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Geosciences, Volume 8, Issue 9 (September 2018)

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Cover Story (view full-size image) Estuaries occur on coastlines worldwide and represent a complex and dynamic interaction of coastal [...] Read more.
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Open AccessArticle Geological Model of a Storage Complex for a CO2 Storage Operation in a Naturally-Fractured Carbonate Formation
Geosciences 2018, 8(9), 354; https://doi.org/10.3390/geosciences8090354
Received: 23 May 2018 / Revised: 11 September 2018 / Accepted: 12 September 2018 / Published: 19 September 2018
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Abstract
Investigation into geological storage of CO2 is underway at Hontomín (Spain). The storage reservoir is a deep saline aquifer formed by naturally fractured carbonates with low matrix permeability. Understanding the processes that are involved in CO2 migration within these formations is [...] Read more.
Investigation into geological storage of CO2 is underway at Hontomín (Spain). The storage reservoir is a deep saline aquifer formed by naturally fractured carbonates with low matrix permeability. Understanding the processes that are involved in CO2 migration within these formations is key to ensure safe operation and reliable plume prediction. A geological model encompassing the whole storage complex was established based upon newly-drilled and legacy wells. The matrix characteristics were mainly obtained from the newly drilled wells with a complete suite of log acquisitions, laboratory works and hydraulic tests. The model major improvement is the integration of the natural fractures. Following a methodology that was developed for naturally fractured hydrocarbon reservoirs, the advanced characterization workflow identified the main sets of fractures and their main characteristics, such as apertures, orientations, and dips. Two main sets of fracture are identified based upon their mean orientation: North-South and East-West with different fracture density for each the facies. The flow capacity of the fracture sets are calibrated on interpreted injection tests by matching their permeability and aperture at the Discrete Fracture Network scale and are subsequently upscaled to the geological model scale. A key new feature of the model is estimated permeability anisotropy induced by the fracture sets. Full article
(This article belongs to the Special Issue Geological Storage of Gases as a Tool for Energy Transition)
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Open AccessReview Highlights on Geochemical Changes in Archaean Granitoids and Their Implications for Early Earth Geodynamics
Geosciences 2018, 8(9), 353; https://doi.org/10.3390/geosciences8090353
Received: 17 August 2018 / Revised: 7 September 2018 / Accepted: 11 September 2018 / Published: 17 September 2018
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Abstract
The Archaean (4.0–2.5 Ga) continental crust is mainly composed of granitoids, whose geochemical characteristics are a function of their formation mechanisms and components, as well as physical conditions of their source. Therefore, revealing changes in Archaean geodynamic processes requires understanding of geochemical changes [...] Read more.
The Archaean (4.0–2.5 Ga) continental crust is mainly composed of granitoids, whose geochemical characteristics are a function of their formation mechanisms and components, as well as physical conditions of their source. Therefore, revealing changes in Archaean geodynamic processes requires understanding of geochemical changes in Archaean granitoids. This paper compares key geochemical signatures in granitoid occurrences from the Eoarchaean to Neoarchaean Eras and aims to highlight changes or variations in their geochemical signatures. The study is performed by exploring and comparing geochemical and geochronological datasets of Archaean granitoids compiled from literature. The results show that two end-members of sodic TTGs (tonalite–trondhjemite–granodiorite) occur throughout the Archaean: low- and high-HREE (heavy rare earth elements) types. A profound change in granitoid geochemistry occurred between 3.0 and 2.5 Ga when multi-source high-K calc-alkaline granitoid batholiths emerged, possibly indicating the onset of modern-type plate tectonics. Full article
(This article belongs to the Special Issue Geology of the Early Earth – Geodynamic Constraints from Cratons)
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Open AccessReview Tracking the Serpentinite Feet of the Mediterranean Salt Giant
Geosciences 2018, 8(9), 352; https://doi.org/10.3390/geosciences8090352
Received: 27 June 2018 / Revised: 4 September 2018 / Accepted: 12 September 2018 / Published: 17 September 2018
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Abstract
Interpretation of seismic profiles and results of scientific drillings in the Mediterranean subseafloor provided indication of gigantic salt deposits which rarely crop out on land, such as in Sicily. The salt giants were ascribed to the desiccation, driven by the solar energy, of [...] Read more.
Interpretation of seismic profiles and results of scientific drillings in the Mediterranean subseafloor provided indication of gigantic salt deposits which rarely crop out on land, such as in Sicily. The salt giants were ascribed to the desiccation, driven by the solar energy, of the entire basin. Nevertheless, the evaporite model hardly explains deep-sea salt deposits. This paper considers a different hypothesis suggesting that seawater reached NaCl saturation during serpentinization of ultramafic rocks. Solid salts and brine pockets were buried within the serpentinite bodies being later (e.g., in the Messinian) released, due to serpentinite breakdown, and discharged at seafloor as hydrothermal heavy brines. Therefore, sea-bottom layers of brine at gypsum and halite saturation were formed. The model is applicable to the Mediterranean area since geophysical data revealed relicts of an aged (hence serpentinized) oceanic lithosphere, of Tethyan affinity, both in its western “Atlantic” extension (Gulf of Cádiz) and in eastern basins, and xenoliths from Hyblean diatremes (Sicily) provided evidence of buried serpentinites in the central area. In addition, the buoyant behavior of muddled serpentinite and salts (and hydrocarbons) gave rise to many composite diapirs throughout the Mediterranean area. Thus, the Mediterranean “salt giant” consists of several independent geobodies of serpentinite and salts. Full article
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Open AccessArticle Identifying Karst Aquifer Recharge Areas using Environmental Isotopes: A Case Study in Central Italy
Geosciences 2018, 8(9), 351; https://doi.org/10.3390/geosciences8090351
Received: 27 July 2018 / Revised: 22 August 2018 / Accepted: 13 September 2018 / Published: 15 September 2018
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Abstract
Water resources management is one of the most important challenges worldwide because water represents a vital resource for sustaining life and the environment. With the aim of sustainable groundwater management, the identification of aquifer recharge areas is a useful tool for water resources [...] Read more.
Water resources management is one of the most important challenges worldwide because water represents a vital resource for sustaining life and the environment. With the aim of sustainable groundwater management, the identification of aquifer recharge areas is a useful tool for water resources protection. In a well-developed karst aquifer, environmental isotopes provide support for identifying aquifer recharge areas, residence time and interconnections between aquifer systems. This study deals with the use of environmental isotopes to identify the main recharge area of a karst aquifer in the Upper Valley of Aniene River (Central Italy). The analysis of 18O/16O and 2H/H values and their spatial distribution make it possible to trace back groundwater recharge areas based on average isotope elevations. The Inverse Hydrogeological Balance Method was used to validate spring recharge elevations obtained by the use of stable isotopes. Areas impacted by direct and rapid rainfall recharge into the study area were delineated, showing groundwater flowpaths from the boundaries to the core of the aquifer. The results of this study demonstrate the contribution that spatial and temporal isotope changes can provide to the identification of groundwater flowpaths in a karst basin, taking into account the hydrogeological setting. Full article
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Open AccessArticle GRACETOOLS—GRACE Gravity Field Recovery Tools
Geosciences 2018, 8(9), 350; https://doi.org/10.3390/geosciences8090350
Received: 13 July 2018 / Revised: 13 August 2018 / Accepted: 31 August 2018 / Published: 15 September 2018
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Abstract
This paper introduces GRACETOOLS, the first open source gravity field recovery tool using GRACE type satellite observations. Our aim is to initiate an open source GRACE data analysis platform, where the existing algorithms and codes for working with GRACE data are shared and [...] Read more.
This paper introduces GRACETOOLS, the first open source gravity field recovery tool using GRACE type satellite observations. Our aim is to initiate an open source GRACE data analysis platform, where the existing algorithms and codes for working with GRACE data are shared and improved. We describe the first release of GRACETOOLS that includes solving variational equations for gravity field recovery using GRACE range rate observations. All mathematical models are presented in a matrix format, with emphasis on state transition matrix, followed by details of the batch least squares algorithm. At the end, we demonstrate how GRACETOOLS works with simulated GRACE type observations. The first release of GRACETOOLS consist of all MATLAB M-files and is publicly available at Supplementary Materials. Full article
(This article belongs to the Special Issue Gravity Field Determination and Its Temporal Variation)
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Open AccessArticle Study and Characterization of Environmental Deposition on Marble and Surrogate Substrates at a Monumental Heritage Site
Geosciences 2018, 8(9), 349; https://doi.org/10.3390/geosciences8090349
Received: 7 August 2018 / Revised: 6 September 2018 / Accepted: 10 September 2018 / Published: 14 September 2018
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In this study, the results of the field exposure activity conducted between 2014 and 2017 on the façade of the Milano cathedral (Italy) are reported. The main research aim was to characterize environmental deposition in real exposure conditions and for this purpose, both [...] Read more.
In this study, the results of the field exposure activity conducted between 2014 and 2017 on the façade of the Milano cathedral (Italy) are reported. The main research aim was to characterize environmental deposition in real exposure conditions and for this purpose, both stone substrates (Candoglia marble) and surrogate substrates (quartz fibre filters) were exposed on the cathedral façade in two sites at different heights. A complete chemical characterization has been performed on quartz filters and marble substrates, i.e., quantification of the deposited aerosol particulate matter (PM) and of the main ions. On quartz filters, the carbonaceous component of deposits was also investigated, as well as the color change induced by soiling, by means of colorimetric measurements. The combined approach exploiting marble and surrogate substrates seems to be a suitable monitoring strategy, although some aspects should be taken into account. In particular, differences in the deposits composition have been highlighted mainly depending on the type of substrate. The environmental data related to atmospheric pollution in Milan for the same period have also been considered but no direct correlations were found between some atmospheric precursors and their related ions in solid deposits. Full article
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Open AccessArticle Detection and Geometrical Characterization of a Buried Landfill Site by Integrating Land Use Historical Analysis, Digital Photogrammetry and Airborne Lidar Data
Geosciences 2018, 8(9), 348; https://doi.org/10.3390/geosciences8090348
Received: 13 August 2018 / Revised: 5 September 2018 / Accepted: 10 September 2018 / Published: 14 September 2018
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Abstract
Abandoned quarries are frequently used as sites of illegal dumping of solid urban waste. These sites often occur nearby or within urban areas so that their detection may turn out to be quite difficult from the surface. This study focuses on the detection [...] Read more.
Abandoned quarries are frequently used as sites of illegal dumping of solid urban waste. These sites often occur nearby or within urban areas so that their detection may turn out to be quite difficult from the surface. This study focuses on the detection and geometrical characterization of a hidden landfill site located along the coastline of the Campi Flegrei, near Naples, Italy. Our approach is based on the analysis of historical topographic maps and aerial photographs, coupled with quantitative comparison of multitemporal digital elevation models obtained by digital photogrammetry and lidar techniques. The comparative analysis of topographic maps and aerial photos clearly shows modifications of the landscape associated with the urban development and quarrying activity, as well as the later filling of the quarry. The change detection analysis reveals that remarkable elevation changes occurred in the study area between 1956 and 2008. The average thickness of the landfill deposits is ca. 8 m, whereas the average volume is ca. 100,000 m3. The results of this work confirm the suitability of the used methodological approach that combines both qualitative and quantitative techniques for the detection of buried landfill sites. The geometric characterization of a landfill represents a fitting starting point for the further planning of geophysical site surveys and direct investigations aimed at the assessment of environmental hazards. Full article
(This article belongs to the Section Natural Hazards)
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Open AccessArticle Indoor Multi-Risk Scenarios of Climate Change Effects on Building Materials in Scandinavian Countries
Geosciences 2018, 8(9), 347; https://doi.org/10.3390/geosciences8090347
Received: 14 July 2018 / Revised: 10 September 2018 / Accepted: 12 September 2018 / Published: 14 September 2018
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Abstract
Within the built environment, historic buildings are among the most vulnerable structures to the climate change impact. In the Scandinavian countries, the risk from climatic changes is more pronounced and the right adaptation interventions should be chosen properly. This article, through a multidisciplinary [...] Read more.
Within the built environment, historic buildings are among the most vulnerable structures to the climate change impact. In the Scandinavian countries, the risk from climatic changes is more pronounced and the right adaptation interventions should be chosen properly. This article, through a multidisciplinary approach, links the majority of climate-induced decay variables for different building materials with the buildings’ capacity to change due to their protection status. The method tends to be general as it assesses the decay level for different building materials, sizes, and locations. The application of the method in 38 locations in the Scandinavian countries shows that the risk from climatic changes is imminent. In the far future (2071–2100), chemical and biological decays will slightly increase, especially in the southern part of the peninsula, while the mechanical decay of the building materials kept indoors will generally decrease. Furthermore, the merge of the decay results with the protection level of the building will serve as a good indicator to plan the right level and time of intervention for adapting to the future climatic changes. Full article
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Open AccessArticle Framework for Offline Flood Inundation Forecasts for Two-Dimensional Hydrodynamic Models
Geosciences 2018, 8(9), 346; https://doi.org/10.3390/geosciences8090346
Received: 19 July 2018 / Revised: 22 August 2018 / Accepted: 11 September 2018 / Published: 13 September 2018
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Abstract
The paper presents a new methodology for hydrodynamic-based flood forecast that focuses on scenario generation and database queries to select appropriate flood inundation maps in real-time. In operational flood forecasting, only discharges are forecasted at specific gauges using hydrological models. Hydrodynamic models, which [...] Read more.
The paper presents a new methodology for hydrodynamic-based flood forecast that focuses on scenario generation and database queries to select appropriate flood inundation maps in real-time. In operational flood forecasting, only discharges are forecasted at specific gauges using hydrological models. Hydrodynamic models, which are required to produce inundation maps, are computationally expensive, hence not feasible for real-time inundation forecasting. In this study, we have used a substantial number of pre-calculated inundation maps that are stored in a database and a methodology to extract the most likely maps in real-time. The method uses real-time discharge forecast at upstream gauge as an input and compares it with the pre-recorded scenarios. The results show satisfactory agreements between offline inundation maps that are retrieved from a pre-recorded database and online maps, which are hindcasted using historical events. Furthermore, this allows an efficient early warning system, thanks to the fast run-time of the proposed offline selection of inundation maps. The framework is validated in the city of Kulmbach in Germany. Full article
(This article belongs to the Special Issue Hydrology of Urban Catchments)
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Open AccessArticle Age and Origin of the Mesoproterozoic Iron Oxide-Apatite Mineralization, Cheever Mine, Eastern Adirondacks, NY
Geosciences 2018, 8(9), 345; https://doi.org/10.3390/geosciences8090345
Received: 2 July 2018 / Revised: 28 August 2018 / Accepted: 7 September 2018 / Published: 12 September 2018
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Abstract
At the Cheever Mine, located in the eastern Adirondack Mountains of the Mesoproterozoic Grenville Province, iron oxide-apatite ore forms a narrow (<3 m) sheet cross-cutting metasomatically altered, magnetite-bearing, albite-rich leucogranitic host rocks of the Lyon Mountain Granite suite. Zircon from the ore and [...] Read more.
At the Cheever Mine, located in the eastern Adirondack Mountains of the Mesoproterozoic Grenville Province, iron oxide-apatite ore forms a narrow (<3 m) sheet cross-cutting metasomatically altered, magnetite-bearing, albite-rich leucogranitic host rocks of the Lyon Mountain Granite suite. Zircon from the ore and five samples of country rock were dated by Laser Ablation-Multi-Collector-Inductively Coupled Plasma-Mass Spectrometry. The ore yielded a Concordia age of 1033.6 ± 2.9 Ma while three samples of host rock yielded ages of 1036.3 ± 2.9, 1040 ± 11, and 1043.9 ± 4.1 Ma. Two additional samples of host rock yielded older ages of 1059.6 ± 3.4 and 1066.0 ± 6.3 Ma and contain zircon xenocrystic cores with 207Pb/206Pb ages up to 1242 Ma. The zircons analyzed, including those separated from the ore, have characteristics typically associated with an igneous origin including size, shape, inclusions, oscillatory zoning, typical chondrite-normalized REE patterns, U contents, and U/Th ratios. This data establishes the age of the ore and alteration and a temporal, and likely genetic, connection between the ore and members of the Lyon Mountain Granite suite. A model invoking melting of Shawinigan country rocks, magmatic differentiation, and long-lived magmatic and metasomatic input along extensional fault conduits is proposed for the ore’s genesis. At the Cheever Mine, magmatic hydrothermal fluids and/or post-intrusion alteration appears not to have had a major impact on zircon, which preserves original U-Pb systematics. Full article
(This article belongs to the Special Issue Geochronology Applied to Metallogeny and Deposit Studies)
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Open AccessArticle Assessment of Specific Yield in Karstified Fractured Rock through the Water-Budget Method
Geosciences 2018, 8(9), 344; https://doi.org/10.3390/geosciences8090344
Received: 26 July 2018 / Revised: 1 September 2018 / Accepted: 1 September 2018 / Published: 11 September 2018
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In this note, the Water Budget Method (WBM) is applied to estimate local values of the specific yield of the deep karst aquifer of Salento peninsula. A selection in a period of two years of relevant short precipitation events has been considered and [...] Read more.
In this note, the Water Budget Method (WBM) is applied to estimate local values of the specific yield of the deep karst aquifer of Salento peninsula. A selection in a period of two years of relevant short precipitation events has been considered and the related localized recharges have been compared to the water table fluctuations measured at two selected wells. The recharge amounts have been corrected by using data of evapotranspiration and soil water storage available from a micrometeorological base. The results are very similar for both the wells and more consistent when the corrections are applied. A discussion involving frequency and apertures of the fractures in the rock mass of the aquifer suggests the effect of the karst dissolution to be dominant in determining these values of the specific yield. Full article
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Open AccessArticle A Study on Variation in Channel Width and Braiding Intensity of the Brahmaputra River in Assam, India
Geosciences 2018, 8(9), 343; https://doi.org/10.3390/geosciences8090343
Received: 26 July 2018 / Revised: 22 August 2018 / Accepted: 23 August 2018 / Published: 11 September 2018
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Abstract
The Brahmaputra River flows through Assam, India, for about 670 km along an alluvial valley as a wide braided river. The width of the river varies with time along its course. The braiding intensity of this river is estimated using the braiding index [...] Read more.
The Brahmaputra River flows through Assam, India, for about 670 km along an alluvial valley as a wide braided river. The width of the river varies with time along its course. The braiding intensity of this river is estimated using the braiding index (BI) of Brice (1964), which also changes with space and time along the course of the river. Temporal changes of both width and BI have been studied using topographic maps of 1912–1928 and 1963–1975, and dry season satellite data of 1996, 2000, 2007 and 2009. The mean widths of the Brahmaputra River channel in Assam during 1912–1928, 1963–1975, 1996, 2000, 2007 and 2009 were 5949 m, 7455 m, 7505 m, 8008 m, 8308 m and 9012 m, respectively, confirming an overall increase in width with time. Both the width and variation of width are lowest in four short narrower segments of the river. Three of these segments represent hard points comprising gneissic rock, and one segment is on alluvium comprising cohesive clay. The increase in width is correlated to enormous sediment load produced by the great Assam earthquake of 1950 and large-scale deforestation in the Himalayas. The mean BIs for the Brahmaputra for 1963–1975, 1996, 2000, 2007 and 2009 were 8.59, 8.43, 6.67, 6.58 and 7.70, respectively, indicating in general a decreasing trend up to 2007. The BI showed low variation at the four narrow segments where there is also a minimum variation of the channel width. The BI has increased significantly in the upstream part of the river. Very high fluctuation of discharge (17,000 m 3 / s 1 in 24 h) and high sediment loads of the Brahmaputra (daily mean sediment discharge of 2.0 million tonnes during monsoon), erodible alluvial banks and high width/depth ratios are the main causes of development of braiding. The interrelationship between channel width and BI of the Brahmaputra shows a positive correlation, indicating an increase in BI with increasing channel width. Full article
(This article belongs to the Special Issue Quantitative Geomorphology)
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Open AccessArticle Waste Concrete Valorization; Aggregates and Mineral Carbonation Feedstock Production
Geosciences 2018, 8(9), 342; https://doi.org/10.3390/geosciences8090342
Received: 20 July 2018 / Revised: 27 August 2018 / Accepted: 3 September 2018 / Published: 11 September 2018
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Abstract
Concrete is a major constituent of our world. Its contributes to building society but is also an important contributor to the global CO2 emissions. The combination of waste concrete recycling and greenhouse gas abatement is obviously an interesting approach. Mineral carbonation is [...] Read more.
Concrete is a major constituent of our world. Its contributes to building society but is also an important contributor to the global CO2 emissions. The combination of waste concrete recycling and greenhouse gas abatement is obviously an interesting approach. Mineral carbonation is the methodology that allows the use of calcium oxide within the concrete and transform it into carbonates with the CO2. Following previous results, carbonation experiments were performed using concrete paste extracted from a waste concrete sample after aggregate separation. The latter was performed after crushing and attrition followed by sieving to obtain three fractions. The coarser one composed of aggregates, the second of sand and the last, a fine powder of waste concrete paste (MCF). The MCF is then used in carbonation experiments in an 18.7 L stirred reactor with a diluted source of CO2 following previously optimized conditions. Different S/L ratios were experimented. The results show that 110 kg of CO2 can be stored per ton of MCF obtained after separation. Using the mass balance obtained from the experiments, an economic evaluation was performed on both aggregate separation and carbonation. While the first step can be profitable, using the MCF as a material for industrial flue gas abatement is less evident, both on the applicability and the feasibility. Full article
(This article belongs to the Special Issue Carbon Sequestration)
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Open AccessArticle Stability of Individuals during Urban Inundations: What Should We Learn from Field Observations?
Geosciences 2018, 8(9), 341; https://doi.org/10.3390/geosciences8090341
Received: 25 July 2018 / Revised: 5 September 2018 / Accepted: 7 September 2018 / Published: 10 September 2018
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Abstract
The flooding of urbanized areas constitutes a major hazard to populations and infrastructure. Flood flows during urban inundations have been studied only recently and the real-life impact of fluid flows on individuals is not well understood. The stability of individuals in floodwaters is [...] Read more.
The flooding of urbanized areas constitutes a major hazard to populations and infrastructure. Flood flows during urban inundations have been studied only recently and the real-life impact of fluid flows on individuals is not well understood. The stability of individuals in floodwaters is re-assessed based upon the re-analysis of detailed field measurements during a major flood event. The results emphasized that hydrodynamic instabilities, linked to local topographic effects and debris, constitute major real-world hazards. A comparison between a number of flow conditions deemed unsafe for individuals, along with guidelines, suggests that many recommendations are over-optimistic and unsafe in real floodwaters and natural disasters. A series of more conservative guidelines is proposed, particularity relevant to flood events. Full article
(This article belongs to the Special Issue River, Urban, and Coastal Flood Risk)
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Open AccessArticle Numerical Modeling of Flow Patterns Applied to Analysis of Susceptibility to Movements of the Ground
Geosciences 2018, 8(9), 340; https://doi.org/10.3390/geosciences8090340
Received: 31 July 2018 / Revised: 6 September 2018 / Accepted: 7 September 2018 / Published: 9 September 2018
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Abstract
Mass movements in deformed areas of natural relief deformed by seismotectonic factors are one of the most destructive and recurrent natural hazards in the Republic of Ecuador, especially during intense rain periods, the El Niño phenomenon, or due to earthquakes such as the [...] Read more.
Mass movements in deformed areas of natural relief deformed by seismotectonic factors are one of the most destructive and recurrent natural hazards in the Republic of Ecuador, especially during intense rain periods, the El Niño phenomenon, or due to earthquakes such as the one that occurred on 16 April 2016 in the Ecuadorian coastline. This study proposes the application of Hydrological Model D8 and its derived morphometric parameters like slope, orientation of the slope, and curvatures, extracted from the high spatial resolution Digital Elevation Model (DEM), implemented in programs such as Rockworks 7 (gridzo), SURFER (downwards slope), ArcView (flowacc), and SAGA (curvatures) to obtain runoff flow, structural geological lineaments, and superficial deformations of the topographic relief that are the origin of erosion, superficial landslides, lateral propagation, of the rock–soil complex, mass flows, and deep gravitational deformations. This methodology has been validated in three locations with intense deformations: two in Ecuador and one in Spain. The DEM were obtained from the Ecuadorian Spatial Institute (ESI) (spatial resolution of 10 m), the Rural Technological Infrastructure and Information National System (SIGTIERRAS) (spatial resolution of 5 m), and the Council of Andalusia (spatial resolution of 5 m). Full article
(This article belongs to the Special Issue Tectonics and Morphodynamics)
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Open AccessArticle δ13C and δ18O Stable Isotope Analysis Applied to Detect Technological Variations and Weathering Processes of Ancient Lime and Hydraulic Mortars
Geosciences 2018, 8(9), 339; https://doi.org/10.3390/geosciences8090339
Received: 18 July 2018 / Revised: 3 September 2018 / Accepted: 4 September 2018 / Published: 8 September 2018
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Abstract
Samples of mortars were collected from lime and hydraulic mortars affected by environmental degradation. A total of 63 samples were obtained from Hellenistic, Late Roman and Byzantine historic constructions located at Kavala, Drama and Makrygialos in North Greece. Samples were collected in sections [...] Read more.
Samples of mortars were collected from lime and hydraulic mortars affected by environmental degradation. A total of 63 samples were obtained from Hellenistic, Late Roman and Byzantine historic constructions located at Kavala, Drama and Makrygialos in North Greece. Samples were collected in sections from the surface up to 6 cm deep using a drill-core material. The first sample was collected from the external layer, while the internal samples were collected each 1cm beeper from the previous, in order to monitor the moisture ingress. Isotopic data will make it possible to create an ideal Hellenistic and Byzantine mortar layer and to provide weathering gradients. The isotopic values comprise a range of δ13C and δ18O values from −17.1‰ to 1.2‰ and −25.9‰ to −2‰, respectively. The weathering process of Hellenistic and Byzantine are expressed, by the regression lines δ18Ocalcite matrix = 0.6 × δ13Ccalcite matrix − 1.9 and δ18Ocalcite matrix = 0.6 × δ13Ccalcite matrix − 2.0 for hydraulic and Lime mortars respectively. Pronounced isotopic shift to heavy or light δ13C and δ18O in the carbonate matrix was attributed to the primary source of CO2 (atmospheric versus biogenic) and H2O (evaporation of local primary water), in residual limestone and in secondary processes such as recrystallization of calcite with pore water and salts attack. Exogenic processes related to biological growth are responsible for further alterations of δ18O and δ13C in lime mortars. This study indicated that stable isotope analysis is an excellent tool to fingerprint the origin of carbonate, the environmental setting conditions of mortar, origin of CO2 and water during calcite formation and to determine the weathering depth and the potential secondary degradation mechanisms. Full article
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Open AccessArticle Assessing the Validity of Negative High Field Strength-Element Anomalies as a Proxy for Archaean Subduction: Evidence from the Ben Strome Complex, NW Scotland
Geosciences 2018, 8(9), 338; https://doi.org/10.3390/geosciences8090338
Received: 26 July 2018 / Revised: 31 August 2018 / Accepted: 6 September 2018 / Published: 8 September 2018
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Abstract
The relative depletion of high field strength elements (HFSE), such as Nb, Ta and Ti, on normalised trace-element plots is a geochemical proxy routinely used to fingerprint magmatic processes linked to Phanerozoic subduction. This proxy has increasingly been applied to ultramafic-mafic units in [...] Read more.
The relative depletion of high field strength elements (HFSE), such as Nb, Ta and Ti, on normalised trace-element plots is a geochemical proxy routinely used to fingerprint magmatic processes linked to Phanerozoic subduction. This proxy has increasingly been applied to ultramafic-mafic units in Archaean cratons, but as these assemblages have commonly been affected by high-grade metamorphism and hydrothermal alteration/metasomatism, the likelihood of element mobility is high relative to Phanerozoic examples. To assess the validity of HFSE anomalies as a reliable proxy for Archaean subduction, we here investigate their origin in ultramafic rocks from the Ben Strome Complex, which is a 7 km2 ultramafic-mafic complex in the Lewisian Gneiss Complex of NW Scotland. Recently interpreted as a deformed layered intrusion, the Ben Strome Complex has been subject to multiple phases of high-grade metamorphism, including separate granulite- and amphibolite-facies deformation events. Additional to bulk-rock geochemistry, we present detailed petrography, and major- and trace-element mineral chemistry for 35 ultramafic samples, of which 15 display negative HFSE anomalies. Our data indicate that the magnitude of HFSE anomalies in the Ben Strome Complex are correlated with light rare earth-element (LREE) enrichment likely generated during interaction with H2O and CO2-rich hydrothermal fluids associated with amphibolitisation, rather than primary magmatic (subduction-related) processes. Consequently, we consider bulk-rock HFSE anomalies alone to be an unreliable proxy for Archaean subduction in Archaean terranes that have experienced multiple phases of high-grade metamorphism, with a comprehensive assessment of element mobility and petrography a minimum requirement prior to assigning geodynamic interpretations to bulk-rock geochemical data. Full article
(This article belongs to the Special Issue Geology of the Early Earth – Geodynamic Constraints from Cratons)
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Open AccessArticle Paleo-Drainage Network, Morphotectonics, and Fluvial Terraces: Clues from the Verde Stream in the Middle Sangro River (Central Italy)
Geosciences 2018, 8(9), 337; https://doi.org/10.3390/geosciences8090337
Received: 18 July 2018 / Revised: 29 August 2018 / Accepted: 31 August 2018 / Published: 8 September 2018
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Abstract
This work analyzes the role of paleo-drainage network, morphotectonics, and surface processes in landscape evolution in a sector of the transition zone between the chain and the piedmont area of Central Apennines. Particularly, it focuses on the Verde Stream, a tributary of the [...] Read more.
This work analyzes the role of paleo-drainage network, morphotectonics, and surface processes in landscape evolution in a sector of the transition zone between the chain and the piedmont area of Central Apennines. Particularly, it focuses on the Verde Stream, a tributary of the middle Sangro River valley, which flows in the southeastern Abruzzo area at the boundary with the Molise region. The Verde Stream was investigated through a drainage basin scale geomorphological analysis incorporating the morphometry of the orography and hydrography, structural geomorphological field mapping, and the investigation of morphological field evidence of tectonics with their statistical azimuthal distributions. The local data obtained were compared with the analysis of the middle Sangro River valley and the tectonic features of the Abruzzo–Molise area. This approach led us to also provide relevant clues about the definition of the role of karst features and paleo-landscapes in the general setting of the study area and to identify the impact of active tectonics, confirmed by recent and active seismicity. In conclusion, the paper contributes to defining the main stages of the geomorphological evolution of this area, driven by uplift and local tectonics and due to a combination of fluvial, karst, and landslide processes. Full article
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Open AccessArticle Combined Geophysical and Geotechnical Approaches for Microzonation Studies in Hispaniola Island
Geosciences 2018, 8(9), 336; https://doi.org/10.3390/geosciences8090336
Received: 6 April 2018 / Revised: 28 August 2018 / Accepted: 28 August 2018 / Published: 5 September 2018
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Abstract
In this paper, we describe recent studies for the geophysical and geomechanical characterization of soils in Hispaniola (Greater Antilles), an island threatened by the eventual rupture of major seismogenic fault systems. The investigations were performed for four different cities settled on complex geological [...] Read more.
In this paper, we describe recent studies for the geophysical and geomechanical characterization of soils in Hispaniola (Greater Antilles), an island threatened by the eventual rupture of major seismogenic fault systems. The investigations were performed for four different cities settled on complex geological formations in Haiti (Cap-Haïtien, Port-au-Prince) and the Dominican Republic (Santo Domingo, Santiago de los Caballeros). We present the complete methodology we implemented for mapping zones of homogeneous seismic response and for microzonation studies, but each main stage of investigation is described as it was conducted in one or two cities. Therefore, first we present our site-characterization technique applied to Santo Domingo and Santiago de los Caballeros, which is based on geotechnical data, geophysical multichannel analysis of surface waves, and ambient-noise recordings. Then we present the site-response analysis through numerical analysis with nonlinear soil models that we performed for the city of Cap-Haïtien. Finally, we describe the amplification factors for site-specific response spectra that we derived for the microzonation of Port-au-Prince. We argue for the implementation of a multidisciplinary approach built upon complementary field geological, geophysical, and geotechnical data rather than solely depending on geophysical measures for the characterization of VS30. In addition, we explore the compatibility of the soil classes recommended by the International Building Code (IBC) in the context of local seismic amplification. Full article
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Open AccessArticle Methodology for Improving the Analysis, Interpretation, and Geo-Visualisation of Erosion Rates in Coastal Beaches—Andalusia, Southern Spain
Geosciences 2018, 8(9), 335; https://doi.org/10.3390/geosciences8090335
Received: 3 August 2018 / Revised: 24 August 2018 / Accepted: 3 September 2018 / Published: 5 September 2018
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Abstract
Erosion is one of the major issues currently facing coastal areas. Some consequences of this process are beach loss and higher flood risk, which will likely be exacerbated given ongoing sea-level rise. With this in mind, those responsible for conservation and management decisions [...] Read more.
Erosion is one of the major issues currently facing coastal areas. Some consequences of this process are beach loss and higher flood risk, which will likely be exacerbated given ongoing sea-level rise. With this in mind, those responsible for conservation and management decisions need appropriate tools with which to identify critical coastal areas, as well as to analyse, interpret, and visualise them with the appropriate geomorphological and environmental background. The aim of this work was to present a methodology for improving the analysis and interpretation of coastal erosion rates, as well as to guarantee wide access and dissemination of erosion data. To that end, an approach for the production, management, and dissemination of shoreline erosion data for the Andalusian coast in Southern Spain was developed. This approach enables the analysis and interpretation of the erosion rates in coasts by linking erosion rates with geomorphological and thematic information using a data model. Additionally, this methodology was proven to be a valid and appropriate tool for the design of a web-based viewer, being the best way to represent the erosion rates obtained every 50 m of shore for the entire Andalusian coast, being an exposed coastal front 917 km long. This is particularly useful for integrated coastal zone management schemes, enabling quick and easy access to valuable information. Full article
(This article belongs to the Special Issue Coastal Geomorphology)
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Open AccessFeature PaperArticle Mapping a Subsurface Water Channel with X-Band and C-Band Synthetic Aperture Radar at the Iron Age Archaeological Site of ‘Uqdat al-Bakrah (Safah), Oman
Geosciences 2018, 8(9), 334; https://doi.org/10.3390/geosciences8090334
Received: 10 July 2018 / Revised: 25 August 2018 / Accepted: 29 August 2018 / Published: 5 September 2018
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Abstract
Subsurface imaging in arid regions is a well-known application of satellite Synthetic Aperture Radar (SAR). Archaeological prospection has often focused on L-band SAR sensors, given the ability of longer wavelengths to penetrate more deeply into sand. In contrast, this study demonstrates capabilities of [...] Read more.
Subsurface imaging in arid regions is a well-known application of satellite Synthetic Aperture Radar (SAR). Archaeological prospection has often focused on L-band SAR sensors, given the ability of longer wavelengths to penetrate more deeply into sand. In contrast, this study demonstrates capabilities of shorter-wavelength, but higher spatial resolution, C-band and X-band SAR sensors in archaeological subsurface imaging at the site of ‘Uqdat al-Bakrah (Safah), Oman. Despite having varying parameters and acquisitions, both the X-band and C-band images analyzed were able to identify a subsurface paleo-channel that is not visible on the ground surface. This feature was first identified through Ground Penetrating Radar (GPR) survey, then recognized in the SAR imagery and further verified by test excavations. Both the GPR and the excavations reveal the base of the paleo-channel at a depth of 0.6 m–0.7 m. Hence, both X-band and C-band wavelengths are appropriate for subsurface archaeological prospection in suitable (dry silt and sand) conditions with specific acquisition parameters. Moreover, these results offer important new insights into the paleo-environmental context of ancient metal-working at ‘Uqdat al-Bakrah and demonstrate surface water flow roughly contemporary with the site’s occupation. Full article
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Open AccessArticle Re-Aeration on Stepped Spillways with Special Consideration of Entrained and Entrapped Air
Geosciences 2018, 8(9), 333; https://doi.org/10.3390/geosciences8090333
Received: 4 August 2018 / Revised: 28 August 2018 / Accepted: 3 September 2018 / Published: 5 September 2018
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Abstract
As with most high-velocity free-surface flows, stepped spillway flows become self-aerated when the drop height exceeds a critical value. Due to the step-induced macro-roughness, the flow field becomes more turbulent than on a similar smooth-invert chute. For this reason, cascades are oftentimes used [...] Read more.
As with most high-velocity free-surface flows, stepped spillway flows become self-aerated when the drop height exceeds a critical value. Due to the step-induced macro-roughness, the flow field becomes more turbulent than on a similar smooth-invert chute. For this reason, cascades are oftentimes used as re-aeration structures in wastewater treatment. However, for stepped spillways as flood release structures downstream of deoxygenated reservoirs, gas transfer is also of crucial significance to meet ecological requirements. Prediction of mass transfer velocities becomes challenging, as the flow regime differs from typical previously studied flow conditions. In this paper, detailed air-water flow measurements are conducted on stepped spillway models with different geometry, with the aim to estimate the specific air-water interface. Re-aeration performances are determined by applying the absorption method. In contrast to earlier studies, the aerated water body is considered a continuous mixture up to a level where 75% air concentration is reached. Above this level, a homogenous surface wave field is considered, which is found to significantly affect the total air-water interface available for mass transfer. Geometrical characteristics of these surface waves are obtained from high-speed camera investigations. The results show that both the mean air concentration and the mean flow velocity have influence on the mass transfer. Finally, an empirical relationship for the mass transfer on stepped spillway models is proposed. Full article
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Open AccessArticle The Influence of Crude Oil on Mechanistic Detachment Rate Parameters
Geosciences 2018, 8(9), 332; https://doi.org/10.3390/geosciences8090332
Received: 18 July 2018 / Revised: 23 August 2018 / Accepted: 25 August 2018 / Published: 4 September 2018
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Abstract
Iraqi soil contamination greatly influenced soil detachment. Previous researchers have not been able to predict the influence of crude oil soil contamination on either the mechanistic dimensional detachment parameter b0 or the threshold parameter b1 of the mechanistic detachment model (Wilson [...] Read more.
Iraqi soil contamination greatly influenced soil detachment. Previous researchers have not been able to predict the influence of crude oil soil contamination on either the mechanistic dimensional detachment parameter b0 or the threshold parameter b1 of the mechanistic detachment model (Wilson model). The aims of this research were (1) to investigate the influence of crude oil on deriving Wilson model parameters, b0 and b1, with two setups at different scales and different soil moisture contents and (2) to predict b0 and b1 in crude oil contaminated dry soils with varying levels of contamination. The “mini” JET apparatus was implemented under laboratory conditions for soil specimens packed at both a small (standard mold) and a large (in-situ soil box) scale. The results showed an inverse correlation between b0 and water content for clean soil. No correlation between b0 and soil moisture content was observed for contaminated soils. There was a huge reduction in the b0 value as the contamination time increased compared to the clean soil. This was related to the role crude oil plays in soil stabilization. Crude oil contamination significantly increased lead contamination level while slightly increasing the pH and total organic carbon. The influence of crude oil on mechanistic soil detachment can be predicted with a priori JET experiments on soils without crude oil based on crude oil parameters. Full article
(This article belongs to the Special Issue Soil Hydrology and Erosion)
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Open AccessArticle Right-Angle Pattern of Minor Fluvial Networks from the Ionian Terraced Belt, Southern Italy: Passive Structural Control or Foreland Bending?
Geosciences 2018, 8(9), 331; https://doi.org/10.3390/geosciences8090331
Received: 14 July 2018 / Revised: 24 August 2018 / Accepted: 29 August 2018 / Published: 3 September 2018
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Abstract
Morphometric analyses of both the topography and drainage network have been carried out in a large sector of the Ionian coastal belt of southern Italy in order to unravel the possible control of Late Quaternary thrust front activity on the evolution of the [...] Read more.
Morphometric analyses of both the topography and drainage network have been carried out in a large sector of the Ionian coastal belt of southern Italy in order to unravel the possible control of Late Quaternary thrust front activity on the evolution of the fluvial net. The study area extends in the southernmost sector of the Bradano Foredeep and is featured by several orders of uplifted marine terraces, ranging in age from Middle Pleistocene to Late Quaternary. The flight of the marine terraces is deeply cut by a trellis-type and regularly spaced minor fluvial network. Morphotectonic investigations based on field survey, photo-aerial interpretation, topographic attributes, morphometric indices, and analysis of longitudinal river profiles suggest a strong control on the drainage network arrangement by a pervasive orthogonal fracture system, produced and preserved into the brittle caprock of the terraces, made by conglomerate. Since a similar pervasive and orthogonal fracture pattern is typically generated by gentle folding of rocks, the development of the Ionian hydrographic networks could be attributed to a general—maybe still active—bending of the foredeep area due to the eastward propagation of blind thrusting of the Apennines orogenic chain. Full article
(This article belongs to the Special Issue Quantitative Geomorphology)
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Open AccessArticle Oxygen and Carbon Stable Isotope Composition of Cretaceous to Pliocene Calcareous Paleosols in the Tian Shan Region (Central Asia): Controlling Factors and Paleogeographic Implications
Geosciences 2018, 8(9), 330; https://doi.org/10.3390/geosciences8090330
Received: 1 May 2018 / Revised: 28 August 2018 / Accepted: 29 August 2018 / Published: 3 September 2018
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Abstract
The Late Mesozoic–Cenozoic topographic and climate evolution of Central Asia remains highly debated. The final retreat of the proto-Paratethys Sea from the western Tarim Basin is thought to correspond in time with the onset of tectonic uplift in the Pamir, Tian Shan and [...] Read more.
The Late Mesozoic–Cenozoic topographic and climate evolution of Central Asia remains highly debated. The final retreat of the proto-Paratethys Sea from the western Tarim Basin is thought to correspond in time with the onset of tectonic uplift in the Pamir, Tian Shan and Altai ranges, as well as with regional aridification. The oxygen and carbon isotope compositions of the sediment deposits in the various Central Asian basins have already been used to decipher both the topographic and climatic changes that occurred in that region during the Cenozoic, generally concentrating on one sedimentary section and/or on a limited time range and either using multiple-type samples including sandstone calcitic cements, marine carbonates, fossils, or paleosols. In order to get a homogeneous dataset, minimizing variations in the isotopic composition of the material depending on its type and/or depositional environment, we selected only calcareous paleosols sampled in several continuous sections covering a wide time range from the Late Jurassic to the Pliocene. Our sampling also covers a wide area encompassing the whole Tian Shan region, which allows detecting regional variations in the δ18O and δ13C values. We show that the influence of the distance to the proto-Paratethys Sea on the paleosol δ18O record was not significant. Besides local factors such as the occurrence of large lakes that can have a significant effect on the isotopic composition of the calcareous paleosols, the long-term evolution of both the δ18O and δ13C values possibly reflects the hypsometry of the river drainage systems that bring water to the basins. However, as it is commonly accepted that the δ18O of soil carbonates is controlled by the δ18O of in-situ precipitation, this last conclusion remains to be further investigated. Full article
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Open AccessReview Tailoring Signs to Engage Two Distinct Types of Geotourists to Geological Sites
Geosciences 2018, 8(9), 329; https://doi.org/10.3390/geosciences8090329
Received: 30 July 2018 / Revised: 16 August 2018 / Accepted: 29 August 2018 / Published: 3 September 2018
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Abstract
Interpretive signs are the silent ambassadors of geosites and serve a diverse audience. The primary aim of this study is to develop signs for geosites targeted at two unique groups of geotourists. A conceptual multidisciplinary geotourist typology is formulated to identify two main [...] Read more.
Interpretive signs are the silent ambassadors of geosites and serve a diverse audience. The primary aim of this study is to develop signs for geosites targeted at two unique groups of geotourists. A conceptual multidisciplinary geotourist typology is formulated to identify two main classes of geotourists comprising the audience. Latent and archetypal geotourists inhabit various roles at geotourism sites depending on their expectations for the event, affecting the visitor experience via fluid contextual factors. Principally, latent geotourists arrive seeking novel touristic experiences while archetypal geotourists seek knowledge-building opportunities. Because signs represent one fragment of the multi-dimensional visitor experience, an approach that offers a palette of options is advocated. After the unified typology to identify the audience is presented, a multi-layered technique that offers both interpretation and a link to augmented information on signs is suggested. Some best practices in sign design are described and preliminary plans for testing are shared. The author’s overriding goal is to refine the mechanics and format of signs to garner maximum attracting and holding power, ensuring that the message is read and the target outcome is achieved. By providing tools to visitors to geological sites that enable them to create narratives that are compatible with their expectations, we facilitate a multi-dimensional constructive experience that engages everyone. Full article
(This article belongs to the Special Issue Geotourism)
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Open AccessArticle Contrasting Textural and Chemical Signatures of Chromitites in the Mesoarchaean Ulamertoq Peridotite Body, Southern West Greenland
Geosciences 2018, 8(9), 328; https://doi.org/10.3390/geosciences8090328
Received: 29 June 2018 / Revised: 24 August 2018 / Accepted: 29 August 2018 / Published: 3 September 2018
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Abstract
Peridotites occur as lensoid bodies within the Mesoarchaean orthogneiss in the Akia terrane of Southern West Greenland. The Ulamertoq peridotite body is the largest of these peridotites hosted within the regional orthogneiss. It consists mainly of olivine, orthopyroxene, and amphibole-rich ultramafic rocks exhibiting [...] Read more.
Peridotites occur as lensoid bodies within the Mesoarchaean orthogneiss in the Akia terrane of Southern West Greenland. The Ulamertoq peridotite body is the largest of these peridotites hosted within the regional orthogneiss. It consists mainly of olivine, orthopyroxene, and amphibole-rich ultramafic rocks exhibiting metamorphic textural and chemical features. Chromitite layers from different localities in Ulamertoq show contrasting characteristics. In one locality, zoned chromites are hosted in orthopyroxene-amphibole peridotites. Compositional zonation in chromites is evident with decreasing Cr and Fe content from core to rim, while Al and Mg increase. Homogeneous chromites from another locality are fairly uniform and Fe-rich. The mineral chemistry of the major and accessory phases shows metamorphic signatures. Inferred temperature conditions suggest that the zoned chromites, homogeneous chromites, and their hosts are equilibrated at different metamorphic conditions. In this paper, various mechanisms during the cumulus to subsolidus stages are explored in order to understand the origin of the two contrasting types of chromites. Full article
(This article belongs to the Special Issue Geology of the Early Earth – Geodynamic Constraints from Cratons)
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Open AccessReview A Comparison of the Dinosaur Communities from the Middle Jurassic of the Cleveland (Yorkshire) and Hebrides (Skye) Basins, Based on Their Ichnites
Geosciences 2018, 8(9), 327; https://doi.org/10.3390/geosciences8090327
Received: 30 July 2018 / Revised: 21 August 2018 / Accepted: 25 August 2018 / Published: 31 August 2018
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Abstract
Despite the Hebrides and Cleveland basins being geographically close, research has not previously been carried out to determine faunal similarities and assess the possibility of links between the dinosaur populations. The palaeogeography of both areas during the Middle Jurassic shows that there were [...] Read more.
Despite the Hebrides and Cleveland basins being geographically close, research has not previously been carried out to determine faunal similarities and assess the possibility of links between the dinosaur populations. The palaeogeography of both areas during the Middle Jurassic shows that there were no elevated landmasses being eroded to produce conglomeratic material in the basins at that time. The low-lying landscape and connected shorelines may have provided connectivity between the two dinosaur populations. The dinosaur fauna of the Hebrides and Cleveland basins has been assessed based primarily on the abundant ichnites found in both areas as well as their skeletal remains. In the two basins, the dinosaur faunas are very similar, consisting of non-neosauropod eusauropods, a possible basal titanosauriform, large and small theropods and ornithopods and europodan thyreophorans. The main difference in the faunas is in the sizes. In the Cleveland Basin, the ichnites suggest that there were medium and large theropods alongside small to medium sized ornithopods, whereas, in the Hebrides Basin, the theropods were from small to large and the ornithopods were medium to large. It is suggested that migrations could have taken place between the two areas during the Middle Jurassic. A tentative food chain from the herbivorous dinosaurs to the top predators can be inferred from the footprints. Full article
(This article belongs to the Special Issue Middle Jurassic Dinosaurs in Context)
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Open AccessArticle An Improved Data-Driven Approach for the Prediction of Rainfall-Triggered Soil Slides Using Downscaled Remotely Sensed Soil Moisture
Geosciences 2018, 8(9), 326; https://doi.org/10.3390/geosciences8090326
Received: 6 June 2018 / Revised: 3 August 2018 / Accepted: 18 August 2018 / Published: 30 August 2018
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Abstract
The infiltration of rainwater into soil slopes leads to an increase of porewater pressure and destruction of matric suction, which causes a reduction in soil shear strength and slope instability. Hence, surface moisture and infiltration properties must be direct inputs in reliable landslide [...] Read more.
The infiltration of rainwater into soil slopes leads to an increase of porewater pressure and destruction of matric suction, which causes a reduction in soil shear strength and slope instability. Hence, surface moisture and infiltration properties must be direct inputs in reliable landslide hazard assessment methods. Since the in situ measurement of pore pressure is expensive, the use of remotely sensed soil moisture is practically feasible. Downscaling improves the spatial resolution of soil moisture for a better representation of specific local conditions. Downscaled soil moisture, the relevant geotechnical properties of saturated hydraulic conductivity and soil type, and the conditioning factors of elevation, slope, and distance to roads are used to develop an improved logistic regression model to predict the soil slide hazard of soil slopes using data from two geographically different regions. A soil moisture downscaling model with a better accuracy than the downscaling models that have been used in previous landslide studies is employed in this study. This model provides a good classification accuracy and performs better than the alternative water drainage-based indices that are conventionally used to quantify the effect that elevated soil moisture has upon the soil slide hazard. Furthermore, the downscaling of soil moisture content is shown to improve the prediction accuracy. Finally, a technique that can provide the threshold probability for identifying locations with a high soil slide hazard is proposed. Full article
(This article belongs to the Section Natural Hazards)
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Open AccessArticle A Quantitative Comparison of Exoplanet Catalogs
Geosciences 2018, 8(9), 325; https://doi.org/10.3390/geosciences8090325
Received: 30 July 2018 / Revised: 23 August 2018 / Accepted: 25 August 2018 / Published: 29 August 2018
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Abstract
In this study, we investigated the differences between four commonly-used exoplanet catalogs (exoplanet.eu; exoplanetarchive.ipac.caltech.edu; openexoplanetcatalogue.com; exoplanets.org) using a Kolmogorov–Smirnov (KS) test. We found a relatively good agreement in terms of the planetary parameters (mass, radius, period) and stellar properties (mass, temperature, metallicity), although [...] Read more.
In this study, we investigated the differences between four commonly-used exoplanet catalogs (exoplanet.eu; exoplanetarchive.ipac.caltech.edu; openexoplanetcatalogue.com; exoplanets.org) using a Kolmogorov–Smirnov (KS) test. We found a relatively good agreement in terms of the planetary parameters (mass, radius, period) and stellar properties (mass, temperature, metallicity), although a more careful analysis of the overlap and unique parts of each catalog revealed some differences. We quantified the statistical impact of these differences and their potential cause. We concluded that although statistical studies are unlikely to be significantly affected by the choice of catalog, it would be desirable to have one consistent catalog accepted by the general exoplanet community as a base for exoplanet statistics and comparison with theoretical predictions. Full article
(This article belongs to the Special Issue Detection and Characterization of Extrasolar Planets)
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