to establish simple and concrete methodologies or procedures to study and analyse this problem. To date, the estimation of the risk of this type of phenomenon has been quantified using empirical methodologies; this approach is considered to be the most operative in responding to such a complex phenomenology in which a multitude of factors intervene. In the field of roads, the most widely used methods are RHRS and RHRON. Therefore, a new rockfall risk classification based on the RHRS (Rockfall Hazard Rating System) methodology is proposed in this article and specifically applied to the Canary Islands region. Full article

The Portofino Conglomerate (PC) cropping out in the Eastern Liguria is an approximately 500 m thick, very gently folded succession mainly composed of poorly bedded and mostly matrix-supported conglomerates. It stratigraphically rests on the Helminthoid Flysch (UA3) thrusted onto the Antola Unit. We vertically distinguished three mostly ruditic litho/petrofacies: (i) Paraggi (fP) with carbonate clasts from an Helminthoid Flysch succession; (ii) Monte Pallone (fMP) with prevailing carbonate and meta-carbonate clasts and minor quartz-rich (meta)siliciclastic and high-pressure–low-pressure (HP-LP) metabasite clasts; and (iii) Monte Bocche (fMB) with dominant quartz-rich (meta)siliciclastic, meta-carbonate clasts, and minor granitoid elements and medium-temperature–high-temperature (MT-HT) regional metamorphic rocks. The middle-upper Eocen age of Paraggi litho/petrofacies is constrained by well-preserved microforaminifers (e.g., Globigerinatheka) recovered in the matrix. During its sedimentation, the directions of the paleocurrents would indicate that the PC underwent a counterclockwise rotation coeval with the first Cenozoic rotational phase of the Sardinia–Corsica system (50–30 Ma) and then stopped before the sedimentation of the Monte Pallone and Monte Bocche litho/petrofacies. The vertical compositional variation in the sedimentary inputs suggested that the PC is the result of a progressive deepening of the erosional level of a tectonic pile that can be located in the Ligurian Alps Chain. We considered the PC as the likely apical part of a submarine fan deposited in a piggy-back/thrust-top basin within the Alpine nappe stack. This sedimentary body was later tectonically transported eastward with its UA3 Helminthoid Flysch substrate (similarly to Epiligurian Units of the Northern Apennines) onto the Apenninic orogenic system (i.e., the Antola Unit). Full article

This work presents an analysis of data obtained through unique laboratory experiments on hydraulic fracturing. In the experiments, sufficiently large artificial samples were used to model a reservoir. Thus, it was possible to simulate several wells simultaneously, given that hydraulic fracture was initiated in one of them. In addition, the setup construction provided a true triaxial stress–strain state. The setup allowed us to investigate parameters that are difficult to access in real conditions. The data processing based on six laboratory experiments on hydraulic fracturing showed discrepancies between the values of the minimum stresses calculated from the fracture closure pressure and the actual values known based on the experimental conditions. There was also a discrepancy between the theoretical values of the fracture breakdown pressure and those obtained through the experiments. This paper examines phenomena such as backstress as the main reasons for this discrepancy. Backstress is stress acting on the walls of a fracture or well and is caused by the filtered hydraulic fracturing fluid. The authors demonstrated that by taking into account this phenomenon, one can significantly reduce the differences between calculated and experimental values. Therefore, the authors call for the careful use of the standard theory when determining the stress state in real fields. Full article

We used LA-ICP-MS U-Pb data for detrital zircon to constrain the Maximum Depositional Age (MDA) and provenance of clastic sedimentary rocks of the Volyn-Orsha sedimentary basin, which filled an elongated (~625 × 250 km) depression in SW Baltica and attained ~900 m in thickness. Eighty-six zircons out of one hundred and three yielded concordant dates, with most of them (86%) falling in the time interval between 1655 ± 3 and 1044 ± 16 Ma and clustering in two peaks at ca. 1630 and 1230 Ma. The remaining zircons yielded dates older than 1800 Ma. The MDA is defined by a tight group of three zircons with a weighted mean age of 1079 ± 8 Ma. This age corresponds to the time of a ~90° clockwise rotation of Baltica and the formation of the Grenvillian—Sveconorwegian—Sunsas orogenic belts. Subsidence was facilitated by the presence of eclogites derived from subducted oceanic crust. The sediments of the Orsha sub-basin in the northeastern part of the basin were derived from the local crystalline basement, whereas the sediments in the Volyn sub-basin, extending to the margin of Baltica, were transported from the orogen between Laurentia, Baltica and Amazonia. Full article

Copper, uranium, and rare earth element (REE) mineralisation occurs in hydrocarbon-bearing Devonian continental sandstones in southwest Orkney, Scotland. The aeolian Yesnaby Sandstone Formation and fluvial Harra Ebb Sandstone Formation were mineralised following oil emplacement. The REE-bearing APS mineral florencite is particularly associated with bituminous nodules, many of which contain brannerite. Subsequently hydrothermal copper and other sulphides, and barite, further mineralised the oil reservoir at a temperature of ~190 °C. Oil was mobilised through mineralised fractures at this stage. Biodegradation of the oil occurred later, following the Carboniferous-Permian uplift. The occurrence confirms that Cu-APS mineralisation is possible in relatively low-temperature regimes in sedimentary basins. Full article

Over the last decade, thanks to the availability of historical satellite observations that have begun to be significantly large and thanks to the exponential growth of artificial intelligence techniques, many advances have been made in the detection of geophysical parameters such as seismic-related anomalies. In this study, the variations of the ionospheric Total Electron Content (TEC), one of the main parameters historically proposed as a seismic-connected indicator, are analyzed. To make a statistically robust analysis of the complex phenomena involved, we propose a completely innovative machine-learning approach developed in the R programming language. Through this approach, an optimal setting of the multitude of methodological inputs currently proposed for the detection of ionospheric anomalies is performed. The setting is optimized by analyzing, for the first time, multi-year—mostly twenty-year—time series of TEC satellite data measured by global navigation satellite systems (GNSS) over the Italian region, matched with the corresponding multi-year time series of seismic events. Seismic events including all the countries of the Mediterranean area, up to Turkey, are involved in the analysis. Tens of thousands of possible combinations of input methodological parameters are simulated and classified according to pre-established criteria. Several inputs examined return clear results. These results combined with each other highlight the presence of anomalous seismic-related sequences that have an extremely low probability of having been detected randomly (up to 2 out of 1 million). The anomalies identified represent the most anomalous behaviors of the TEC recorded during the entire period under investigation (e.g., 20 years). Some of the main conclusions are that, at mid-latitudes, ① the detection of seismic-TEC anomalies can be more efficient looking for punctual rather than persistent phenomena; ② the optimal thresholds for the identification of co-seismic anomalies can assume different values depending on type of anomaly (positive or negative) and type of observation; ③ single GNSS receiver data can be useful for capturing local earthquake-ionospheric effects and Global Ionospheric Maps (GIM) data can be functional in detecting large-scale earthquake-ionospheric effects; ④ earthquakes deeper than 50 km are less likely to affect the ionosphere. Full article

The penultimate glaciation (marine isotope stage (MIS) 6) is considered regionally extreme compared to the last glacial maximum, in which the European ice sheets had a vast areal extent. In contrast to the last deglaciation (19–7 ka), the penultimate deglaciation (140–130 ka) hosts one of the most rapid oceanographic changes of the late Pleistocene. In this study, we reconstructed changes in the near-surface and thermocline in the central to northeast Atlantic by analyzing sediments from two Integrated Ocean Drilling Program Expedition 306 sites. Sites U1313 (41°00.6′ N, 32°57.4′ W) and U1314 (56°21.9′ N, 27°53.3′ W) were drilled on the eastern flank of the mid-Atlantic ridge and Gardar Drift of the eastern subpolar North Atlantic, respectively. We analyzed planktonic foraminiferal assemblages, ice-rafted debris (IRD), and oxygen isotopes in two planktonic foraminifers, Globigerina bulloides, and Globorotalia inflata, from MIS 6 to 5e (185–115 ka). Warmer and colder sea-surface conditions were marked by a change in the relative abundance of polar, subpolar, and transitional planktonic foraminifers. Oxygen isotopes in G. bulloides and G. inflata suggest that the thermocline deepened at the subtropical Site U1313 during MIS 6. The lack of Globorotalia inflata prevented us from profiling the mixed layer and thermocline at the subpolar Site U1314. In contrast to MIS 6, the mixed layer and thermocline were re-stratified during the last interglacial. The lack of major IRD events at both sites suggests the stability of the Laurentide ice sheet during MIS 6 compared to the subsequent glaciation. The presence of Heinrich event 11 indicates the discharge of freshwater that freshened the sea surface, resulting in mixing between the mixed layer and thermocline. Our results were placed into a broader context using published data that shed light on the sensitivity of freshwater discharge to the North Atlantic and the following changes with a transition from a penultimate glacial to an interglacial period in surface circulation. Full article

The assessment of slope susceptibility to seismically-induced displacements receives wide attention in the geotechnical earthquake engineering field, but the alteration of the seismic wave inside the slope and at the ground surface due to the presence of a shear band confining a quiescent landslide body is rarely investigated. This paper describes the preliminary results of the numerical analysis of two step-like FE models, reproducing a gentle slope and steep cutting subjected to weak earthquakes, thus focusing on seismic wave amplification processes only. The results show that the higher the thickness of the weakened zone, the higher the maximum value of the amplification factors predicted at the ground surface. For gentle slopes affected by a landslide body confined by a thick shear band, the highest amplification factors are expected in the longer period range of 0.7–1.1 s, while the highest level of amplification is achieved in the intermediate period interval of 0.4–0.8 s in the case of steep slopes. In addition, the parasitic vertical component of acceleration can be considerably amplified beyond the crest and at the toe of the slope for increasing band thickness, especially in the case of steep topography, for which the effects of the shear band morphology enhance those related to the topographic profile. Finally, the fundamental frequency of the sloping deposit is not particularly affected by the presence of the shear band, while the amplitude of the amplification function at the fundamental frequency is clearly related to its thickness. Full article

Anchored drapery meshes represent a worldwide adopted protective solution against rockfall. The mechanical performance of a wire mesh is evaluated through laboratory procedures in which the boundary conditions strongly differ from the ones typical of field applications. This shows that the laboratory characterization is, in general, not representative of the field behavior. In this work, referring to a double-twisted wire mesh, a simple approach allowing the extension of the laboratory characteristic values to field conditions is proposed. The approach is based on the definition of analytical relations for evaluating the effects of both the mesh’s system geometry and the loading condition on the force–displacement response. These relations are derived from previously calibrated laboratory tests and are extended to different configurations on the basis of a large number of discrete element simulations. A master curve allowing the prediction of the entire force–displacement response of a general configuration of the drapery system is then defined. The results of this study can provide useful information for designing anchored drapery systems and can be easily associated with standard limit equilibrium calculations to move toward a hybrid design approach that couples forces with mesh deformations. Full article

Large-scale groundwater flow modelling demands comprehensive geological investigation (GI) to accurately predict groundwater dynamics during open-cut and underground mining. Due to the existence of large-scale heterogeneity (e.g., fault and fracture) in natural geological strata (e.g., overburden soil, rock mass and coal seam), the in-situ flow measurement in boreholes, compared to laboratory seepage tests, can bring more reliable information to estimating the in-situ seepage properties (e.g., hydraulic conductivity, intrinsic permeability, transmissivity and specific yield). In this paper, a flow-measuring technique-heat pulse flowmeter (HPFM) is methodologically introduced and then practically applied for GI in the mining extension zone of Hunter Valley Operations (HVO), New South Wales, Australia. The measuring experiences, including both positive and negative outcomes, are reported and discussed with a series of datasets of in-situ flow rates measured in the selected boreholes. The pros and cons of the HPFM application in HVO are also discussed and summarised based on the user experience collected through this field trip. Finally, through a thorough reflection, some practical recommendations are provided to help other HPFM practitioners bypass all difficulties experienced on this trip. It is anticipated that valuable user information can contribute to better GI in other sites when performing this measuring technique. Full article

Between 2020 and 2022, more than sixty lava fountains occurred at Mt. Etna (Italy), which formed high eruption columns rising up to 15 km above sea level (a.s.l.). During those events, several ballistics fell around the summit craters, sometimes reaching touristic areas. The rather frequent activity poses questions on how the impact associated with the fallout of those particles, can be estimated. In this work, we present field data collected soon after the lava fountain on 21 February 2022. This event produced a volcanic plume of about 10 km a.s.l. which was directed toward the southeast. Several ballistics fell in the area of the Barbagallo Craters (just southeast of the summit area at around 2900 m a.s.l.), which is one of the most popular touristic areas on Etna. Hence, we collected several samples and performed laboratory analyses in order to retrieve their size, shape and density. Those values together with a quantitative analysis of the lava fountain were compared with results obtained by a free-available calculator of ballistic trajectories named the ‘Eject!’. A similar approach was hence applied to other lava fountains of the 2020–2022 sequence for which the fallout of large clasts was reported. This work is a first step to identifying in near real-time the area affected by the fallout of ballistics during Etna lava fountains and quantifying their hazard. Full article

Subsea permafrost stability is the key to whether pre-performed methane sequestered in hydrate deposits escapes to the overlying strata. By making use of the 1D numerical modeling and field data, we analyze the capabilities of the time-domain (transient) electromagnetic method (TDEM) when being applied for subsea permafrost mapping, and study the effect of the background resistivity structure on the inversion models’ accuracy for a series of settings typical for the East Siberian Arctic Shelf—the broadest and shallowest shelf in the world ocean, which represents more than 70% of the subsea permafrost. The synthetic response analysis included the construction of a series of resistivity models corresponding to different settings (presence/absence of ice-bonded permafrost layer, different position of its top and bottom boundaries, different width and thickness of thawed bodies or taliks, variable seawater depth and its resistivity), and calculation of synthetic apparent resistivity responses used to assess their sensitivity to changes in the target parameters of the resistivity structure. This was followed by regularized inversion of synthetic responses and comparing resulting models with original (true) ones, which allowed us to understand the possible uncertainties in the geometry and resistivity of the reconstructed permafrost layer, depending on seawater depth and unfrozen layer thickness, as well as confirm the overall efficacy of TDEM technology for the subsea permafrost imaging. That is crucially important for understanding the current state of the subsea permafrost-hydrate system and possible future dynamics. Full article

The geosites of Lemnos represent local touristic products that, beyond their high aesthetic value, display significant scientific links to the geological past as well as prehistory and history, archaeology, mythology and religious heritage of the island. The unique wealth of Lemnos geosites in combination with the abundance of archaeological sites, cultural monuments and museums composes the basis of what we define here as “Geo-Archaeo-Routes”: certain routes that can be geographically defined, offered, guided and finally followed by the touristic masses. The outcome of the performed quantitative Lemnos geosite assessment enables decision making, thus providing a toolbox useful for sustainable Geo-Archaeo-tourism development at a local level and forms the basis for designing “Geo-Archaeo-Routes”. “Geo-Archaeo-Routes” are particularly favorable of environmentally friendly alternative types of tourism, attracting naturalists, hikers, fans of cultural or religious tourism and many others who represent a major part of the touristic needs of the 21st century. The established hiking and road “Geo-Archaeo-Routes” on Lemnos Island may represent a distinctive touristic product as they offer a high level of “nalture” entertainment, blending “nature with culture” in the framework of a holistic geotouristic approach. Full article

Studies of lithotectonic formations within the Keivy domain of the NE Baltic Shield have shown that the domain was tectonically overlapped by adjacent microcontinents during regional collision processes in the Late Archean. As a consequence, the continental crust of the Keivy domain was submerged, relative to other blocks of the continental crust, and the described domain acquired the features of a classical median massif. Surrounded on all sides by collision systems, the Keivy median massif entered the cratonization regime. This led to intensive processes of denudation of the surrounding domains of the crust and the accumulation of a thick sedimentary cover on the surface. The described processes occurred during the formation of the first supercontinent (Monogea) in the history of the Earth and the manifestation of the Early Precambrian Huronian glaciation, which left its traces on most domains of the Earth’s continental crust. Thus, the processes of peneplain formation within the Keivy massif occurred under the cold weather conditions, high volcanic activity in the peripheral zones, and sedimentary cover saturation with the products of the physical and chemical mineral transformation of tonalite–trondhjemite and greenstone rock assemblages. The unique combination of certain geodynamic and climatic cycles on the Baltic Shield in the Late Archean led to the accumulation of extensive stratiform deposits of alumina raw materials within the Keivy median massif. Full article

The paper presents a simple yet efficient way to track the void ratio, the water content, and the degree of saturation of a swelling material during saturation. The research aimed to quantitatively describe the drying and wetting processes of the swelling material, which should enable their better understanding and easier modelling. Two identical tall samples, named “twins”, were formed by consolidating the paste prepared from the swelling material in which montmorillonite is the dominant mineral. The twins were together exposed to one-dimensional drying. After drying, lasting for 40 days, one twin was dissected to determine its water content profile. The other twin was subjected to 1D wetting (ponded infiltration experiment) with a constant water column for a period of 21 days and then dissected to determine the moisture profile. The sample preparation reduces uncertainties about the initial state. The results show that during wetting, the material follows a path in the e-w plot which is parallel to the full saturation curve. After reaching some degree of saturation, the path becomes parallel to the residual (shrinking) line. The proposed model predicts the primary and secondary phases of swelling, and under appropriate conditions, it assumes the tertiary phase. Full article

The objective of this study was to assess the temporal and spatial variability of aquatic invertebrates and microbial parameters (biomass and activity) with environmental data in springs, and to determine the impact of key parameters on the ecological situation of a groundwater system. Eight springs in the two study areas of Baumberge and Schöppinger Berg (W-NW of Münster, North Rhine Westphalia, Germany) were sampled at three sampling campaigns between 2018 and 2019. Physicochemical parameters of the spring samples and abundances of aquatic invertebrates were determined at each sampling event. Samples for hydro(geo)chemical and microbial analyses were collected during each sampling campaign in the springs. Spearman correlation and principal component analysis were used to identify the key parameters. The abundance of aquatic invertebrates and microbial activity were significantly positively correlated with groundwater table fluctuation. The abundance of stygobite individuals was significantly positively correlated with the Groundwater-Fauna-Index and phosphate in Baumberge, and negatively correlated with chloride in Schöppinger Berg. Most notably, the stable isotopes of water and microbial activity were significantly inversely correlated. The hydro(geo)chemical results showed no significant spatial differences in groundwater in both groundwater systems. Stable isotopes of water indicate a meteoric origin, with an effect of evaporation for two months, even though the downward percolation and groundwater recharge rates are high. The nitrate concentration was higher than 50 mg/L only in SB due to the agricultural activities. Nitrate input into groundwater comes from two sources in Baumberge, while it comes from one source in Schöppinger Berg. There was no evidence of denitrification in both areas. Secondary gypsum is assumed to be the source of sulfate in groundwater in Schöppinger Berg, but anaerobic oxidation of pyrite in the deeper part of the groundwater system as a source of sulfate cannot be excluded. Full article

In recent years, an international consortium of research organizations conducted investigations at the Chicxulub Crater in Yucatan, Mexico, to better understand the crater’s formation mechanisms and the effects produced by the impact of the asteroid that is hypothesized to have caused one of the major life extinctions on Earth. This study aims to reproduce the asteroid’s impact mechanics by matching computer simulations obtained with the use of the distinct element method (DEM) against the latest topographic data observed across the crater footprint. A 2D model was formulated using ITASCA’s PFC2D software to reproduce the asteroid’s impact on Earth. The model ground conditions prior to impact were replicated based on available geological and geophysical field information. Also, the proposed DEM model configuration was designed to reproduce a far-field effect to ascertain the energy dissipation of the asteroid’s impact at the model’s boundaries. Impact conditions of the asteroid were defined based on previous asteroid impact investigations. A parametric analysis including the asteroid’s impact angle and the asteroid’s impact velocity was conducted to assess their influence on the crater formation process. Results of the simulations included the final crater topography and stratigraphy, stress profiles, contact force chains, and velocity fields. Numerical simulations showed that both the asteroid velocity and impact inclination play a major role in the crater formation process, and that the use of DEM provides interesting insights into impact crater formation. Full article