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1.
  • Abdullah, Twana, et al. (författare)
  • Possibility of Groundwater Pollution in Halabja Saidsadiq Hydrogeological Basin, Iraq Using Modified DRASTIC Model Based on AHP andTritium Isotopes
  • 2018
  • Ingår i: Geosciences. - : MDPI. - 2076-3263. ; 8:7
  • Tidskriftsartikel (refereegranskat)abstract
    • An anthropogenic activity is one of the most severe environmental causes for groundwatercontamination in the urban area. Groundwater thought to be one of the principal sources of water supply in Halabja Saidsadiq Basin, and therefore its vulnerability evaluation to define areas that are more vulnerable to pollution is incredibly vital.  The objectives of this paper are to reveal weight modified of DRASTIC model based on the Analytical Hierarchical Process to estimate the proportional likelihood of groundwater resources pollution. Tritium isotopes analysis was chosen and applied as a pollution marker to confirm the result of this adjustment. Based on this modification, vulnerability classes that were achieved for the studied basin were alienated into five classes, including very low, low, medium, high, and very high, with vulnerability index value of (<100, >100–125, >125–150,>150–200, and >200), respectively.
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2.
  • Anders, Bébhinn, et al. (författare)
  • Wildfires and Monsoons: Cryptic Drivers for Highly Variable Provenance Signals within a Carboniferous Fluvial System
  • 2022
  • Ingår i: Geosciences. - : MDPI AG. - 2076-3263. ; 12:1, s. 20-20
  • Tidskriftsartikel (refereegranskat)abstract
    • Sediment delivery and supply are explicitly controlled by variations in broad-scale processes such as climate, tectonics and eustasy. These in turn influence fluvial processes and hinterland evolution. A bespoke multi-proxy approach (integrating apatite and zircon U-Pb geochronology, trace elements in apatite, and Pb-in-K-feldspar provenance tools) coupled with outcrop investigation is used to constrain the temporal trends in sediment delivery to channel sandstones of the fluvio-estuarine mid-Viséan Mullaghmore Sandstone Formation, Ireland. Provenance data indicate unique detrital signatures for all sampled horizons, indicating the fluctuating nature of sediment supply to this medium-sized basin. Tectonism and/or abrupt relative sea-level fall likely caused fluvial rejuvenation, resulting in local basement sourcing of the initial fill. Older and more distal sources, such as the Nagssugtoqidian Belt of East Greenland, become more prominent in stratigraphically younger channel sandstones suggesting catchment expansion. Paleoproterozoic to Mesoproterozoic sources are most dominant, yet the detrital grain cargo varies in each channel sandstone. Proximal sources such as the Donegal Batholith and Dalradian Supergroup are variable and appear to switch on and off. These signal shifts are likely the result of channel migration and paleoclimatic fluctuation. A monsoonal climate and large-scale wildfire events (evidenced by fusain) likely contributed to modify plant cover, intensify erosion, and increase run-off and sediment delivery rates from specific areas of the hinterland.
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3.
  • Baranov, Alexey, et al. (författare)
  • Combined Gravimetric-Seismic Moho Model of Tibet
  • 2018
  • Ingår i: Geosciences. - : MDPI. - 2076-3263. ; 8:12
  • Tidskriftsartikel (refereegranskat)abstract
    • Substantial progress has been achieved over the last four decades to better understand a deep structure in the Himalayas and Tibet. Nevertheless, the remoteness of this part of the world still considerably limits the use of seismic data. A possible way to overcome this practical restriction partially is to use products from the Earth's satellite observation systems. Global topographic data are provided by the Shuttle Radar Topography Mission (SRTM). Global gravitational models have been derived from observables delivered by the gravity-dedicated satellite missions, such as the Gravity Recovery and Climate Experiment (GRACE) and the Gravity field and steady-state Ocean Circulation Explorer (GOCE). Optimally, the topographic and gravity data should be combined with available results from tomographic surveys to interpret the lithospheric structure, including also a Moho relief. In this study, we use seismic, gravity, and topographic data to estimate the Moho depth under orogenic structures of the Himalayas and Tibet. The combined Moho model is computed based on solving the Vening Meinesz-Moritz (VMM) inverse problem of isostasy, while incorporating seismic data to constrain the gravimetric solution. The result of the combined gravimetric-seismic data analysis exhibits an anticipated more detailed structure of the Moho geometry when compared to the solution obtained merely from seismic data. This is especially evident over regions with sparse seismic data coverage. The newly-determined combined Moho model of Tibet shows a typical contrast between a thick crustal structure of orogenic formations compared to a thinner crust of continental basins. The Moho depth under most of the Himalayas and the Tibetan Plateau is typically within 60-70 km. The maximum Moho deepening of similar to 76 km occurs to the south of the Bangong-Nujiang suture under the Lhasa terrane. Local maxima of the Moho depth to similar to 74 km are also found beneath Taksha at the Karakoram fault. This Moho pattern generally agrees with the findings from existing gravimetric and seismic studies, but some inconsistencies are also identified and discussed in this study.
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4.
  • Bernardi, Francesco, et al. (författare)
  • OH-Defects in Detrital Quartz Grains from the Julian Basin (NE Italy and Slovenia): A Fourier Transform Infrared Study
  • 2022
  • Ingår i: Geosciences. - : MDPI AG. - 2076-3263. ; 12
  • Tidskriftsartikel (refereegranskat)abstract
    • In this study, we analyzed up to 80 detrital quartz grains from four lithic greywackes along the stratigraphic column of the Julian Basin, a synorogenic basin in the southeastern Alps between Italy and Slovenia. Fourier transform infrared spectroscopy of detrital quartz was used to investigate the sample set with interest to its OH-defect speciation and content of each associated substitution. According to several recent studies, OH-defects in quartz are correlated to petrogenetic conditions of the source material and can be used as a provenance tool. The aim of this study is to compare results based on this method with previous studies that used other methods, to better constrain the palaeogeographical reconstruction of sedimentary fluxes. Detrital quartz within the samples of the basin shows different patterns of OH-defects and water content, indicating substantial petrogenetic differences between the sediment source rocks. For the oldest analyzed sample (ca. 66 Ma), the distribution of OH-defects suggests a mixed source between igneous and non-igneous rocks, with a predominance of metamorphic material supply. Another sample (56 Ma) reveals a great variability of OH-defects and water content, indicating that the magmatic component dominates over the metamorphic component. The distribution of OH-defects in the samples at the top of the sequence (52–53 Ma) suggests an almost solely metamorphic source. These results are in line with previous studies based on heavy minerals and geochemistry.
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5.
  • Carlsson, Diana, et al. (författare)
  • Fossilized endolithic microorganisms in pillowlavas from the Troodos ophiolite, Cyprus
  • 2019
  • Ingår i: Geosciences. - Basel : MDPI. - 2076-3263. ; 9:11
  • Tidskriftsartikel (refereegranskat)abstract
    • The last decade has revealed the igneous oceanic crust to host a more abundant and diverse biota than previously expected. These underexplored rock-hosted deep ecosystems dominated Earth’s biosphere prior to plants colonized land in the Ordovician, thus the fossil record of deep endoliths holds invaluable clues to early life and the work to decrypt them needs to be intensified. Here, we present fossilized microorganisms found in open and sealed pore spaces in pillow lavas from the Troodos Ophiolite (91 Ma) on Cyprus. A fungal interpretation is inferred upon the microorganisms based on characteristic morphological features. Geochemical conditions are reconstructed using data from mineralogy, fluid inclusions and the fossils themselves. Mineralogy indicates at least three hydrothermal events and a continuous increase of temperature and pH. Precipitation of 1) celadonite and saponite together with the microbial introduction was followed by 2) Na and Ca zeolites resulting in clay adherence on the microorganisms as protection, and finally 3) Ca carbonates resulted in final fossilization and preservation of the organisms in-situ. Deciphering the fossil record of the deep subseafloor biosphere is a challenging task, but when successful, can unlock doors to life’s cryptic past.
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6.
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7.
  • Drake, Henrik, 1979-, et al. (författare)
  • Ancient microbial activity in deep hydraulically conductive fracture zones within the Forsmark target area for deep geological nuclear waste disposal, Sweden
  • 2018
  • Ingår i: Geosciences. - : MDPI AG. - 2076-3263. ; 8
  • Tidskriftsartikel (refereegranskat)abstract
    • Recent studies reveal that organisms from all three domains of life—Archaea, Bacteria, and even Eukarya—can thrive under energy-poor, dark, and anoxic conditions at large depths in the fractured crystalline continental crust. There is a need for an increased understanding of the processes and lifeforms in this vast realm, for example, regarding the spatiotemporal extent and variability of the different processes in the crust. Here, we present a study that set out to detect signs of ancient microbial life in the Forsmark area—the target area for deep geological nuclear waste disposal in Sweden. Stable isotope compositions were determined with high spatial resolution analyses within mineral coatings, and mineralized remains of putative microorganisms were studied in several deep water-conducting fracture zones (down to 663 m depth), from which hydrochemical and gas data exist. Large isotopic variabilities of 13Ccalcite (?36.2 to +20.2‰V-PDB) and 34Spyrite (?11.7 to +37.8‰V-CDT) disclose discrete periods of methanogenesis, and potentially, anaerobic oxidation of methane and related microbial sulfate reduction at several depth intervals. Dominant calcite–water disequilibrium of 18O and 87Sr/86Sr precludes abundant recent precipitation. Instead, the mineral coatings largely reflect an ancient archive of episodic microbial processes in the fracture system, which, according to our microscale Rb–Sr dating of co-genetic adularia and calcite, date back to the mid-Paleozoic. Potential Quaternary precipitation exists mainly at ~400 m depth in one of the boreholes, where mineral–water compositions corresponded.
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8.
  • Drake, Henrik, 1979-, et al. (författare)
  • Geochronology and Stable Isotope Analysis of Fracture-Fill and Karst Mineralization Reveal Sub-Surface Paleo-Fluid Flow and Microbial Activity of the COSC-1 Borehole, Scandinavian Caledonides
  • 2020
  • Ingår i: Geosciences. - : MDPI AG. - 2076-3263.
  • Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
    • The deep biosphere hosted in fractured rocks within the upper continental crust is one of the least understood and studied ecological realms on Earth. Scarce knowledge of ancient life and paleo-fluid flow within this realm is owing to the lack of deep drilling into the crust. Here we apply microscale high spatial-resolution analytical techniques to fine-grained secondary minerals in a deep borehole (COSC-1) drilled into the Silurian-Devonian Scandinavian Caledonide mountain range in central Sweden. The aim is to detect and date signs of ancient microbial activity and low-temperature fluid circulation in micro-karsts (foliation-parallel dissolution cavities in the rock) and fractures at depth in the nappe system. Vein carbonates sampled at 684 to 2210 m show a decreased C isotope variability at depths below 1050 m; likely due to decreased influence of organic-C at great depth. Micro-karsts at 122–178 m depth feature at least two generations of secondary calcite and pyrite growth in the voids as shown by secondary ion mass spectrometry analytical transects within individual grains. The younger of these two precipitation phases shows 34S-depleted δ34Spyrite values (−19.8 ± 1.6‰ vs. Vienna-Canyon Diablo Troilite (V-CDT)) suggesting microbial sulfate reduction in situ. The calcite of this late phase can be distinguished from the older calcite by higher δ18Ocalcite values that correspond to precipitation from ambient meteoric water. The late stage calcite gave two separate laser ablation inductively coupled mass spectrometry-derived U-Pb ages (9.6 ± 1.3 Ma and 2.5 ± 0.2 Ma), marking a minimum age for widespread micro-karst formation within the nappe. Several stages of fluid flow and mineral precipitation followed karst formation; with related bacterial activity as late as the Neogene-Quaternary; in structures presently water conducting. The results show that our combined high spatial-resolution stable isotope and geochronology approach is suitable for characterizing paleo-fluid flow in micro-karst; in this case, of the crystalline crust comprising orogenic nappe units.
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9.
  • Drake, Henrik, Docent, 1979-, et al. (författare)
  • Tracking the Deep Biosphere through Time
  • 2020
  • Ingår i: Geosciences. - : MDPI. - 2076-3263. ; 10:11, s. 1-6
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • The oceanic and continental lithosphere constitutes Earth’s largest microbial habitat, yet it is scarcely investigated and not well understood. The physical and chemical properties here are distinctly different from the overlaying soils and the hydrosphere, which greatly impact the microbial communities and associated geobiological and geochemical processes. Fluid–rock interactions are key processes for microbial colonization and persistence in a nutrient-poor and extreme environment. Investigations during recent years have spotted microbial processes, stable isotope variations, and species that are unique to the subsurface crust. Recent advances in geochronology have enabled the direct dating of minerals formed in response to microbial activity, which in turn have led to an increased understanding of the evolution of the deep biosphere in (deep) time. Similarly, the preservation of isotopic signatures, as well as organic compounds within fossilized micro-colonies or related mineral assemblages in voids, cements, and fractures/veins in the upper crust, provides an archive that can be tapped for knowledge about ancient microbial activity, including both prokaryotic and eukaryotic life. This knowledge sheds light on how lifeforms have evolved in the energy-poor subsurface, but also contributes to the understanding of the boundaries of life on Earth, of early life when the surface was not habitable, and of the preservation of signatures of ancient life, which may have astrobiological implications. The Special Issue “Tracking the Deep Biosphere through Time” presents a collection of scientific contributions that provide a sample of forefront research in this field. The contributions involve a range of case studies of deep ancient life in continental and oceanic settings, of microbial diversity in sub-seafloor environments, of isolation of calcifying bacteria as well as reviews of clay mineralization of fungal biofilms and of the carbon isotope records of the deep biosphere.
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10.
  • Drake, Henrik, 1979-, et al. (författare)
  • Using 87Sr/86Sr LA-MC-ICP-MS Transects within Modern and Ancient Calcite Crystals to Determine Fluid Flow Events in Deep Granite Fractures
  • 2020
  • Ingår i: Geosciences. - : MDPI AG. - 2076-3263. ; 10, s. 1-23
  • Tidskriftsartikel (refereegranskat)abstract
    • The strontium isotope signature (87Sr/86Sr) of calcite precipitated in rock fractures and faults is a frequently used tool to trace paleofluid flow. However, bedrock fracture networks, such as in Precambrian cratons, have often undergone multiple fracture reactivations resulting in complex sequences of fracture mineral infillings. This includes numerous discrete calcite crystal overgrowths. Conventional 87Sr/86Sr analysis of dissolved bulk samples of such crystals is not feasible as they will result in mixed signatures of several growth zonations. In addition, the zonations are too fine-grained for sub-sampling using micro-drilling. Here, we apply high spatial resolution 87Sr/86Sr spot analysis(80 um) in transects through zoned calcite crystals in deep Paleoproterozoic granitoid fractures using laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) to trace discrete signs of paleofluid flow events. We compare the outermost calcite growth zone with 87Sr/86Sr values of the present-day groundwater sampled in the same boreholes to distinguish potential modern precipitates. We then connect our results to previously reported radiometric dating and C and O isotope signatures to understand the temporal history and physicochemical evolution of fluid flow within the fractures. Comparisons of modern calcite precipitated in a borehole over a period of 17 years with modern waters prove the concept of using 87Sr/86Sr as a marker for fluid origin in this environment and for how 87Sr/86Sr changed during marine water infiltration. Intermittent calcite precipitation over very long time spans is indicated in calcite of the currently open fractures, showing an evolution of 87Sr/86Sr from ~0.705–0.707—a population dated to ~1.43 billion years—to crystal overgrowth values at ~0.715–0.717 that overlap with the present-day groundwater values.This shows that high spatial resolution Sr isotope analysis of fine-scaled growth zonation within single calcite crystals is applicable for tracing episodic fluid flow in fracture networks.
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11.
  • Fomin, Ilya, et al. (författare)
  • Water, Hydrous Melting, and Teleseismic Signature of the Mantle Transition Zone
  • 2019
  • Ingår i: Geosciences. - : MDPI AG. - 2076-3263. ; 9:12
  • Tidskriftsartikel (refereegranskat)abstract
    • Recent geophysical and petrological observations indicate the presence of water and hydrous melts in and around the mantle transition zone (MTZ), for example, prominent low-velocity zones detected by seismological methods. Experimental data and computational predictions describe the influence of water on elastic properties of mantle minerals. Using thermodynamic relationships and published databases, we calculated seismic velocities and densities of mantle rocks in and around the MTZ in the presence of water for a plausible range of mantle potential temperatures. We then computed synthetic receiver functions to explore the influence of different water distribution patterns on the teleseismic signature. The results may improve our understanding and interpretation of seismic observations of the MTZ.
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12.
  • Georgiou, Nikos, et al. (författare)
  • Spatio-Seasonal Hypoxia/Anoxia Dynamics and Sill Circulation Patterns Linked to Natural Ventilation Drivers, in a Mediterranean Landlocked Embayment : Amvrakikos Gulf, Greece
  • 2021
  • Ingår i: Geosciences. - : MDPI. - 2076-3263. ; 11:6
  • Tidskriftsartikel (refereegranskat)abstract
    • Amvrakikos Gulf is a Mediterranean landlocked, fjord-like embayment and marine protected area suffering from natural, human-induced hypoxia/anoxia and massive fish mortality events. Seasonal marine geophysical and oceanographic surveys were conducted focusing on the water-circulation patterns at the sill and the spatial-seasonal distribution of dissolved oxygen (DO) in the gulf. Detailed surveys at the sill, the only communication route between the gulf and the open sea, revealed a two-layer water circulation pattern (top brackish outflow-bottom seawater inflow) and the role of the tide in the daily water exchange. Statistical analysis of the known natural drivers of DO distribution (density difference between the Ionian Sea and Amvrakikos, river inflow, wind) revealed that horizontal density gradients strongly affect anoxia reduction and seafloor oxygenation, while river inflow and wind mainly oxygenate volume/areas located above or within the pycnocline range, with DO concentrations > 2 mg/L. Complex geomorphology with well-formed internal basins contributes to the development and preservation of low DO conditions below the pycnocline. Finally, 43% of the seafloor and 36% of the gulf's total water volume are permanently hypoxic, and reach a maximum of 70% and 62%, respectively, in September and July. This work is tailored to future ecosystem management plans, decisions, and future research on coastal ecosystems.
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13.
  • Hall, Adrian M., et al. (författare)
  • Glacial Ripping in Sedimentary Rocks : Loch Eriboll, NW Scotland
  • 2021
  • Ingår i: Geosciences. - : MDPI AG. - 2076-3263. ; 11:6
  • Tidskriftsartikel (refereegranskat)abstract
    • Glacial ripping is a newly recognized process sequence in which subglacial erosion is triggered by groundwater overpressure. Investigations in gneiss terrain in lowland Sweden indicate that ripping involves three stages of (i) hydraulic jacking, (ii) rock disruption under subglacial traction, and (iii) glacial transport of rock blocks. Evidence for each stage includes, respectively, dilated fractures with sediment fills, disintegrated roches moutonnees, and boulder spreads. Here, we ask: can glacial ripping also occur in sedimentary rocks, and, if so, what are its effects? The case study area is in hard, thinly bedded, gently dipping Cambrian quartz-arenites at Loch Eriboll, NW Scotland. Field surveys reveal dilated, sediment filled, bedding-parallel fractures, open joints, and brecciated zones, interpreted as markers for pervasive, shallow penetration of the quartz-arenite by water at overpressure. Other features, including disintegrated rock surfaces, boulder spreads, and monomict rubble tills, indicate glacial disruption and short distance subglacial transport. The field results together with cosmogenic isotope ages indicate that glacial ripping operated with high impact close to the former ice margin at Loch Eriboll at 17.6-16.5 ka. Glacial ripping thus can operate effectively in bedded, hard sedimentary rocks, and the accompanying brecciation is significant-if not dominant-in till formation. Candidate markers for glacial ripping are identified in other sedimentary terrains in former glaciated areas of the Northern Hemisphere.
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14.
  • Hasab, Hashim Ali, et al. (författare)
  • Monitoring and Assessment of Salinity and Chemicals in Agricultural Lands by a Remote Sensing Technique and Soil Moisture with Chemical Index Models
  • 2020
  • Ingår i: Geosciences. - Switzerland : MDPI. - 2076-3263. ; 10:6
  • Tidskriftsartikel (refereegranskat)abstract
    • Agricultural land in the south of Iraq provides habitat for several types of living creatures. This land has a significant impact on the ecosystem. The agricultural land of Al-Hawizeh marsh covers an area of more than 3500 km2 and is considered an enriched resource to produce several harvests. A total of 74% of this area suffers from a high degree of salinity and chemical pollution, which needs to be remedied. Several human-made activities and post-war-related events have caused radical deterioration in soil quality in the agricultural land. The goal of this research was to integrate mathematical models, remote sensing data, and GIS to provide a powerful tool to predict, assess, monitor, manage, and map the salinity and chemical parameters of iron (Fe), lead (Pb), copper (Cu), chromium (Cr), and zinc (Zn) in the soils of agricultural land in Al-Hawizeh marsh in southern Iraq during the four seasons of 2017. The mathematical model consists of four parts. The first depends on the B6 and B11 bands of Landsat-8, to calculate the soil moisture index (SMI). The second is the salinity equation (SE), which depends on the SMI result to retrieve the salinity values from Landsat-8 images. The third part depends on the B6 and B7 bands of Landsat-8, which calculates the clay chemical index (CCIs). The fourth part is the chemical equation (CE), which depends on the CCI to retrieve the chemical values (Fe, Pb, Cu, Cr, and Zn) from Landsat-8 images. The average salinity concentrations during autumn, summer, spring, and winter were 1175, 1010, 1105, and 1789 mg/dm3, respectively. The average Fe concentrations during autumn, summer, spring and winter were 813, 784, 842, and 1106 mg/dm3, respectively. The average Pb concentrations during autumn, summer, spring, and winter were 4.85, 3.79, 4.74, and 7.2 mg/dm3, respectively. The average Cu concentrations during autumn, summer, spring, and winter were 3.9, 3.1, 4.45, and 7.5 mg/dm3, respectively. The average Cr concentrations during autumn, summer, spring, and winter seasons were 1.28, 0.73, 1.03, and 2.91 mg/dm3, respectively. Finally, the average Zn concentrations during autumn, summer, spring, and winter were 8.25, 6, 7.05, and 12 mg/dm3, respectively. The results show that the concentrations of salinity and chemicals decreased in the summer and increased in the winter. The decision tree (DT) classification depended on the output results for salinity and chemicals for both SE and CE equations. This classification refers to all the parameters simultaneously in one stage. The output of DT classification results can display all the soil quality parameters (salinity, Fe, Pb, Cu, Cr, and Zn) in one image. This approach was repeated for each season in this study. In conclusion, the developed systematic and generic approach may constitute a basis for determining soil quality parameters in agricultural land worldwide.
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15.
  • Haugen, Annika, et al. (författare)
  • A Methodology for Long-Term Monitoring of Climate Change Impacts on Historic Buildings
  • 2018
  • Ingår i: Geosciences. - : MDPI AG. - 2076-3263. ; 8:10
  • Tidskriftsartikel (refereegranskat)abstract
    • A new methodology for long-term monitoring of climate change impacts on historic buildings and interiors has been developed. This paper proposes a generic framework for how monitoring programs can be developed and describes the planning and arrangement of a Norwegian monitoring campaign. The methodology aims to make it possible to establish a data-driven decision making process based on monitored decay related to climate change. This monitoring campaign includes 45 medieval buildings distributed over the entirety of Norway. Thirty-five of these buildings are dated to before 1537 and include wooden buildings as well as 10 medieval churches built in stone while the remaining 10 buildings are situated in the World Heritage sites of Bryggen, in Bergen on the west coast of Norway, and in Røros, which is a mining town in the inland of the country. The monitoring is planned to run for 30 to 50 years. It includes a zero-level registration and an interval-based registration system focused on relevant indicators, which will make it possible to register climate change-induced decay at an early stage.
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16.
  • Higgins, Lindsey, et al. (författare)
  • Surface Area Variability of a North-Central Tanzanian Crater Lake
  • 2016
  • Ingår i: Geosciences. - : MDPI AG. - 2076-3263. ; 6:2
  • Tidskriftsartikel (refereegranskat)abstract
    • A history of modern (1973–2015) surface area variability for Lake Basotu in north-central Tanzania has been reconstructed using archived Landsat images from the dry season between June and October. This record was compared to local weather data as well as larger scale weather patterns. The lake has been in a state of decline interrupted by major flood events since the beginning of the satellite record. From 1973 to 1997, the lake area was between 0.97 km2 and 4.28 km2. Lake extent abruptly increased to 13.86 km2 in 1998, when a co-occurrence of El Niño and a positive Indian Ocean Dipole led to extensive flooding. It is hypothesized that local agricultural practices leading to soil erosion and subsequent basin sedimentation have most likely increased the sensitivity of Lake Basotuto climatic fluctuations.
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17.
  • Islam, M. M.Majedul, et al. (författare)
  • Modelling the present and futurewater level and discharge of the tidal betna river
  • 2018
  • Ingår i: Geosciences (Switzerland). - : MDPI AG. - 2076-3263. ; 8:8
  • Tidskriftsartikel (refereegranskat)abstract
    • Climate change, comprising of changes in precipitation patterns, higher temperatures and sea level rises, increases the likelihood of future flooding in the Betna River basin, Bangladesh. Hydrodynamic modellingwas performed to simulate the present and future water level and discharge for different scenarios using bias-corrected, downscaled data from two general circulation models. The modelling results indicated that, compared to the baseline year (2014–2015), the water level is expected to increase by 11–16% by the 2040s and 14–23% by the 2090s, and the monsoon daily maximum discharge is expected to increase by up to 13% by the 2040s and 21% by the 2090s. Sea level rise is mostly responsible for the increase in water level. The duration of water level exceedance of the established danger threshold and extreme discharge events can increase by up to half a month by the 2040s and above one month by the 2090s. The combined influence of the increased water level and discharge has the potential to cause major floods in the Betna River basin. The results of our study increase the knowledge base on climate change influence on water level and discharge at a local scale. This is valuable for water managers in flood-risk mitigation and water management.
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18.
  • Jackson, Marie, et al. (författare)
  • Authigenic mineral textures in submarine 1979 basalt drill core, Surtsey volcano, Iceland
  • 2019
  • Ingår i: Geochemistry Geophysics Geosystems. - New York : American Geophysical Union (AGU). - 1525-2027. ; 20:7, s. 3751-3773
  • Tidskriftsartikel (refereegranskat)abstract
    • Micrometer‐scale maps of authigenic microstructures in submarine basaltic tuff from a 1979 Surtsey volcano, Iceland, drill core acquired 15 years after eruptions terminated describe the initial alteration of oceanic basalt in a low‐temperature hydrothermal system. An integrative investigative approach uses synchrotron source X‐ray microdiffraction, microfluoresence, micro‐computed tomography, and scanning transmission electron microscopy coupled with Raman spectroscopy to create finely resolved spatial frameworks that record a continuum of alteration in glass and olivine. Microanalytical maps of vesicular and fractured lapilli in specimens from 157.1‐, 137.9‐, and 102.6‐m depths and borehole temperatures of 83, 93.9, and 141.3 °C measured in 1980, respectively, describe the production of nanocrystalline clay mineral, zeolites, and Al‐tobermorite in diverse microenvironments. Irregular alteration fronts at 157.1‐m depth resemble microchannels associated with biological activity in older basalts. By contrast, linear microstructures with little resemblance to previously described alteration features have nanocrystalline clay mineral (nontronite) and zeolite (amicite) texture. The crystallographic preferred orientation rotates around an axis parallel to the linear feature. Raman spectra indicating degraded and poorly ordered carbonaceous matter of possible biological origin are associated with nanocrystalline clay mineral in a crystallographically oriented linear microstructure in altered olivine at 102.6 m and with subcircular nanoscale cavities in altered glass at 137.9‐m depth. Although evidence for biotic processes is inconclusive, the integrated analyses describe the complex organization of previously unrecognized mineral texture in very young basalt. They provide a foundational mineralogical reference for longitudinal, time‐lapse characterizations of palagonitized basalt in oceanic environments.
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19.
  • Ketzer, João Marcelo, et al. (författare)
  • Gas Seeps at the Edge of the Gas Hydrate Stability Zone on Brazil’s Continental Margin
  • 2019
  • Ingår i: Geosciences. - : MDPI. - 2076-3263. ; 9:5, s. 1-11
  • Tidskriftsartikel (refereegranskat)abstract
    • Gas hydrate provinces occur in two sedimentary basins along Brazil’s continental margin: (1) The Rio Grande Cone in the southeast, and (2) the Amazon deep-sea fan in the equatorial region. The occurrence of gas hydrates in these depocenters was first detected geophysically and has recently been proven by seafloor sampling of gas vents, detected as water column acoustic anomalies rising from seafloor depressions (pockmarks) and/or mounds, many associated with seafloor faults formed by the gravitational collapse of both depocenters. The gas vents include typical features of cold seep systems, including shallow sulphate reduction depths (<4 m), authigenic carbonate pavements, and chemosynthetic ecosystems. In both areas, gas sampled in hydrate and in sediments is dominantly formed by biogenic methane. Calculation of the methane hydrate stability zone for water temperatures in the two areas shows that gas vents occur along its feather edge (water depths between 510 and 760 m in the Rio Grande Cone and between 500 and 670 m in the Amazon deep-sea fan), but also in deeper waters within the stability zone. Gas venting along the feather edge of the stability zone could reflect gas hydrate dissociation and release to the oceans, as inferred on other continental margins, or upward fluid flow through the stability zone facilitated by tectonic structures recording the gravitational collapse of both depocenters. The potential quantity of venting gas on the Brazilian margin under different scenarios of natural or anthropogenic change requires further investigation. The studied areas provide natural laboratories where these critical processes can be analyzed and quantified.
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20.
  • Lenaz, Davide, et al. (författare)
  • The Österplana Fossil Meteorites and… What Else? Terrestrial Cr-Spinels and Zircons in the Ordovician Limestones of the Thorsberg Quarry (Sweden)
  • 2022
  • Ingår i: Geosciences (Switzerland). - : MDPI AG. - 2076-3263. ; 12:2
  • Tidskriftsartikel (refereegranskat)abstract
    • In the Ordovician limestone of the Thorsberg quarry (South Sweden), about 130 meteorites have been found. Among the extraterrestrial material, several terrestrial Cr-spinels and zircons have been found too. In particular, in the interval 416–447 cm above the Arkeologen bed, terrestrial Cr-spinels, compositionally different from previous studied Cr-spinels of the same sequence, are present. Previous studies on zircon provided depositional ages that range from 464.22 ± 0.37 Ma to 465.01 ± 0.26 Ma. The trace element content of zircons suggests different possible source rocks. In fact, zircons from the oldest ash layer resemble those from dolerite, while those in the youngest layers are similar to zircons commonly found in granitoids, with more than 65% wt. SiO2 . The chemistry of Cr-spinels suggests a strong alteration, so that it is difficult to assign them to a specific area, however they recall the chemistry of altered spinels from ophiolitic occurrences (among other possibilities). The geological setting of the Laurentia and Baltica areas, including the description of basalts to rhyolite association and the presence of ophiolitic slices, makes us confident about the derivation of these zircons and Cr-spinels from those areas.
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21.
  • Mayer, Larry, et al. (författare)
  • The Nippon Foundation-GEBCO Seabed 2030 Project : The Quest to See the World's Oceans Completely Mapped by 2030
  • 2018
  • Ingår i: Geosciences. - : MDPI AG. - 2076-3263. ; 8:2
  • Tidskriftsartikel (refereegranskat)abstract
    • Despite many of years of mapping effort, only a small fraction of the world ocean's seafloor has been sampled for depth, greatly limiting our ability to explore and understand critical ocean and seafloor processes. Recognizing this poor state of our knowledge of ocean depths and the critical role such knowledge plays in understanding and maintaining our planet, GEBCO and the Nippon Foundation have joined forces to establish the Nippon Foundation GEBCO Seabed 2030 Project, an international effort with the objective of facilitating the complete mapping of the world ocean by 2030. The Seabed 2030 Project will establish globally distributed regional data assembly and coordination centers (RDACCs) that will identify existing data from their assigned regions that are not currently in publicly available databases and seek to make these data available. They will develop protocols for data collection (including resolution goals) and common software and other tools to assemble and attribute appropriate metadata as they assimilate regional grids using standardized techniques. A Global Data Assembly and Coordination Center (GDACC) will integrate the regional grids into a global grid and distribute to users world-wide. The GDACC will also act as the central focal point for the coordination of common data standards and processing tools as well as the outreach coordinator for Seabed 2030 efforts. The GDACC and RDACCs will collaborate with existing data centers and bathymetric compilation efforts. Finally, the Nippon Foundation GEBCO Seabed 2030 Project will encourage and help coordinate and track new survey efforts and facilitate the development of new and innovative technologies that can increase the efficiency of seafloor mapping and thus make the ambitious goals of Seabed 2030 more likely to be achieved.
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22.
  • Melin, Charlotta Bylund, et al. (författare)
  • Simulations of moisture gradients in wood subjected to changes in relative humidity and temperature due to climate change
  • 2018
  • Ingår i: Geosciences (Switzerland). - : MDPI AG. - 2076-3263. ; 8:10
  • Tidskriftsartikel (refereegranskat)abstract
    • Climate change is a growing threat to cultural heritage buildings and objects. Objects housed in historic buildings are at risk because the indoor environments in these buildings are difficult to control and often influenced by the outdoor climate. Hygroscopic materials, such as wood, will gain and release moisture during changes in relative humidity and temperature. These changes cause swelling and shrinkage, which may result in permanent damage. To increase the knowledge of climate-induced damage to heritage objects, it is essential to monitor moisture transport in wood. Simulation models need to be developed and improved to predict the influence of climate change. In a previous work, relative humidity and temperature was monitored at different depths inside wooden samples subjected to fluctuating climate over time. In this article, two methods, the hygrothermal building simulation software WUFI® Pro and the Simplified model, were compared in relation to the measured data. The conclusion was that both methods can simulate moisture diffusion and transport in wooden object with a sufficient accuracy. Using the two methods for predicted climate change data show that the mean RH inside wood is rather constant, but the RH minimum and maximum vary with the predicted scenario and the type of building used for the simulation.
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23.
  • Merisalu, Johanna, 1990, et al. (författare)
  • A Framework for Risk-Based Cost-Benefit Analysis for Decision Support on Hydrogeological Risks in Underground Construction
  • 2021
  • Ingår i: Geosciences (Switzerland). - : MDPI AG. - 2076-3263. ; 11:2, s. 1-19
  • Tidskriftsartikel (refereegranskat)abstract
    • Construction below the ground surface and underneath the groundwater table is often associated with groundwater leakage and drawdowns in the surroundings which subsequently can result in a wide variety of risks. To avoid groundwater drawdown-associated damages, risk-reducing measures must often be implemented. Due to the hydrogeological system's inherent variability and our incomplete knowledge of its conditions, the effects of risk-reducing measures cannot be fully known in advance and decisions must inevitably be made under uncertainty. When implementing risk-reducing measures there is always a trade-off between the measures' benefits (reduced risk) and investment costs which needs to be balanced. In this paper, we present a framework for decision support on measures to mitigate hydrogeological risks in underground construction. The framework is developed in accordance with the guidelines from the International Standardization Organization (ISO) and comprises a full risk-management framework with focus on risk analysis and risk evaluation. Cost-benefit analysis (CBA) facilitates monetization of consequences and economic evaluation of risk mitigation. The framework includes probabilistic risk estimation of the entire cause-effect chain from groundwater leakage to the consequences of damage where expert elicitation is combined with data-driven and process-based methods, allowing for continuous updating when new knowledge is obtained.
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24.
  • Næraa, Tomas, et al. (författare)
  • The ca. 2785–2805 Ma high temperature ilivertalik intrusive complex of southern west Greenland
  • 2018
  • Ingår i: Geosciences (Switzerland). - : MDPI AG. - 2076-3263. ; 8:9
  • Tidskriftsartikel (refereegranskat)abstract
    • Ferroan granitoid intrusions are rare in the Archaean rock record, but have played a large role in the evolution of the Proterozoic crust, particular in relation to anorthosite-mangerite-charnockite-granite suites. Here we discuss the petrogenesis of the ca. 2785–2805 Ma ferroan Ilivertalik Intrusive Complex, which has many geochemical similarities to Proterozoic iron rich granitoids. We present major and trace element whole rock chemistry and combined in-situ zircon U-Pb, Hf and O isotope data. The intrusive complex divides into: (i) minor tabular units of mainly diorite-tonalite compositions, which are typically situated along contacts to the host basement and (ii) interior larger, bodies of mainly granite-granodiorite composition. Geochemically these two unites display continuous to semi-continuous trends in Haker-diagrams. Whole rock REE enrichment display increases from Yb to La, from 10–25 to 80–100 times chondrite, respectively. The diorite-tonalite samples are generally more enriched in REE compared to the granite-granodiorite samples. The complex has hafnium isotope compositions from around +1.5 to −2.5 epsilon units and δ18O compositions in the range of 6.3 to 6.6‰. The complex is interpreted to be derived from partial melting in a crustal source region during anomalously high crustal temperatures.
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25.
  • Olafsdottir, Elin Asta, et al. (författare)
  • Open-source MASW inversion tool aimed at shear wave velocity profiling for soil site explorations
  • 2020
  • Ingår i: Geosciences. - : MDPI AG. - 2076-3263. ; 10:8, s. 1-30
  • Tidskriftsartikel (refereegranskat)abstract
    • The shear wave velocity profile is of primary interest for geological characterization of soil sites and elucidation of near-surface structures. Multichannel Analysis of Surface Waves (MASW) is a seismic exploration method for determination of near-surface shear wave velocity profiles by analyzing Rayleigh wave propagation over a wide range of wavelengths. The inverse problem faced during the application of MASW involves finding one or more layered soil models whose theoretical dispersion curves match the observed dispersion characteristics. A set of open-source MATLAB-based tools for acquiring and analyzing MASW field data, MASWaves, has been under development in recent years. In this paper, a new tool, using an efficient Monte Carlo search technique, is introduced to conduct the inversion analysis in order to provide the shear wave velocity profile. The performance and applicability of the inversion scheme is demonstrated with synthetic datasets and field data acquired at a well-characterized geotechnical research site. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
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26.
  • Paulo, Carlos, et al. (författare)
  • Effects of phosphorus in growth media on biomineralization and cell surface properties of marine cyanobacteria synechococcus
  • 2018
  • Ingår i: Geosciences (Switzerland). - : MDPI AG. - 2076-3263. ; 8:12
  • Tidskriftsartikel (refereegranskat)abstract
    • Through geological time, cyanobacterial picoplankton have impacted the global carbon cycle by sequestrating CO 2 and forming authigenic carbonate minerals. Various studies have emphasized the cyanobacterial cell envelopes as nucleation sites for calcium carbonate formation. Little is known, however, about how environmental conditions (e.g., nutrient content) trigger a cell surface and its properties and, consequently, influence biomineralization. Our study aims to understand how phosphorus (P) concentration impacts the properties of cell surfaces and cell–mineral interactions. Changes to the surface properties of marine Synechococcus strains grown under various P conditions were characterized by potentiometric titrations, X-ray photoelectron spectroscopy (XPS), and tip-enhanced Raman spectroscopy (TERS). Biomineralization experiments were performed using cyanobacterial cells, which were grown under different P concentrations and exposed to solutions slightly oversaturated with respect to calcium carbonate. We observed the changes induced by different P conditions in the macromolecular composition of the cyanobacteria cell envelope and its consequences for biomineralization. The modified properties of cell surfaces were linked to carbonate precipitation rates and mineral morphology from biomineralization experiments. Our analysis shows that the increase of phosphoryl groups and surface charge, as well as the relative proportion of polysaccharides and proteins, can impact carbonate precipitation by picocyanobacteria.
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27.
  • Peace, Alexander L., et al. (författare)
  • Evidence for Basement Reactivation during the Opening of the Labrador Sea from the Makkovik Province, Labrador, Canada : Insights from Field Data and Numerical Models
  • 2018
  • Ingår i: Geosciences. - : MDPI. - 2076-3263. ; 8:8
  • Tidskriftsartikel (refereegranskat)abstract
    • The onshore exposures adjacent to modern, offshore passive continental margins may preserve evidence of deformation from the pre-, syn-, and post-rift phases of continental breakup that allow us to investigate the processes associated with and controlling rifting and breakup. Here, we characterize onshore brittle deformation and pre-rift basement metamorphic mineral fabric from onshore Labrador in Eastern Canada in the Palaeoproterozoic Aillik Domain of the Makkovik Province. Stress inversion (1) was applied to these data and then compared to (2) numerical models of hybrid slip and dilation tendency, (3) independent calculations of the regional geopotential stress field, and (4) analyses of palaeo-stress in proximal regions from previous work. The stress inversion shows well-constrained extensional deformation perpendicular to the passive margin, likely related to pre-breakup rifting in the proto-Labrador Sea. Hybrid slip and dilatation analysis indicates that inherited basement structures were likely oriented in a favorable orientation to be reactivated during rifting. Reconstructed geopotential stresses illuminate changes of the ambient stress field over time and confirm the present paleo-stress estimates. The new results and numerical models provide a consistent picture of the late Mesozoic-Cenozoic lithospheric stress field evolution in the Labrador Sea region. The proto-Labrador Sea region was characterized by a persistent E-W (coast-perpendicular) extensional stress regime, which we interpret as the pre-breakup continental rifting that finally led to continental breakup. Later, the ridge push of the Labrador Sea spreading ridge maintained this general direction of extension. We see indications for anti-clockwise rotation of the direction of extension along some of the passive margins. However, extreme persistent N-S-oriented extension as indicated by studies further north in West Greenland cannot be confirmed.
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28.
  • Pfeffer, M. A., et al. (författare)
  • Ground-Based measurements of the 2014-2015 holuhraun volcanic cloud (Iceland)
  • 2018
  • Ingår i: Geosciences (Switzerland). - : MDPI AG. - 2076-3263. ; 8:1
  • Tidskriftsartikel (refereegranskat)abstract
    • The 2014-2015 Bárðarbunga fissure eruption at Holuhraun in central Iceland was distinguished by the high emission of gases, in total 9.6 Mt SO 2 , with almost no tephra. This work collates all ground-based measurements of this extraordinary eruption cloud made under particularly challenging conditions: remote location, optically dense cloud with high SO 2 column amounts, low UV intensity, frequent clouds and precipitation, an extensive and hot lava field, developing ramparts, and high-latitude winter conditions. Semi-continuous measurements of SO 2 flux with three scanning DOAS instruments were augmented by car traverses along the ring-road and along the lava. The ratios of other gases/SO 2 were measured by OP-FTIR, MultiGAS, and filter packs. Ratios of SO 2 /HCl = 30-110 and SO 2 /HF = 30-130 show a halogen-poor eruption cloud. Scientists on-site reported extremely minor tephra production during the eruption. OPC and filter packs showed low particle concentrations similar to non-eruption cloud conditions. Three weather radars detected a droplet-rich eruption cloud. Top of eruption cloud heights of 0.3-5.5 km agl were measured with ground-and aircraft-based visual observations, web camera and NicAIR II infrared images, triangulation of scanning DOAS instruments, and the location of SO 2 peaks measured by DOAS traverses. Cloud height and emission rate measurements were critical for initializing gas dispersal simulations for hazard forecasting.
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29.
  • Rashidi, Amin, et al. (författare)
  • A Review of Tsunami Hazards in the Makran Subduction Zone
  • 2020
  • Ingår i: Geosciences. - : MDPI AG. - 2076-3263. ; 10:9
  • Forskningsöversikt (refereegranskat)abstract
    • The uncertain tsunamigenic potential of the Makran Subduction Zone (MSZ) has made it an interesting natural laboratory for tsunami-related studies. This study aims to review the recent activities on tsunami hazard in the Makran subduction zone with a focus on deterministic and probabilistic tsunami hazard assessments. While almost all studies focused on tsunami hazard from the Makran subduction thrust, other local sources such as splay faults and landslides can be also real threats in the future. Far-field tsunami sources such as Sumatra-Andaman and Java subduction zones, commonly lumped as the Sunda subduction zone, do not seem to pose a serious risk to the Makran coastlines. The tsunamigenic potential of the western segment of the MSZ should not be underestimated considering the new evidence from geological studies and lessons from past tsunamis in the world. An overview of the results of tsunami hazard studies shows that the coastal area between Kereti to Ormara along the shoreline of Iran-Pakistan and the coastal segment between Muscat and Sur along Oman's shoreline are the most hazardous areas. Uncertainties in studying tsunami hazard for the Makran region are large. We recommend that future studies mainly focus on the role of thick sediments, a better understanding of the plates interface geometry, the source mechanism and history of extreme-wave deposits, the contribution of other local tsunamigenic sources and vulnerability assessment for all coastlines of the whole Makran region.
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30.
  • Richter, M., et al. (författare)
  • Assessment of Five Monazite Reference Materials for U-Th/Pb Dating Using Laser-Ablation ICP-MS
  • 2019
  • Ingår i: Geosciences. - : MDPI AG. - 2076-3263. ; 9:9
  • Tidskriftsartikel (refereegranskat)abstract
    • Monazite is a common accessory phosphate mineral that occurs under a wide range of pressure and temperature conditions in sedimentary, metamorphic and igneous rocks. Monazite contains high amounts of Th and U, rendering single monazite grains suitable for in-situ U-Th/Pb dating using laser ablation inductively-coupled mass spectrometry (LA-ICP-MS). Two key aspects of monazite dating that are critical for accurate age data with maximum precision are (i) optimized instrumental conditions to minimize analytical scatter and (ii) a well characterized reference material to ensure the accuracy of the obtained aged. Here, we analyzed five monazite reference materials (USGS 44069, 94-222, MAdel, Moacir and Thompson Mine Monazite) for their U-Th/Pb ages using LA-ICP-MS technique and applied a variety of laser spot diameters and repetition rates to find the best operational conditions to achieve accurate age data while maintaining maximum precision. We find that a spot diameter of 10 mu m and a repetition rate of 10 Hz yield the most precise ages with a deviation of +/- 2.0% from their respective high-precision U/Pb literature age data. Ages were reproduced in three different LA-ICP-MS laboratories using these parameters. Each reference material was tested for its suitability as a matrix-matched age reference material. For this, a rotating, iterative approach was adopted in which one reference monazite was used as calibration reference material against all others, which were treated as unknowns. The results reveal that USGS 44069, 94-222, Thompson Mine Monazite and MAdel all agree with their respective calculated ages and ID-TIMS reference ages and thus are suggested as suitable calibration reference materials. Moacir, however, appears slightly older than previously suggested (up to 4%), thus, caution is advised here when using Moacir as reference material for U-Th/Pb LA-ICP-MS dating in the absence of further absolute age calibration.
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31.
  • Rodrigues, Luiz, et al. (författare)
  • Molecular and Isotopic Composition of Hydrate-Bound, Dissolved and Free Gases in the Amazon Deep-Sea Fan and Slope Sediments, Brazil
  • 2019
  • Ingår i: Geosciences. - : MDPI. - 2076-3263. ; 9:2, s. 1-15
  • Tidskriftsartikel (refereegranskat)abstract
    • In this work, we investigated the molecular stable isotope compositions of hydrate-bound and dissolved gases in sediments of the Amazon deep-sea fan and adjacent continental slope, Foz do Amazonas Basin, Brazil. Some cores were obtained in places with active gas venting on the seafloor and, in one of the locations, the venting gas is probably associated with the dissociation of hydrates near the edge of their stability zone. Results of the methane stable isotopes (δ13C and δD) of hydrate-bound and dissolved gases in sediments for the Amazon fan indicated the dominant microbial origin of methane via carbon dioxide reduction, in which 13C and deuterium isotopes were highly depleted (δ13C and δD of −102.2% to −74.2% V-PDB and −190 to −150% V-SMOW, respectively). The combination of C1/(C2+C3) versus δ13C plot also suggested a biogenic origin for methane in all analysed samples (commonly >1000). However, a mixture of thermogenic and microbial gases was suggested for the hydrate-bound and dissolved gases in the continental slope adjacent to the Amazon fan, in which the combination of chemical and isotopic gas compositions in the C1/(C2+C3) versus δ13C plot were <100 in one of the recovered cores. Moreover, the δ13C-ethane of −30.0% indicates a thermogenic origin.
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32.
  • Sallstedt, Therese, et al. (författare)
  • Instant Attraction : Clay Authigenesis in Fossil Fungal Biofilms
  • 2019
  • Ingår i: Geosciences. - Basel : MDPI. - 2076-3263. ; 9:9, s. 1-21
  • Forskningsöversikt (refereegranskat)abstract
    • Clay authigenesis associated with the activity of microorganisms is an important process for biofilm preservation and may provide clues to the formation of biominerals on the ancient Earth. Fossilization of fungal biofilms attached to vesicles or cracks in igneous rock, is characterized by fungal-induced clay mineralization and can be tracked in deep rock and deep time, from late Paleoproterozoic (2.4 Ga), to the present. Here we briefly review the current data on clay mineralization by fossil fungal biofilms from oceanic and continental subsurface igneous rock. The aim of this study was to compare the nature of subsurface fungal clays from different igneous settings to evaluate the importance of host rock and ambient redox conditions for clay speciation related to fossil microorganisms. Our study suggests that the most common type of authigenic clay associated with pristine fossil fungal biofilms in both oxic (basaltic) and anoxic (granitic) settings are montmorillonite-like smectites and confirms a significant role of fungal biofilms in the cycling of elements between host rock, ocean and secondary precipitates. The presence of life in the deep subsurface may thus prove more significant than host rock geochemistry in directing the precipitation of authigenic clays in the igneous crust, the extent of which remains to be fully understood.
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33.
  • Serovaiskii, Aleksandr, et al. (författare)
  • The Role of Iron Carbide in the Abyssal Formation of Hydrocarbons in the Upper Mantle
  • 2021
  • Ingår i: Geosciences. - : MDPI AG. - 2076-3263. ; 11:4
  • Tidskriftsartikel (refereegranskat)abstract
    • The existence of iron carbide in the upper mantle allows an assumption to be made about its possible involvement in the abyssal abiogenic synthesis of hydrocarbons as a carbon donor. Interacting with hydrogen donors of the mantle, iron carbide can form hydrocarbon fluid. In order to investigate the role of iron carbide in the abiogenic synthesis of hydrocarbons, the chemical reaction between cementite Fe3C and water was modeled under thermobaric conditions, corresponding to the upper mantle. A series of experiments were conducted using a high-pressure high-temperature Toroid-type large reactive volume unit with further analysis by means of gas chromatography. The results demonstrated the formation of hydrocarbon fluid in a wide range of thermobaric conditions (873-1223 K, 2.5-6.0 GPa) corresponding to the upper mantle. A strong correlation between the composition of the fluid and the pT conditions of the synthesis was illustrated in the investigation. The higher temperature of the synthesis resulted in the formation of a "poor" hydrocarbon mixture, primarily comprising methane, while a higher pressure yielded the opposite effect, converting iron carbide into a complex hydrocarbon system, containing normal and iso-alkanes up to C-7 and benzene. This correlation explains the diversity of hydrocarbon systems produced experimentally, thus expanding the thermobaric range of the possible existence of complex hydrocarbon systems in the upper mantle. The results support the suggestion that the carbide-water reaction can be a source of both the carbon and hydrogen required for the abyssal abiogenic synthesis of hydrocarbons.
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34.
  • Sivalneva, Olga, et al. (författare)
  • Structure and Composition of Basement and Sedimentary Cover in the Southwestern Part of the Siljan Ring, Central Sweden : New Data from the C-C-1 Drill Core
  • 2021
  • Ingår i: Geosciences. - : MDPI AG. - 2076-3263. ; 11:7
  • Tidskriftsartikel (refereegranskat)abstract
    • The results from the geological and geophysical investigations of the Siljan Ring impact structure (central Sweden) have shown that the Paleozoic sedimentary succession and the Precambrian basement were strongly affected by complex deformational processes. Studies of a new drill core from the C-C-1 well provide valuable additional information necessary for the reconstruction of the geological setting in the southwestern part of the Siljan Ring. It was found that the contact between the basement and the sedimentary cover is tectonic, not normal sedimentary, in origin. The basement interval comprises Precambrian metavolcanic and metasedimentary rocks with a single mafic intrusion (gabbro-dolerite) in the upper part. The rocks have only been partially metamorphosed. The intercalation of calcareous mudstones, skeletal wackstones, and black shales in the sedimentary cover interval is not consistent with the regional lithostratigraphy scheme. Thus, more likely that the sedimentary sequence is not complete as a result of tectonic displacements, and a significant part of the Lower and Middle Ordovician succession is missing. The Post-Proterozoic tectonic reactivation and impact event also caused the formation of four types of fracture. The third type of fracture is accompanied by cataclastic zones and probably have an impact-related nature. In the highly fractured basement rocks, a dissolution along the second type of fracture has resulted in the development of open vugs. Open vugs and microporosity in cataclastic zones have been considered to be an effective storage space for hydrocarbons.
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35.
  • Sjöberg, Lars E. (författare)
  • Topographic effects in geoid determinations
  • 2018
  • Ingår i: Geosciences. - : MDPI AG. - 2076-3263. ; 8:4
  • Tidskriftsartikel (refereegranskat)abstract
    • Traditionally, geoid determination is applied by Stokes’ formula with gravity anomalies after removal of the attraction of the topography by a simple or refined Bouguer correction, and restoration of topography by the primary indirect topographic effect (PITE) after integration. This technique leads to an error of the order of the quasigeoid-to-geoid separation, which is mainly due to an incomplete downward continuation of gravity from the surface to the geoid. Alternatively, one may start from the modern surface gravity anomaly and apply the direct topographic effect on the anomaly, yielding the no-topography gravity anomaly. After downward continuation of this anomaly to sea-level and Stokes integration, a theoretically correct geoid height is obtained after the restoration of the topography by the PITE. The difference between the Bouguer and no-topography gravity anomalies (on the geoid or in space) is the “secondary indirect topographic effect”, which is a necessary correction in removing all topographic signals. In modern applications of an Earth gravitational model (EGM) in geoid determination a topographic correction is also needed in continental regions. Without the correction the error can range to a few metres in the highest mountains. The remove-compute-restore and Royal Institute of Technology (KTH) techniques for geoid determinations usually employ a combination of Stokes’ formula and an EGM. Both techniques require direct and indirect topographic corrections, but in the latter method these corrections are merged as a combined topographic effect on the geoid height. Finally, we consider that any uncertainty in the topographic density distribution leads to the same error in gravimetric and geometric geoid estimates, deteriorating GNSS-levelling as a tool for validating the topographic mass distribution correction in a gravimetric geoid model.
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36.
  • Tillberg, Mikael, 1990, et al. (författare)
  • Re-Evaluating the Age of Deep Biosphere Fossils in the Lockne Impact Structure
  • 2019
  • Ingår i: Geosciences. - Basel : MDPI AG. - 2076-3263. ; 9:5
  • Tidskriftsartikel (refereegranskat)abstract
    • Impact-generated hydrothermal systems have been suggested as favourable environments for deep microbial ecosystems on Earth, and possibly beyond. Fossil evidence from a handful of impact craters worldwide have been used to support this notion. However, as always with mineralized remains of microorganisms in crystalline rock, certain time constraints with respect to the ecosystems and their subsequent fossilization are difficult to obtain. Here we re-evaluate previously described fungal fossils from the Lockne crater (458 Ma), Sweden. Based on in-situ Rb/Sr dating of secondary calcite-albite-feldspar (356.6 +/- 6.7 Ma) we conclude that the fungal colonization took place at least 100 Myr after the impact event, thus long after the impact-induced hydrothermal activity ceased. We also present microscale stable isotope data of C-13-enriched calcite suggesting the presence of methanogens contemporary with the fungi. Thus, the Lockne fungi fossils are not, as previously thought, related to the impact event, but nevertheless have colonized fractures that may have been formed or were reactivated by the impact. Instead, the Lockne fossils show similar features as recent findings of ancient microbial remains elsewhere in the fractured Swedish Precambrian basement and may thus represent a more general feature in this scarcely explored habitat than previously known.
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37.
  • Craddock, John P., et al. (författare)
  • Deformation of the European Plate (58-0 Ma) : Evidence from Calcite Twinning Strains
  • 2022
  • Ingår i: Geosciences. - : MDPI AG. - 2076-3263. ; 12:6
  • Tidskriftsartikel (refereegranskat)abstract
    • We present a data set of calcite twinning strain results (n = 209 samples; 9919 measured calcite twins) from the internal Alpine nappes northwestward across the Alps and Alpine foreland to the older extensional margin along the Atlantic coast in Ireland. Along the coast of Northern Ireland, Cretaceous chalks and Tertiary basalts are cross-cut by calcite veins and offset by calcite-filled normal and strike-slip faults. Both Irish sample suites (n = 16 with four U-Pb vein calcite ages between 70–42 Ma) record a sub-horizontal SW-NE shortening strain with vertical extension and no strain overprint. This sub-horizontal shortening is parallel to the margin of the opening of the Atlantic Ocean (~58 Ma), and this penetrative fabric is only observed ~100 km inboard of the margin to the southeast. The younger, collisional Alpine orogen (~40 Ma) imparted a stress–strain regime dominated by SE-NW sub-horizontal shortening ~1200 km northwest from the Alps preserved in Mesozoic limestones and calcite veins (n = 32) in France, Germany and Britain. This layer-parallel shortening strain (−3.4%, 5% negative expected values) is preserved across the foreland in the plane of Alpine thrust shortening (SE-NW) along with numerous outcrop-scale contractional structures (i.e., folds, thrust faults). Calcite veins were observed in the Alpine foreland in numerous orientations and include both a SE-NW layer-parallel shortening fabric (n = 11) and a sub-vertical NE-SW vein-parallel shortening fabric (n = 4). Alpine foreland strains are compared with twinning strains from the frontal Jura Mountains (n = 9; layer-parallel shortening), the Molasse basin (n = 26; layer-parallel and layer-normal shortening), Pre-Alp nappes (n = 39; layer-parallel and layer-normal shortening), Helvetic and Penninic nappes (Penninic klippe; n = 46; layer-parallel and layer-normal shortening plus four striated U-Pb calcite vein ages ~24 Ma) and calcsilicates from the internal Tauern window (n = 4; layer-normal shortening). We provide a chronology of the stress–strain history of the European plate from 58 Ma through the Alpine orogen.
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38.
  • Cristóbal, Andrés, et al. (författare)
  • Automatic Characterization of Block-In-Matrix Rock Outcrops through Segmentation Algorithms and Its Application to an Archaeo-Mining Case Study
  • 2024
  • Ingår i: Geosciences. - : MDPI AG. - 2076-3263. ; 14:2
  • Tidskriftsartikel (refereegranskat)abstract
    • The mechanical behavior of block-in-matrix materials is heavily dependent on their block content. This parameter is in most cases obtained through visual analyses of the ground through digital imagery, which provides the areal block proportion (ABP) of the area analyzed. Nowadays, computer vision models have the capability to extract knowledge from the information stored in these images. In this research, we analyze and compare classical feature-detection algorithms with state-of-the-art models for the automatic calculation of the ABP parameter in images from surface and underground outcrops. The outcomes of this analysis result in the development of a framework for ABP calculation based on the Segment Anything Model (SAM), which is capable of performing this task at a human level when compared with the results of 32 experts in the field. Consequently, this model can help reduce human bias in the estimation of mechanical properties of block-in-matrix materials as well as contain underground technical problems due to mischaracterization of rock block quantities and dimensions. The methodology used to obtain the ABP at different outcrops is combined with estimates of the rock matrix properties and other characterization techniques to mechanically characterize the block-in-matrix materials. The combination of all these techniques has been applied to analyze, understand and try, for the first time, to model Roman gold-mining strategies in an archaeological site in NW Spain. This mining method is explained through a 2D finite-element method numerical model.
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39.
  • Fichtner, Vanessa, et al. (författare)
  • The Relationship between Bacterial Sulfur Cycling and Ca/Mg Carbonate Precipitation : Old Tales and New Insights from Lagoa Vermelha and Brejo do Espinho, Brazil
  • 2023
  • Ingår i: Geosciences. - : MDPI. - 2076-3263. ; 13:8
  • Tidskriftsartikel (refereegranskat)abstract
    • Over the few past decades, the concept of microbial sulfur cycling catalyzing the precipitation of CaMg (CO3)2 at low temperatures (<40 °C) has been studied intensely. In this respect, two hypersaline lagoons, Lagoa Vermelha and Brejo do Espinho, in Brazil, have been the subject of numerous studies investigating sedimentary Ca/Mg carbonate formation. Here, we present the sulfur and oxygen isotopic compositions of dissolved sulfate from surface water, as well as sulfate and sulfide from pore-water (δ34SSO4, δ18OSO4, and δ34SH2S), the sulfur isotopic composition of sedimentary pyrite (δ34SCRS), and sulfur and oxygen isotopic compositions of carbonate-associated sulfate (CAS, δ34SCAS and δ18OCAS). The pore-water profiles at Lagoa Vermelha indicate ongoing bacterial sulfate reduction by increasing δ34SSO4, δ18OSO4 and δ34SCRS values downcore. At Brejo do Espinho, the pore-water profiles displayed no depth-dependent isotope trends; the Ca/Mg ratio was, on average, lower, and the δ18OSO4 values in both surface and pore-water were strongly enriched in 18O. There was an overall mismatch between δ34SSO4 and the significantly higher δ34SCAS values. A negative correlation was observed between the Ca/Mg ratio and higher δ34SCAS values. The results show that the size difference between the two lagoons induces differences in the intensity of evaporation, which leads to the increased secretion of extrapolymeric substances (EPSs) by microbes in the smaller Brejo do Espinho. EPS provides the microenvironment where Ca/Mg carbonate can nucleate and preserve increased δ34SCAS values. Apart from EPS, increased sulfur oxidation is proposed to be a second factor causing relative enrichment of Ca/Mg carbonates at Brejo do Espinho. Our results emphasize the role of evaporative processes on Ca/Mg carbonate formation, and indicate that the respective δ34SCAS values reflect microenvironments rather than preserving an open marine δ34SSO4 signature.
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40.
  • Flowerdew, Michael J., et al. (författare)
  • The Importance of Eurekan Mountains on Cenozoic Sediment Routing on the Western Barents Shelf
  • 2023
  • Ingår i: Geosciences. - : MDPI AG. - 2076-3263. ; 13:3, s. 91-91
  • Tidskriftsartikel (refereegranskat)abstract
    • The importance of topography generated by Eocene Eurekan deformation as a sediment source for sandstones deposited on the western Barents Shelf margin is evaluated through a sediment provenance study conducted on wellbore materials retrieved from Spitsbergen and from the Vestbakken Volcanic Province and the Sørvestsnaget Basin in the southwest Barents Sea. A variety of complementary techniques record a provenance change across the Paleocene-Eocene boundary in wellbore BH 10-2008, which samples Paleogene strata of the Central Tertiary Basin in Spitsbergen. Sandstones containing K-feldspar with radiogenic Pb isotopic compositions, chrome spinel in the heavy mineral assemblage, and detrital zircons and rutiles with prominent Palaeoproterozoic and Late Palaeozoic—Early Mesozoic U-Pb age populations are up-section replaced by sandstone containing albitic plagioclase feldspar, metasedimentary schist rock fragments, a heavy mineral assemblage with abundant chloritoid, metamorphic apatite with low REE contents, metapelitic rutile with Silurian U-Pb ages and zircons with predominantly Archaean and Palaeoproterozoic U-Pb age populations. Our results clearly demonstrate the well-known regional change in source area from an exposed Barents Shelf terrain east of the Central Tertiary Basin during the Paleocene to the emerging Eurekan mountains west and north of the Central Tertiary Basin during the Eocene. Eocene sandstones deposited in the marginal basins of the southwestern Barents Shelf, which were sampled in wellbores 7316/5-1 and 7216/11-1S, contain elements of both the Eurekan and the eastern Barents Shelf provenance signatures. The mixing of the two sand types and delivery to the southwest margin of the Barents Shelf is consistent with a fill and spill model for the Central Teritary Basin, with transport of Eurekan-derived sediment east then south hundreds of kilometres across the Shelf.
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41.
  • Gao, Jingyu, 1992-, et al. (författare)
  • A Comparison Study of Explicit and Implicit 3-D Transient Electromagnetic Forward Modeling Schemes on Multi-Resolution Grid
  • 2021
  • Ingår i: Geosciences. - : MDPI. - 2076-3263. ; 11:6
  • Tidskriftsartikel (refereegranskat)abstract
    • This study compares the efficiency of 3-D transient electromagnetic forward modeling schemes on the multi-resolution grid for various modeling scenarios. We developed time-domain finite-difference modeling based on the explicit scheme earlier. In this work, we additionally implement 3-D transient electromagnetic forward modeling using the backward Euler implicit scheme. The iterative solver is used for solving the system of equations and requires a proper initial guess that has significant effect on the convergence. The standard approach usually employs the solution of a previous time step as an initial guess, which might be too conservative. Instead, we test various initial guesses based on the linear extrapolation or linear combination of the solutions from several previous steps. We build up the implicit scheme forward modeling on the multi-resolution grid, which allows for the adjustment of the horizontal resolution with depth, hence improving the performance of the forward operator. Synthetic examples show the implicit scheme forward modeling using the linearly combined initial guess estimate on the multi-resolution grid additionally reduces the run time compared to the standard initial guess approach. The result of comparison between the implicit scheme developed here with the previously developed explicit scheme shows that the explicit scheme modeling is more efficient for more conductive background models often found in environmental studies. However, the implicit scheme modeling is more suitable for the simulation with highly resistive background models, usually occurring in mineral exploration scenarios. Thus, the inverse problem can be solved using more efficient forward solution depending on the modeling setup and background resistivity.
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42.
  • Gonzales, Andrés, et al. (författare)
  • Electrical resistivity tomography and induced polarization for mapping the subsurface of alluvial fans : A case study in Punata (Bolivia)
  • 2016
  • Ingår i: Geosciences (Switzerland). - : MDPI AG. - 2076-3263. ; 6:4
  • Tidskriftsartikel (refereegranskat)abstract
    • Conceptual models of aquifer systems can be refined and complemented with geophysical data, and they can assist in understanding hydrogeological properties such as groundwater storage capacity. This research attempts to use geoelectrical methods, Electrical Resistivity Tomography and Induced Polarization parameters, for mapping the subsurface in alluvial fans and to demonstrate its applicability; the Punata alluvial fan was used as a case study. The resistivity measurements proved to be a good tool for mapping the subsurface in the fan, especially when used in combination with Induced Polarization parameters (i.e., Normalized Chargeability). The Punata alluvial fan characterization indicated that the top part of the subsurface is composed of boulders in a matrix of finer particles and that the grain size decreases with depth; the electrical resistivity of these deposits ranged from 200 to 1000 Ωm, while the values of normalized chargeability were lower than 0.05 mS/m. The bottom of the aquifer system consisted of a layer with high clay content, and the resistivity ranged from 10 to 100 Ωm, while the normalized chargeability is higher than 0.07 mS/m. With the integration of these results and lithological information, a refined conceptual model is proposed; this model gives a more detailed description of the local aquifer system. It can be concluded that geoelectrical methods are useful for mapping aquifer systems in alluvial fans.
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43.
  • Nikiforov, Sergey, et al. (författare)
  • The Extent of Glaciation in the Pechora Sea, Eurasian Arctic, Based on Submarine Glacial Landforms
  • 2023
  • Ingår i: Geosciences. - : MDPI AG. - 2076-3263. ; 13:2
  • Tidskriftsartikel (refereegranskat)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 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.
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44.
  • Nivorlis, Aristeidis, et al. (författare)
  • Multidisciplinary characterization of chlorinated solvents contamination and in-situ remediation with the use of the direct current resistivity and time-domain induced polarization tomography
  • 2019
  • Ingår i: Geosciences (Switzerland). - : MDPI AG. - 2076-3263. ; 9:12
  • Tidskriftsartikel (refereegranskat)abstract
    • Soil contamination is a widespread problem and action needs to be taken in order to prevent damage to the groundwater and the life around the contaminated sites. In Sweden, it is estimated that more than 80,000 sites are potentially contaminated, and therefore, there is a demand for investigations and further treatment of the soil. In this paper, we present the results from a methodology applied in a site contaminated with chlorinated solvents, for characterization of the contamination in order to plan the remediation and to follow-up the initial step of in-situ remediation in an efficient way. We utilized the results from three different methods; membrane interface probe for direct measurement of the contaminant concentrations; seismic refraction tomography for investigating the depth to the bedrock interface; and direct current resistivity and time-domain induced polarization tomography to acquire a high-resolution imaging of the electrical properties of the subsurface. The results indicate that our methodology is very promising in terms of site characterization, and furthermore, has great potential for real-time geophysical monitoring of contaminated sites in the future.
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45.
  • Pointon, Michael A., et al. (författare)
  • A Multi-proxy Provenance Study of Late Carboniferous to Middle Jurassic Sandstones in the Eastern Sverdrup Basin and Its Bearing on Arctic Palaeogeographic Reconstructions
  • 2022
  • Ingår i: Geosciences. - : MDPI AG. - 2076-3263. ; 13:1, s. 10-10
  • Tidskriftsartikel (refereegranskat)abstract
    • A multi-proxy provenance study of Late Carboniferous to Middle Jurassic sandstones from the eastern Sverdrup Basin was undertaken employing optical petrography and heavy mineral analysis, chemical analysis of apatite, garnet and rutile grains, as well as detrital zircon U–Pb geochronology and Hf isotope analysis. Late Carboniferous to Middle Jurassic strata on the southern basin margin are inferred as being predominantly reworked from Silurian to Devonian strata within the adjacent Franklinian Basin succession. Higher-grade metamorphic detritus appeared during Middle to Late Triassic times and indicates exhumation and erosion of lower (Neoproterozoic to Cambrian) levels within the Franklinian Basin succession and/or a direct detrital input from the Canadian-Greenland Shield. The provenance of northern-derived sediments is more enigmatic owing to the subsequent opening of the Arctic Ocean. Northern-derived Middle Permian to Early Triassic sediments were likely derived from proximal areas of the Chukotkan part of the Arctic Alaska-Chukotka microplate. Late Triassic northern-derived sediments have different detrital zircon U–Pb age spectra from Middle Permian to Early Triassic ones and were likely derived from the Uralian orogenic belt and/or the Arctic Uralides. The loss of this sand input during latest Triassic times is interpreted to reflect drainage reorganisation farther upstream on the Barents Shelf. Middle Jurassic sands in the northern and axial parts of the basin were largely reworked from local northern-derived Late Triassic strata. This may have been facilitated by rift flank uplift of the northern basin margin in response to rifting in the adjacent proto-Amerasia Basin.
  •  
46.
  • Rößler, Sebastian, et al. (författare)
  • Remote Sensing of Snow Cover Variability and Its Influence on the Runoff of Sápmi’s Rivers
  • 2021
  • Ingår i: Geosciences. - : MDPI AG. - 2076-3263. ; 11:3
  • Tidskriftsartikel (refereegranskat)abstract
    • The boreal winter 2019/2020 was very irregular in Europe. While there was very little snow in Central Europe, the opposite was the case in northern Fenno-Scandia, particularly in the Arctic. The snow cover was more persistent here and its rapid melting led to flooding in many places. Since the last severe spring floods occurred in the region in 2018, this raises the question of whether more frequent occurrences can be expected in the future. To assess the variability of snowmelt related flooding we used snow cover maps (derived from the DLR’s Global SnowPack MODIS snow product) and freely available data on runoff, precipitation, and air temperature in eight unregulated river catchment areas. A trend analysis (Mann-Kendall test) was carried out to assess the development of the parameters, and the interdependencies of the parameters were examined with a correlation analysis. Finally, a simple snowmelt runoff model was tested for its applicability to this region. We noticed an extraordinary variability in the duration of snow cover. If this extends well into spring, rapid air temperature increases leads to enhanced thawing. According to the last flood years 2005, 2010, 2018, and 2020, we were able to differentiate between four synoptic flood types based on their special hydrometeorological and snow situation and simulate them with the snowmelt runoff model (SRM).
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47.
  • Vandelli, Vittoria, et al. (författare)
  • Towards Enhanced Understanding and Experience of Landforms, Geohazards, and Geoheritage through Virtual Reality Technologies in Education : Lessons from the GeoVT Project
  • 2024
  • Ingår i: Geosciences. - 2076-3263. ; 14:5
  • Tidskriftsartikel (refereegranskat)abstract
    • Virtual reality is a technological development that, among others, has revolutionized Earth sciences. Its advantages include an opportunity to examine places otherwise difficult or impossible to access and it may also become an important component of education, fostering a better understanding of processes and landforms, geohazard awareness, and an appreciation of geoheritage. This paper reports on the GeoVT project, which aims to create a platform to build and disseminate Virtual Field Trips (VFTs) focused on geomorphology, natural hazards associated with geomorphological processes, and geoheritage sites. To put the GeoVT project in context, an overview of applications of VR in geosciences is provided. This paper subsequently proceeds with a presentation of the project and the GeoVT Authoring application, which is an innovative platform designed to help teachers and students, followed by brief presentations of a number of VFTs developed within the project. They address themes such as fluvial landforms and valley development, coastal landforms, evidence of past glaciation, coastal erosion, wildfire effects, mud volcanoes, and landslides.
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