Hasil untuk "Geology"

A. Watts

Isostasy is a simple concept, yet it has long perplexed students of geology and geophysics. This fully updated edition provides the tools to better understand this concept using a simplified mathematical treatment, numerous geological examples, and an extensive bibliography. It starts by tracing the ideas behind local and regional models of isostasy before describing the theoretical background, the observational evidence. It now also includes an exploration of the role of flexure in landscape evolution and dynamic topography and discussions of lithosphere memory, inheritance, and new NASA mission topography and gravity data. The book concludes with a discussion of flexure's role in understanding the evolution of the surface features of the Earth and its neighboring planets. Intended for advanced undergraduate and graduate students of geology and geophysics, it will also be of interest to researchers in gravity, geodesy, sedimentary basin formation, mountain building and planetary geology.

Feten Chihi, Gabriella Varga, Katalin Kopecskó

This experimental study examines the effects of landfill leachate contamination on soil hydraulic conductivity over a 12-month period, addressing the current lack of long-term experimental data in this field. Laboratory permeability tests were performed on sandy clayey silt samples contaminated with leachate at concentrations ranging from 5% to 25%. Microstructural and mineralogical analyses were conducted using SEM and XRD to identify the mechanisms behind observed changes. The results identify a critical threshold at 15% contamination, where soil behavior transitions from granular to cohesive characteristics. Hydraulic conductivity increases at low contamination levels (5–10%, up to 1.2 × 10⁻⁷ m/s) but decreases significantly at higher levels (4.172 × 10⁻⁸ m/s at 15%, 8.545 × 10⁻⁹ m/s at 20%). These changes are controlled by contamination level rather than exposure time, with values remaining stable throughout the 12-month period. The study provides essential parameters for landfill design and contamination assessment, demonstrating how leachate concentration affects long-term soil hydraulic properties through mineral formation and structural modification.

Musaab A.A. Mohammed, Ladislav Tometz, Norbert P. Szabó et al.

The Sobranecké Spa (“Salus per Aquam”) is historically known for its therapeutic mineral waters and recognized as a heritage site for its cultural significance. Despite its rich tradition and well-documented therapeutic effects, the spa ceased operations in 2004 and now remains in disrepair. However, renewed interest from the Košice self-governing region has prompted efforts to restore its activity. To support this initiative, a hydrogeological study was commissioned by the Technical University of Košice to provide a comprehensive assessment of the physical, chemical, and microbial properties of the mineral water and evaluate health risks related to dermal exposure. The study integrates hydrochemical classification, microbial assessment, and probabilistic risk analysis using Monte Carlo simulation and Sobol sensitivity analysis to evaluate dermal absorption dose (DAD), dermal hazard quotient (HQ) and hazard index (HI) for both adults and children. Hydrochemical results indicated a Na-Cl-type highly mineralized water, shaped by mineral dissolution and ion exchange processes. The microbial analysis focused on coliforms, Escherichia coli, and heterotrophic bacteria to assess potential biological risks. The results showed individual hazard quotients below 1 for most parameters, but H2S drove cumulative hazard index values to 9.5 for adults and 12.1 for children, with children facing 28 % higher risk and persistent dermal health concerns across all scenarios. However, the findings confirm that the mineral waters meet Slovak and European standards for therapeutic use. Due to the study’s single sampling event, long-term seasonal monitoring is recommended to ensure water quality stability and safety for future spa use.

Andrew Birkey, Heather A. Ford, Megan Anderson et al.

Dense seismic arrays such as EarthScope’s Transportable Array (TA) have enabled high-resolution seismic observations that show the structure of cratonic lithosphere is more heterogeneous and complex than previously assumed. In this study, we pair TA data with data from the Bighorn Arch Seismic Experiment and the Crust and lithosphere Investigation of the Easternmost expression of the Laramide Orogeny (CIELO) to provide unprecedented detail on the seismic anisotropic structure of the eastern margin of the Wyoming Craton, where several orogens emerged from nominally strong cratonic lithosphere during the Laramide Orogeny. In this study, we use the splitting of teleseismic shear waves to characterize fabrics associated with deformation in the Earth’s crust and mantle. We constrain distinct anisotropic domains in the study area, and forward modeling shows that each of these domains can be explained by a single layer of anisotropy. Most significantly, we find a fast direction in the southern part of the Powder River Basin, which we refer to as the Thunder Basin Block (TBB), that deviates from absolute plate motion (APM). This change in splitting behavior coincides with changes in other modeled geophysical observations, such as active source P-wave velocity models, potential field modeling, and seismic attenuation analysis, which all show a significant change moving from the Bighorn Mountains to the TBB. We argue that these results correspond to structure predating the Laramide Orogeny, and most likely indicate a Neoarchean boundary preserved within the lithosphere.

Yuanning Li, Chao Xu, Fei Geng et al.

为揭示诱发地震和天然地震对建筑结构影响及其破坏概率分布的影响，本文以我国典型砌体结构为研究对象，开展了考虑诱发地震影响的易损性研究。首先建立了典型三层和六层砌体结构分析模型，然后以40条震级和震中距都接近的天然地震地震动和诱发地震地震动为输入开展Pushover分析，分别建立基于峰值加速度PGA和结构基本周期加速度反应谱值Sa的易损性曲线，最后采用循环往复加载方法对两次诱发地震作用下的结构倒塌易损性进行了分析讨论。结果表明：当以PGA作为易损性输入地震动参数时，天然地震地震动作用下的易损性显著高于诱发地震地震动；当以Sa作为易损性输入地震动参数时，三层砌体结构由于以基本振型为主导，在两类地震动作用下其易损性曲线比较接近，而六层砌体结构高阶振型由于对结构地震响应具有一定影响，且诱发地震地震动的高频成分较天然地震地震动丰富，因此六层砌体结构在诱发地震地震动作用下的易损性高于天然地震。此外，对两次诱发地震作用下的砌体结构易损性分析结果表明两次地震作用下结构的损伤概率明显增加。

Abebaw Demelash, Abunu Atlabachew, Muralitharan Jothimani et al.

Groundwater is a primary drinking, agricultural, domestic, and nondomestic water source in Ethiopia’s Yisr River watershed of the Blue Nile River basin. There has been no systematic investigation of the hydrogeochemical properties of groundwater in the research area. The study investigated the hydrogeochemical parameters of groundwater in the catchment to find out if it is fit for drinking and irrigation. A total of 26 samples of groundwater were collected and analyzed for seventeen parameters, including pH, temperature, EC, TDS, TH, K+, Na+, Ca2+, Mg2+, Fe2+, Cl−, HCO3−, CO32−, SO42−, F−, PO42−, and NO3−. The data were processed and evaluated using integrated hydrogeochemical techniques, including individual ionic signatures, interionic ratios, and multivariate statistical methods, such as multiple correlation analysis, principal component analysis, and hierarchical cluster analysis. The water quality index (WQI) and Na%, PI, RSC, SAR, EC, TDS, and MH were used to judge the quality of water for drinking and irrigation, respectively. The box plot diagram shows the dominant ions in descending order of Ca2+ > Mg2+ > Na+ > K+ and HCO32− > Cl- > SO42− > NO3− > F− for cations and anions, respectively. The chemical composition of shallow wells and springs indicates freshwater. At the same time, the deep groundwater wells are brackish. The two-factor loadings (principal component analysis) were used to explain the existence of anthropogenic and geogenic sources. Three clusters are identified in the dendrogram. The third cluster has the most significant linkage distance among all the clusters. This means that the groundwater sample in this cluster is geochemically different from the other two clusters, and that this cluster is made up of only deep wells. Water quality indices showed that water quality ranged from excellent to very poor, with the majority (53.85%) being excellent and 26.9% being good. The results of the calculated indices for agricultural water quality indicated that the water quality in most collected samples was in the good and excellent categories; however, the EC, RSC, MH, and TDS indices in deep groundwater wells were found to be hazardous. The findings of this study are useful for understanding groundwater sustainability for various reasons. However, they are also helpful in supporting water management and protection in the future.

Alexander Yu. Kissin, Mikhail E. Pritchin, Danil A. Ozornin

The paper presents the geological and structural position of the large Svetlinsky gold deposit in the Kochkar anticline (Southern Urals), localized in the zone of the Late Paleozoic (D3) deep thrust of the western dip. The study confirms and clarifies the notion of its multiphase and polychronism. The thrust caused bending moments in its wings, subsidence of the lying crust, emergence of a shallow marine basin with rapid accumulation of terrigenous carbonate sediments (C1v), and formation of numerous landslide structures. The heating of rocks in the anticline core was accompanied by granitization and dome formation. A small Svetlinsky dome formed in the immediate vicinity of the thrust, creating a thermobaric gradient field (С2). The zone of dome dynamic influence also includes the adjoining thrust area, complicated by a series of sub-vertical thrusts of sub meridional strike and numerous steeply dipping subparallel cracks of the latitudinal strike, synchronously filled with vein quartz and accompanied by hydrothermal metasomatic rock transformations. The formation of the gold deposit occurred during the post-collisional relaxation stage (from P1 to, probably, the Early Jurassic). The association of gold mineralization with the Svetlinsky dome is indicated by the presence of native gold in Neogene ravine placers in the dome area and marbles of the Svetlinsky deposit, in association with fluorite, F-phlogopite, Cr-muscovite, pink topaz, pure quartz, and native sulphur. The presence of native gold in Neogene ravine placers in the dome area and marbles of the Svetlinsky deposit, in association with fluorite, F-phlogopite, Cr-muscovite, pink topaz, pure quartz, and native sulphur, indicates the association of gold mineralization with the Svetlinsky dome.

Baizan Tang, Wenchao Deng, Su Chen et al.

Based on the the large shaking table test results on irregular section subway station structure in soft soil, an overall time-history numerical simulation is conducted to study the nonlinear dynamic interaction of the soil-irregular underground structure. Typical test results, including the acceleration of the soil, acceleration, and deformation of the structure, were analyzed. Satisfactory consistency between the simulation and test results is verified, and the difference between these results was discussed in detail. The maximum inter-story drift ratio was approximately 1/472 under input PGA ​= ​0.54 g. The strain responses of columns were significantly larger than those of the side walls and slabs. The components in the lower layers of the irregular subway station structure, particularly in the central columns, underwent cumulative damage. The research results could provide a simplified analysis method to quantitatively evaluate the damage of irregular underground structures in soft soil.

Bruce Currie-Alder, Cynthia Rosenzweig, Minpeng Chen et al.

Adaptation to climate change must be ramped up urgently. This Comment proposes three avenues to transform ambition to action: improve tracking of actions and progress, upscale investment especially in critical areas, and accelerate learning through practice.

Pin Jia, Defeng Wu, Hengfei Yin et al.

Fractured horizontal wells have been widely used to develop unconventional oil and gas reservoirs. In previous studies, most studies on the transient pressure behavior of multistage horizontal wells were based on the assumption of single porosity medium, in which the coupling relationship of natural fractures and artificial fractures was not taken into account or artificial fractures were assumed to be infinitely conductive. In this paper, the fracture is finite conductive, which means that there is flow resistance in the fracture. Based on point-source method and superposition principle, a transient model for multistage fractured horizontal wells, which considers the couple of fracture flow and reservoir seepage, is built and solved with the Laplace transformation. The transient pressure behavior in multistage fractured horizontal wells is discussed, and effects of influence factors are analyzed. The result of this article can be used to identify the response characteristic of fracture conductivity to pressure and pressure differential and provide theoretical basis for effective development of tight oil reservoirs. The findings of this study can help for better understanding of transient pressure behavior of multistage fractured horizontal wells with finite conductivity in tight oil reservoirs.

Chengyu Xie, Hoang Nguyen, Xuan-Nam Bui et al.

Due to the rapid industrialization and the development of the economy in each country, the demand for energy is increasing rapidly. The coal mines have to pace up the mining operations with large production to meet the energy demand. This requirement has led underground coal mines to go deeper with more difficult conditions, especially the mining hazards, such as large deformations, rockburst, coal burst, roof collapse, to name a few. Therefore, this study aims at investigating and predicting the stability of the roadways in underground coal mines exploited by longwall mining method, using various novel intelligent techniques based on physics-based optimization algorithms (i.e. multi-verse optimizer (MVO), equilibrium optimizer (EO), simulated annealing (SA), and Henry gas solubility optimization (HGSO)) and adaptive neuro-fuzzy inference system (ANFIS), named as MVO-ANFIS, EO-ANFIS, SA-ANFIS and HGSO-ANFIS models. Accordingly, 162 roof displacement events were investigated based on the characteristics of surrounding rocks, such as cohesion, Young's modulus, density, shear strength, angle of internal friction, uniaxial compressive strength, quench durability index, rock mass rating, and tensile strength. The MVO-ANFIS, EO-ANFIS, SA-ANFIS and HGSO-ANFIS models were then developed and evaluated based on this dataset for predicting roof displacements in roadways of underground mines. The results indicated that the proposed intelligent techniques could accurately predict the roof displacements in roadways of underground mines with an accuracy in the range of 83%–92%. Remarkably, the SA-ANFIS model yielded the most dominant accuracy (i.e. 92%). Based on the accurate predictions from the proposed techniques, the reinforced solutions can be timely suggested to ensure the stability of roadways during exploiting coal, especially in the underground coal mines exploited by the longwall mining.

A. V. Dyrrdal, K. Isaksen, J. K. S. Jacobsen et al.

<p>A number of seaside communities in Troms, northern Norway, are vulnerable to sudden weather-induced access disruptions due to high-impact weather and dependency on one or few roads. In this paper we study changes in winter weather known to potentially cause access disruptions in Troms, for the present climate (1958–2017) and two future periods (2041–2070; 2071–2100). We focus on climate indices associated with snow avalanches and weather that may lead to for example slippery road conditions. In two focus areas, the most important results show larger snow amounts now compared to 50 years ago, and heavy snowfall has become more intense and frequent. This trend is expected to turn in the future, particularly at low elevations where snow cover during winter might become a rarity by 2100. Strong snow drift, due to a combination of snowfall and wind speed, has slightly increased in the two focus areas, but a strong decrease is expected in the future due to less snow. Events of heavy rain during winter are rather infrequent in the present winter climate of Troms, but we show that these events are likely to occur much more often in all regions in the future.</p>

Nanjun Lai, Nanjun Lai, Nanjun Lai et al.

During CO2 flooding, serious gas channeling occurs in ultra-low permeability reservoirs due to the high mobility of CO2. The chief end of this work was to research the application of responsive nanoparticles for mobility control to enhance oil recovery. Responsive nanoparticles were developed based on the modification of nano-silica (SiO2) by 3-aminopropyltrimethoxysilane (KH540) via the Eschweiler-Clark reaction. The proof of concept for responsive nanoparticles was investigated by FT-IR, 1H-NMR, TEM, DLS, CO2/N2 response, wettability, plugging performance, and core flooding experiments. The results indicated that responsive nanoparticles exhibited a good response to control nanoparticle dispersity due to electrostatic interaction. Subsequently, responsive nanoparticles showed a better plugging capacity of 93.3% to control CO2 mobility, and more than 26% of the original oil was recovered. Moreover, the proposed responsive nanoparticles could revert oil-wet surfaces to water-wet, depending on surface adsorption to remove the oil from the surface of the rocks. The results of this work indicated that responsive nanoparticles might have potential applications for improved oil recovery in ultra-low permeability reservoirs.

Viviana Valdez, Shirley Moncayo, Xavier Cornejo et al.

En el presente trabajo se realizó el tamizaje fitoquímico, cuantificación de flavonoides y fenoles totales y la evaluación de la actividad antioxidante y antibacteriana de los extractos etanólicos obtenidos de hojas de Hibiscus escobariae, Loxopterygium huasango y Croton ferrugineus, contra tres bacterias Gram Positivas (Staphylococcus aureus, Bacillus subtilis, Listeria monocytogenes) y tres Gram negativas (Escherichia coli, Pseudomonas aeruginosa, Vibrio parahaemolyticus). Para el análisis de las muestras se realizó el tamizaje fitoquímico por el método de Domínguez, la cuantificación de flavonoides por el método colorimétrico cloruro de aluminio, la cuantificación de fenoles totales por el método Folin-Ciocalteu, actividad antibacteriana por ensayos de difusión por disco y actividad antioxidante mediante la técnica DPPH. En el tamizaje fitoquímico los flavonoides y taninos se presentaron en mayor cantidad, mientras que los alcaloides, quinonas, antraquinonas, esteroides y saponinas estuvieron presentes en menor proporción. El contenido de flavonoides varió de 100,95 ± 1,73 a 995,42 ± 3,16 mg CE / g extracto en H. escobariae y L. huasango y el contenido de fenoles varió de 10,17 ± 0,22 a 314,72 ± 1,91 mg GAE/ g extracto en Croton ferrugineus y L. huasango que también obtuvo la mejor actividad antibacteriana frente a las cepas evaluadas con CMI que varían de 2.5 a 5 mg/mL y la mejor actividad antioxidante con IC50 de 0,1 mg/m y de 0,7 mg/mL para Croton ferrugineus con una diferencia significativa p<0.05. Estos resultados son los primeros reportados los que servirán como línea base para estudios posteriores.

HE Ling, SUN Bin-bin, WU Chao et al.

BACKGROUND The orchard soil environment is closely related to kiwifruit yield, quality and its edible safety. Research shows that the nutrient insufficiency and uneven distribution in kiwifruit orchard soil is a common problem in China, and in some areas, the content of heavy metals in soil has been found to exceed the environmental quality standard for soils. In recent years, the planting area of Kiwifruit in Zhejiang Province has been expanded year by year, being one of the important kiwifruit producing areas in China. OBJECTIVES To study the present situation of soil environmental quality in kiwifruit orchards in Jiangshan City, Zhejiang Province. METHODS Two typical kiwifruit orchards were selected to collect samples of soil, rock and fruit, and the content of heavy metals, nutrients and physical and chemical parameters of soil and rock samples were determined by atomic fluorescence spectrometry (AFS) and inductively coupled plasma-optical emission spectrometry (ICP-OES). The environmental quality and ecological risk assessment of orchard soil were carried out with the main research contents of nutrient abundance and deficiency in orchard soil, influence factors, heavy metal content and fruit edible safety. RESULTS The results showed that the content of Ag, Bi, Co, Cr, Ni, Sb, Se, V and SiO2 in the soil of the two orchards were lower than those of Quzhou City and Zhejiang Province, while Pb and Al2O3 contents were higher than those of Quzhou City and Zhejiang Province. The characteristics of soil element content were obviously controlled by the natural geological background. Soil pH value ranged from 4.61 to 6.30. According to the classification standard in DZ/T 0295-2016, the soils in the studied area belonged to strong acidic and acidic soils. Nutrient elements K, Ge, Mo and Zn were abundant, but N, P, Mn and S were deficient. The maximum value of As, Cd, Cr, Cu, Hg, Ni, Pb and Zn in the soil samples were 21.84, 0.22, 23.53, 20.47, 0.06, 8.82, 53.84 and 133mg/kg, respectively, which were far lower than the screening value of soil pollution risk for agricultural land (standard limit were 40, 0.3, 150, 150, 1.3, 60, 70, 200mg/kg when pH ≤ 5.5). The risk of soil pollution was low. The contents of heavy metals in kiwifruit fruit were lower than the limits of green food and food hygiene standards. For example, the highest content of As was 0.009mg/kg, the limit were 0.2mg/kg and 0.5mg/kg, respectively. CONCLUSIONS On the whole, the soils in the study area have the characteristics of strong acidity, uneven distribution of nutrients and low content of heavy metals. It is necessary to take scientific measures to supple and balance soil nutrients and prevent the risk of heavy metals activation caused by soil acidification.

G. Millot, W. Farrand, H. Paquet et al.

J. V. Hinte

Tjaša Kanduč, Nataša Mori, Ajda Koceli et al.

The geochemical and isotopic composition of groundwater in the Velenje Basin, Slovenia, was investigated between the years 2014 to 2015 to identify the geochemical processes in the major aquifers (Pliocene and Triassic) and the water–rock interactions. Thirty-eight samples of groundwater were taken from the aquifers, 19 in the mine and 19 from the surface. Groundwater in the Triassic aquifer is dominated by HCO3–, Ca2+ and Mg2+ with δ13C DIC values in the range from -19.3 to -2.8 ‰, indicating degradation of soil organic matter and dissolution of carbonate minerals. In contrast, groundwater in the Pliocene aquifers is enriched in Mg2+, Na+, Ca2+, K+, and Si, and has high alkalinity, with δ13CDIC values in the range of -14.4 to +4.6 ‰. Based on the δ13CDIC values in all the aquifers (Pliocene and Triassic), both processes inflence the dissolution of carbonate minerals and dissolution of organic matter and in the Pliocene aquifers, methanogenesis as well. Based on Principal Component Analysis (PCA), and on geochemical and isotopic data we conclude that the following types of groundwater in Velenje Basin are present: Triassic aquifers with higher pH and lower conductivity and chloride, Pliocene, Pliocene 1 and Pliocene 2 aquifers with lower pH and higher conductivity and chloride contents, and Pliocene 3 and Pliocene 2, 3 aquifers with the highest pH values and lowest conductivities and chloride contents. 87Sr/86Sr tracer was used for the fist time in Slovenia to determine geochemical processes (dissolution of silicate versus carbonate fraction) in Velenje Basin groundwater of different aquifers dewatering Pliocene and Triassic strata. 87Sr/86Sr values range from 0.70820 to 0.71056 in groundwater of Pliocene aquifers and from 0.70808 to 0.70910 in groundwater of the Triassic aquifer. This indicates that dissolution of the carbonate fraction prevails in both aquifers, while in Pliocene aquifers, an additional silicate weathering prevails with higher 87Sr/86Sr isotope ratios.

J. Escuder-Viruete, Á. Suárez-Rodríguez, J. Gabites et al.

In northern Hispaniola, the Imbert Formation (Fm) has been interpreted as an orogenic “mélange” originally deposited as trench-fill sediments, an accretionary (subduction) complex formed above a SW-dipping subduction zone, or the sedimentary result of the early oblique collision of the Caribbean plate with the Bahama Platform in the middle Eocene. However, new stratigraphical, structural, geochemical and geochronological data from northern Hispaniola indicate that the Imbert Fm constitutes a coarsening-upward stratigraphic sequence that records the transition of the sedimentation from a pre-collisional forearc to a syn-collisional basin. This basin was transported on top of the Puerto Plata ophiolitic complex slab and structurally underlying accreted units of the Rio San Juan complex, as it was emplaced onto the North America continental margin units.</p><p class="p">The Imbert Fm unconformably overlies different structural levels of the Caribbean subduction-accretionary prism, including a supra-subduction zone ophiolite, and consists of three laterally discontinuous units that record the exhumation of the underlying basement. The distal turbiditic lower unit includes the latest volcanic activity of the Caribbean island arc; the more proximal turbiditic intermediate unit is moderately affected by syn-sedimentary faulting; and the upper unit is a (chaotic) olistostromic unit, composed of serpentinite-rich polymictic breccias, conglomerates and sandstones, strongly deformed by syn-sedimentary faulting, slumping and sliding processes. The Imbert Fm is followed by subsidence and turbiditic deposition of the overlying El Mamey Group.</p><p class="p">The ⁴⁰Ar ∕ ³⁹Ar plagioclase plateau ages obtained in gabbroic rocks from the Puerto Plata ophiolitic complex indicate its exhumation at  ∼  45–40 Ma (lower-to-middle Eocene), contemporaneously to the sedimentation of the overlying Imbert Fm. These cooling ages imply the uplift to the surface and submarine erosion of the complex to be the source of the ophiolitic fragments in the Imbert Fm, during or shortly after the emplacement of the intra-oceanic Caribbean island arc onto the continental margin.

R. Grim, N. Güven