Geosciences

23 pages, 6804 KiB

Open AccessArticle

Mineralogy, Geochemistry and Fluid Inclusion Study of the Stibnite Vein-Type Mineralization at Rizana, Northern Greece

by Christos L. Stergiou, Grigorios-Aarne Sakellaris, Vasilios Melfos, Panagiotis Voudouris, Lambrini Papadopoulou, Nikolaos Kantiranis and Evaggelos Skoupras

Geosciences 2023, 13(2), 61; https://doi.org/10.3390/geosciences13020061 - 17 Feb 2023

Cited by 2 | Viewed by 1804

Abstract

The stibnite mineralization at Rizana (Kilkis ore district; Serbo-Macedonian metallogenic province; northern Greece) occurs along a NE–SW-trending brittle shear-zone, which transects a two-mica and an augen-gneiss of the Vertiskos Unit. Barren Triassic A-type granites and satellite pegmatites and aplites, as well as Oligocene-Miocene [...] Read more.

The stibnite mineralization at Rizana (Kilkis ore district; Serbo-Macedonian metallogenic province; northern Greece) occurs along a NE–SW-trending brittle shear-zone, which transects a two-mica and an augen-gneiss of the Vertiskos Unit. Barren Triassic A-type granites and satellite pegmatites and aplites, as well as Oligocene-Miocene plutonic, subvolcanic and volcanic rocks that are variably hydrothermally altered and mineralized, outcrop in the broader region. The mineralization appears as veins, discordant lodes and disseminations. Veins and discordant lodes exhibit massive and brecciated textures. Historic underground mining (1930s–1950s) produced 9000 t of stibnite ore, grading 40% Sb on average. The main ore mineral assemblage includes stibnite + berthierite + sphalerite + pyrite + chalcopyrite + native antimony and traces of wolframite, galena, tetrahedrite, marcasite, pyrrhotite, arsenopyrite, realgar, native arsenic and native gold. Quartz, minor barite and ankerite are the gangue minerals. Sericitization and silicification developed along the shear-zone, forming hydrothermal halos of moderate intensity in the two-mica gneiss. Locally, valentinite, goethite and claudetite are present due to the supergene oxidation of the stibnite mineralization. Bulk ore geochemistry shows enrichments in specific elements including As, Au, Cd, Se, Tl and W. Fluid inclusion microthermometry showed that the mineralization was formed under a limited range of temperatures and salinities. The fluids had low to slightly moderate salinities (6.6–8.1 wt% equiv. NaCl) with low homogenization temperatures (217–254 °C, with a maximum at 220 °C). Full article

(This article belongs to the Collection Geological Features on Magmatic–Hydrothermal Mineralization)

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24 pages, 44222 KiB

Open AccessArticle

Hydrodynamic Processes Controlling Sand Bank Mobility and Long-Term Base Stability: A Case Study of Arklow Bank

by Shauna Creane, Michael O’Shea, Mark Coughlan and Jimmy Murphy

Geosciences 2023, 13(2), 60; https://doi.org/10.3390/geosciences13020060 - 17 Feb 2023

Cited by 2 | Viewed by 2143

Abstract

Offshore sand banks are an important resource for coastal protection, marine aggregates, and benthic habitats and are the site of many offshore wind farms. Consequently, a comprehensive understanding of the baseline processes controlling sand bank morphodynamics is imperative. This knowledge will aid the [...] Read more.

Offshore sand banks are an important resource for coastal protection, marine aggregates, and benthic habitats and are the site of many offshore wind farms. Consequently, a comprehensive understanding of the baseline processes controlling sand bank morphodynamics is imperative. This knowledge will aid the development of a long-term robust marine spatial plan and help address the environmental instability arising from anthropogenic activities. This study uses a validated, dynamically coupled, two-dimensional hydrodynamic and sediment transport model to investigate the hydrodynamic processes controlling the highly mobile upper layer of Arklow Bank, while maintaining overall long-term bank base stability. The results reveal a flood and ebb tidal current dominance on the west and east side of the bank, respectively, ultimately generating a large anticlockwise residual current eddy encompassing the entire bank. This residual current flow distributes sediment along the full length of the sand bank. The positioning of multiple off-bank anticlockwise residual current eddies on the edge of this cell is shown to influence east–west fluctuations of the upper slopes of the sand bank and act as a control on long-term stability. These off-bank eddies facilitate this type of movement when the outer flows of adjacent eddies, located on both sides of the bank, flow in a general uniform direction. Whereas they inhibit this east–west movement when the outer flows of adjacent eddies, on either side of the bank, flow in converging directions towards the bank itself. These residual eddies also facilitate sediment transport in and out of the local sediment transport system. Within Arklow Bank’s morphological cell, eight morphodynamically and hydrodynamically unique bank sections or ‘sub-cells’ are identified, whereby a complex morphodynamic–hydrodynamic feedback loop is present. The local east–west fluctuation of the upper slopes of the bank is driven by migratory on-bank stationary and transient clockwise residual eddies and the development of ‘narrow’ residual current cross-flow zones. Together, these processes drive upper slope mobility but maintain long-term bank base stability. This novel understanding of sand bank morphodynamics is applicable to bedforms in tidally dominated continental shelf seas outside the Irish Sea. Full article

(This article belongs to the Special Issue Seabed Morphodynamics)

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21 pages, 5996 KiB

Open AccessEditor’s ChoiceReview

Shoreline Change and Coastal Erosion in West Africa: A Systematic Review of Research Progress and Policy Recommendation

by Johnson Ankrah, Ana Monteiro and Helena Madureira

Geosciences 2023, 13(2), 59; https://doi.org/10.3390/geosciences13020059 - 17 Feb 2023

Cited by 8 | Viewed by 3510

Abstract

Shoreline change and coastal erosion resulting from natural events such as sea level rise and negative anthropogenic activities continue to be problems in many of the world’s coastal regions. Many coastal socio-ecological systems have become vulnerable as a result, especially in developing countries [...] Read more.

Shoreline change and coastal erosion resulting from natural events such as sea level rise and negative anthropogenic activities continue to be problems in many of the world’s coastal regions. Many coastal socio-ecological systems have become vulnerable as a result, especially in developing countries with less adaptive capacity. We utilized the systematic method to understand the research progress and policy recommendations on shoreline change and coastal erosion in West Africa. A total of 113 documents were retrieved from Scopus and the Web of Sciences databases, and 43 documents were eligible following established criteria. It was revealed that research on shoreline change and coastal erosion has progressed substantially since 1998, with most research studies originating from the Ghanaian territory. Again, most of the shoreline change and erosion problems in West Africa result from natural events such as sea level rise. However, there was evidence of anthropogenic influences such as sand mining, dam construction, and human encroachment causing shoreline change and erosion in the region. Research in the region has also progressed in terms of methodological approaches. Since 2004, researchers have utilized remote sensing and GIS techniques to source and analyze shoreline change and erosion. However, a combination of remote sensing and field observation approaches is required to clearly depict the erosion problems and aid policy direction. The overall call to action regarding policy recommendations revolves around improving coastal adaptation measures and the resilience of communities, instituting proper coastal zone management plans, and improving shoreline change and coastal erosion research. To protect lives and property, policymakers in the region need to set up good coastal zone management plans, strengthen adaptation measures, and make coastal communities more resistant to possible risks. Full article

(This article belongs to the Special Issue Shoreline Dynamics and Beach Erosion, 2nd Edition)

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15 pages, 1582 KiB

Open AccessArticle

Unraveling the Arctic Sea Ice Change since the Middle of the Twentieth Century

by Nathan Kong and Wei Liu

Geosciences 2023, 13(2), 58; https://doi.org/10.3390/geosciences13020058 - 16 Feb 2023

Cited by 2 | Viewed by 1410

Abstract

Changes in Arctic sea ice since the middle of the last century are explored in this study. Both observations and climate model simulations show an overall sea ice expansion during 1953–1970 but a general sea ice decline afterward. Anthropogenic aerosols, nature forcing and [...] Read more.

Changes in Arctic sea ice since the middle of the last century are explored in this study. Both observations and climate model simulations show an overall sea ice expansion during 1953–1970 but a general sea ice decline afterward. Anthropogenic aerosols, nature forcing and atmospheric ozone changes are found to contribute to the sea ice expansion in the early period. Their effects are strong generally in late boreal summer. On the other hand, greenhouse gas warming has a dominant effect on diminishing Arctic sea ice cover during 1971–2005, especially in September. Internal climate variability also plays a role in the Arctic sea ice change during 1953–1970. However, it cannot solely explain the Arctic sea ice decline since the 1970s. Full article

(This article belongs to the Special Issue Sea Ice-Ocean Interaction and Their Impacts on Climate)

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29 pages, 18804 KiB

Open AccessArticle

The Influence of the DSM Spatial Resolution in Rockfall Simulation and Validation with In Situ Data

by Maria P. Kakavas, Konstantinos G. Nikolakopoulos, Aggeliki Kyriou and Ioannis Koukouvelas

Geosciences 2023, 13(2), 57; https://doi.org/10.3390/geosciences13020057 - 14 Feb 2023

Viewed by 1581

Abstract

Remote sensing constitutes an advantageous tool towards the landslide/rockfall susceptibility mapping by incorporating optical satellite or radar data and photogrammetric data in Geographical Information System environment. A plethora of rockfall data can be derived by gigital surface models (DSMs). This article focuses on [...] Read more.

Remote sensing constitutes an advantageous tool towards the landslide/rockfall susceptibility mapping by incorporating optical satellite or radar data and photogrammetric data in Geographical Information System environment. A plethora of rockfall data can be derived by gigital surface models (DSMs). This article focuses on the effect of the spatial resolution of DSMs in rockfall investigations solely. DSMs with pixel size ranging from 5 cm to 90 m were taken into account for the study of three different rockfall events occurring in Western Greece, namely, at Moira, Myloi and Platiana settlements. Elevation profiles along the rockfall bodies were created from the diverse DSMs in GIS environment. Then, these profiles were implemented into the RocFall software for 2D rockfall simulations. The produced simulations were evaluated against their spatial resolution of DSMs and were confirmed with field observations and measurements. The ultimate scope of this paper is to conclude to the most appropriate DSM for rockfall simulations via RocFall software. It is observed that DSMs with high spatial resolution depicted a detailed and realistic topography, while DSMs with coarse/low resolution flattened the surface roughness. As rockfall simulations are linked to slope profile, this observation has an impact on RocFall outcomes. According to this study the most appropriate DSM, pertaining to this type of research, is the UAV, which produces the more accurate and realistic results. These results were assessed through the use of in situ measurements taken by the real rockfall events. Full article

(This article belongs to the Section Natural Hazards)

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23 pages, 5494 KiB

Open AccessArticle

Holocene Paleoenvironmental Implications of Diatom, Non-Pollen Palynomorph, and Organic Carbon Records from the Kandalaksha Bay of the White Sea (European Arctic)

by Yelena Polyakova, Elizaveta Agafonova, Ekaterina Novichkova and Anne de Vernal

Geosciences 2023, 13(2), 56; https://doi.org/10.3390/geosciences13020056 - 11 Feb 2023

Viewed by 1535

Abstract

Variations in sea surface conditions and sea level through the Holocene in the Kandalaksha Bay, the White Sea, were reconstructed based on the study of core sediments from the outer Kandalaksha Bay, using the modern analog technique applied to dinocysts in addition to [...] Read more.

Variations in sea surface conditions and sea level through the Holocene in the Kandalaksha Bay, the White Sea, were reconstructed based on the study of core sediments from the outer Kandalaksha Bay, using the modern analog technique applied to dinocysts in addition to diatoms, TOC, δ¹³C_org, CaCO₃, and grain size data. The chronostratigraphy of the core sediments was defined from accelerator mass spectrometry ¹⁴C dates on mollusk shells. The results indicated an increase in water depth in the outer Kandalaksha Bay and in the central Dvina Bay until the late Holocene. From about 9.5 to 7.5 cal kyr BP, the data suggested a general trend of increasing sea surface temperatures (up to 14 °C), at least in areas with inflow of Atlantic waters. The last 2.5 kyr were characterized by increased freshwater runoff to the White Sea. Full article

(This article belongs to the Special Issue Advances in Marine Geology—Selected Papers from P.P. Shirshov Institute of Oceanology, Russian Academy of Sciences)

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16 pages, 5461 KiB

Open AccessArticle

Reappraisal of Data of Hydrological Changes Associated with Some Strong Historical Italian Earthquakes

by Corrado Castellano, Luigi Cucci and Andrea Tertulliani

Geosciences 2023, 13(2), 55; https://doi.org/10.3390/geosciences13020055 - 10 Feb 2023

Cited by 1 | Viewed by 1219

Abstract

Historical seismology retrieves information about the effects of earthquakes that occurred in the past, mostly regarding the damage, but also on environmental effects. In this paper, we describe the methodology of our research on earthquake-induced hydrological effects, which have been long observed and [...] Read more.

Historical seismology retrieves information about the effects of earthquakes that occurred in the past, mostly regarding the damage, but also on environmental effects. In this paper, we describe the methodology of our research on earthquake-induced hydrological effects, which have been long observed and documented, and are among the most outstanding coseismic phenomena. The method of research follows two distinct paths, depending on whether the investigated event occurred before or after the end of the 18th Century. For the most ancient events, we present examples of historical accounts, local reports, private letters, and diaries, in which the information of interest is often hidden within broader descriptions and mentioned as a minor curiosity. On the contrary, for more recent earthquakes, the research benefits from the growing interest in naturalistic observations that marked the onset of the 19th Century, and is achieved through detailed descriptions, journals, seismic postcards, and through the first systematic collections of instrumental data. Finally, we describe a possible method of classification of the hydrological data and show an analysis of the potential applications and outcomes of this type of research. Full article

(This article belongs to the Special Issue Modern Perspectives in Historical Seismology)

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4 pages, 164 KiB

Open AccessEditorial

Editorial of Special Issue “Soil–Structure Interaction”

by Dominic E. L. Ong, Wen-Chieh Cheng and Hannah Zhou

Geosciences 2023, 13(2), 54; https://doi.org/10.3390/geosciences13020054 - 10 Feb 2023

Viewed by 1097

Abstract

In today’s world, construction projects tend to be more complex due to one or a combination of the following reasons: climate change impacting design requirements; enhanced material properties; the scarcity of greenfield sites in highly built-up cities, leading to challenging underground construction; easily [...] Read more.

In today’s world, construction projects tend to be more complex due to one or a combination of the following reasons: climate change impacting design requirements; enhanced material properties; the scarcity of greenfield sites in highly built-up cities, leading to challenging underground construction; easily accessible scientific knowledge; the prowess of computational speed; the advent of new technologies driving innovation; and stringent health and safety requirements to safeguard the public [...] Full article

(This article belongs to the Special Issue Soil-Structure Interaction)

11 pages, 3820 KiB

Open AccessArticle

The Extent of Glaciation in the Pechora Sea, Eurasian Arctic, Based on Submarine Glacial Landforms

by Sergey Nikiforov, Roman Ananiev, Martin Jakobsson, Evgeny Moroz, Sergey Sokolov, Nikolay Sorokhtin, Nikolay Dmitrevsky, Elena Sukhikh, Igor Chickiryov, Yulia Zarayskaya, Anatoly Razumovskiy and Igor Semiletov

Geosciences 2023, 13(2), 53; https://doi.org/10.3390/geosciences13020053 - 09 Feb 2023

Viewed by 1613

Abstract

The Pechora Sea is optimally located for studying the coalescence of a glacial and periglacial continental shelf zone in the high Arctic. Here, we present data acquired during cruises of the RV Akademik Nikolaj Strakhov in 2018–2021, revealing the distribution of submarine glacial [...] Read more.

The Pechora Sea is optimally located for studying the coalescence of a glacial and periglacial continental shelf zone in the high Arctic. Here, we present data acquired during cruises of the RV Akademik Nikolaj Strakhov in 2018–2021, revealing the distribution of submarine glacial landforms in the central part of the Pechora shelf area. Based on moraines and the distribution of glacial lineations, the extent of the ice sheet during the Last Glacial Maximum (LGM) is proposed. The crests of the moraine ridges and the slopes of their sides express a variation in morphology, and the ridges combine into irregular complexes. The moraines are primarily composed of coarse cobble-sized material with an addition of coarse sand and other sedimentary fractions. The mapped glacial landforms clearly indicate that an ice sheet extended over the area, while the Pechora basin, at the same time, was comprised of lowland characterized by a cryogenic subaerial landscape. Based on the result from this study, the extent and ice-flow pattern of the Barents-Kara Ice Sheet during the LGM were determined. Full article

(This article belongs to the Special Issue Advances in Marine Geology—Selected Papers from P.P. Shirshov Institute of Oceanology, Russian Academy of Sciences)

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31 pages, 27108 KiB

Open AccessEditor’s ChoiceReview

The Importance of Rock Mass Damage in the Kinematics of Landslides

by Davide Donati, Doug Stead and Lisa Borgatti

Geosciences 2023, 13(2), 52; https://doi.org/10.3390/geosciences13020052 - 09 Feb 2023

Cited by 2 | Viewed by 2405

Abstract

The stability and kinematics of rock slopes are widely considered to be functions of lithological, structural, and environmental features. Conversely, slope damage features are often overlooked and considered as byproducts of slope deformation. This paper analyzes and discusses the potential role of slope [...] Read more.

The stability and kinematics of rock slopes are widely considered to be functions of lithological, structural, and environmental features. Conversely, slope damage features are often overlooked and considered as byproducts of slope deformation. This paper analyzes and discusses the potential role of slope damage, its time-dependent nature, and its control on both the stability of rock slopes and their kinematics. The analysis of several major landslides and unstable slopes, combined with a literature survey, shows that slope damage can play an important role in controlling short- and long-term slope stability. Seasonal and continuously active events cause permanent deformation within the slope due to the accumulation of slope damage features, including rock mass dilation and intact rock fracturing. Rock mass quality, lithology, and scale control the characteristics and complexity of slope damage, as well as the failure mechanism. The authors propose that the role of slope damage in slope kinematics should always be considered in slope stability analysis, and that an integrated characterization–monitoring–numerical modelling approach can enhance our understanding of slope damage, its evolution, and the controlling factors. Finally, it is emphasized that there is currently a lack of guidelines or frameworks for the quantitative assessment and classification of slope damage, which requires a multidisciplinary approach combining rock mechanics, geomorphology, engineering geology, remote sensing, and geophysics. Full article

(This article belongs to the Special Issue Landslide Behavior: From Monitoring to Kinematic Characterization through Both Traditional and Innovative Approaches)

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25 pages, 5874 KiB

Open AccessArticle

Seasonal Dynamics of Gaseous CO₂ Concentrations in a Karst Cave Correspond with Aqueous Concentrations in a Stagnant Water Column

by Holger Class, Leon Keim, Larissa Schirmer, Bettina Strauch, Kai Wendel and Martin Zimmer

Geosciences 2023, 13(2), 51; https://doi.org/10.3390/geosciences13020051 - 06 Feb 2023

Cited by 1 | Viewed by 1589

Abstract

Dissolved CO₂ in karst water is the key driving force of karstification. Replenishment of CO₂ concentrations in karst water occurs by meteoric water that percolates through the vadose zone, where CO₂ produced from microbial activity is dissolved. CO₂ can [...] Read more.

Dissolved CO₂ in karst water is the key driving force of karstification. Replenishment of CO₂ concentrations in karst water occurs by meteoric water that percolates through the vadose zone, where CO₂ produced from microbial activity is dissolved. CO₂ can thus be transported with the percolating water or in the gas phase due to ventilation in karst systems. We measured seasonally fluctuating CO₂ concentrations in the air of a karst cave and their influence on aqueous CO₂ concentrations in different depths of a stagnant water column. The observed data were compared to numerical simulations. The data give evidence that density-driven enhanced dissolution of gaseous CO₂ at the karst water table is the driving force for a fast increase of aqueous CO₂ during periods of high gaseous concentrations in the cave, whereas during periods of lower gaseous concentrations, the decline of aqueous CO₂ is limited to shallow water depths in the order of 1 m. This is significant because density-driven CO₂ dissolution has not been previously considered relevant for karst hydrology in the literature. Attempts at reproducing the measured aqueous CO₂ concentrations with numerical modeling revealed challenges related to computational demands, discretization, and the high sensitivity of the processes to tiny density gradients. Full article

(This article belongs to the Special Issue Dynamics of Hydrological and Geomorphological Processes in Karst Systems)

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17 pages, 8812 KiB

Open AccessArticle

Career in Geology: An Educational Project in Geosciences for the Enhancement of Student Learning in STEM Disciplines

by Filippo Russo and Michele Sisto

Geosciences 2023, 13(2), 50; https://doi.org/10.3390/geosciences13020050 - 06 Feb 2023

Cited by 1 | Viewed by 1502

Abstract

For about 15 years, Italian universities have been experiencing a shortage in the choice of degree programs concerning Earth Sciences, in accordance with the national trend of disaffection to STEM disciplines, both for educational reasons and because of problems in the labor market. [...] Read more.

For about 15 years, Italian universities have been experiencing a shortage in the choice of degree programs concerning Earth Sciences, in accordance with the national trend of disaffection to STEM disciplines, both for educational reasons and because of problems in the labor market. To counter this phenomenon, in 2016, the Ministry launched the National Geology Plan (NGP) through which universities interacted directly with educational institutions in their territory. Although the numbers were small, the increase in enrollment was encouraging until the 2018/2019 academic year, before the COVID-19 pandemic. The local project “GEOLAB-UNISANNIO” of the University of Sannio in Benevento is trying to implement an educational program related to STEM fields. The authors believe that either all undergraduates or the public in general would benefit from improved Geoscience education. Accordingly, the authors, as the scientific leaders of an educational program (“Career in Geology”) under the GEOLAB–UNISANNIO project, foresee the positive effects on students’ basic scientific knowledge and academic careers of this type of approach in students’ retaining. This educational program is illustrated in its articulations with the results obtained (field experiences, production of scientific reports and posters, documentaries, general satisfaction). Full article

(This article belongs to the Collection Education in Geosciences)

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20 pages, 3299 KiB

Open AccessArticle

Piuro Landslide: 3D Hydromechanical Numerical Modelling of the 1618 Event

by Andrea Morcioni, Tiziana Apuani and Francesco Cecinato

Geosciences 2023, 13(2), 49; https://doi.org/10.3390/geosciences13020049 - 05 Feb 2023

Cited by 3 | Viewed by 1651

Abstract

The Piuro 1618 landslide represents a well-known case history of a large Alpine landslide. It destroyed the ancient village of Piuro (Italian Bregaglia Valley), renowned as an important trading center between the Mediterranean region and Northern Europe. The event had a significant impact [...] Read more.

The Piuro 1618 landslide represents a well-known case history of a large Alpine landslide. It destroyed the ancient village of Piuro (Italian Bregaglia Valley), renowned as an important trading center between the Mediterranean region and Northern Europe. The event had a significant impact among communities of all Alpine regions and was well documented by chronicles and paintings during subsequent decades. However, some aspects, such as the geometry reconstruction of the landslide body, the location of the landslide scarp, and its dynamics, remained undefined in previous studies, and a geomechanical characterization of the failure area is completely missing. Using field and laboratory analysis followed by stress–strain numerical modelling, this work develops a 3D conceptual geomechanical model of the slope considering its complex geological framework. The aim is to back-analyze the 1618 event, defining predisposing and triggering factors of the sliding event, and providing verifications on the geometry and location of the failure scar, as well as on the landslide dynamics. A coupled hydro-mechanical analysis with a 3D numerical approach is presented, assuming a rainfall scenario as a possible triggering factor. Simulated displacement and the development of a deep region of shear strain localization at a depth roughly corresponding to that of the detected Piuro sliding surface, allow us to highlight the mechanical role of geological elements outcropping along the slope and to validate the proposed scenario as a likely triggering factor for the 1618 event. Full article

(This article belongs to the Special Issue Landslide Characteristics and Susceptibility Assessment)

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12 pages, 8663 KiB

Open AccessCase Report

Embankments Damaged in the Magnitude M_w 6.4 Petrinja Earthquake and Remediation

by Ivan Mihaljević and Sonja Zlatović

Geosciences 2023, 13(2), 48; https://doi.org/10.3390/geosciences13020048 - 31 Jan 2023

Viewed by 1346

Abstract

The main shock of the Petrinja earthquake occurred on 29 December 2020 with a magnitude Mw = 6.4. The earthquake and the aftershocks caused most of their damage in the alluvial plains of the rivers Kupa and Sava, where liquefaction occurred in the [...] Read more.

The main shock of the Petrinja earthquake occurred on 29 December 2020 with a magnitude Mw = 6.4. The earthquake and the aftershocks caused most of their damage in the alluvial plains of the rivers Kupa and Sava, where liquefaction occurred in the loose layers of sands and silty sands. Maybe most important was the damage to some of the embankments built in the mid-20th century to protect the area from floods. Longitudinal cracks along the embankments, in some places transverse cracks, followed by settlement, with some sandy ejecta near the embankments, were obvious consequences of liquefaction in the lower layers, and lateral spreading. The presence of the sandy layers at a depth of 6 to 8 m was known from previous investigations performed in order to improve the flood protection system. Representatives of the Croatian Waters Authorities (Hrvatske vode) who own, manage, and maintain the embankments, inspected all the embankments and, in the first days after the earthquake, carried out the necessary emergency repairs or built temporary secondary embankments. Soon after, the necessary investigation and design of the remediation began. In 2022, construction got underway. This paper gives an overview of the damage, an interpretation of the failure mechanisms, the rationale for the reconstruction methods and the solutions, together with a short overview of the liquefaction analysis performed. Full article

(This article belongs to the Special Issue Assessment of Earthquake-Induced Soil Liquefaction Hazard)

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12 pages, 2579 KiB

Open AccessArticle

Assessment of the Response of Trenched–Backfilled Pipelines to Strike-Slip Faults: An Analytical Approach

by Mozhgan Asgarihajifirouz, Xiaoyu Dong and Hodjat Shiri

Geosciences 2023, 13(2), 47; https://doi.org/10.3390/geosciences13020047 - 31 Jan 2023

Cited by 1 | Viewed by 1072

Abstract

Trenched pipelines may experience significant lateral displacement due to natural geohazards such as strike slip-fault movements, landslides, etc. Using pre-excavated soil to backfill trenches is a cost-effective option to protect pipelines against large deformations. These backfilling materials are heavily remolded and therefore softer [...] Read more.

Trenched pipelines may experience significant lateral displacement due to natural geohazards such as strike slip-fault movements, landslides, etc. Using pre-excavated soil to backfill trenches is a cost-effective option to protect pipelines against large deformations. These backfilling materials are heavily remolded and therefore softer than the native ground. Therefore, the shear strength difference between the backfill and native ground may affect the pipeline–backfill–trench interaction and the failure mechanism of the surrounding soil. By assuming a simplified uniform soil domain, the influence of softer pre-excavated backfilling material on the pipeline–backfill–trench interaction is neglected in the analytical methods that are usually used in the structural health monitoring of buried pipelines. In this study, the effects of trenching and backfilling were incorporated into an analytical solution for a fast assessment of the pipeline response at the early stages of engineering design projects and structural health monitoring. In comparison with other methods, this methodology provides a convenient and efficient method for computing pipeline strain and deflection curves in geohazardous regions. Full article

(This article belongs to the Special Issue Civil Structural Health Monitoring under Natural Hazards)

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36 pages, 14223 KiB

Open AccessArticle

Columbia River Rhyolites: Age-Distribution Patterns and Their Implications for Arrival, Location, and Dispersion of Continental Flood Basalt Magmas in the Crust

by Martin J. Streck, Vanessa M. Swenton, William McIntosh, Mark L. Ferns and Matt Heizler

Geosciences 2023, 13(2), 46; https://doi.org/10.3390/geosciences13020046 - 31 Jan 2023

Cited by 3 | Viewed by 1804

Abstract

Columbia River province magmatism is now known to include abundant and widespread rhyolite centers even though the view that the earliest rhyolites erupted from the McDermitt Caldera and other nearby volcanic fields along the Oregon–Nevada state border has persisted. Our study covers little-studied [...] Read more.

Columbia River province magmatism is now known to include abundant and widespread rhyolite centers even though the view that the earliest rhyolites erupted from the McDermitt Caldera and other nearby volcanic fields along the Oregon–Nevada state border has persisted. Our study covers little-studied or unknown rhyolite occurrences in eastern Oregon that show a much wider distribution of older centers. With our new data on distribution of rhyolite centers and ages along with literature data, we consider rhyolites spanning from 17.5 to 14.5 Ma of eastern Oregon, northern Nevada, and western Idaho to be a direct response to flood basalts of the Columbia River Basalt Group (CRBG) and collectively categorize them as Columbia River Rhyolites. The age distribution patterns of Columbia River Rhyolites have implications for the arrival, location, and dispersion of flood basalt magmas in the crust. We consider the period from 17.5 to 16.4 Ma to be the waxing phase of rhyolite activity and the period from 15.3 to 14.5 Ma to be the waning phase. The largest number of centers was active between 16.3–15.4 Ma. The existence of crustal CRBG magma reservoirs beneath rhyolites seems inevitable, and hence, rhyolites suggest the following. The locations of centers of the waxing phase imply the arrival of CRBG magmas across the distribution area of rhyolites and are thought to correspond to the thermal pulses of arriving Picture Gorge Basalt and Picture-Gorge-Basalt-like magmas of the Imnaha Basalt in the north and to those of Steens Basalt magmas in the south. The earlier main rhyolite activity phase corresponds with Grande Ronde Basalt and evolved Picture Gorge Basalt and Steens Basalt. The later main phase rhyolite activity slightly postdated these basalts but is contemporaneous with icelanditic magmas that evolved from flood basalts. Similarly, centers of the waning phase span the area distribution of earlier phases and are similarly contemporaneous with icelanditic magmas and with other local basalts. These data have a number of implications for long-held notions about flood basalt migration through time and the age-progressive Snake River Plain Yellowstone rhyolite trend. There is no age progression in rhyolite activity from south-to-north, and this places doubt on the postulated south-to-north progression in basalt activity, at least for main-phase CRBG lavas. Furthermore, we suggest that age-progressive rhyolite activity of the Snake River Plain–Yellowstone trend starts at ~12 Ma with activity at the Bruneau Jarbidge center, and early centers along the Oregon–Nevada border, such as McDermitt, belong to the early to main phase rhyolites identified here. Full article

(This article belongs to the Special Issue Continental Flood Basalt Provinces)

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27 pages, 7528 KiB

Open AccessArticle

Defining Regional and Local Sediment Sources in the Ancestral Colorado River System: A Heavy Mineral Study of a Mixed Provenance Unit in the Fish Creek-Vallecito Basin, Southern California

by Paula McGill, Uisdean Nicholson, Dirk Frei and David Macdonald

Geosciences 2023, 13(2), 45; https://doi.org/10.3390/geosciences13020045 - 31 Jan 2023

Viewed by 3481

Abstract

The Colorado River has flowed across the dextral strike-slip plate boundary between the North American and Pacific plates since the latest Miocene or earliest Pliocene. The Fish Creek-Vallecito Basin (FCVB) lies on the Pacific Plate in southern California, dextrally offset from the point [...] Read more.

The Colorado River has flowed across the dextral strike-slip plate boundary between the North American and Pacific plates since the latest Miocene or earliest Pliocene. The Fish Creek-Vallecito Basin (FCVB) lies on the Pacific Plate in southern California, dextrally offset from the point where the modern Colorado river enters the Salton Trough; it contains a record of ancestral Colorado River sedimentation from 5.3–2.5 Ma. The basin stratigraphy exhibits a changing balance between locally derived (L-Suite) and Colorado River (C-Suite) sediments. This paper focuses on the Palm Springs Group (PSG), a thick fluvial and alluvial sequence deposited on the upper delta plain (between 4.2–2.5 Ma) when the Colorado was active in the area, allowing the detailed examination of the processes of sediment mixing from two distinct provenance areas. The PSG consists of three coeval formations: 1) Canebrake Conglomerate, a basin margin that has coarse alluvial fan deposits derived from surrounding igneous basement; 2) Olla Formation, fan-fringe sandstones containing L-Suite, C-Suite, and mixed units; and 3) Arroyo Diablo Formation, mineralogically mature C-Suite sandstones. Stratigraphic analysis demonstrates that the river flowed through a landscape with relief up to 2000 m. Satellite mapping and detailed logging reveal a variable balance between the two suites in the Olla Formation with an apparent upward increase in L-Suite units before abrupt cessation of Colorado sedimentation in the basin. Stable heavy mineral indices differentiate L-Suite (high rutile:zircon index: RZi 40–95) from C-Suite (RZi: 0–20). Both suites have garnet:zircon index (GZi) and apatite:tourmaline index (ATi) mostly above 50, although many L-suite and mixed Olla samples have much lower ATi (20–50), suggesting that the distal floodplain was wet and the local sediment had a longer residence time there, or went through several cycles of erosion and redeposition. Heavy mineral analysis, garnet geochemical analysis, and detrital zircon U-Pb age spectra allow us to quantify the amount of mixing from different sediment sources. These data show that about 30% of the mixed units are derived from the Colorado River and that up to 20% of the L-Suite is also derived from the Colorado River, suggesting that there was mutual cannibalisation of older deposits by fluvial channels in a transitional area at the basin margin. Although this study is local in scope, it provides an insight into the extent and nature of sediment mixing in a two-source system. We conclude that most ‘mixing’ is actually interbedding from separate sources; true mixing is facilitated by low subsidence rates and the rapid migration of fluvial channels. Full article

(This article belongs to the Collection Detrital Minerals: Their Application in Palaeo-Reconstruction)

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21 pages, 26647 KiB

Open AccessArticle

The Lower Cretaceous “Vigla” Shales Potentiality to Be Source Rocks in the Ionian Basin, Greece

by Nicolina Bourli, Nikolaos Pasadakis, Eleni Chamilaki, Maria Sianni and Avraam Zelilidis

Geosciences 2023, 13(2), 44; https://doi.org/10.3390/geosciences13020044 - 31 Jan 2023

Cited by 1 | Viewed by 1248

Abstract

As Lower Cretaceous “Vigla” shales have been suggested as one of the main source rocks for the Ionian Basin in Greece, a geochemical analysis was performed for “Vigla” shales in Kastos Island and the Araxos peninsula, far from the already studied areas. Results, [...] Read more.

As Lower Cretaceous “Vigla” shales have been suggested as one of the main source rocks for the Ionian Basin in Greece, a geochemical analysis was performed for “Vigla” shales in Kastos Island and the Araxos peninsula, far from the already studied areas. Results, based on Rock-Eval VI analysis, sample fractionation, and biomarkers analysis, showed that the studied rocks could be of low production capacity, are type II/III of kerogen, and can produce liquid and gas hydrocarbons for Kastos Island. Organic matter (total organic carbon-TOC 0.02–3.45%) of the studied samples is thermally immature, in the early stages of diagenesis, and was accumulated in an anoxic environment. Additionally, the geochemical analyses confirmed the combination of marine and terrestrial origin of the organic matter. On the other hand, TOC (0.01–0.72%) from the Araxos peninsula shows fair oil potential and type IV kerogen. The results based on the Odd–Even Predominance, OEP (27–31), OEP (2), and OEP (1), valued for samples AG1, AG2, AG5, and AG6, indicated an anoxic deposition environment. As the Ionian Basin was sub-divided into three sub-basins (internal, middle, and external) during its syn-rift evolution, different depositional conditions were developed from one sub-basin to the other, with different sedimentary thicknesses within the same sub-basin or among different sub-basins and with different amounts of TOC. The fact that there is a great difference in geochemical indices between the two studied areas during the same period suggests that probable different depositional conditions could exist. It seems that the richness in Kastos Island could be related to the neighboring Apulian Platform, whereas the poorness in the Araxos peninsula could be related to the Gavrovo platform, or the differences could be related to restrictions produced regions. The comparison with previous studies indicates that different quality and quantity of organic matter could be accumulated either within the same sub-basin or from one sub-basin to the other. Full article

(This article belongs to the Special Issue Selected Papers from the 16th International Congress of the Geological Society of Greece—Special Session “The Hydrocarbon Prospectivity of SE Mediterranean: Targets and Opportunities”)

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17 pages, 26873 KiB

Open AccessArticle

Geomorphometric and Geophysical Constraints on Outlining Drained Shallow Mountain Mires

by Stanisław Burliga, Marek Kasprzak, Artur Sobczyk and Wioletta Niemczyk

Geosciences 2023, 13(2), 43; https://doi.org/10.3390/geosciences13020043 - 30 Jan 2023

Viewed by 1158

Abstract

Long-term draining of peatlands results in transformation of vegetation and obliteration of their morphological features. In many areas, efforts are made to restore the original ecosystems and increase their water retention potential. Using combined analyses of a LiDAR-based digital terrain model (DTM), colour-infrared [...] Read more.

Long-term draining of peatlands results in transformation of vegetation and obliteration of their morphological features. In many areas, efforts are made to restore the original ecosystems and increase their water retention potential. Using combined analyses of a LiDAR-based digital terrain model (DTM), colour-infrared (CIR) imagery data, ground-penetrating radar (GPR) data and electrical resistivity tomography (ERT) data, we tested the applicability of these methods in outlining the extent and subsurface structure of drained mires located in the Stolowe Mountains National Park area, Poland. The LiDAR-DTMs enabled parameterisation of physiographic features of the mires and determination of their extent, runoff directions and potential waterlogging areas. CIR analysis enabled classification of vegetation types. GPR prospecting revealed the bedrock morphology, thickness and internal structure of the peat deposits, showing that this technique can also provide data on variability in the decomposition of phytogenic deposits. The obtained ERT sections indicate both the thickness of peat deposits and variability in the bedrock internal structure. The results show that integrated analyses of data obtained with different methods can be an effective tool in outlining the original extent of peatlands, with potential application in the planning of peatland ecosystem restitution. Full article

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22 pages, 19331 KiB

Open AccessArticle

Impact of Dead Sea Halo-Karst Development on an Earthen Dike Rehabilitation Project

by Damien Closson, Akshay Patil, Mohamed Musthafa, Megan Gallagher and Nitin Das

Geosciences 2023, 13(2), 42; https://doi.org/10.3390/geosciences13020042 - 30 Jan 2023

Viewed by 1816

Abstract

From the 1970s, the Dead Sea experienced severe halo-karstification and anthropogenic modifications. Progressively, but at an accelerating rate, subsidence, landslides, and sinkholes have increased in number and magnitude. The hazards’ triggering factors are the terminal lake level lowering at more than one meter [...] Read more.

From the 1970s, the Dead Sea experienced severe halo-karstification and anthropogenic modifications. Progressively, but at an accelerating rate, subsidence, landslides, and sinkholes have increased in number and magnitude. The hazards’ triggering factors are the terminal lake level lowering at more than one meter per year and the dynamic equilibrium of the hydrogeological system. Over the Lisan peninsula, archived satellite images revealed the extent of the damaged areas. On 22 March 2000, the destruction of dike 19 represented a loss of 38 M USD. This is the most important event recorded since the beginning of the Dead Sea recession some 50 years ago. In 2018, a rehabilitation project of that dike started. This research analyses the viability of the reinstatement works. The advanced space borne radar interferometry technique is applied to map ground deformations before and during the project. This article reveals that the ongoing rehabilitation and reinstatement works of dike 19 are threatened by ongoing halo-karstification processes. Field observations and subsidence/uplift dynamics support this statement. The past experiences are taken into consideration to adapt industrial expansion strategies. However, the permeability of the salt pan floor could trigger a fast development of a karst system able to destroy the rehabilitated dike 19. Full article

(This article belongs to the Special Issue Dynamics of Hydrological and Geomorphological Processes in Karst Systems)

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17 pages, 5220 KiB

Open AccessArticle

Escape Mechanism with Shallow Ramp and Décollements in Southwest Taiwan

by Fang-Yi Lee, Eh Tan and Emmy T.-Y. Chang

Geosciences 2023, 13(2), 41; https://doi.org/10.3390/geosciences13020041 - 30 Jan 2023

Viewed by 1313

Abstract

The escape structure in southwest Taiwan has long been discussed. The counterclockwise rotation in GPS ground motion is argued to be evidence of tectonic escape. However, tectonic escape events worldwide are always bounded by lithosphere-cutting strike-slip faults at the boundary of the lithospheric-scale [...] Read more.

The escape structure in southwest Taiwan has long been discussed. The counterclockwise rotation in GPS ground motion is argued to be evidence of tectonic escape. However, tectonic escape events worldwide are always bounded by lithosphere-cutting strike-slip faults at the boundary of the lithospheric-scale rotating block, and these have not observed in Taiwan. In this study, we propose that the escape structure in southwest Taiwan is a thin-skinned deformation due to the open boundary in the continental slope, the ramp, and the shallow décollements. We tested this shallow escape hypothesis using a 3D numerical simulation with elastoplastic rheology. We found that a conjugate pair of forethrust and backthrust developed above the ramp. The strike and location of the forethrust mainly follow the ramp. However, the strike of the forethrust rotates perpendicular to the open boundary when in proximity. From north to south, the strike of the forethrust transfers from NNE to NE, and the deformation transfers from thrust to dextral thrust. This leads to a counterclockwise rotation in ground motion, which matches the GPS observation. This research provides a different explanation of the mechanism for the escape structure in southwest Taiwan. Full article

(This article belongs to the Topic Stochastic Geomechanics: From Experimentation to Forward Modeling)

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31 pages, 12780 KiB

Open AccessArticle

The Infierno Glacier (Pyrenees, Aragon, Spain): Evolution 2016–2022

by Luis Cancer-Pomar, Gonzalo Fernández-Jarne, José Antonio Cuchí and Javier del Valle-Melendo

Geosciences 2023, 13(2), 40; https://doi.org/10.3390/geosciences13020040 - 30 Jan 2023

Viewed by 1763

Abstract

The Infierno Glacier is located in Aragon (Spain), Pyrenees Mountain range, the only one in this country that still preserves white glaciers. These are the southernmost glaciers in Europe and are currently in rapid decline. The work analyzes the evolution of the glacier [...] Read more.

The Infierno Glacier is located in Aragon (Spain), Pyrenees Mountain range, the only one in this country that still preserves white glaciers. These are the southernmost glaciers in Europe and are currently in rapid decline. The work analyzes the evolution of the glacier between 2016 and 2022 and provides data, for this period, which lacked this information, in an area bordering the glacial ice survival. In addition to the observations on the glacier itself, the variables (precipitation, temperature, snow volume and thickness) that allow an understanding of this evolution are studied. The results show a setback of the glacier (thickness losses: 4.6 m; front retreat; 14.9 m). The evolution has frequent trend changes, linked to the interannual climatic irregularity characteristic of the Pyrenees. The main explanatory factor is the thermal increase. The thermal anomalies with respect to the average reference values have increased, in this period, by +0.55 °C. The year 2022 has been particularly warm and has recorded the greatest losses for this glacier. With respect to precipitation, it has an irregular behavior and shows a tendency to decrease (−9% in the same period). This work has the additional interest of analyzing a glacier in the terminal phase, which if current trends continue, evolves into dead ice. Full article

(This article belongs to the Special Issue Mountain Glaciers, Permafrost, and Snow)

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12 pages, 2392 KiB

Open AccessReview

Worldwide Trends in Methods and Resources Promoting Geoconservation, Geotourism, and Geoheritage

by Michael E. Quesada-Valverde and Adolfo Quesada-Román

Geosciences 2023, 13(2), 39; https://doi.org/10.3390/geosciences13020039 - 30 Jan 2023

Cited by 20 | Viewed by 2387

Abstract

This study aims to provide a systematic analysis of the literature of methods and resources supporting geoconservation and geotourism worldwide, while identifying current and future trends in the field. This paper offers a comprehensive bibliometric analysis which comprises the period of 2011–2021 after [...] Read more.

This study aims to provide a systematic analysis of the literature of methods and resources supporting geoconservation and geotourism worldwide, while identifying current and future trends in the field. This paper offers a comprehensive bibliometric analysis which comprises the period of 2011–2021 after an in-depth systematic literature review of 169 papers, using Web of Science. The volume of research on these topics is growing rapidly, especially in Italy, Poland, Brazil, Russia, and China; these constitute the most productive countries. The main identified geomorphological environments are sedimentary, volcanic, aeolian, coastal, fluvial, and karstic. We discovered that the main methods for evaluating geoconservation and geotourism are geomorphological mapping, the study of economic values for geotourism, field work as a research tool, geoheritage management, documentation, exploration, and inventories of geoheritage at a regional level. The main determined resources are UNESCO Geoparks, educational activities, digital tools, geomanagement, economic values, geoitineraries, and geoeducation programs. To our knowledge, this is the first study dealing with methods and resources publicizing geoconservation and geotourism, worldwide. Knowing about the most successful methods and resources for promoting geoconservation and geotourism can definitely be useful for future endeavors in countries where geoheritage studies are starting to be developed. Full article

(This article belongs to the Special Issue Geoheritage and Geotourism Resources: Education, Recreation, Sustainability II)

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20 pages, 4921 KiB

Open AccessArticle

Hydrogeochemical Characteristics and Isotopic Tools Used to Identify the Mineralization Processes of Bottled Mineral Water in Morocco

by Mohammad Ghalit, Mohamed Bouaissa, Elkhadir Gharibi, Jean-Denis Taupin and Nicolas Patris

Geosciences 2023, 13(2), 38; https://doi.org/10.3390/geosciences13020038 - 29 Jan 2023

Cited by 3 | Viewed by 1464

Abstract

Bottled waters are among the most important products in the human diet. In Morocco, eleven bottled mineral waters were analyzed (physicochemical composition and water stable isotopes) to identify their geologic origins and hydrochemical characteristics. The study of the ionic ratios shows that the [...] Read more.

Bottled waters are among the most important products in the human diet. In Morocco, eleven bottled mineral waters were analyzed (physicochemical composition and water stable isotopes) to identify their geologic origins and hydrochemical characteristics. The study of the ionic ratios shows that the mechanisms of water–rock interaction, such as the dissolution of carbonate and silicate minerals, influence the chemistry of these mineral waters, which are controlled by lithology and tectonics, sometimes with the influence of deep flux through fractures. The water from the Oulmes plateau shows a Na-HCO₃ chemical facies in relationship with alkaline granite. Moreover, the carbonated waters (EM_G and EM_GL) are characterized by high concentrations of Si, Li, Rb, Sr, and Cs due to deep CO₂ flux origin. The waters of Saiss, Middle Atlas, and Rif are of the Ca-HCO₃ type linked mainly to carbonate formation. The stable isotope contents of water range from −7.74 to −5.35‰ for δ¹⁸O and −45.4 to −30.4‰ for δD. The recharge altitude of the aquifer was estimated to be between 250 and 1200 m, following a δ¹⁸O altitudinal gradient between 0.25 and 0.27‰ per 100 m. The industrial production process and the natural presence or artificial addition of CO₂ can also influence the isotopic composition of water. These results can be a relevant guide to decision makers for better exploitation and assessment of the water quality. Full article

(This article belongs to the Section Hydrogeology)

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12 pages, 1493 KiB

Open AccessReview

The Status of Geoethical Thinking in the Educational System of Greece: An Overview

by Spyros Mosios, Efthymios Georgousis and Hara Drinia

Geosciences 2023, 13(2), 37; https://doi.org/10.3390/geosciences13020037 - 29 Jan 2023

Cited by 8 | Viewed by 1411

Abstract

In recent years, the concern about geoethics in Greece has begun to grow. This review aims to present the current geoethical thinking in Greece’s educational system through a thorough research of all educational levels’ curricula and the actions developed on this topic in [...] Read more.

In recent years, the concern about geoethics in Greece has begun to grow. This review aims to present the current geoethical thinking in Greece’s educational system through a thorough research of all educational levels’ curricula and the actions developed on this topic in the Greek geoscientific community. In the Greek educational reality, geoeducation is not widespread, and geoethics is used in limited school curricula. The research highlighted a significant lack of initiatives to promote geoethical thinking and the values related to geological heritage and the need to protect it. Full article

(This article belongs to the Special Issue Geoheritage and Geotourism Resources: Education, Recreation, Sustainability II)

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13 pages, 3952 KiB

Open AccessArticle

Application of Tempe Cell to Measure Soil Water Characteristic Curve along with Geotechnical Properties of Oil Sands Tailings

by Louis K. Kabwe, G. Ward Wilson, Nicholas A. Beier and David Barsi

Geosciences 2023, 13(2), 36; https://doi.org/10.3390/geosciences13020036 - 28 Jan 2023

Viewed by 1743

Abstract

The traditional Tempe cell can be used to adequately determine the soil water characteristic curve (SWCC) for soils that do not undergo significant volume change as matric suction is increased, such as coarse-grained material such as sand with a low air entry value [...] Read more.

The traditional Tempe cell can be used to adequately determine the soil water characteristic curve (SWCC) for soils that do not undergo significant volume change as matric suction is increased, such as coarse-grained material such as sand with a low air entry value (AEV) (<500 kPa). When soils undergo substantial volume change as soil suction increases, such as fine-grained silts, clays, and oil sands tailings material, the soils need to be tested with distinctly different methods involving two apparatuses when using the Tempe cell. A single-step Tempe cell technique was developed and tested to measure the geotechnical and unsaturated properties of oil sands tailings samples. A series of nine Tempe cells were simultaneously used to measure the geotechnical and unsaturated soil properties of untreated fluid fine tailings (FFT) and treated flocculated centrifuged tailings (FCT). The results of the single-step Tempe cell technique provide several useful engineering functions relating matric suction to water content (SWCC), void ratio (volume change), solids content, and undrained shear strength. Both the traditional and single-step Tempe cell techniques yield comparable SWCC results, but the single-step Tempe cell yields result about three times faster than the traditional Tempe cell. The geotechnical results indicate that both the solids content and undrained shear strength of the FCT are greater than those of the untreated FFT and this indicates that flocculation and centrifugation increase solids content and undrained shear strength of the treated samples. Furthermore, the results indicate that the FFT starts at higher fine void ratio than the FCT and loses more water (volume change) at matric suctions lower than 7 kPa. Beyond 7 kPa, the compressions of both samples become the same. The single-step Tempe cell technique is, however, labor-intensive. The number of Tempe cell can be reduced to six depending on the starting load of the test. The use of the single-step Tempe cell technique in providing fast estimates of SWCC and geotechnical properties for oil sands tailings will be attractive to practitioners who intend to incorporate matric suction in oil sands geotechnical engineering problems. Full article

(This article belongs to the Collection New Advances in Geotechnical Engineering)

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21 pages, 7217 KiB

Open AccessArticle

Ostracod and Foraminifer Responses to Late Pleistocene–Holocene Volcanic Activity in Northern Victoria Land as Recorded in Ross Sea (Antarctica) Marine Sediments

by Gianguido Salvi, Romana Melis, Paola Del Carlo and Alessio Di Roberto

Geosciences 2023, 13(2), 35; https://doi.org/10.3390/geosciences13020035 - 28 Jan 2023

Viewed by 1289

Abstract

The impacts on ostracods and foraminifers caused by three Late Quaternary ashfalls of different intensities and recovered in the ANTA02-NW2 core sediments (Drygalski Basin, western Ross Sea) were analysed for the first time. Albeit with different timing, both associations demonstrated similar response patterns [...] Read more.

The impacts on ostracods and foraminifers caused by three Late Quaternary ashfalls of different intensities and recovered in the ANTA02-NW2 core sediments (Drygalski Basin, western Ross Sea) were analysed for the first time. Albeit with different timing, both associations demonstrated similar response patterns associated with the deposition of material from volcanic eruptions. In particular, based on the palaeontological evidence, it was possible to divide the cores into four intervals/phases recording the evolution of the ecosystem before and after the deposition events: (1) Pre-extinction phase (high abundance and high diversity values). (2) Extinction phase, characterised by the complete disappearance of ostracod fauna; the foraminiferal assemblage, although not entirely absent, records extremely low values of abundance and diversity (survivor assemblage). (3) Recovery phase (increasing abundance and diversity values), characterised by the recolonisation of some opportunistic taxa; species such as Australicythere devexa and Australicythere polylyca dominate the ostracod assemblage. (4) Post-extinction phase (high abundance and high diversity values), with the return to an environmental equilibrium characterised by the colonisation of specialised taxa such as Argilloecia sp., Cytheropteron sp., Echinocythereis sp., and Hemicytherura spp. Our results may aid in the understanding of how communities (i.e., ostracods and foraminifers) recovered after the impact of direct deposits of volcanic ash into ocean waters. The mechanisms by which disappearance and/or mortality was induced are still not clear. The release of toxic metals during the reaction of the volcanic ash with seawater, the resulting chemical alteration in the seawater, and the change in pH, together with the possible suppression of planktonic organisms, may have caused the two main extinction phases recorded by the ANTA02-NW2 core sediments. Full article

(This article belongs to the Section Sedimentology, Stratigraphy and Palaeontology)

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21 pages, 5955 KiB

Open AccessEditor’s ChoiceArticle

High-Resolution Lidar-Derived DEM for Landslide Susceptibility Assessment Using AHP and Fuzzy Logic in Serdang, Malaysia

by Jude Okoli, Haslinda Nahazanan, Faten Nahas, Bahareh Kalantar, Helmi Zulhaidi Mohd Shafri and Zailani Khuzaimah

Geosciences 2023, 13(2), 34; https://doi.org/10.3390/geosciences13020034 - 28 Jan 2023

Cited by 7 | Viewed by 2171

Abstract

Landslide impact is potentially hazardous to an urban environment. Landslides occur at certain slope levels over time and require practical slope analysis to assess the nature of the slope where a landslide is likely to occur. Thus, acquiring very high-resolution remote sensing data [...] Read more.

Landslide impact is potentially hazardous to an urban environment. Landslides occur at certain slope levels over time and require practical slope analysis to assess the nature of the slope where a landslide is likely to occur. Thus, acquiring very high-resolution remote sensing data plays a significant role in determining the slope surface. For this study, 12 landslide conditioning parameters with 10 × 10 cell sizes that have never been previously collectively applied were created. These factors were created directly from the LiDAR (Light Detection and Ranging) DEM (digital elevation model)using their layer toolboxes, which include slope, aspect, elevation, curvature, and hill shade. Stream power index (SPI), topographic wetness index (TWI), and terrain roughness index (TRI) were created from spatial layers such as slope, flow direction, and flow accumulation. Shapefiles of distances to roads, lakes, trees, and build-up were digitized as land use/cover from the LiDAR image and produced using the Euclidean distance method in ArcGIS. The parameters were selected based on expert knowledge, previous landslide literature, and the study area characteristics. Moreover, multicriteria decision-making analysis, which includes the analytic hierarchy process (AHP) and fuzzy logic approaches not previously utilized with a LiDAR DEM, was used in this study to predict the possibility of a landslide. The receiver operating characteristics (ROC) were used for the validation of results. The area under the curve (AUC) values obtained from the ROC method for the AHP and fuzzy were 0.859 and 0.802, respectively. The final susceptibility results will be helpful to urban developers in Malaysia and for sustainable landslide hazard mitigation. Full article

(This article belongs to the Special Issue Soil Erosion and Shallow Landslides: Prediction of the Phenomena and Measures of Sediments Delivery)

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18 pages, 10556 KiB

Open AccessArticle

The Bologna Interpretation of Rock Bridges

by Davide Elmo

Geosciences 2023, 13(2), 33; https://doi.org/10.3390/geosciences13020033 - 28 Jan 2023

Cited by 2 | Viewed by 1274

Abstract

One can only know where a rock bridge is once one measures it. In addition, to measure it, you need the rock mass to fail. This critical problem is ignored by many, and engineers continue to refer to rock bridges as geometrical distances [...] Read more.

One can only know where a rock bridge is once one measures it. In addition, to measure it, you need the rock mass to fail. This critical problem is ignored by many, and engineers continue to refer to rock bridges as geometrical distances between non-persistent fractures. This paper argues that this rather simplistic approach can lead to non-realistic failure mechanisms. We also raise the critical question of whether the inappropriate functioning of strength equations centred on the measurement of rock bridge percentages could result in misinterpreting the risk of failure. We propose a new interpterion, aptly called the Bologna Interpretation, as an analogy to the Copenhagen Interpretation of quantum mechanics, to highlight the indeterministic nature of rock bridges and to honour the oldest university in Europe (Bologna University). The Bologna Interpretation does not negate the existence of rock bridges. What rock bridges look like, how many there are, and where they are, we do not know; we can assume their existence and account for their contribution to rock mass strength using a potential analogue. Full article

(This article belongs to the Special Issue Rock Slope Stability Analysis)

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18 pages, 10158 KiB

Open AccessEditor’s ChoiceArticle

Berriasian–Valanginian Geochronology and Carbon-Isotope Stratigraphy of the Yellow Cat Member, Cedar Mountain Formation, Eastern Utah, USA

by Robert M. Joeckel, Celina A. Suarez, Noah M. McLean, Andreas Möller, Gregory A. Ludvigson, Marina B. Suarez, James I. Kirkland, Joseph Andrew, Spencer Kiessling and Garrett A. Hatzell

Geosciences 2023, 13(2), 32; https://doi.org/10.3390/geosciences13020032 - 26 Jan 2023

Cited by 3 | Viewed by 6598

Abstract

The Early Cretaceous Yellow Cat Member of the terrestrial Cedar Mountain Formation in Utah, USA. has been interpreted as a “time-rich” unit because of its dinosaur fossils, prominent paleosols, and the results of preliminary chemostratigraphic and geochronologic studies. Herein, we refine prior interpretations [...] Read more.

The Early Cretaceous Yellow Cat Member of the terrestrial Cedar Mountain Formation in Utah, USA. has been interpreted as a “time-rich” unit because of its dinosaur fossils, prominent paleosols, and the results of preliminary chemostratigraphic and geochronologic studies. Herein, we refine prior interpretations with: (1) a new composite C-isotope chemostratigraphic profile from the well-known Utahraptor Ridge dinosaur site, which exhibits δ¹³C features tentatively interpreted as the Valanginian double-peak carbon isotope excursion (the so-called “Weissert Event”) and some unnamed Berriasian features; and (2) a new cryptotephra zircon eruption age of 135.10 ± 0.30/0.31/0.34 Ma (2σ) derived from the CA-ID-TIMS U-Pb analyses of zircons from a paleosol cryptotephra. Our interpretations of δ¹³C features on our chemostratigraphic profile, in the context of our new radiometric age, are compatible with at least one prior age model for the “Weissert Event” and the most recent revision of the Cretaceous time scale. Our results also support the interpretation that the Yellow Cat Member records a significant part of Early Cretaceous time. Full article

(This article belongs to the Special Issue Terrestrial Paleoclimatology and Paleohydrology of the Cretaceous Greenhouse World)

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