Next Issue
Volume 12, May
Previous Issue
Volume 12, March

Geosciences, Volume 12, Issue 4 (April 2022) – 38 articles

Cover Story (view full-size image): The impacts of a changing climate are of major societal concern with great interest on mitigation or modeling how a future, warmer world would look. It is also broadly recognized that the impacts of a warming Earth are most profoundly expressed in the polar regions. Climate change encompasses many components. Our new study reviews the ample evidence for a flourishing ancient Arctic terrestrial ecosystem during the Late Cretaceous greenhouse mode in Earth history, an ecosystem where the local paleoclimate was a primary driver in structuring the relative abundances of large-bodied herbivores in local environments. Further, analysis suggests that mean annual precipitation (MAP) played a more direct role in determining the distribution of herbivorous dinosaurs than mean annual temperature (MAT) did. View this paper.
  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Readerexternal link to open them.
Order results
Result details
Section
Select all
Export citation of selected articles as:
Article
Estimating Water Content in Water–Oil Mixtures and Porous MEDIA They Saturate: Joint Interpretation of NMR Relaxometry and Dielectric Spectroscopy
Geosciences 2022, 12(4), 179; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040179 - 17 Apr 2022
Viewed by 785
Abstract
This article deals with the topical problem of estimating water content in water–oil mixtures within porous media they saturate, according to low-field NMR relaxometry and dielectric spectroscopy. The aim of the research is experimental validation of the capability of complex data interpretation to [...] Read more.
This article deals with the topical problem of estimating water content in water–oil mixtures within porous media they saturate, according to low-field NMR relaxometry and dielectric spectroscopy. The aim of the research is experimental validation of the capability of complex data interpretation to acquire information on the filtration-volumetric properties of drill cuttings, relaxation characteristics of oil-containing fluids, the water/oil ratio in water–oil mixtures, and their saturation of drill cuttings to control the composition of liquids produced from boreholes. The studies are carried out on samples of cuttings and oils taken from fields in the Northern regions of the West Siberian oil-and-gas province, where NMR studies have not been performed before. Based on the experimental data obtained, the possibility of water content assessment in water-in-oil mixtures and porous media they saturate were proved through NMR relaxometry. With the use of the proposed methodology, the amount of water in oil–water mixtures was established, and their main NMR characteristics were determined. The relative error in evaluating the proportion of water in mixtures based on high-viscosity oils is less than 10%, and about 20% for those based on light oils. When determining the oil–water ratio in the pore space of the drill cuttings, the error is about 15%. It was proven that joint use of these two techniques makes it possible to increase the reliability of the oil–water ratio assessment of all the samples studied. Furthermore, it was revealed that the NMR spectrum shifts to the right, and the spectrum of the complex permittivity shifts downwards during the transition from high-viscosity oils to light ones. Full article
Show Figures

Figure 1

Article
3D Migration Depth Focus Velocity Analysis of Hand-Held Ground Penetrating Radar
Geosciences 2022, 12(4), 178; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040178 - 16 Apr 2022
Viewed by 832
Abstract
Hand-held ground penetrating radar (GPR) systems have been widely applied to landmine detections during recent decades. The accuracy of an imaging result by migration for a hand-held GPR is strongly related to the accuracy of subsurface velocity distribution obtained from multi offset data. [...] Read more.
Hand-held ground penetrating radar (GPR) systems have been widely applied to landmine detections during recent decades. The accuracy of an imaging result by migration for a hand-held GPR is strongly related to the accuracy of subsurface velocity distribution obtained from multi offset data. For shallow targets like landmines, the hyperbolas are usually not distinct in 2D slices and are masked by the surface reflections. In this article, we propose a 3D migration depth focus velocity analysis method for hand-held GPRs to estimate the background velocity of the subsurface. This method is performed based on the images generated by migrations. The objective function is defined as the proportion of the target on the depth slice containing the target. After migrating a GPR radargram with different velocities, the background velocity, which minimizes the objective function, can be determined by comparing the imaging results by migration using different velocities. To test the proposed method, we apply this procedure to experimental GPR data collected with an advanced landmine imaging system (ALIS) in the laboratory. Subsequently, the velocity of the background is obtained, 3D diffraction migration with the obtained velocity achieves subsurface imaging with high quality. The accurate position and depth of the target are obtained from the optimal migration image. Full article
(This article belongs to the Special Issue Ground Penetrating Radar Velocities)
Show Figures

Figure 1

Technical Note
Shallow Landslides and Rockfalls Velocity Assessment at Regional Scale: A Methodology Based on a Morphometric Approach
Geosciences 2022, 12(4), 177; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040177 - 16 Apr 2022
Viewed by 793
Abstract
Velocity is one of the most important parameters to evaluate the damaging potential of a mass movement, but its assessment, especially for extremely rapid landslides, is a complex task. In the literature, several models to assess mass movement velocity exist, but they usually [...] Read more.
Velocity is one of the most important parameters to evaluate the damaging potential of a mass movement, but its assessment, especially for extremely rapid landslides, is a complex task. In the literature, several models to assess mass movement velocity exist, but they usually require many detailed parameters, and therefore, they are applicable only to a single slope and not usable for regional-scale analyses. This study aims to propose a simple morphometric methodology, based on the spatialisation of the Energy Line method, to determine the velocity of shallow landslides and rockfalls at a regional scale. The proposed method requires a limited amount of input data (landslide perimeters and a digital elevation model), and its application can be carried out using GIS software and a Matlab code. The test area of this work is the Valle d’Aosta Region (Northern Italy), selected due to its peculiar geological and geomorphological setting that makes this region susceptible to the occurrence of both shallow landslides and rockfalls. Since measured velocity values for rockfalls and shallow landslides were not available, the results obtained with the proposed method have been validated through the implementation of a model in the literature, namely the Gravitational Process Path (GPP) model, for some selected landslides. Full article
(This article belongs to the Special Issue Landslide Monitoring and Mapping)
Show Figures

Figure 1

Article
Chimney Identification Tool for Automated Detection of Hydrothermal Chimneys from High-Resolution Bathymetry Using Machine Learning
Geosciences 2022, 12(4), 176; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040176 - 15 Apr 2022
Viewed by 966
Abstract
Identifying the locations of hydrothermal chimneys across mapped areas of seafloor spreading ridges unlocks the ability to research questions about their correlations to geology, the cooling of the lithosphere, and deep-sea biogeography. We developed a Chimney Identification Tool (CIT) that utilizes a Convolutional [...] Read more.
Identifying the locations of hydrothermal chimneys across mapped areas of seafloor spreading ridges unlocks the ability to research questions about their correlations to geology, the cooling of the lithosphere, and deep-sea biogeography. We developed a Chimney Identification Tool (CIT) that utilizes a Convolutional Neural Network (CNN) to classify 1 m gridded AUV bathymetry and identify the locations of hydrothermal vent chimneys. A CNN is a type of Machine-Learning model that is able to classify raster data based on the shapes and textures in the input, making it ideal for this task. The criteria that have been used in previous manual classifications of chimneys have focused on the round base and spire shape of the features, and are not easily quantifiable. Machine-Learning techniques have previously been implemented with sonar data to classify seafloor geology, but this is the first application of these methods to hydrothermal systems. In developing the CIT, we compiled the bathymetry data from two rasters from the Endeavor Ridge—each gridded at a 1 m resolution—containing 34 locations of known hydrothermal chimneys, and from the 92° W segment of the Galapagos Spreading Center (GSC) containing 14. The CIT produced a primary group of outputs with 96% agreement with the manual classification; moreover, it correctly caught 29 of the 34 known chimneys from Endeavor and 10 of the 14 from the GSC. The CIT is trained to identify features with the characteristic shape of a hydrothermal vent chimney; therefore, it is susceptible to the misclassification of unusually shaped cases, given the limited training data. As a result, to provide the option of having a more inclusive application, the CIT also produced a secondary group of output locations with 61% agreement with the manual classification; moreover, it caught three of the four additional known chimneys from the GSC and four of the five from Endeavor. The CIT will be used in future investigations where an inventory of individual chimneys is important, such as the cataloguing of off-axis hydrothermal venting and the investigation of chimney distribution in connection to seafloor eruptions. Full article
Show Figures

Figure 1

Article
Complexity and Geoheritage Importance of Granite Pseudokarst from the Belaya River Gorge (Western Caucasus)
Geosciences 2022, 12(4), 175; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040175 - 15 Apr 2022
Viewed by 657
Abstract
New investigations in the Western Caucasus contribute to the understanding of granite pseudokarst (sensu lato) and megaclasts linked to river erosion. A plot on the bank of the Belaya River (Mountainous Adygeya, Western Caucasus) was selected to examine diverse and abundant pseudokarst features [...] Read more.
New investigations in the Western Caucasus contribute to the understanding of granite pseudokarst (sensu lato) and megaclasts linked to river erosion. A plot on the bank of the Belaya River (Mountainous Adygeya, Western Caucasus) was selected to examine diverse and abundant pseudokarst features (small rock basins, hollows, potholes, and channels) and large clasts. Morphological analysis of these features clarifies their general characteristics and genetic interpretations. Pseudokarst features can be classified into two major categories, namely the relatively small (<1 m) and large (>1 m) features. Potholes, which are usually 1–3 m in size, are the most characteristic features occurring on two levels, i.e., on steep walls of the gorge (half-filled with river water) and on slightly inclined surfaces of a terrace-like landform (subaerial exposure). In both cases, their walls from the side of the river are broken. Apparently, these potholes were formed on the river bottom. Subsequent incision of the gorge elevated potholes and the river has eroded them from one side. Apparently, some pseudokarst features are related to macroturbulent flood flows and granite weathering. Due to its scientific uniqueness and aesthetic attractiveness, this granite pseudokarst constitutes geoheritage, which can be exploited for the purposes of geoscience research and geotourism development. Full article
Show Figures

Figure 1

Article
Examining Rock Engineering Knowledge through a Philosophical Lens
Geosciences 2022, 12(4), 174; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040174 - 15 Apr 2022
Viewed by 681
Abstract
This paper presents a philosophical examination of classical rock engineering problems as the basis to move from traditional knowledge to radical (innovative) knowledge. While this paper may appear abstract to engineers and geoscientists more accustomed to case studies and practical design methods, the [...] Read more.
This paper presents a philosophical examination of classical rock engineering problems as the basis to move from traditional knowledge to radical (innovative) knowledge. While this paper may appear abstract to engineers and geoscientists more accustomed to case studies and practical design methods, the aim is to demonstrate how the analysis of what constitutes engineering knowledge (what rock engineers know and how they know it) should always precede the integration of new technologies into empirical disciplines such as rock engineering. We propose a new conceptual model of engineering knowledge that combines experience (practical knowledge) and a priori knowledge (knowledge that is not based on experience). Our arguments are not a critique of actual engineering systems, but rather a critique of the (subjective) reasons that are invoked when using those systems, or to defend conclusions achieved using those systems. Our analysis identifies that rock engineering knowledge is shaped by cognitive biases, which over the years have created a sort of dogmatic barrier to innovation. It therefore becomes vital to initiate a discussion on the subject of engineering knowledge that can explain the challenges we face in rock engineering design at a time when digitalisation includes the introduction of machine algorithms that are supposed to learn from conditions of limited information. Full article
(This article belongs to the Section Geomechanics)
Show Figures

Figure 1

Editorial
40 Years Later: New Perspectives on the 23 November 1980, Ms 6.9, Irpinia-Lucania Earthquake
Geosciences 2022, 12(4), 173; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040173 - 15 Apr 2022
Viewed by 849
Abstract
After more than forty years since the 1980 Irpinia-Lucania earthquake, with this Special Issue “The 23 November 1980 Irpinia-Lucania, Southern Italy Earthquake: Insights and Reviews 40 Years Later” we revisit this milestone geological and seismological event, bringing together the latest views and news [...] Read more.
After more than forty years since the 1980 Irpinia-Lucania earthquake, with this Special Issue “The 23 November 1980 Irpinia-Lucania, Southern Italy Earthquake: Insights and Reviews 40 Years Later” we revisit this milestone geological and seismological event, bringing together the latest views and news on this earthquake, with the aim of improving the dissemination of wide-ranging information on this remarkable case history [...] Full article
Show Figures

Figure 1

Article
How Greek Students Perceive Concepts Related to Geoenvironment: A Semiotics Content Analysis
Geosciences 2022, 12(4), 172; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040172 - 14 Apr 2022
Cited by 1 | Viewed by 750
Abstract
In order to design a geoeducation program in the context of the possibilities given to the Experimental Schools of Greece of Lower Secondary Education, teachers identified the need for diagnostically assess students’ understanding of basic concepts of the geoenvironment and particularly the concepts [...] Read more.
In order to design a geoeducation program in the context of the possibilities given to the Experimental Schools of Greece of Lower Secondary Education, teachers identified the need for diagnostically assess students’ understanding of basic concepts of the geoenvironment and particularly the concepts of geodiversity, geoheritage, geoethics and geotourism. In addition, there was a need to apply the educational technique of creating cognitive conflicts in order to promote the scientific perceptions of these concepts. Thus, research questions were identified which led the research to assess the current latent state of students’ perceptions regarding the thematic areas of the concepts and to identify concepts whose perceptions can be used in the educational process in order to achieve effective cognitive conflicts in order to promote scientific perceptions of them. The students briefly answered a four-question questionnaire, wherein each question examined their perceptions regarding the four concepts of geoenvironment: geodiversity, geoheritage, geoethics and geotourism. All 45 students of the geoeducation program that took part in the survey were aged between 12 and 15 years old. The qualitative research strategy approach was selected and specifically the hybrid technique of semiotics content analysis in combination with thematic analysis. This technique was selected due to the need to identify, code, categorize and count both obvious and latent meanings in the students’ written answers; these meanings were related to the four concepts under examination. The results of the research show that the current latent state of students’ perceptions regarding the thematic fields of the four concepts of the geoenvironment can be considered as particularly confused since the majority of students did not understand the concepts as they are employed in the international literature. The research also highlighted concepts that can be used by teachers in their efforts to develop students’ clear or even scientifically acceptable perceptions for the concepts of geodiversity, geoheritage, geoethics and geotourism in the thematic field of the geoenvironment. Full article
Show Figures

Figure 1

Article
Transmedia in Geosciences Education
Geosciences 2022, 12(4), 171; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040171 - 13 Apr 2022
Cited by 1 | Viewed by 743
Abstract
This paper describes a research study related to the development (conception, production, implementation and evaluation) of a set of transmedia activities associated with the study of humans ‘use of rocks. To do so, a narrative was created to guide students through a set [...] Read more.
This paper describes a research study related to the development (conception, production, implementation and evaluation) of a set of transmedia activities associated with the study of humans ‘use of rocks. To do so, a narrative was created to guide students through a set of tasks—namely, during and after a field trip. During this field trip, students had to macroscopically identify a rock sample and record its geographical location, as well as take pictures in six stations. According to the data collected, students would, after the field trip, share this knowledge in a digital learning environment and collect pieces of a puzzle and, in some cases, badges. These transmedia activities, in line with the STS (Science-Technology-Society) perspective, aimed at contributing to the diversification of educational resources for Geosciences education. The study, predominantly qualitative in nature, reached 104 students from the 7th and 5th grades in a Natural Sciences course and the analysis of data suggests that students showed some skills in areas such as “interpersonal relationships”, “scientific, technical, and technological knowledge” and “information and communication”, although in this case they can be considered rather limited. Full article
(This article belongs to the Collection Education in Geosciences)
Show Figures

Figure 1

Article
Rockfall Vulnerability of a Rural Road Network—A Methodological Approach in the Harz Mountains, Germany
Geosciences 2022, 12(4), 170; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040170 - 13 Apr 2022
Viewed by 610
Abstract
Mass movements are linked to increasing amounts of damage and disruptions to transportation infrastructures. A valid risk assessment in order to reduce future costs is not always appropriate, as adequate information on landslide data is missing. The presented study estimates the rockfall susceptibility [...] Read more.
Mass movements are linked to increasing amounts of damage and disruptions to transportation infrastructures. A valid risk assessment in order to reduce future costs is not always appropriate, as adequate information on landslide data is missing. The presented study estimates the rockfall susceptibility on a rural road network in the Harz mountains using a bivariate statistical method (information value method). The model is validated using a receiver operating characteristic (ROC) analysis. In addition, the vulnerability of the road network is estimated using vulnerability indicators. The susceptibility model assigns a high or very high susceptibility to 23% of the area in the road network corridor. The relevant road sections are linked to high slope values, NE orientations of road sections, and low-to-moderate vulnerability values. The highest vulnerability values can be found on marginal road sections with high average daily traffic volumes. The combination of the presented methods proposes an easily applicable estimate of vulnerability where conventional methods (i.e., vulnerability curves, matrices) cannot be implemented. Full article
(This article belongs to the Special Issue Landslide Monitoring and Mapping)
Show Figures

Figure 1

Article
Geoheritage and Geosites: A Bibliometric Analysis and Literature Review
Geosciences 2022, 12(4), 169; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040169 - 13 Apr 2022
Viewed by 958
Abstract
Geological heritage represents and brings together geological elements of great local and global relevance. It also promotes conservation and sustainable use. This study aims to perform a bibliometric analysis of the contributions that address the topics of geological heritage and geosites, using the [...] Read more.
Geological heritage represents and brings together geological elements of great local and global relevance. It also promotes conservation and sustainable use. This study aims to perform a bibliometric analysis of the contributions that address the topics of geological heritage and geosites, using the Scopus and Web of Science databases for the knowledge of trends and research focuses in this area. The methodology consists of: (i) the preparation of the idea and gathering information from a search on the subjects of interest (geoheritage and geosites); (ii) the merging of the databases and applying automated conversions; and (iii) the analysis of the results and the literature review. The first phase of the work identified 2409 and 1635 documents indexed in Scopus and WoS, respectively. The merged global database (2565 documents) identified the following words as analysis topics: geoconservation, geotourism, geopark, and geodiversity. The analysis also revealed the top five countries in scientific contributions as Italy (12.1%), Spain (8.77%), China (5.67%), Portugal (5.35%), and Brazil (5.31%). Finally, most of the publications focus on the characterisation, assessment, and development of geosite initiatives. The main lines of action and contributions to the topics (7.91%) highlight the fact that geoscientists worldwide value geosites for geoconservation and geotourism strategies. Full article
(This article belongs to the Special Issue Featured Papers in Geoheritage, Geoparks and Geotourism)
Show Figures

Figure 1

Review
A Review of the Studies on CO2–Brine–Rock Interaction in Geological Storage Process
Geosciences 2022, 12(4), 168; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040168 - 12 Apr 2022
Viewed by 709
Abstract
CO2–brine–rock interaction impacts the behavior and efficiency of CO2 geological storage; a thorough understanding of these impacts is important. A lot of research in the past has considered the nature and impact of CO2–brine–rock interaction and much has [...] Read more.
CO2–brine–rock interaction impacts the behavior and efficiency of CO2 geological storage; a thorough understanding of these impacts is important. A lot of research in the past has considered the nature and impact of CO2–brine–rock interaction and much has been learned. Given that the solubility and rate of mineralization of CO2 in brine under reservoir conditions is slow, free and mobile, CO2 will be contained in the reservoir for a long time until the phase of CO2 evolves. A review of independent research indicates that the phase of CO2 affects the nature of CO2–brine–rock interaction. It is important to understand how different phases of CO2 that can be present in a reservoir affects CO2–brine–rock interaction. However, the impact of the phase of CO2 in a CO2–brine–rock interaction has not been given proper attention. This paper is a systematic review of relevant research on the impact of the phase of CO2 on the behavior and efficiency of CO2 geological storage, extending to long-term changes in CO2, brine, and rock properties; it articulates new knowledge on the effect of the phase of CO2 on CO2–brine–rock behavior in geosequestration sites and highlights areas for further development. Full article
Show Figures

Figure 1

Article
Ground Displacements Estimation through GNSS and Geometric Leveling: A Geological Interpretation of the 2016–2017 Seismic Sequence in Central Italy
Geosciences 2022, 12(4), 167; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040167 - 12 Apr 2022
Viewed by 735
Abstract
Between August 2016 and January 2017, a very energetic seismic sequence induced substantial horizontal and vertical ground displacements in the Central Italian Apennines. After this event, the Italian Military Geographical Institute (IGM), owner and manager of the Italian geodetic networks, executed several topographic [...] Read more.
Between August 2016 and January 2017, a very energetic seismic sequence induced substantial horizontal and vertical ground displacements in the Central Italian Apennines. After this event, the Italian Military Geographical Institute (IGM), owner and manager of the Italian geodetic networks, executed several topographic surveys in the earthquake area in order to update the coordinates of vertices belonging to the IGM95 geodetic network. The measurements began in the areas where the most significant deformation occurred: the localities of Amatrice and Accumoli, in the Rieti Province, and the area covering Norcia and Castelluccio, in the Province of Perugia, all the way to Visso (Province of Macerata). The activities described in this paper focused on the updated measurement of the IGM95 network points through GNSS and the restatement of extensive parts of the high precision geometric lines that were levelled until reaching stable zones. This unprecedented amount of data was used for a new geological interpretation of the seismic sequence, which confirms some of the previous hypotheses of the scientific community. In the analyzed territory, the latest estimate of the geodetic position points has allowed for an accurate determination of the east and the north and of the altitude components of the displacement induced by the earthquake through a comparison with the previous coordinates. The results confirm that the seismicity was induced by normal faults system activity. Still, they also indicate the possible influence of a significant regional thrust that conditioned the propagation of the seismicity in the area. The obtained maps of the displacement are coherent with other geodetic works and with a rupture propagation driven by the documented geotectonic structure. Full article
Show Figures

Figure 1

Article
The Formation of the North Qilian Shan through Time: Clues from Detrital Zircon Fission-Track Data from Modern River Sediments
Geosciences 2022, 12(4), 166; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040166 - 07 Apr 2022
Viewed by 838
Abstract
Understanding the formation of the North Qilian Shan in the NE Tibetan Plateau provides insights into the growth mechanisms of the northern region of the plateau across time. Detrital zircon fission-track (ZFT) analyses of river sediments can provide a comprehensive understanding of the [...] Read more.
Understanding the formation of the North Qilian Shan in the NE Tibetan Plateau provides insights into the growth mechanisms of the northern region of the plateau across time. Detrital zircon fission-track (ZFT) analyses of river sediments can provide a comprehensive understanding of the exhumation history during prolonged orogenesis. Here, we applied the detrital thermochronology approach to the Qilian Shan orogenic belt. This work presents the first single-grain detrital ZFT data from river-bed sediments of the upper Hei River catchment in North Qilian Shan. The single ZFT ages are widely distributed between about 1200 Ma and about 40 Ma. These data record the protracted history of the Qilian Shan region from the Neoproterozoic evolution of Rodinia and late Paleozoic amalgamation of Central Asia to the accretion of the Gondwanian blocks during the Meso-Cenozoic era. Strong post-magmatic cooling events occurred in North Qilian Shan at 1200~1000 Ma, corresponding to the assembly of the Rodinia supercontinent. The age population at 800 Ma documents the oceanic spreading in the late Neoproterozoic dismantling of Rodinia. ZFT ages ranging from about 750 Ma to 550 Ma (with age peaks at 723 Ma and 588 Ma) are consistent with the timing of the opening and spreading of the Qilian Ocean. The age peaks at 523 Ma and 450 Ma mark the progressive closure of that ocean ending with the collision of the Qilian block with the Alxa block—North China craton in the Devonian. The Qilian Ocean finally closed in Late Devonian (age peak at 375 Ma). In the late Paleozoic (275 Ma), the subduction of the Paleotethys Ocean led to extensive magmatic activity in the North Qilian Shan. During the Lower Cretaceous (145 Ma), the accretion of the Lhasa block to the south (and potentially the closure of the Mongol-Okhotsk Ocean to the northeast) triggered a renewed tectonic activity in the Qilian Shan. Finally, a poorly defined early Eocene exhumation event (50 Ma) suggests that the NE Tibetan Plateau started to deform nearly synchronously with the onset of the India-Asia collision. This study demonstrates the usefulness of combining modern-river detrital thermo-/geochronological ages and bedrock geochronological ages to understand large-scale orogenic evolution processes. Full article
(This article belongs to the Collection Tectonic and Paleo-Landscape Evolution of the Tibetan Plateau)
Show Figures

Figure 1

Article
Oxygen Isotopes from Apatite of Middle and Late Ordovician Conodonts in Peri-Baltica (The Holy Cross Mountains, Poland) and Their Climatic Implications
Geosciences 2022, 12(4), 165; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040165 - 07 Apr 2022
Viewed by 847
Abstract
This report provides oxygen isotopes from apatite of late Middle and Late Ordovician conodonts from the southern Holy Cross Mountains in south-eastern Poland. It was a unique time interval characterised by a significant change in the Ordovician climate, tectonic, and ocean chemistry. In [...] Read more.
This report provides oxygen isotopes from apatite of late Middle and Late Ordovician conodonts from the southern Holy Cross Mountains in south-eastern Poland. It was a unique time interval characterised by a significant change in the Ordovician climate, tectonic, and ocean chemistry. In the Middle and early Late Ordovician, the Holy Cross Mountains were located in the mid-latitude climatic zone at the southwestern periphery of Baltica; therefore, the δ18Oapatite values from this region provide new data on the 18O/16O budget in the Ordovician seawater reconstructed mainly from the tropical and subtropical realms. Oxygen isotopes from mixed conodont samples were measured using the SHRIMP IIe/MC ion microprobe in the Polish Geological Institute in Warsaw. The δ18Oapatite values range from 16.75‰VSMOW to 20.66‰VSMOW with an average of 18.48‰VSMOW. The oxygen isotopes from bioapatite of the studied section display an increasing trend, suggesting a progressive decrease in sea-surface temperature roughly consistent with an overall cooling of the Ordovician climate. Two distinctive positive excursions of δ18Oapatite have been reported in the upper Sandbian and middle Katian of the studied section and correlated with cooling events recognised in Baltica. They are interpreted as an isotope temperature proxy of climate changes triggered by a growing continental polar ice cap, but increased δ18Oapatite in the late Sandbian contradicts recently postulated climate warming during that time in subtropical Laurentia. Full article
(This article belongs to the Special Issue Isotope Applied in Palaeogeography and Palaeoclimatology)
Show Figures

Figure 1

Article
Evaluating Sexual Dimorphism in Postcranial Elements of Eurasian Extinct Stephanorhinus etruscus (Falconer, 1868) (Mammalia, Rhinocerotidae)
Geosciences 2022, 12(4), 164; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040164 - 07 Apr 2022
Viewed by 896
Abstract
Sexual dimorphism has been poorly evaluated or investigated in Pleistocene Eurasian Stephanorhinus species, leaving a gap in our knowledge about their morphometric variability. Among the representatives of this genus, S. etruscus is the most abundant species, with several remains collected from Western European [...] Read more.
Sexual dimorphism has been poorly evaluated or investigated in Pleistocene Eurasian Stephanorhinus species, leaving a gap in our knowledge about their morphometric variability. Among the representatives of this genus, S. etruscus is the most abundant species, with several remains collected from Western European localities, allowing us to investigate the presence of sexual dimorphism in the limb bones of this taxon. We considered measurements taken on 45 postcranial variables and three different statistical metrics to identify patterns of bimodality in the dataset. This work represents the first application of sex-combined statistical analysis to a dataset composed of individuals from various European localities. The morphometrical analyses revealed that a relatively weak sexual dimorphism is present in all the considered bones. Larger forelimbs and hindlimbs are interpreted as belonging to adult males of S. etruscus, similarly to what was observed in the modern Sumatran rhino, where males are a little bit larger than females. The recognition of a weak sexual dimorphism in the postcranial bones of S. etruscus increases our understanding of the paleoecology of this extinct taxon. However, only a better study of the morphological and morphometrical variability of the crania of fossil rhinoceroses could deeply contribute to the investigation of the social habits and behavior of these taxa. Full article
(This article belongs to the Section Sedimentology, Stratigraphy and Palaeontology)
Show Figures

Figure 1

Article
Quantifying Strombolian Activity at Etna Volcano
Geosciences 2022, 12(4), 163; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040163 - 06 Apr 2022
Viewed by 914
Abstract
Understanding the dynamics of mild explosive activity is a fundamental tool for hazard assessment at open conduit volcanoes. This is a particularly critical task for Etna volcano. Etna is in fact characterized by frequent, mild explosive activity, punctuated by lava flows and paroxysmal [...] Read more.
Understanding the dynamics of mild explosive activity is a fundamental tool for hazard assessment at open conduit volcanoes. This is a particularly critical task for Etna volcano. Etna is in fact characterized by frequent, mild explosive activity, punctuated by lava flows and paroxysmal events (‘lava fountains’), which, because of their greater impact, have been the main target for hazard studies, whereas more frequent Strombolian activity has been overlooked. As a result, their impact and associated hazards have been never quantified, despite the extensive monitoring and surveillance activities carried out on this volcano. In this paper, we analyze video recordings of a sequence of Strombolian explosions occurring at the summit craters of Mt. Etna, in Italy, in February 2020. Data were also integrated with a petrographic analysis of collected samples, and drone surveys were performed at the same time as the video recordings. We estimate the frequency of explosions (20–12 per min); particle exit speeds (1–50 m/s), and erupted mass (100–102 kg) of those explosions. A very regular, small-scale activity (marked by a single burst of gas breaking the magma free surface into bombs and lapilli fragments) was occasionally punctuated by larger explosions, (at least one every 5 min), with a longer duration, fed by larger magma volumes, and consisting of two to three distinct pulses followed by a stationary phase. We found that the repose times between explosions follows a log logistic distribution, which is in agreement with the behavior of open vent explosive activity. The four largest explosions of the sequence were analyzed in detail: they emitted particles with median diameters (Mdphi) ranging from −10.1 to −8.8 phi, with bimodal distributions. Full article
(This article belongs to the Special Issue Magma Degassing from Magma at Depth to the Surface)
Show Figures

Figure 1

Article
Suitability of Screened Monitoring Wells for Temperature Measurements Regarding Large-Scale Geothermal Collector Systems
Geosciences 2022, 12(4), 162; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040162 - 04 Apr 2022
Viewed by 672
Abstract
Groundwater temperature (GWT) is usually measured using screened monitoring wells (MWs). The aim of this study was to investigate whether MWs are suitable for monitoring the effects of large-scale geothermal collector systems (LSCs) on GWT, focusing on possible vertical flows within the MWs [...] Read more.
Groundwater temperature (GWT) is usually measured using screened monitoring wells (MWs). The aim of this study was to investigate whether MWs are suitable for monitoring the effects of large-scale geothermal collector systems (LSCs) on GWT, focusing on possible vertical flows within the MWs due to both natural and forced convection. Comparative temperature depth profiles were therefore recorded over a period of nine months in both shallow MWs and in small-diameter, non-screened temperature monitoring stations (TMSs), each of which was installed in a single borehole. Particularly high temperature deviations were measured in MWs in the upper part of the water column where the GWT reached up to 1.8 K warmer than in the surrounding subsurface. These deviations correlate unambiguously with the prevailing positive thermal gradients and are caused by thermal convection. Where forced convection occurred, the GWT was measured to be up to 0.8 K colder. Potential temperature deviations must be considered when monitoring very shallow GWT as thermal gradients can be particularly high in these zones. For monitoring concepts of LSCs, a combination of MW and TMS is proposed for GWT measurements decoupled by the effects of convection and in order to enable further investigations such as pumping tests. Full article
(This article belongs to the Section Hydrogeology)
Show Figures

Figure 1

Article
Cretaceous Dinosaurs across Alaska Show the Role of Paleoclimate in Structuring Ancient Large-Herbivore Populations
Geosciences 2022, 12(4), 161; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040161 - 02 Apr 2022
Viewed by 2586
Abstract
The partially correlative Alaskan dinosaur-bearing Prince Creek Formation (PCF), North Slope, lower Cantwell Formation (LCF), Denali National Park, and Chignik Formation (CF), Aniakchak National Monument, form an N–S transect that, together, provides an unparalleled opportunity to examine an ancient high-latitude terrestrial ecosystem. The [...] Read more.
The partially correlative Alaskan dinosaur-bearing Prince Creek Formation (PCF), North Slope, lower Cantwell Formation (LCF), Denali National Park, and Chignik Formation (CF), Aniakchak National Monument, form an N–S transect that, together, provides an unparalleled opportunity to examine an ancient high-latitude terrestrial ecosystem. The PCF, 75–85° N paleolatitude, had a Mean Annual Temperature (MAT) of ~5–7 °C and a Mean Annual Precipitation (MAP) of ~1250 mm/year. The LCF, ~71° N paleolatitude, had a MAT of ~7.4 °C and MAP of ~661 mm/year. The CF, ~57° N paleolatitude, had a MAT of ~13 °C and MAP of ~1090 mm/year. The relative abundances of the large-bodied herbivorous dinosaurs, hadrosaurids and ceratopsids, vary along this transect, suggesting that these climatic differences (temperature and precipitation) played a role in the ecology of these large-bodied herbivores of the ancient north. MAP played a more direct role in their distribution than MAT, and the seasonal temperature range may have played a secondary role. Full article
Show Figures

Figure 1

Article
Three-Dimensional Numerical Modeling of Flow Hydrodynamics and Cohesive Sediment Transport in Enid Lake, Mississippi
Geosciences 2022, 12(4), 160; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040160 - 02 Apr 2022
Viewed by 779
Abstract
Enid Lake is one of the largest reservoirs located in Yazoo River Basin, the largest basin in the state of Mississippi. The lake was impounded by Enid Dam on the Yocona River in Yalobusha County and covers an area of 30 square kilometers. [...] Read more.
Enid Lake is one of the largest reservoirs located in Yazoo River Basin, the largest basin in the state of Mississippi. The lake was impounded by Enid Dam on the Yocona River in Yalobusha County and covers an area of 30 square kilometers. It provides significant natural and recreational resources. The soils in this region are highly erodible, resulting in a large amount of fine-grained cohesive sediment discharged into the lake. In this study, a 3D numerical model was developed to simulate the free surface hydrodynamics and transportation of cohesive sediment with a median diameter of 0.0025 to 0.003 mm in Enid Lake. Flow fields in the lake are generally induced by wind and upstream river inflow, and the sediment is also introduced from the inflow during storm events. The general processes of sediment flocculation and settling were considered in the model, and the erosion rate and deposition rate of cohesive sediment were calculated. In this model, the sediment simulation was coupled with flow simulation. In this research, remote sensing technology was applied to estimate the sediment concentration at the lake surface and provide validation data for numerical model simulation. The model results and remote sensing data help us to understand the transport, deposition and resuspension processes of cohesive sediment in large reservoirs due to wind-induced currents and upstream river flows. Full article
(This article belongs to the Special Issue Recent Advances on Sediment Transport and River Morphodynamics)
Show Figures

Figure 1

Article
Uses of Sentinel-1 and -2 Images in Heritage Management: A Case Study from Lednica Landscape Park (Poland)
Geosciences 2022, 12(4), 159; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040159 - 01 Apr 2022
Viewed by 791
Abstract
This article aims to demonstrate the use of Sentinel images to develop strategies for heritage protection and management in rural landscapes that are currently undergoing dynamic transformations. Construction works are causing rapid and extensive land use changes that threaten archaeological structures. Moreover, the [...] Read more.
This article aims to demonstrate the use of Sentinel images to develop strategies for heritage protection and management in rural landscapes that are currently undergoing dynamic transformations. Construction works are causing rapid and extensive land use changes that threaten archaeological structures. Moreover, the modernisation of farming practices may also negatively affect the efficiency of archaeological prospection. The rapidity of those processes requires the application of relevant tools to monitor changes and highlight negative tendencies in areas surrounding archaeological sites. High frequency of Sentinel-1 and -2′s acquisition may offer an immediate insight into current tendencies. Radar and optical data obtained from those satellites between 2016 and 2020 were analysed to identify trends in building development and land use/cover changes in Lednica Landscape Park. Preliminary results indicate a considerable potential of spectral analysis based on Sentinel-2 to monitor changes related to building development, as well as for the precise planning of a field survey. Sentinel-1 proved more problematic due to a range of factors related to data characteristics and processing. Using those results, we will discuss the potential and limitations of the proposed methodology and data. Full article
Show Figures

Figure 1

Article
Evaluating the Existence of Vertebrate Deadfall Communities from the Early Jurassic Posidonienschiefer Formation
Geosciences 2022, 12(4), 158; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040158 - 01 Apr 2022
Viewed by 1525
Abstract
Large vertebrate carcasses contain significant amounts of nutrients that upon death are transferred from the water column to the benthos, enriching the immediate environment. The organisms exploiting these ephemeral resources vary as the carcass decays, creating an ecological succession: mobile scavengers arrive first, [...] Read more.
Large vertebrate carcasses contain significant amounts of nutrients that upon death are transferred from the water column to the benthos, enriching the immediate environment. The organisms exploiting these ephemeral resources vary as the carcass decays, creating an ecological succession: mobile scavengers arrive first, followed by enrichment opportunists, sulfophilic taxa, and lastly reef species encrusting the exposed bones. Such communities have been postulated to subsist on the carcasses of Mesozoic marine vertebrates, but are rarely documented in the Jurassic. In particular, these communities are virtually unknown from the Early Jurassic, despite the occurrence of several productive fossil Lagerstätte that have produced thousands of vertebrate bones and skeletons. We review published occurrences and present new findings related to the development of deadfall communities in the Toarcian Posidonienschiefer Formation of southwestern Germany, focusing on the classic locality of Holzmaden. We report the presence of the mobile scavenger, enrichment opportunist, and reef stages, and found potential evidence for the poorly documented sulfophilic stage. Although rare in the Posidonienschiefer Formation, such communities do occur in association with exceptionally preserved vertebrate specimens, complementing a growing body of evidence that a temporarily oxygenated benthic environment does not preclude exceptional vertebrate fossil preservation. Full article
(This article belongs to the Special Issue Jurassic Paleoenvironments)
Show Figures

Figure 1

Article
Mantle Xenoliths from Huanul Volcano (Central-West Argentina): A Poorly Depleted Mantle Source under Southern Payenia
Geosciences 2022, 12(4), 157; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040157 - 01 Apr 2022
Viewed by 781
Abstract
Huanul is a shield volcano with several lava flows hosting mantle xenoliths erupted during the Pleistocene (0.84 ± 0.05 Ma). It is located in the southern part of the Payenia Volcanic Province, which is among the largest Neogene-Quaternary volcanic provinces of South America. [...] Read more.
Huanul is a shield volcano with several lava flows hosting mantle xenoliths erupted during the Pleistocene (0.84 ± 0.05 Ma). It is located in the southern part of the Payenia Volcanic Province, which is among the largest Neogene-Quaternary volcanic provinces of South America. The volcanism here has been ascribed as the northernmost expression of the back-arc volcanism of the Andean Southern Volcanic Zone. We present the first petrographic and mineral chemistry study of mantle xenoliths collected from Huanul lavas with the aim of reconstructing directly the mantle source of the Payenia Volcanic Province. Xenoliths are commonly small (<5 cm in radius) but scarcely crossed by basaltic veins. All xenoliths have a fertile lherzolitic modal composition and are equilibrated in the spinel-facies. Most of them exhibit an almost primitive-mantle geochemical affinity, characterized by slightly depleted clinopyroxene REE patterns reproducible by partial melting degrees between 0 and 4% of a PM source. Geothermobarometric P-T estimates of clinopyroxene-orthopyroxene couples form a linear trend between 10 and 24 kbar with constant increase of T from 814 to 1170 °C along a 50–60 mW/m2 geotherm. Evidences of interaction with the host basalts occur as spongy textures in clinopyroxene and reacted spinel, which tend to became more restitic in composition and show chromatographic or complete overprinting of the trace element compositions. The presence of plagioclase and calculated P-T values constrain this melt/rock reaction process between 6 and 14 kbar, during magma ascent, and fit the mantle adiabat model. Calculated melts in equilibrium with the primary clinopyroxenes do not fit the composition of the host basalt and, together with the geothermobarometric estimations, point to an asthenospheric mantle source for the magmatism in southern Payenia. The PM geochemical affinity of the xenoliths of Huanul is an extremely rare finding in the South America lithospheric mantle, which is commonly extensively refertilized by subduction-derived melts. Full article
Show Figures

Figure 1

Article
Multidecadal Land-Use Changes and Implications on Soil Protection in the Calore River Basin Landscape (Southern Italy)
Geosciences 2022, 12(4), 156; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040156 - 01 Apr 2022
Cited by 1 | Viewed by 652
Abstract
In Southern Italy, studies dealing with the analysis of multidecadal land-use changes at the basin scale are scarce. This is an important gap, considering the deep interrelationships between land-use changes, soil erosion, and river dynamics, and hazards at the basin scale and the [...] Read more.
In Southern Italy, studies dealing with the analysis of multidecadal land-use changes at the basin scale are scarce. This is an important gap, considering the deep interrelationships between land-use changes, soil erosion, and river dynamics, and hazards at the basin scale and the proneness of Southern Italy to desertification. This study provides a contribution in filling this gap by analyzing the land-use changes occurring in an inner area of Southern Italy, i.e., the Calore River basin, between 1960 and 2018. Working to this aim, we conducted a GIS-aided comparison and analysis of three land-use maps of the study area from 1960, 1990, and 2018, respectively. We analyzed land-use changes at the basin, physiographic unit, and land-use class scale. We also interpreted the results in terms of variations in soil protection against erosion. Most of the detected land-use changes occurred between 1960 and 1990 and mainly consisted of the afforestation of agricultural lands. The latter was mainly concentrated in the alluvial plains and, to a lesser extent, on mountainous reliefs. In contrast, between 1990 and 2018, the land-use remained unchanged in more than 90% of the studied landscape. Artificial surfaces increased by about six times over a period of ~60 years; notwithstanding, they currently occupy about 4% of the basin area. The detected changes led to an overall increase in soil protection against erosion at the basin scale. Full article
Show Figures

Figure 1

Article
3D Engineering Geological Modeling to Investigate a Liquefaction Site: An Example in Alluvial Holocene Sediments in the Po Plain, Italy
Geosciences 2022, 12(4), 155; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040155 - 29 Mar 2022
Viewed by 880
Abstract
Liquefaction-induced surface manifestations are the result of a complex geological–geotechnical phenomenon, driven by several controlling factors. We propose a multidisciplinary methodological approach, involving engineering geologists, geomorphologists, sedimentologists, and geotechnical engineers, to build a 3D engineering geological model for liquefaction assessment studies. The study [...] Read more.
Liquefaction-induced surface manifestations are the result of a complex geological–geotechnical phenomenon, driven by several controlling factors. We propose a multidisciplinary methodological approach, involving engineering geologists, geomorphologists, sedimentologists, and geotechnical engineers, to build a 3D engineering geological model for liquefaction assessment studies. The study area is Cavezzo (Po Plain, Italy), which is a municipality hit by superficial liquefaction manifestations during the Emilia seismic crisis of May–June 2012. The site is characterized by a Holocene alluvial sequence of the floodplain, fluvial channel, and crevasse splay deposits prone to liquefaction. The integration of different geotechnical investigations, such as boreholes, CPTm, CPTu, and laboratory tests, allowed us to recognize potentially liquefiable lithological units, crucial for hazard assessment studies. The resulting 3D engineering geological model reveals a strict correlation of co-seismic surface manifestations with buried silty sands and sandy silts within the shallow 10 m in fluvial channel setting, which is capped and laterally confined by clayey and silty deposits. Full article
(This article belongs to the Special Issue Assessment of Earthquake-Induced Soil Liquefaction Hazard)
Show Figures

Figure 1

Article
Early Evolution of the Adelaide Superbasin
Geosciences 2022, 12(4), 154; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040154 - 29 Mar 2022
Viewed by 1529
Abstract
Continental rifts have a significant role in supercontinent breakup and the development of sedimentary basins. The Australian Adelaide Superbasin is one of the largest and best-preserved rift systems that initiated during the breakup of Rodinia, yet substantial challenges still hinder our understanding of [...] Read more.
Continental rifts have a significant role in supercontinent breakup and the development of sedimentary basins. The Australian Adelaide Superbasin is one of the largest and best-preserved rift systems that initiated during the breakup of Rodinia, yet substantial challenges still hinder our understanding of its early evolution and place within the Rodinian supercontinent. In the past decade, our understanding of rift and passive margin development, mantle plumes and their role in tectonics, geodynamics of supercontinent breakup, and sequence stratigraphy in tectonic settings has advanced significantly. However, literature on the early evolution of the Adelaide Superbasin has not been updated to reflect these advancements. Using new detrital zircon age data for provenance, combined with existing literature, we examine the earliest tectonic evolution of the Adelaide Superbasin in the context of our modern understanding of rift system development. A new maximum depositional age of 893 ± 9 Ma from the lowermost stratigraphic unit provides a revised limit on the initiation of sedimentation and rifting within the basin. Our model suggests that the basin evolved through an initial pulse of extension exploiting pre-existing crustal weakness to form half-grabens. Tectonic quiescence and stable subsidence followed, with deposition of a sourceward-shifting facies tract. Emplacement and extrusion of the Willouran Large Igneous Province occurred at c. 830 Ma, initiating a new phase of rifting. This rift renewal led to widespread extension and subsidence with the deposition of the Curdimurka Subgroup, which constitutes the main cyclic rift sequence in the Adelaide Superbasin. Our model suggests that the Adelaide Superbasin formed through rift propagation to an apparent triple junction, rather than apical extension outward from this point. In addition, we provide evidence suggesting a late Mesoproterozoic zircon source to the east of the basin, and show that the lowermost stratigraphy of the Centralian Superbasin, which is thought to be deposited coevally, had different primary detrital sources. Full article
(This article belongs to the Collection Detrital Minerals: Their Application in Palaeo-Reconstruction)
Show Figures

Figure 1

Article
Numerical Modelling of Reactive Flows through Porous Media
Geosciences 2022, 12(4), 153; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040153 - 28 Mar 2022
Viewed by 699
Abstract
We consider a lattice Boltzmann (LB) model to solve the coupled Navier–Stokes and advection–diffusion equation with reactive boundary conditions at the interface between fluid and solid domains. The reactive boundary condition results in the position of the boundary changing continuously, and so boundary [...] Read more.
We consider a lattice Boltzmann (LB) model to solve the coupled Navier–Stokes and advection–diffusion equation with reactive boundary conditions at the interface between fluid and solid domains. The reactive boundary condition results in the position of the boundary changing continuously, and so boundary nodes may be partially filled with fluid at any instant. We develop the LB boundary conditions for both the velocity and concentration fields in the presence of partially filled boundary nodes and then validate this algorithm on some test cases—the Stefan problem for diffusion-dominated dissolution and kinetic-dominated dissolution. It is shown that the developed model agrees well with analytic results, so that they can be used for more general boundaries of arbitrary shape. Numerical simulations in three dimensions are then carried out on demonstration problems at various Peclet numbers to elucidate the transport mechanisms and their influence on solid grain dissolution. Full article
(This article belongs to the Special Issue Digital Rock Analysis)
Show Figures

Figure 1

Opinion
Viewpoint on the Integration of Geochemical Processes into Tracer Transport Models for the Marine Environment
Geosciences 2022, 12(4), 152; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040152 - 28 Mar 2022
Viewed by 626
Abstract
Two types of models are used to describe the interactions of tracers dissolved in the ocean with marine sediments: equilibrium and dynamic models. A brief description of these models is given in this opinion paper, and some examples are presented to show that [...] Read more.
Two types of models are used to describe the interactions of tracers dissolved in the ocean with marine sediments: equilibrium and dynamic models. A brief description of these models is given in this opinion paper, and some examples are presented to show that preference should be given to the dynamic descriptions in modern pollutant transport models to be used in emergencies as well as in the case of chronic tracer releases to the sea. Full article
Show Figures

Figure 1

Article
Foredune and Beach Dynamics on the Southern Shores of Lake Michigan during Recent High Water Levels
Geosciences 2022, 12(4), 151; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040151 - 28 Mar 2022
Viewed by 654
Abstract
From 18 January 2013 (175.16 m a.s.l.) to 8 September 2020 (177.82 m a.s.l.), Lake Michigan experienced its fastest and highest rise (2.67 m) since 1860, when instrumental measurements began. Extensive foredunes developed since the last high lake levels began eroding in 1997 [...] Read more.
From 18 January 2013 (175.16 m a.s.l.) to 8 September 2020 (177.82 m a.s.l.), Lake Michigan experienced its fastest and highest rise (2.67 m) since 1860, when instrumental measurements began. Extensive foredunes developed since the last high lake levels began eroding in 1997 at fast rates. This study focuses on coastal morphodynamics along the 800 m coast within the central Indiana Dunes State Park on Lake Michigan’s southern shores during this time. Severe foredune erosion, in terms of total horizontal dune loss and total volume of eroded sand, occurred unevenly over the three-year period, both temporally, during a single storm, a season, a year, or three years, and spatially, in the eastern, central, and western study areas. Late autumn storms accounted for most foredune erosion in 2018 and 2019, when foredune scarps retreated up to 4 and 9 m, respectively. Erosion was highest in the updrift eastern study area, where about 8 m3/m of sand was removed in 2018 and about 19 m3/m of sand was removed in 2019. The lack of shelf ice along the shore, rising lake levels, and convective storms that triggered meteotsunamis changed the foredune erosion pattern in 2020. Erosion became most vigorous in the downdrift central (13 m scarp retreat) and western (11 m scarp retreat) study areas. The average volume of eroded sand (21.5 m3/m) was more than double that of 2019 (8 m3/m), and almost quadruple the 2018 volume (5.5 m3/m). After foredune erosion events, the beach rapidly recovered and maintained its width as the shoreline migrated landward. On many occasions following these severe erosion events the dry portion of the beach aggraded and absorbed significant sand amounts removed from the foredunes. The remaining sand was transferred to the surf zone, where it changed the sand bar morphology and led to their coalescence and flattening. Full article
(This article belongs to the Special Issue Advanced Research in Coastal Morphodynamics)
Show Figures

Figure 1

Article
Stress-Dependent Permeability of Naturally Micro-Fractured Shale
Geosciences 2022, 12(4), 150; https://0-doi-org.brum.beds.ac.uk/10.3390/geosciences12040150 - 27 Mar 2022
Viewed by 724
Abstract
The permeability characteristics of natural fracture systems are crucial to the production potential of shale gas wells. To investigate the permeability behavior of a regional fault that is located within the Wufeng Formation, China, the gas permeability of shale samples with natural micro-fractures [...] Read more.
The permeability characteristics of natural fracture systems are crucial to the production potential of shale gas wells. To investigate the permeability behavior of a regional fault that is located within the Wufeng Formation, China, the gas permeability of shale samples with natural micro-fractures was measured at different confining pressures and complemented with helium pycnometry for porosity, computed micro-tomographic (µCT) imaging, and a comparison with well testing data. The cores originated from a shale gas well (HD-1) drilled at the Huayingshan anticline in the eastern Sichuan Basin. The measured Klinkenberg permeabilities are in the range between 0.059 and 5.9 mD, which roughly agrees with the permeability of the regional fault (0.96 mD) as estimated from well HD-1 productivity data. An extrapolation of the measured permeability to reservoir pressures in combination with the µCT images shows that the stress sensitivity of the permeability is closely correlated to the micro-fracture distribution and orientation. Here, the permeability of the samples in which the micro-fractures are predominantly oriented along the flow direction is the least stress sensitive. This implies that tectonic zones with a large fluid potential gradient can define favorable areas for shale gas exploitation, potentially even without requirements for hydraulic fracture treatments. Full article
(This article belongs to the Section Geomechanics)
Show Figures

Figure 1

Previous Issue
Next Issue
Back to TopTop