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Geosciences, Volume 13, Issue 12 (December 2023) – 36 articles

Cover Story (view full-size image): Accurate analysis is crucial for effective early warnings of high-alpine landslides. Optical remote sensing images can be used to monitor displacements using digital image correlation (DIC) algorithms. However, these algorithms require significant expert input and lack a universal mathematical description for the temporal and spatial resolution of input data. This study presents generic DIC input formulas that considerably reduce manual optimization time and aid in selecting the most suitable remote sensing images. Using an open-source DIC-FFT code on optical remote sensing data from 2014 to 2020 in Switzerland, the effects of spatial resolution on slope displacement detection, from satellite to aerial orthophotos, are demonstrated. View this paper
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27 pages, 44852 KiB  
Article
Holocene Depositional History of Low-Lying Reef-Rim Carbonate Islets of Fakarava Atoll, Northwest Tuamotu, Central South Pacific
Geosciences 2023, 13(12), 389; https://doi.org/10.3390/geosciences13120389 - 18 Dec 2023
Viewed by 1326
Abstract
Assumptions about the fate of low-lying coral reef islands (atolls) facing global warming are poorly constrained, due to insufficient information on their depositional history. Based on the U/Th dating of 48 coral clasts, the chronostratigraphic analysis of excavated sections through rim islets ( [...] Read more.
Assumptions about the fate of low-lying coral reef islands (atolls) facing global warming are poorly constrained, due to insufficient information on their depositional history. Based on the U/Th dating of 48 coral clasts, the chronostratigraphic analysis of excavated sections through rim islets (motu) at the windward and leeward sides of Fakarava Atoll (Tuamotu, French Polynesia) reveal that the deposition of coral detritus started approximately 2000 years ago. Most of these deposits lie on conglomerate pavements or reef flat surfaces, and are about 4500 to 3000 years old. The islet expansion at the windward sites seems to have operated coevally across the reef rim, from the ocean-facing shore lagoonwards. Meanwhile, well-developed, continuous, elongated, vegetated islets mostly occur along the windward, northeast to southeast coast, and isolated islets, vegetated or not, associated with the dense networks of conglomerates, are common on the leeward, partly submerged, western rim. Islet accretion on the windward rim sides is believed to have been mainly triggered by winter storms and occasional cyclonic events, whilst the leeward atoll parts were most likely shaped by distant-source swells from mid to high latitudes. The projections of the accelerated sea level rise in the future suggest that the long-term islet stability at Fakarava could be altered because the islets have accreted under the conditions of the falling sea level. Full article
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13 pages, 3937 KiB  
Article
Uranium Isotope Characterization in Volcanic Deposits in a High Natural Background Radiation Area, Mamuju, Indonesia
Geosciences 2023, 13(12), 388; https://doi.org/10.3390/geosciences13120388 - 17 Dec 2023
Viewed by 1165
Abstract
Mamuju is an area of high natural radiation in Indonesia with high natural radiation levels (average 613 nSv h−1). Mamuju is anomalous due to its high average 238U and 232Th concentrations of 22,882 and 33,549 Bq kg−1, [...] Read more.
Mamuju is an area of high natural radiation in Indonesia with high natural radiation levels (average 613 nSv h−1). Mamuju is anomalous due to its high average 238U and 232Th concentrations of 22,882 and 33,549 Bq kg−1, respectively, in laterite and rock. High natural radionuclide concentrations of 238U, 232Th, and 40K have also been reported in soil samples from several locations in Mamuju, including Botteng, Northern Botteng, Takandeang, Ahu, and Taan. High radiation levels are related to radioactive mineral occurrences in the Adang volcanic complex, comprised of phonolitoid and foiditoid lithologies. According to the International Atomic Energy Agency (IAEA), uranium deposits can be classified into several types, among them a volcanic-related deposits, which include three sub-types: stratabound, structure-bound, and volcano-sedimentary deposits. This study aims to characterize volcanic rock deposit sub-types in the Mamuju area based on uranium radioisotope measurements. The uranium isotopes were measured using a tandem quadrupole inductively coupled plasma mass spectrometer combined with chemical separation by extraction chromatography using UTEVA resin. The analytical results for the 234U/238U ratios are used to determine the formation characteristics of minerals in each deposit sub-type based on mineral formation age, post-formation processes, and disturbances that affected the formation processes. Based on geochronological calculations using 234U/238U mineralization age, the deposits in the Mamuju area are 0.914–1.11 million years old and are classified as recent mineralization. These data have important implications for tracing uranium source rocks in the Mamuju area and may explain the anomalously high radiation levels in the Mamuju area. Full article
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20 pages, 2706 KiB  
Article
Fractal Features in kHz Electromagnetic Observations Preceding Near-Field Earthquakes in Ilia, Greece
Geosciences 2023, 13(12), 387; https://doi.org/10.3390/geosciences13120387 - 15 Dec 2023
Viewed by 882
Abstract
This paper reports kHz EM observations recorded by the Kardamas station in Ilia, Greece a few days before four near-field earthquakes occurred within a 24 km radius, with epicentral depths below 29 km. This work investigated the fractal features hidden in the EM [...] Read more.
This paper reports kHz EM observations recorded by the Kardamas station in Ilia, Greece a few days before four near-field earthquakes occurred within a 24 km radius, with epicentral depths below 29 km. This work investigated the fractal features hidden in the EM observations via power-law analysis. All EM signals exhibited characteristic fractal epochs with organisation in space and time. A significant number of accurate fractal segments were delineated in the majority of the EM observations. A significant number of fractal areas corresponded to predictable Class I fBm category with 1 ≤ b ≤ 3 (0 ≤ H ≤ 1). Numerous persistent key-periods are reported with 2 < b ≤ 3 (0.5 ≤ H ≤ 1) which are deemed as signs of impeding earthquakes according to the literature. Numerous segments were found with strong persistent b-values in the range (2.3 ≤ b ≤ 3) (0.65 ≤ H ≤ 1) and b-values corresponding to switching between antipersistency and persistency with (1.7 ≤ b < 2.3) (0.35 ≤ H < 0.65). These are deemed as the most significant precursory signs. Interpretations are given via the asperity model. Full article
(This article belongs to the Section Natural Hazards)
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14 pages, 15893 KiB  
Article
A Novel Approach to Assess the Influence of Rockfall Source Areas: The Case Study of Bardonecchia (Italy)
Geosciences 2023, 13(12), 386; https://doi.org/10.3390/geosciences13120386 - 15 Dec 2023
Viewed by 890
Abstract
In this research article, we propose a practical methodology for evaluating the affecting potential of detachment areas in rockfalls. Our innovative approach combines an assessment of the visibility of rockfall source areas, with reference to specific rockfall scenarios and elements at risk, considering [...] Read more.
In this research article, we propose a practical methodology for evaluating the affecting potential of detachment areas in rockfalls. Our innovative approach combines an assessment of the visibility of rockfall source areas, with reference to specific rockfall scenarios and elements at risk, considering the rockfall Susceptibility Index to Failure (SIF) of these areas. The result is the characterization of source areas through a rockfall Source Affecting Index (SAI), which considers both the morphology of the slope and the geostructural conditions of the rock walls. This information can be very useful since it aids in optimizing more in-depth analyses, as well as the placement of monitoring instruments or stabilization systems. The proposed methodology has been implemented in the open-source software QGIS through the development of an easy-to-use plugin named Ranking of the Affecting Potential of Detachment Areas in Rockfalls, or “RADAR”. RADAR is designed to be used in conjunction with QPROTO, a well-known QGIS plugin for preliminary rockfall susceptibility/hazard analyses based on a visibility analysis and a simplified mechanical method. To demonstrate the effectiveness of the proposed approach, an application to a case study located in the Western Alps (Bardonecchia, Italy) is presented and discussed in the paper. Full article
(This article belongs to the Section Natural Hazards)
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14 pages, 16379 KiB  
Article
Inland Record of the Last Interglacial Maximum in the Western Mediterranean: Revealing the Aljezares Pleistocene Basin (Alicante, SE-Spain)
Geosciences 2023, 13(12), 385; https://doi.org/10.3390/geosciences13120385 - 15 Dec 2023
Viewed by 1063
Abstract
The search for a continuous continental record of interglacial periods in semi-arid regions is problematic due to the absence of stable and continuous sedimentary systems over time in this type of climate. In this work, a relatively stable basin is described and analyzed [...] Read more.
The search for a continuous continental record of interglacial periods in semi-arid regions is problematic due to the absence of stable and continuous sedimentary systems over time in this type of climate. In this work, a relatively stable basin is described and analyzed during the last interglacial period in a semi-arid region of the western Mediterranean. For this purpose, a geomorphological, stratigraphic and sedimentological study has been carried out, with dating through 230Th. A semi-endorheic Pleistocene section has been identified, with two units that correspond to a fluvial-lacustrine system (unit P1) and an alluvial system (unit P2). Unit P1 has been dated to the MIS 5e interglacial episode. A framework for future studies is described, in which the Aljezares Pleistocene basin can be considered as a possible source of paleoenvironmental and paleoclimatic information in semi-arid regions from the last interglacial period. Full article
(This article belongs to the Section Sedimentology, Stratigraphy and Palaeontology)
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18 pages, 4283 KiB  
Article
A Feature-Informed Data-Driven Approach for Predicting Maximum Flood Inundation Extends
Geosciences 2023, 13(12), 384; https://doi.org/10.3390/geosciences13120384 - 14 Dec 2023
Viewed by 1030
Abstract
As climate change increases the occurrences of extreme weather events, like flooding threaten humans more often. Hydrodynamic models provide spatially distributed water depths as inundation maps, which are essential for flood protection. Such models are not computationally efficient enough to deliver results before [...] Read more.
As climate change increases the occurrences of extreme weather events, like flooding threaten humans more often. Hydrodynamic models provide spatially distributed water depths as inundation maps, which are essential for flood protection. Such models are not computationally efficient enough to deliver results before or during an event. To ensure real-time prediction, we developed a feature-informed data-driven forecast system (FFS), which interpreted the forecasting process as an image-to-image translation, to predict the maximum water depth for a fluvial flood event. The FFS combines a convolutional neural network (CNN) and feature-informed dense layers to allow the integration of the distance to the river of each cell to be predicted into the FFS. The aim is to ensure training for the whole study area on a standard computer. A hybrid database with pre-simulated scenarios is used to train, validate, and test the FFS. The FFS delivers predictions within seconds making a real-time application possible. The quality of prediction compared with the results of the pre-simulated physically-based model shows an average root mean square error (RMSE) of 0.052 for thirty-five test events, and of 0.074 and 0.141 for two observed events. Thus, the FFS provides an efficient alternative to hydrodynamic models for flood forecasting. Full article
(This article belongs to the Section Natural Hazards)
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21 pages, 80416 KiB  
Article
Present Climate Change as a Threat to Geoheritage: The Wildfire in Bohemian Switzerland National Park and Its Use in Place-Based Learning
Geosciences 2023, 13(12), 383; https://doi.org/10.3390/geosciences13120383 - 14 Dec 2023
Viewed by 1030
Abstract
Bohemian Switzerland is a national park in Northern Czechia famous for its sandstone rocks, which were affected by a massive fire in 2022. Specific geomorphology of the region affected the spreading of the fire and complicated its extinguishing. The fire directly or indirectly [...] Read more.
Bohemian Switzerland is a national park in Northern Czechia famous for its sandstone rocks, which were affected by a massive fire in 2022. Specific geomorphology of the region affected the spreading of the fire and complicated its extinguishing. The fire directly or indirectly damaged several geosites in Bohemian Switzerland. The catastrophe brought a possibility of showing the unique connection between geoheritage and present climate change and increasing awareness about the problems. The text is focused on field education of geography, striving to strengthen environmental awareness among students through educating their teachers. The research is based on desk research, field observation and didactic principles application. The causes of the fire were complex, including physical geographical (drought and bark beetle calamity within climate change) and human geographical phenomena (mass tourism and tourist misbehavior, inappropriate forestry practices). The teachers we worked with reached similar conclusions at the end of our course. Our fieldwork educational concept proved viable and was appreciated by them mainly thanks to the incorporation of research-based learning and the absence of unnatural emphasis on climate change. Climate change is a politicized topic, bringing controversies to the classrooms in the peripheral region. The approach we proposed is anchored in inquiry-based methods and touches on the issue indirectly. Full article
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37 pages, 6807 KiB  
Article
Flood Susceptibility Assessment through Statistical Models and HEC-RAS Analysis for Sustainable Management in Essaouira Province, Morocco
Geosciences 2023, 13(12), 382; https://doi.org/10.3390/geosciences13120382 - 12 Dec 2023
Viewed by 1078
Abstract
Floods are natural disasters that often impact communities living in low-lying areas in the northern and central parts of Morocco. In this study, our aim was to create a flood susceptibility map using three methods; the hierarchy process (AHP) frequency ratio model (FR) [...] Read more.
Floods are natural disasters that often impact communities living in low-lying areas in the northern and central parts of Morocco. In this study, our aim was to create a flood susceptibility map using three methods; the hierarchy process (AHP) frequency ratio model (FR) and the weights of evidence (WoE) model. We extensively examined the area identified by these approaches using a hydraulic analysis software called HEC-RAS (version 6.3.1). Our analysis focused on the Essaouira watersheds in Morocco, where we identified around 197 flood locations. Out of these, we randomly selected 70% for modeling purposes while the remaining 30% were used for validation. Ten factors that influence floods were considered, such as slope, elevation, proximity to rivers, drainage density, stream order, land use patterns, rainfall data, lithology (permeability level) index (TWI), and curvature. We obtained these factors from data sources. Finally, we generated a flood susceptibility map and evaluated its accuracy by calculating the area under the curve (AUC). The validation results confirmed that all three models were robust and effective with an AUC of 90. Moreover, the research uncovered a trend of vulnerability with the most susceptible area being in close proximity to the city of Essaouira along the Oued Ksob. A detailed analysis using HEC-RAS was conducted at this identified location, pinpointing the village of Diabat as highly exposed. These findings hold significance for flood management, empowering decision makers, scholars, and urban planners to make informed choices and implement strategies that can minimize the impact of floods in susceptible regions while minimizing potential damages. Full article
(This article belongs to the Special Issue Flood Hazard and Risk in Urban Areas)
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17 pages, 6855 KiB  
Article
Hyperspectral Facies Analysis as a Lithological Interpretation Tool for Carbonate Rocks
Geosciences 2023, 13(12), 381; https://doi.org/10.3390/geosciences13120381 - 12 Dec 2023
Viewed by 1417
Abstract
In a pilot study, hyperspectral image analysis was applied to four boreholes from the North Midlands Block in Ireland. The selected holes are extremely well characterised lithologically and have a detailed micropalaeontology accurately constraining stratigraphic positions. Hyperspectral facies were defined using features extracted [...] Read more.
In a pilot study, hyperspectral image analysis was applied to four boreholes from the North Midlands Block in Ireland. The selected holes are extremely well characterised lithologically and have a detailed micropalaeontology accurately constraining stratigraphic positions. Hyperspectral facies were defined using features extracted from the hyperspectral data and compared with existing litho- and biostratigraphic logs and samples. These were able to distinguish changes in the lithologies of the cores and were useful for defining unbiased lithological contacts and for regional correlations. Full article
(This article belongs to the Section Sedimentology, Stratigraphy and Palaeontology)
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14 pages, 1764 KiB  
Article
Probabilistic Models and Deep Learning Models Assessed to Estimate Design and Operational Ocean Wave Statistics to Reduce Coastal Hazards
Geosciences 2023, 13(12), 380; https://doi.org/10.3390/geosciences13120380 - 12 Dec 2023
Viewed by 970
Abstract
Probabilistic models for long-term estimations and deep learning models for short-term predictions have been evaluated and analyzed for ocean wave parameters. Estimation of design and operational wave parameters for long-term return periods is essential for various coastal and ocean engineering applications. Three probability [...] Read more.
Probabilistic models for long-term estimations and deep learning models for short-term predictions have been evaluated and analyzed for ocean wave parameters. Estimation of design and operational wave parameters for long-term return periods is essential for various coastal and ocean engineering applications. Three probability distributions, namely generalized extreme value distribution (EV), generalized Pareto distribution (PD), and Weibull distribution (WD), have been considered in this work. The design wave parameter considered is the maximal wave height for a specified return period, and the operational wave parameters are the mean maximal wave height and the highest occurring maximal wave height. For precise location-based estimation, wave heights are considered from a nested wave model, which has been configured to have a 10 km spatial resolution. As per availability, buoy-observed data are utilized for validation purposes at the Agatti, Digha, Gopalpur, and Ratnagiri stations along the Indian coasts. At the stations mentioned above, the long short-term memory (LSTM)-based deep learning model is applied to provide short-term predictions with higher accuracy. The probabilistic approach for long-term estimation and the deep learning model for short-term prediction can be used in combination to forecast wave statistics along the coasts, reducing hazards. Full article
(This article belongs to the Section Natural Hazards)
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12 pages, 3116 KiB  
Technical Note
Maximum Likelihood Instead of Least Squares in Fracture Analysis by Means of a Simple Excel Sheet with VBA Macro
Geosciences 2023, 13(12), 379; https://doi.org/10.3390/geosciences13120379 - 11 Dec 2023
Viewed by 990
Abstract
This technical note illustrates a linear regression algorithm based on the Maximum Likelihood Estimation (MLE), with a related Excel spreadsheet and VBA program, adapted to the case of fracture aperture data sets in which sampling of the smallest values is problematic. The method [...] Read more.
This technical note illustrates a linear regression algorithm based on the Maximum Likelihood Estimation (MLE), with a related Excel spreadsheet and VBA program, adapted to the case of fracture aperture data sets in which sampling of the smallest values is problematic. The method has been tested by means of Monte Carlo simulations and exhibits significantly better convergence against Least Squares criterion (LSM). As the method is conceptually simple and, following the indications illustrated here, the relative spreadsheet can be easily designed, it may be routinely used, instead of the Least Squares, in fracture analysis. Furthermore, the proposed method, with the appropriate modifications, might be potentially extended to other cases in geology and geophysics, in which significant biases at the lower limits of the sampling scale occur. Full article
(This article belongs to the Section Structural Geology and Tectonics)
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17 pages, 13988 KiB  
Article
Numerical Modelling and Sensitivity Analysis of the Pitztal Valley Debris Flow Event
Geosciences 2023, 13(12), 378; https://doi.org/10.3390/geosciences13120378 - 11 Dec 2023
Viewed by 1070
Abstract
Debris flows characterized by their rapid velocity and composition of water, mud, soil, and boulders, have the potential to inflict significant harm and present hazards to human life, infrastructure, and the natural surroundings. Numerical simulations provide a cost-effective approach for investigating different scenarios, [...] Read more.
Debris flows characterized by their rapid velocity and composition of water, mud, soil, and boulders, have the potential to inflict significant harm and present hazards to human life, infrastructure, and the natural surroundings. Numerical simulations provide a cost-effective approach for investigating different scenarios, hence boosting comprehension of flow dynamics and interactions. However, accurate modelling of these flows typically face difficult challenges arising from inherent modeling constraints and insufficient historical event data. The primary objective of the present study is to conduct numerical modeling and sensitivity analysis of the debris flow event that occurred in the Pitztal Valley, Austria in August of 2009, based on a multi-phase model for debris flows. The validation of the simulation results involves the comparison with the observed deposition patterns in the field. Various validation factors are employed to evaluate the accuracy of the simulated deposit and demonstrate a satisfactory level of precision in predicting deposition patterns. A sensitivity analysis is also conducted to examine the influence of in situ conditions on the effects of debris flow. The results demonstrate that numerical modelling can play an important role in engineering hazard assessment by analyzing the existing model’s effectiveness in simulating both historical and projected debris flow events. Full article
(This article belongs to the Special Issue Advanced Numerical Modelling and Analysis in Geotechnical Engineering)
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19 pages, 18310 KiB  
Article
Melting Processes of Pelitic Rocks in Combustion Metamorphic Complexes of Mongolia: Mineral Chemistry, Raman Spectroscopy, Formation Conditions of Mullite, Silicate Spinel, Silica Polymorphs, and Cordierite-Group Minerals
Geosciences 2023, 13(12), 377; https://doi.org/10.3390/geosciences13120377 - 11 Dec 2023
Viewed by 1074
Abstract
Melted rocks (clinkers and paralavas) of the Mongolian combustion metamorphic (CM) complexes were formed during modern and ancient (since the Quaternary) wild-fires of brown coal layers in the sedimentary strata of the Early Cretaceous Dzunbain Formation. According to XRD, Raman spectroscopy, and SEM-EDS [...] Read more.
Melted rocks (clinkers and paralavas) of the Mongolian combustion metamorphic (CM) complexes were formed during modern and ancient (since the Quaternary) wild-fires of brown coal layers in the sedimentary strata of the Early Cretaceous Dzunbain Formation. According to XRD, Raman spectroscopy, and SEM-EDS data, cordierite, sekaninaite, indialite, ferroindialite, silica polymorphs, mullite, Fe-mullite, anhydrous Al-Fe-Mg silicate spinel (presumably new mineral), and other phases were identified. It has been established that isomorphic impurity of potassium in the cordierite-group minerals does not correlate with their crystal structure (hexagonal or orthorhombic). Indialite and ferroindialite retained their hexagonal structure in some fragments of the CM rocks, possibly due to the very fast cooling of local zones of sedimentary strata and the quenching of high-temperature K-rich peraluminous melt. Clinkers, tridymite–sekaninaite, and cristobalite–fayalite ferroan paralavas were produced by partial melting of Fe-enriched pelitic rocks (mudstone, siltstone, and silty sandstone) in a wide temperature range. The formation of mullite, Fe-mullite, and Al-Fe-Mg silicate spinel in clinkers developed from dehydration–dehydroxylation and incongruent partial melting of Fe-enriched pelitic matter (Al-Mg-Fe-rich phyllosilicates, ‘meta-kaolinite’, and ‘meta-illite’). Large-scale crystallization of these minerals in the K-rich peraluminous melts occurred, presumably, in the range of T > 850–900 °C. The subsurface combustion of coal layers heated the overburden pelitic rocks from sedimentary strata to T > 1050 °C (judging by the formation of cordierite-group minerals) or locally till the melting point of detrital quartz grains at T > 1300 °C and, possibly, till the stability field of stable β-cristobalite at T > 1470 °C. Ferroan paralavas were formed during the rapid crystallization of Fe-rich silicate melts under various redox conditions. From the analysis of the liquidus surface in the Al2O3–FeO–Fe2O3–SiO2 major-oxide system, it follows that the least high-temperature (<1250 °C) and the most oxidizing conditions occurred during the crystallization of mineral assemblages in the most-enriched iron silicate melts parental for cristobalite–fayalite paralava. Full article
(This article belongs to the Section Geochemistry)
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18 pages, 11556 KiB  
Article
3D Geophysical Modeling Based on Multi-Scale Edge Detection, Magnetic Susceptibility Inversion, and Magnetization Vector Inversion in Panjshir, Afghanistan to Detect Probabilistic Fe-Polymetallic Bearing Zone
Geosciences 2023, 13(12), 376; https://doi.org/10.3390/geosciences13120376 - 09 Dec 2023
Viewed by 1756
Abstract
The Panjshir Fe-Polymetallic ore deposit is a valuable geological resource in Afghanistan, rich in iron and multiple essential metallic minerals, with substantial potential for industrial development. The exploration phase faces challenges related to the complex geological settings, high variability of mineral compositions, and [...] Read more.
The Panjshir Fe-Polymetallic ore deposit is a valuable geological resource in Afghanistan, rich in iron and multiple essential metallic minerals, with substantial potential for industrial development. The exploration phase faces challenges related to the complex geological settings, high variability of mineral compositions, and the need for advanced geophysical techniques to accurately locate and assess valuable metallic resources. Considering the strong magnetic characteristics exhibited by Fe-Polymetallic elements, geomagnetic data were employed to analyze and map the likely prospectivity of Fe-Polymetallic deposits within the study area. Multi-scale edge detection techniques were employed to accurately map the boundaries of magnetic bodies by utilizing the upward continued analytical signal amplitude. The presence of a fault system on the geological map confirmed the structural information derived from our edge detection techniques. Advanced magnetic data inversion techniques were employed to create a three-dimensional representation of the distribution of magnetic bodies linked to Fe-Polymetallic deposits. In our efforts to reduce the impact of remnant magnetization in the study area, we adopted a comprehensive strategy by employing both magnetic susceptibility and magnetization vector inversion techniques. The use of a sparse and blocky norm regularization [0,1,1,1] is well-suited for magnetic susceptibility inversion, while a blocky norm [0000,0000,0000] is the appropriate choice for magnetization vector inversion in our study. Ultimately, the zones characterized by a high magnetic susceptibility and a high magnetization amplitude are considered promising areas for potential Fe-polymetallic occurrences. Full article
(This article belongs to the Section Geophysics)
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21 pages, 15527 KiB  
Article
Comparative Study of Deterioration in Built Heritage in a Coastal Area: Barbanza Peninsula (Galicia, NW Spain)
Geosciences 2023, 13(12), 375; https://doi.org/10.3390/geosciences13120375 - 09 Dec 2023
Cited by 1 | Viewed by 1173
Abstract
The Barbanza Peninsula (Galicia, NW Spain) is located on the west coast of Galicia. It is a narrow tongue of terrain with an area of 416 km2 and a high altitudinal gradient, with the top having a maximum height of more than [...] Read more.
The Barbanza Peninsula (Galicia, NW Spain) is located on the west coast of Galicia. It is a narrow tongue of terrain with an area of 416 km2 and a high altitudinal gradient, with the top having a maximum height of more than 600 m at a distance of less than 5 Km from the sea. As a result of this, there is a significant rainfall gradient (from 900 to more than 3300 mm per year). In the peninsula, there are valuable historical buildings built with granite rock that show variable decay patterns. In this work, we have considered 14 of them, located in several parts of the peninsula, and we have studied their deterioration patterns. Some of them are close to the sea, with sea salt being a possible cause of decay, while for those located far from the sea, the high humidity and rainfall can be the most important cause of decay. A macroscopic study was carried out to determine the deterioration patterns. We have also analyzed the possible role of salts in the decay by using X-ray fluorescence as a screening technique to assess the presence of salts and the possible correlation of salts with the distance to the sea and using scanning electron microscopy to directly identify salts in some of the buildings. The most frequently reported decay is due to lichen growth (biological colonization). Depending on the proximity to the coast, the study area was divided into two zones: zone 1, closer to the sea (<1 km), with an important influence of sea salts and wind, and zone 2, further from the sea, with higher altitudes (center of the peninsula) and important rainfall, humidity, and therefore, biological colonization of stone surfaces. Crusts (to a lesser degree, because it is a mainly rural area) are more frequent in zone 1, but the state of conservation of stone in zone 1 is better than that in zone 2, possibly due to the concentration of urban centers in this zone and more interventions for cleaning stone surfaces. Finally, although we did not observe clear patterns in the appearance of salts in the buildings in agreement with the distance to the sea, we observed different patterns of salts in two of the buildings, one in each zone, which clearly show that, to some extent, salts are involved in decay. Full article
(This article belongs to the Section Geoheritage, Geoparks and Geotourism)
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33 pages, 25776 KiB  
Article
Mass-Transfer and Fluid Flow along Extensional Detachment Faults in Hyperextended Rift Systems: The Examples of Tasna in the Alps, Mauléon in the Pyrenees, and Hobby High Offshore Iberia
Geosciences 2023, 13(12), 374; https://doi.org/10.3390/geosciences13120374 - 08 Dec 2023
Viewed by 1120
Abstract
Hyperextended rift systems are characterized by extreme crustal thinning and mantle exhumation associated with extensional detachment faults. These faults cut through thinned continental crust, reaching the underlying mantle and allowing for seawater to infiltrate and react with the crustal and mantle rocks. Hydrothermal [...] Read more.
Hyperextended rift systems are characterized by extreme crustal thinning and mantle exhumation associated with extensional detachment faults. These faults cut through thinned continental crust, reaching the underlying mantle and allowing for seawater to infiltrate and react with the crustal and mantle rocks. Hydrothermal fluid systems linked to detachment faults result in fluid–rock reactions occurring along the detachments, resulting in the breakdown and alteration of minerals, loss of elements and strain weakening in both mantle and crustal rocks. We present new geological observations and geochemical data from the modern Iberia and fossil Alpine Tethys Ocean Continent Transition and the West Pyrenean Mauléon hyperextended rift basin. We show evidence for a km-scale fluid flow along detachment faults and discuss the conditions under which fluid flow and mass transfer occurred. Convective fluid systems are of major importance for mass transfer between the mantle, crustal and marine reservoirs. We identified gains in Si, Mg, Fe, Mn, Ca, Ni, Cr and V along extensional detachment faults that we relate to channelized, hydrothermal crust- and mantle-reacted fluid systems migrating along detachments in the hyperextended continental crust. The observation that fault rocks of extensional detachment and syn-extensional sedimentary rocks are enriched in mantle-derived elements such as Cr, Ni and V enables us to define the pathways of fluids, as well as to estimate their age relative to detachment faulting and sedimentation. Because all three examples show a similar mass transport of elements along detachment systems at km-scale, we conclude that these examples are linked to convective fluid systems that may affect the thermal state of the lithosphere, as well as the rheology and chemistry of rocks in hyperextended systems, and may have implications for ore mineral exploration in hyperextended rift systems. Full article
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21 pages, 3724 KiB  
Article
Composition of Rare Earth Elements in Fluvial Sediments of the Lesser Zab River Basin, Northeastern Iraq: Implications for Tectonic Setting and Provenance
Geosciences 2023, 13(12), 373; https://doi.org/10.3390/geosciences13120373 - 08 Dec 2023
Viewed by 1338
Abstract
During the past few decades, rare earth elements (REEs) have gained enormous attention in geochemical studies worldwide as a result of their important role in the manufacturing of high-tech equipment. REEs in river sediment have been widely used for provenance determination and in [...] Read more.
During the past few decades, rare earth elements (REEs) have gained enormous attention in geochemical studies worldwide as a result of their important role in the manufacturing of high-tech equipment. REEs in river sediment have been widely used for provenance determination and in geochemical studies of continental crust, rock and sediment environments, and anthropogenic pollution. This study aims to elucidate the origin and tectonic setting of Little Zab River Basin (LZRB) sediments by examining 23 fluvial sediment samples of rare earth elements (REEs) collected from both the primary river and the inter-sub-basin regions during the rainy or high-flow season. The ICP-MS method was employed to analyze all samples to identify and assess the compositions of REEs. A fraction of the river sediments, smaller than 2 mm, which is more representative and more homogeneous, was used to carry out geochemical analysis. REE concentrations in the Little Zab River (LZR) and the upper parts of the LZRB were generally higher than those in the lower parts. The concentration of REEs in nearly all samples was lower than that of the North American Shale Composite (NASC), and the Upper Continental Crust (UCC), except for the sub-basin sediment Sbs2, which was higher than these references; also, the sediment sample Zrs4 was slightly higher than NASC. Light rare earth elements (LREEs) display enrichment relative to heavy rare earth elements (HREEs) with a range between 7.15 μg/g and 12.37 μg/g for LZR samples and between 5.95 μg/g and 13.03 μg/g for the sub-basin samples. The REE discrimination diagrams, along with the chondrodite-normalized pattern of the studied sediments, confirm that the sediment is predominantly sourced from the alkaline basaltic unit of the late Cretaceous Walsh group of an arc tectonic affinity. Full article
(This article belongs to the Section Geochemistry)
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12 pages, 8905 KiB  
Technical Note
On the Occurrence of the Gar Obaichthys africanus Grande in the Cretaceous of Portugal: Palaeoecological and Palaeobiogeographical Implications
Geosciences 2023, 13(12), 372; https://doi.org/10.3390/geosciences13120372 - 07 Dec 2023
Viewed by 1860
Abstract
Several disarticulated fish scales and a vertebral centrum were collected from the uppermost middle to lowermost upper Cenomanian beds of the vertebrate fossil site of Casais dos Carecos (Baixo Mondego region, Coimbra, West Portugal), corresponding to shallow carbonate and mixed facies (“Unit B”) [...] Read more.
Several disarticulated fish scales and a vertebral centrum were collected from the uppermost middle to lowermost upper Cenomanian beds of the vertebrate fossil site of Casais dos Carecos (Baixo Mondego region, Coimbra, West Portugal), corresponding to shallow carbonate and mixed facies (“Unit B”) of the Tentúgal Formation. The taphonomic preservation of these remains is adequate for their detailed taxonomical study. The scales are diagnosable for the species Obaichthys africanus Grande, as each one has a strong spine protruding from the middle of the posterior border in a rostrocaudal direction, a dorsoventral peg and socket, and a small anterodorsal process for articulation of adjacent scales. The sculpture with ganoid ridges and grooves distinguishes the studied remains from those of O. decoratus Wenz and Brito, which display rounded tubercles. The isolated Lepisosteoidea centrum is tentatively attributed to O. africanus as well, as it was found together with the scales, and no other compatible remains were found in the site. The fish material reported here constitutes the first record of O. africanus in the Baixo Mondego region and northern ranges of the Albian–Turonian West Portuguese Carbonate Platform, as well as in the uppermost middle to basal upper Cenomanian of Portugal. Full article
(This article belongs to the Section Sedimentology, Stratigraphy and Palaeontology)
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21 pages, 290958 KiB  
Article
Systematic Quantification and Assessment of Digital Image Correlation Performance for Landslide Monitoring
Geosciences 2023, 13(12), 371; https://doi.org/10.3390/geosciences13120371 - 03 Dec 2023
Viewed by 1808
Abstract
Accurate and reliable analyses of high-alpine landslide displacement magnitudes and rates are key requirements for current and future alpine early warnings. It has been proved that high spatiotemporal-resolution remote sensing data combined with digital image correlation (DIC) algorithms can accurately monitor ground displacements. [...] Read more.
Accurate and reliable analyses of high-alpine landslide displacement magnitudes and rates are key requirements for current and future alpine early warnings. It has been proved that high spatiotemporal-resolution remote sensing data combined with digital image correlation (DIC) algorithms can accurately monitor ground displacements. DIC algorithms still rely on significant amounts of expert input; there is neither a general mathematical description of type and spatiotemporal resolution of input data nor DIC parameters required for successful landslide detection, accurate characterisation of displacement magnitude and rate, and overall error estimation. This work provides generic formulas estimating appropriate DIC input parameters, drastically reducing the time required for manual input parameter optimisation. We employed the open-source code DIC-FFT using optical remote sensing data acquired between 2014 and 2020 for two landslides in Switzerland to qualitatively and quantitatively show which spatial resolution is required to recognise slope displacements, from satellite images to aerial orthophotos, and how the spatial resolution affects the accuracy of the calculated displacement magnitude and rate. We verified our results by manually tracing geomorphic markers in orthophotos. Here, we show a first generic approach for designing and optimising future remote sensing-based landslide monitoring campaigns to support time-critical applications like early warning systems. Full article
(This article belongs to the Special Issue Landslide Monitoring and Mapping II)
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25 pages, 1361 KiB  
Article
Short- and Mid-Term Forecasting of Pan-Arctic Sea Ice Volume Using Variational Mode Decomposition and Bidirectional Long Short-Term Memory
Geosciences 2023, 13(12), 370; https://doi.org/10.3390/geosciences13120370 - 29 Nov 2023
Viewed by 1121
Abstract
The well-documented decrease in the annual minimum Arctic sea ice extent over the past few decades is an alarming indicator of current climate change. However, much less is known about the thickness of the Arctic sea ice. Developing accurate forecasting models is critical [...] Read more.
The well-documented decrease in the annual minimum Arctic sea ice extent over the past few decades is an alarming indicator of current climate change. However, much less is known about the thickness of the Arctic sea ice. Developing accurate forecasting models is critical to better predict its changes and monitor the impacts of global warming on the total Arctic sea ice volume (SIV). Significant improvements in forecasting performance are possible with the advances in signal processing and deep learning. Accordingly, here, we set out to utilize the recent advances in machine learning to develop non-physics-based techniques for forecasting the sea ice volume with low computational costs. In particular, this paper aims to provide a step-wise decision process required to develop a more accurate forecasting model over short- and mid-term horizons. This work integrates variational mode decomposition (VMD) and bidirectional long short-term memory (BiLSTM) for multi-input multi-output pan-Arctic SIV forecasting. Different experiments are conducted to identify the impact of several aspects, including multivariate inputs, signal decomposition, and deep learning, on forecasting performance. The empirical results indicate that (i) the proposed hybrid model is consistently effective in time-series processing and forecasting, with average improvements of up to 60% compared with the case of no decomposition and over 40% compared with other deep learning models in both forecasting horizons and seasons; (ii) the optimization of the VMD level is essential for optimal performance; and (iii) the use of the proposed technique with a divide-and-conquer strategy demonstrates superior forecasting performance. Full article
(This article belongs to the Section Cryosphere)
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34 pages, 9073 KiB  
Review
Can Extractive Industries Make Countries Happy? What Are Potential Implications for the Geoscientist? Overview and Case Study Examples from Papua New Guinea and Worldwide
Geosciences 2023, 13(12), 369; https://doi.org/10.3390/geosciences13120369 - 29 Nov 2023
Viewed by 1234
Abstract
Geoscientists are involved in both the upstream and downstream side of the extractive industries. As explorationists and field geologists, they are often the first technical people related to extractive industries that communities meet. It is imperative in an increasingly globalized and holistic world [...] Read more.
Geoscientists are involved in both the upstream and downstream side of the extractive industries. As explorationists and field geologists, they are often the first technical people related to extractive industries that communities meet. It is imperative in an increasingly globalized and holistic world that geoscientists gain greater awareness of the socio-economic impact of extractive industries and become a more proactive part of improving outcomes for all with respect to extractive industries. When Jigme Singye Wangchuk, the King of Bhutan, first suggested the concept of ‘Gross National Happiness’ (GNH) in 1972, it was met with widespread cynicism and puzzlement. Was the concept meaningful in a hard, economically competitive world? A series of measures, including the Human Development Index (HDI), the Gini Coefficient (GC), and the now annual World Happiness Report (WHR), are evolutionary responses to the 1972 GNH and are widely accepted as proxy measures of holistic human progress. These measures go beyond the narrow confines of Gross Domestic Product and similar economic proxies, placing economic parameters alongside the social, environmental, spiritual, human rights, health, and holistic societal issues. The broad conclusions of the plethora of metrics are that ‘happiness’ links to issues and ideas such as equity, minimal economic inequality, excellent governance, human rights, individual freedom, and so forth. We ask the question: what is the relationship between extractive industries (EIs) and GNH? We present a wide range of data and analytical diagrams/text examining potential correlations and associations between GNH and EIs. We examine potential relationships using global data and case studies for Papua New Guinea, Mongolia, the DRC, and Jamaica. The conclusions of this analysis of course suggest a complex relationship between EIs and GNH. We acknowledge that in situations of weak governance and institutions, EIs struggle to make any tangible difference with respect to GNH. A counter conclusion that EIs may even be a major cause of weak governance, which in turn suppresses happiness, must be seriously considered. We document examples where EIs have made a definitive positive improvement to GNH. Data suggest that hydrocarbon-rich countries have made better progress with respect to GNH than mineral-rich countries. However, the main conclusion is that the link between EIs and GNH remains a work in progress, and that a narrow focus on profit and shareholder return is an antithetical approach to the GNH paradigm. A key recommendation is that industry must adopt a far more active role (rather than merely a passive role) with respect to translating the many potential benefits of EIs into GNH than has hitherto been the case. Full article
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21 pages, 70941 KiB  
Article
Numerical Simulation of Rockfall Protection Embankments in Natural Soil
Geosciences 2023, 13(12), 368; https://doi.org/10.3390/geosciences13120368 - 28 Nov 2023
Viewed by 1092
Abstract
Rockfall events represent a significant hazard in mountainous regions, putting human safety and critical infrastructure at risk. Various mitigation devices are available, among which, Rockfall protection embankments (RPEs) located in natural soil are passive defense work suitable for high-energy and high-frequency events. Currently, [...] Read more.
Rockfall events represent a significant hazard in mountainous regions, putting human safety and critical infrastructure at risk. Various mitigation devices are available, among which, Rockfall protection embankments (RPEs) located in natural soil are passive defense work suitable for high-energy and high-frequency events. Currently, limited research has been conducted in this area, with the Austrian standard ONR 24810 providing the sole codified design method. A parametrical analysis involving both the RPE geometry and the impact features was developed by Abaqus/Explicit FEM code, with 2270 cases overall. The research aims to identify conditions under which RPEs effectively stop falling blocks, focusing on two failure mechanisms: the block pass over the RPE after impacting the upstream side bank and the RPE structural collapse. Additionally, the interaction between RPEs and their foundations during the impact is explored. The results provide valuable insights into the dynamic behavior of these structures. In terms of design considerations, this study offers analytical equations to quantify crater depth and foundation stress induced by the impact. Furthermore, design charts are developed to assess the block passing over verification and the structural collapse verification. Full article
(This article belongs to the Special Issue Advanced Numerical Modelling and Analysis in Geotechnical Engineering)
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17 pages, 7254 KiB  
Article
Signatures of Pleistocene Marine Transgression Preserved in Lithified Coastal Dune Morphology of The Bahamas
Geosciences 2023, 13(12), 367; https://doi.org/10.3390/geosciences13120367 - 28 Nov 2023
Viewed by 1160
Abstract
The morphology of some lithified wind-blown, carbonate dunes in The Bahamas preserves the signature of erosion from paleo-marine processes: wave-induced swash, scarping, and longshore transport. Digital elevation models were used to distinguish between two dune morphotypes—those disconnected versus connected to beach processes. Dune [...] Read more.
The morphology of some lithified wind-blown, carbonate dunes in The Bahamas preserves the signature of erosion from paleo-marine processes: wave-induced swash, scarping, and longshore transport. Digital elevation models were used to distinguish between two dune morphotypes—those disconnected versus connected to beach processes. Dune sinuosity and upwind slope were quantified and used to interpret which dunes remained beach-attached and subject to marine erosion and processes versus dunes that became disconnected from the shoreline via inland migration or shoreline regression. Disconnected dunes possess low slopes over stoss surfaces with sinuous planforms mimicking their crestlines. Beach-connected foredunes preserve steep, kilometers-long linear upwind faces, which are interpreted to be signatures of beach-dune morphodynamics. Foredune morphology serves as a proxy for shoreline position during past sea-level high-stands, while the basal elevations of their stoss dune toes provide an upper limit on the beach and adjacent sea level. A growing library of digital topography will allow for this tool to be used to interpret global paleo-shoreline positions through time and space. Full article
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14 pages, 25737 KiB  
Article
An Analysis of Slope Stability in the Penipe–Baños Road by Applying Empirical Methods, Kinematic Analysis and Remote Photogrammetry Techniques
Geosciences 2023, 13(12), 366; https://doi.org/10.3390/geosciences13120366 - 28 Nov 2023
Viewed by 1121
Abstract
The purpose of this work is to analyze the stability of four slopes along the Penipe–Baños road, which is situated in the provinces of Chimborazo and Tungurahua and where there are occasionally rockfalls that hinder passage and endanger road users. The methodology used [...] Read more.
The purpose of this work is to analyze the stability of four slopes along the Penipe–Baños road, which is situated in the provinces of Chimborazo and Tungurahua and where there are occasionally rockfalls that hinder passage and endanger road users. The methodology used to conduct the analysis was based on data collection with the help of remote techniques such as structure from motion, which allows us to obtain slope data using photogrammetry. Empirical methods such as slope mass rating, Q-slope, the kinematic method and the Rockfall Hazard Rating System method were used. These methods were evaluated with Rocfall3 software for the analysis of the fall trajectory of rock blocks. The results of this work show that the slopes studied do not represent a greater risk to the road than other slopes close to those studied, but these could not be analyzed due to their lack of accessibility and the danger of obtaining data under those conditions. The study of these different methods demonstrates the reliability of low-cost, remote techniques in the facilitation of analysis in places with similar conditions. Full article
(This article belongs to the Section Geomechanics)
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16 pages, 6365 KiB  
Article
Balanced Definition of Thresholds for Mode Tracking in a Long-Term Seismic Monitoring System
Geosciences 2023, 13(12), 365; https://doi.org/10.3390/geosciences13120365 - 27 Nov 2023
Viewed by 999
Abstract
The catastrophic events of recent years have strengthened the awareness of the fragility of the built heritage and the importance of careful and targeted maintenance. This, in combination with the development of modern techniques for the analysis of large datasets, has favoured the [...] Read more.
The catastrophic events of recent years have strengthened the awareness of the fragility of the built heritage and the importance of careful and targeted maintenance. This, in combination with the development of modern techniques for the analysis of large datasets, has favoured the diffusion of long-term seismic monitoring systems for the protection of structures. In the field of structural health monitoring, data-driven techniques allow crucial information to be extracted from measurements without the need to model the physical phenomena involved, circumventing potential limitations that may arise. On the other hand, however, the results of data-driven approaches are based entirely on the measured structural response; this is why a high reliability of the procedure for extracting diagnostic parameters is essential. In this perspective, a Mode Tracking procedure is proposed to obtain coherent time histories of the modal frequencies of a structure as environmental conditions vary. The procedure is applied to the Sanctuary of Vicoforte, an important monumental structure located in Piedmont, known for its imposing oval dome and characterized by a permanent structural monitoring system. This study aims to disentangle the frequency time series and obtain a rigorous database on which to set up damage identification processes. Full article
(This article belongs to the Special Issue New Trends in Earthquake Engineering and Seismotectonics)
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21 pages, 9744 KiB  
Article
The Contribution of Digital Image Correlation for the Knowledge, Control and Emergency Monitoring of Earth Flows
Geosciences 2023, 13(12), 364; https://doi.org/10.3390/geosciences13120364 - 25 Nov 2023
Viewed by 1140
Abstract
Earth flows are complex geological processes that, when interacting with linear infrastructures, have the potential to cause significant damage. Consequently, conducting comprehensive investigations and continuous monitoring are becoming paramount in designing effective mitigation measures and ensuring sustainable risk management practices. The use of [...] Read more.
Earth flows are complex geological processes that, when interacting with linear infrastructures, have the potential to cause significant damage. Consequently, conducting comprehensive investigations and continuous monitoring are becoming paramount in designing effective mitigation measures and ensuring sustainable risk management practices. The use of digital image correlation (DIC) algorithms for the displacement monitoring of earth flows is a relatively new and growing field with a limited number of dedicated works in the literature. Within this framework, the present paper contributes by evaluating DIC techniques at several earth flow sites. These assessments were founded upon data obtained from both low-cost and multi-platform sensors, used to assess the displacement field, pinpointing the most active sectors, and gauging their rates of movement during different kinematic phases. In this regard, the highest localized movement velocities reached in the Pietrafitta (0.01 m/day) and Grillo (0.63 m/day) earth flows experience different ongoing kinematic processes. The versatility of these techniques is notable, manifesting in the ease of installation, cost-effectiveness, and adaptability to various platforms. The proven reliability in terms of maximum accuracy (1 pixel) and sensitivity (0.05 m) lays the foundation for the extensive use of the presented techniques. The amalgamation of these attributes positions DIC techniques as competitive, adaptable, and readily deployable tools in earth flow studies. Full article
(This article belongs to the Special Issue Remote Sensing Monitoring of Geomorphological Hazards)
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23 pages, 11044 KiB  
Article
The Mahout Structure in the Central Desert of Oman: A Possible Simple Impact Crater
Geosciences 2023, 13(12), 363; https://doi.org/10.3390/geosciences13120363 - 24 Nov 2023
Viewed by 1110
Abstract
The present work reports on the first evidence of a possible hypervelocity impact crater in the Sultanate of Oman. The impact origin of the structure is determined based on field observations, microscopic observations of shatter cones, planar fractures (PFs) and feather features (FFs) [...] Read more.
The present work reports on the first evidence of a possible hypervelocity impact crater in the Sultanate of Oman. The impact origin of the structure is determined based on field observations, microscopic observations of shatter cones, planar fractures (PFs) and feather features (FFs) in quartz, calcite, and feldspar, and melt-bearing polymict breccias with various types of melts. The structure consists of an elliptical bowl-shaped ridge 750 m long and 550 m wide, oriented roughly north-northeast to south-southwest. The elliptical shape and relief asymmetry indicate an oblique collision. The precursor target lithologies include local late Proterozoic Masirah Bay siliciclastic formations, carbonate and acidic volcanic rocks of the late Precambrian Halfayn Formation, and basement rocks. The crater rim, up to 15–20 m above ground, is composed of quartzite, jasper, agate, monomict siliceous and hematite breccia, and metamorphosed shale (hornfels). An ejecta blanket composed of target rocks covers the floor, outer rim, and the area extending to the immediate northeast and east of the structure. Quaternary aeolian sand covers most of the crater surface, including the 1 to 2 m thick melt-rich polymict breccia found in the crater center. The planar fractures (PFs) and feather features (FFS) in quartz and feldspar suggest a low shock pressure between 5 and 14 GPa. Our observations are consistent with set criterions for impact crater identification, confirming the possible impact origin of the Mahout structure. Full article
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13 pages, 2616 KiB  
Article
Th-Rich Zircon from a Pegmatite Vein Hosted in the Wiborg Rapakivi Granite Massif
Geosciences 2023, 13(12), 362; https://doi.org/10.3390/geosciences13120362 - 24 Nov 2023
Viewed by 987
Abstract
Zircon from a pegmatite vein hosted in the rapakivi granites occurring in the Gubanov Intrusion of the Wiborg Massif was shown by the EPMA method to contain an anomalously high Th of 18.3 wt% ThO2 (about 161,000 ppm Th). The SIMS method [...] Read more.
Zircon from a pegmatite vein hosted in the rapakivi granites occurring in the Gubanov Intrusion of the Wiborg Massif was shown by the EPMA method to contain an anomalously high Th of 18.3 wt% ThO2 (about 161,000 ppm Th). The SIMS method obtained a close value for thorium content—146,000 ppm. U increases to 6800 ppm. Zircon contains high values of other non-formula elements: Y (up to 51,500 ppm), Ti (up to 12,500 ppm), P (up to 9000 ppm), Nb (up to 3500 ppm), Ca (up to 2800 ppm) and Ba (up to 600 ppm). The average Hf value is 10,900 ppm. Total REE ranges from 25,500 to 49,400 ppm, and the average REE is 33,300 ppm. The REE patterns show poorly HREE fractionation over the LREE (LuN/LaN ratio average is 6.34) with well-marked negative Eu anomalies (Eu/Eu* averages 0.10) and slight positive Ce anomalies (Ce/Ce* averages 1.16). The formation of Th-rich zircon indicates that residual fluid-saturated pegmatite melt is saturated with Th and other trace elements (REE, Y, U, Ti and Nb). Full article
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16 pages, 5891 KiB  
Article
Verification of C-Band Geophysical Model Function for Wind Speed Retrieval in the Open Ocean and Inland Water Conditions
Geosciences 2023, 13(12), 361; https://doi.org/10.3390/geosciences13120361 - 24 Nov 2023
Viewed by 1002
Abstract
Verification of the C-band geophysical model functions (GMF) for the open ocean and the Gorky reservoir was carried out using Sentinel-1 IW-mode Synthetic aperture radar (SAR) images. CMOD5.N, CMOD7, GMF for the Caspian Sea, and CSARMOD2 were considered. The motivation for this study [...] Read more.
Verification of the C-band geophysical model functions (GMF) for the open ocean and the Gorky reservoir was carried out using Sentinel-1 IW-mode Synthetic aperture radar (SAR) images. CMOD5.N, CMOD7, GMF for the Caspian Sea, and CSARMOD2 were considered. The motivation for this study is concerned with the clarification of applying C-band GMFs for SAR images including for the conditions of inland water bodies, as well as with the study of the influence of various wind speed direction sources on the results of wind speed magnitude retrieval for ocean conditions. Comparison of wind speed from the CMOD5.N algorithm using wind direction data from NOAA NDBC oceanographic buoys together with the data provided by NCEP reanalysis data showed that regardless of the geographic location, the result does not depend significantly on the choice of the wind direction source. Novel results of CMOD5.N, CMOD7, GMF for the Caspian Sea, and CSARMOD2 applications to the conditions of the Gorky reservoir are presented. The comparison of these results with the meteorological station measurements showed the best agreement for CMOD5.N. The preliminary results on the construction of new C-band GMF adjusted to the Gorky Reservoir have shown statistical parameters better than for Caspian Sea GMF and CSARMOD2. Full article
(This article belongs to the Special Issue Earth Observation by GNSS and GIS Techniques)
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12 pages, 1567 KiB  
Review
Causes of Chronic Kidney Disease of Non-Traditional Origin in Central America: An Approach Based on Medical Geology
Geosciences 2023, 13(12), 360; https://doi.org/10.3390/geosciences13120360 - 24 Nov 2023
Viewed by 1264
Abstract
Chronic kidney disease of non-traditional origin (CKDnt) in Central America, also known as Mesoamerican Nephropathy (MeN), is of particular concern in agricultural populations. The member states of the Central American Integration System (SICA) determined in 2013 that there was an imperative need to [...] Read more.
Chronic kidney disease of non-traditional origin (CKDnt) in Central America, also known as Mesoamerican Nephropathy (MeN), is of particular concern in agricultural populations. The member states of the Central American Integration System (SICA) determined in 2013 that there was an imperative need to address the situation in a comprehensive manner and defined policies for the intervention of the disease. A situation that currently worries health authorities is that cases are on the rise—without distinguishing or implementing effective actions to achieve a decrease in disease prevalence. The incidence of heat and strenuous activities on renal health is undeniable; however, labeling these variables as the only responsible causes for MeN has not catalyzed the implementation of health measures to lead to a preventive approach to solve the epidemic or to achieve a decrease in the number of new cases. This review addresses the role nephrotoxic metals present in the environment, mainly in soils and water, may have as part of a scenario of exposure to environmental toxins in which environmental, occupational, geographic and population variables interact. An integral approach was used to encompass the multicausality that is attributed to MeN and based on the multidisciplinary concept of the re-emerging discipline called medical geology. Full article
(This article belongs to the Section Biogeosciences)
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