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Topic Review
Ground-Penetrating Radar in Soil Studies
Information on the spatiotemporal variability of soil properties and states within the agricultural landscape is vital to identify management zones supporting precision agriculture (PA). Ground-penetrating radar (GPR) and electromagnetic induction (EMI) techniques have been applied to assess soil properties, states, processes, and their spatiotemporal variability. 
  • 7.8K
  • 14 Jun 2023
Topic Review
Social Vulnerability of Landslide Hazard
Landslides represent one of the world’s most dangerous and widespread risks, annually causing thousands of deaths and billions of dollars worth of damage. Building on and around hilly areas in many regions has increased, and it poses a severe threat to the physical infrastructure and people living within such zones. Quantitative assessment of social vulnerability is worrying because it has been given less attention than hazard-related studies.
  • 2.1K
  • 15 Apr 2021
Topic Review
Uranium Mineralization of Fossil Wood
Sandstone-hosted uranium deposits commonly contain abundant organic matter, including fossil logs. The precipitation of uranium minerals is often related to reducing environments associated with these organic materials. Below the water table, uranium is likely to be precipitated as uraninite (UO2), but in drier zones a variety of uranium minerals may be found. These minerals may occur as replacements for cellular tissue, or as surface crusts or fracture fillings.
  • 2.0K
  • 28 Oct 2020
Topic Review
Carbon-Isotope Signature of Diagenetic Carbonates
Diagenetic carbonates often show large variations in their carbon isotope compositions. Variations are mainly the result of isotope fractionation effects during microbial metabolic processes, and these processes themselves may induce carbonate formation. Inorganic carbon from dissimilatory microbial activity shows negative carbon isotope values (d13C), in particular if methane is used as a carbon source. In turn, inorganic carbon produced during methanogenesis shows positive d13C values. The range of isotope values preserved in the carbonate phase ultimately depends on the reservoir sizes, diffusive mixing of different carbon sources, and episodic formation of carbonate. The carbon-isotope signature of diagenetic carbonates therefore represents an archive of past biogeochemical activity in the subsurface.
  • 1.9K
  • 30 Oct 2020
Topic Review
Exploring Geochemical Signatures in Production Water
Produced water denotes the water co-produced during hydrocarbon exploration and includes flow-back water, gas condensates, basinal brine, and/or mixtures. The hydrostatic pressure of coal bed formation water traps the gas generated in coal and shale beds.
  • 1.9K
  • 18 Mar 2024
Topic Review
Structure of the Earth
The internal structure of the Earth is layered in spherical shells: an outer silicate solid crust, a highly viscous asthenosphere and mantle, a liquid outer core that is much less viscous than the mantle, and a solid inner core. Scientific understanding of the internal structure of the Earth is based on observations of topography and bathymetry, observations of rock in outcrop, samples brought to the surface from greater depths by volcanoes or volcanic activity, analysis of the seismic waves that pass through the Earth, measurements of the gravitational and magnetic fields of the Earth, and experiments with crystalline solids at pressures and temperatures characteristic of the Earth's deep interior.
  • 1.8K
  • 26 Oct 2022
Topic Review
Organic Matter in Forming Gold-Deposits
Carbonaceous organic matter occurs under various phases and forms, where its fine characterization is mostly restricted to petroleum and coal geology. As a consequence, few studies have integrated the complete link between various forms of organic matter and metals to decipher hydrothermal ore concentrating processes. The study of Dill et al., integrating the concentration of sulfides and oxides with the interaction of silicates and organic matters, is an example of the next step to reach for defining the complex role of organic matter for the formation of orogenic gold deposits.
  • 1.7K
  • 27 Aug 2021
Topic Review
Portable Analytical Instruments in Mineral Exploration Studies
The classic approach to mineral exploration studies was to bring the field samples/drill cores collected during field studies to the laboratory, followed by laborious analysis procedures to generate the analytical data. This is very expensive, time-consuming, and difficult for exploring vast areas. However, rapid technological advances in field-portable analytical instruments, such as portable visible and near-infrared spectrophotometers, gamma-ray spectrometer, portable X-ray fluorescence spectrometers (pXRF), portable X-ray diffractometers (pXRD), portable laser-induced breakdown spectrometers (pLIBS), and µRaman spectrometer, have changed this scenario completely and increased their on-site applications in mineral exploration studies. LED fluorimeter is a potential portable tool in the hydrogeochemical prospecting studies of uranium. These instruments are currently providing direct, rapid, on-site, real-time, non-destructive, cost-effective identification, and determination of target elements, indicator minerals and pathfinder elements in rock, ore, soil, sediment, and water samples. These portable analytical instruments are currently helping to obtain accurate chemical and mineralogical information directly in the field with minimal or no sample preparation and providing decision-making support during fieldwork, as well as during drilling operations in several successful mineral exploration programs. 
  • 1.7K
  • 08 Apr 2022
Topic Review
Earthquake Warning System Using Low-Cost Sensors in Taiwan
With advancements in technology and data processing speed, risk mitigation tools, such as earthquake early warnings (EEW), have emerged as life-saving guards in many earthquake-prone countries. The seconds-long warning achieved during EEW may be very helpful in saving the lives of human beings by allowing them to flee from buildings (if possible), or to take the proper shelter, or to move to a safer place within a building. 
  • 1.5K
  • 29 Nov 2021
Topic Review
Microbial Mats: Extraterrestrial Life Models
Extant microbial mats already present on Earth provide useful working analog models for the exploration of life in extraterrestrial hydrospheres.
  • 1.3K
  • 08 Sep 2021
Topic Review
Particle-Bound Mercury Characterization
Particulate Bound Hg (PBM) consists of all airborne particulate containing Hg, including both stable condensed and gaseous forms adsorbed on atmospheric particulate matter (PM); it is operationally sampled and quantified by pulling air through a glass fiber or a quartz filter. PBM usually includes all those particles with a diameter <2.5 μm, even if its characterization depends on the pore size of the filter used for its collection. The accurate dimensional characterization is then essential to estimate the dry deposition of PBM, as well as any other particulate pollutant; the particles diameters directly influence gravitational sedimentation and the PBM residence time in the atmosphere. In addition, PBM chemical speciation, as well as for the other Hg forms, is fundamental to understand PBM bioavailability and therefore the effects on human .
  • 1.2K
  • 05 Jul 2021
Topic Review
Geochemical Modeling Applications
The geochemical computer model is an important innovation that exponentially evolved in the last decades, and that now plays a vital role in several areas of study, ranging from developing new models for surface complexation, reactive transport models, or the generation of thermodynamic data used to simulate or predict solubility reactions. An important application of geochemical modeling involves supporting the explanation or characterization of engineering systems related to waste management, wastewater reuse, evaluation of water quality from a landfill, metal speciation within soils in industrial areas, new technologies or process for waste treatment, and even the evaluation of the potential to use solid wastes in carbon sequestering processes.
  • 1.1K
  • 03 Aug 2021
Topic Review
Pyrolysis of Technogenic-Redeposited Coal-Bearing Rocks
Hydrocarbon products formed under high-temperature and low-temperature pyrolysis of coal-bearing rocks were studied by using a chromatography-mass spectrometer GCMS-QP2010NC Plus (made by Shimadzu Company). The average temperature of low-temperature natural pyrolysis does not exceed 120°C, and its average speed is approximately 2 m/year. In this case, three pyrolysis zones gradually built metamorphic rock mass (from bottom to top) are clearly established: heating (focal) activated and enriched. The average temperature of high-temperature pyrolysis reaches 850°C, and its average speed is approximately 20 m/year. Unlike low-temperature pyrolysis, high-temperature pyrolysis is accompanied by the presence of two major zones (from bottom to top): pyrogenic (focal) and enriched (coke). The chemical composition of the enriched pyrolysis zone was studied in detail. It has been established that hydrocarbon compounds in samples of the pyrolysis zone are presented by six classes: asphaltic-resinous substances; polycyclic aromatic hydrocarbons, heterocyclic compounds, organic sulphur compounds; pyrolytic hydrocarbon and heavy hydrocarbon residue. Quantitative content of hydrocarbon compounds in the analyzed samples varies from 0.35% to 41.88%.   Based on the materials of fieldwork, we created a video film that can be seen on the website https://youtu.be/Tqs6YiKfDdE
  • 1.0K
  • 29 Oct 2020
Topic Review
Microbially Induced Carbonate Precipitation
 Microbially induced carbonate precipitation (MICP) is a promising technology for solidifying sandy soil, ground improvement, repairing concrete cracks, and remediation of polluted land. By solidifying sand into soil capable of growing shrubs, MICP can facilitate peak and neutralization of CO2 emissions because each square meter of shrub can absorb 253.1 grams of CO2 per year.
  • 986
  • 01 Dec 2021
Topic Review
Mineralizing Fluids at Porphyry Deposits of Cu−Mo−Au System
The porphyry type of hydrothermal mineral deposits is of paramount economic importance because deposits of this type host much of the world’s reserves of Cu, Mo, and Re, as well as much Re and remarkable reserves of critical elements such as Ag, Pd, Te, Se, Bi, Zn, and Pb. Porphyry deposits are conventionally classified into mineralogical–geochemical types according to their dominant valuable components. The most economically important porphyry-type deposits are those of the Cu (Au), Cu–Mo (Au), Mo, and Au types.
  • 976
  • 05 May 2022
Topic Review
Impact of Nanoparticles on Plants under Drought Stress
Drought is a chronic abiotic stress affecting crop growth and development, accounting for approximately 70% of the potential loss of global crop yield and productivity. Drought hinders agriculture and forestry worldwide, due to very little rainfall or significant differences in moisture. The current trends of global warming are causing a major impact on the moisture levels of the soil and the environment, and are increasing the intensity of droughts. Plants are subjected to various stresses during their growth, and the morphology of plants is affected at all stages of development due to drought stress, with productivity losses expected to reach 30% globally by 2025. 
  • 963
  • 22 Nov 2022
Topic Review
The BrIdge voLcanic LIdar—BILLI
Volcanologists have demonstrated that carbon dioxide (CO2) fluxes are precursors of volcanic eruptions. Controlling volcanic gases and, in particular, the CO2 flux, is technically challenging, but we can retrieve useful information from magmatic/geological process studies for the mitigation of volcanic hazards including air traffic security. Existing techniques used to probe volcanic gas fluxes have severe limitations such as the requirement of near-vent in situ measurements, which is unsafe for operators and deleterious for equipment. In order to overcome these limitations, a novel range-resolved DIAL-Lidar (Differential Absorption Light Detection and Ranging) has been developed as part of the ERC (European Research Council) Project “BRIDGE”, for sensitive, remote, and safe real-time CO2 observations.
  • 953
  • 09 Oct 2020
Topic Review
“Every Earthquake a Precursor According to Scale” Model
The observation that major earthquakes are generally preceded by an increase in the seismicity rate on a timescale from months to decades was embedded in the “Every Earthquake a Precursor According to Scale” (EEPAS) model. EEPAS has since been successfully applied to regional real-world and synthetic earthquake catalogues to forecast future earthquake occurrence rates with time horizons up to a few decades. When combined with aftershock models, its forecasting performance is improved for short time horizons. As a result, EEPAS has been included as the medium-term component in public earthquake forecasts in New Zealand. EEPAS has been modified to advance its forecasting performance despite data limitations. One modification is to compensate for missing precursory earthquakes. Precursory earthquakes can be missing because of the time-lag between the end of a catalogue and the time at which a forecast applies or the limited lead time from the start of the catalogue to a target earthquake. An observed space-time trade-off in precursory seismicity, which affects the EEPAS scaling parameters for area and time, also can be used to improve forecasting performance. Systematic analysis of EEPAS performance on synthetic catalogues suggests that regional variations in EEPAS parameters can be explained by regional variations in the long-term earthquake rate.
  • 927
  • 21 Oct 2022
Topic Review
Eudialyte-group minerals (EGMs)
       Eudialyte-group minerals (EGMs) are typical components of some kinds of agpaitic igneous rocks and related pegmatites and metasomatic assemblages. Crystal-chemical features of these minerals are important indicators reflecting conditions of their formation (pressure, temperature, fugacity of oxygen and volatile species, and activity of non-coherent elements.        A unique crystal-chemical diversity of EGMs is determined by a wide variability of their chemical composition involving more than 30 main elements and complex mechanisms of homovalent, heterovalent, and, especially, blocky isomorphism involving groups of atoms having different valency and coordination. The uniqueness of these minerals lies in the fact that they exhibit ability to blocky isomorphism at several sites of high-force-strength cations belonging to the framework and at numerous sites of extra-framework cations and anions.
  • 891
  • 26 Aug 2020
Topic Review
Global Marine Dissolved Organic Matter
Marine dissolved organic matter (DOM) holds ~660 billion metric tons of carbon, making it one of Earth’s major carbon reservoirs that is exchangeable with the atmosphere on annual to millennial time scales. The global ocean scale dynamics of the pool have become better illuminated over the past few decades. 
  • 872
  • 15 Sep 2021
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