Arabian Journal of Geosciences最新文献

Increasing the soil shear strength is necessary to prepare the soil before construction. Chemical and physical stabilization can increase the soil-bearing capacity. The latest chemical stabilization method is the calcite method. The calcite precipitation method of Soybean Crude Urease Calcite Precipitation (SCU-CP), which utilizes soybeans as a biocatalyst, was used in this study. In previous studies, the improvement in sand parameters after treatment with calcite precipitation has been verified; however, the results varied. Therefore, it is necessary to conduct a durability test to evaluate the resistance strengthened by calcite. In this study, a durability test was conducted using a wet-dry cycle test, which evaluated the shear strength to determine changes in the parameters of shear strength, volume degradation, and sample mass. The soil treated by SCU-CP had a cohesion and an internal friction angle of 37.05 kPa and 14.27°, respectively. The durability test results showed that the cycle progressed, resulting in a decrease in the cohesion and internal friction of 58.68% and an internal friction angle of 70.15%, respectively, after the 5th cycle. In addition, the volume and mass of the treated soil decreased by 13.22%. This study elucidated that the improved soil using SCU-CP has great potential as an alternative soil improvement method; however, the control of wet-dry conditions in real field applications should be considered.

This study assesses groundwater Quality and subsurface lithology in a residential area built on a reclaimed municipal waste dumpsite in Enugu, Nigeria. It addresses the potential environmental and health impacts of such sites, aligning with SDG 6 (Clean Water and Sanitation) and SDG 11 (Sustainable Cities and Communities). The objectives include groundwater Quality evaluation, subsurface characterization, and groundwater suitability assessment. Water samples from hand-dug wells were collected during both rainy and dry seasons over 2 years. Electrical Resistivity Tomography (ERT) was employed to identify subsurface leachate pathways, while Atomic Absorption Spectrometry (AAS) was used to analyze eight heavy metals and 13 physicochemical parameters for groundwater quality index (WQI) calculation. ERT results revealed zones of low resistivity (0.5–7 Ωm) at depths of 5–16 m, indicating leachate presence. These zones were bordered by moderately resistive lateritic materials (58–199 Ωm). Most parameters fell within WHO permissible limits, except for cadmium (dry, 0.02 mg/L; wet, 0.17 mg/L), cobalt (dry, 0.02 mg/L; wet, 0.04 mg/L), temperature (dry, 28 °C; wet, 25 °C), and TSS (dry, 290 mg/L; wet, 110 mg/L). During the dry season, lead (0.15 mg/L) and total solids (TS) (720 mg/L) exceeded acceptable limits. pH values were slightly acidic, ranging from 5.0 (dry) to 5.5 (wet). The WQI scores of 987 (dry) and 3005 (wet) indicated high contamination in both seasons. Statistical analysis showed no significant seasonal variation in contaminant levels. Overall, geophysical and laboratory findings confirm that the groundwater is highly contaminated and poses serious health risks to residents.

The northeastern part of the Indian plate is undergoing a unique geological setting; two arcuated orogens such as collision And subduction meet in the extreme northeast corner to form the eastern syntaxial bend. Over the past 200 years, these plate boundaries have caused numerous strong And great earthquakes, and the comprehensive study that followed led to the creation of modern seismology. During 2023, three moderate magnitude earthquakes with shallow focus (1) A 5.4 M with 16 km depth on 14 August 2023 in Bangladesh, (2) A 5.2 M with depth of 10 km on 2 October 2023 near North Garo Hills, Meghalaya, and (3) 5.6 M with depth of 55 km on 2 December 2023 near Ramganj, Bangladesh, occurred And created a widespread shaking and small-scale damages in various parts of Northeast India. Isoseismal lines of these earthquakes have been prepared using more than 200 crowdsource datasets and field survey in the different demographic spectrum of the area. These earthquakes have caused rupture of (1) 2.86% in Sylhet fault, (2) 19.70% in Cherdang fault, and (3) 4.98% in Gomati fault. This study highlights the significance of collecting extensive data on numerous faults in order to comprehend the current tectonics in various tectonic frameworks and to prepare for a better mitigation plan.

Stabilization of an expansive soil containing sulfate with lime fails to effectively mitigate the swelling behavior of these soils as a result of the occurrence of ettringite, a highly expansive mineral. This study evaluated the effectiveness of utilizing 15% Soma fly ash (SFA) as an alternative to 4% lime (L) in enhancing the stability of expansive soil containing sulfate (SO₄) against swelling. Maximum allowable SO₄ content for the stabilization of the expansive sulfate clay with SFA was investigated to achieve the greatest reduction in swell potential and simultaneously inhibit the formation of ettringite. Index, swelling, and unconfined compressive strength (UCS) tests, together with scanning electron microscope (SEM) views and X-ray diffraction (XRD) analysis, were used to assess the impact of fly ash on the behavior of sulfate-bearing expansive soil. SO₄ concentration exhibited varying effects on the swell potential of treated specimens. A noticeable increase in the swell potential of expansive sulfate clay was observed when treated with 4% L, but no significant increase was observed when treated with 15% SFA. The UCS of the expansive sulfate clay specimens treated with both additives generally decreased. A significant reduction in strength was recorded for expansive sulfate clay treated with 15% SFA and exposed to 27,000 ppm SO₄ when cured at 10 °C, primarily due to ettringite/thaumasite and thenardite formation. The results indicated that 15% SFA can be safely used for stabilizing expansive soils containing SO₄ without causing heave or durability problems, provided that the SO₄ concentration of the expansive soil is below the threshold level of 6750 ppm.

Soil quality (SQ) is crucial for sustaining agricultural productivity, environmental health, and human well-being. Evaluating SQ involves analyzing soil properties and their spatial distribution. Utilization of geographic information systems (GIS) helps in understanding soil heterogeneity and provides a robust framework for SQ monitoring. This study focuses on the state of Mizoram, Northeast India, characterized by its hilly terrain, high rainfall, and diverse forest types. Soil samples were collected from 103 points across 11 districts, representing four different forest types, to assess SQ variability throughout the state using various physical, chemical, and biological parameters. Key soil parameters, including pH, electrical conductivity (EC), moisture content, bulk density (BD), available nitrogen (N), phosphorus (P), potassium (K), micronutrients (Fe, Mn, Zn, Cu), soil organic carbon (SOC), soil microbial biomass carbon (SMBC), and dehydrogenase activity (DHA), were measured. The GMA was employed to integrate these parameters into a comprehensive Soil Quality Index (SQI). The GIS-based spatial modeling facilitated the creation of detailed SQ maps with 84% overall accuracy, revealing significant variability in soil properties across the region. The SQ was classified into five grades, with grade III being the most extensive, covering 40.75% of Mizoram. Notably, the Assam subtropical pine forests exhibited overall higher soil quality compared to other forest types. This study emphasizes the critical role of GIS-based spatial analysis in capturing soil heterogeneity and developing an effective framework for SQ monitoring. The results provide valuable insights for land management and sustainable agricultural practices, aiding efforts to maintain soil health and improve productivity in Mizoram.

The Neogene sedimentary successions in peninsular India remain poorly understood due to limited surface exposures. Recent infrastructural developments in northern Kerala, especially around Kasargod, have enabled detailed investigations of the Cheruvathur Formation, a stratigraphic equivalent of the Neogene Warkalli Formation. Multiple sedimentary sections were studied using granulometry, SEM, XRD, XRF, and ICP-MS techniques. The sediments are predominantly silty, with lesser amounts of gravel, sand, and clay, and show poor to moderate sorting with near-symmetrical grain distributions. Mineralogical data highlight kaolinite dominance, alongside quartz and goethite, reflecting intense chemical weathering in a warm, humid paleoclimate. Geochemical trends indicate that sediments are derived from intermediate to felsic source rocks, as supported by REE patterns. The sediments exhibit passive continental margin affinities, with high chemical maturity due to prolonged weathering. Grain size distributions and elemental ratios (Sr/Ba < 1; variable V/(V + Ni)) suggest deposition in a fluvial to shallow marine environment, with fluctuating freshwater-brackish conditions and redox alternations. This study establishes the Cheruvathur Formation as a product of intense tropical weathering, mixed-energy depositional systems, and a tectonically stable margin, providing critical insights into the paleoenvironmental and stratigraphic evolution of northern Kerala.

An integrated k-means clustering of well log data from Mara field, Niger Delta, Nigeria, has been carried out. This is with a view to segmenting well data into different facies based on their physical and geological properties. The relationship between the cluster labels and the facies types was studied using cross-plots, histograms, and statistical analysis. The results obtained from cluster prediction were compared with conventional methods of well log interpretation. Three well datasets from Mara field (Mara-1, Mara-2, and Mara-3) containing gamma ray, neutron porosity, density, and deep resistivity logs were used. The well data was subjected to data preprocessing, exploratory data analysis, outlier detection and removal, feature selection, and scaling to make the data more suitable for machine learning (ML) methods. Due to missing data in density and neutron porosity logs that might have occurred as a result of various reasons, including tool failures, depth misalignments, and manual removal of bad data, Mara-3 well was dropped for clustering as the issue could significantly impact petrophysical analyses and machine learning model performance. The k-means clustering algorithm was implemented using the Scikit-learn library. The elbow method and silhouette score were then applied to cluster the datasets as well as evaluate the number of clusters. The elbow method approximated the cluster level to be at 3, while with further evaluation, the silhouette score gave the optimum level of clustering with its highest value at cluster level of 2. A cluster level of 2 was selected to be the best with the highest score of 0.552, denoting that the data points are very compact within the cluster to which they belong. Based on the clustering results, different facies (shale and sandstone) were recognized successfully. The reservoir unit of sandstone and shale intercalations was delineated from the two wells and a dynamic depositional environment. Comparison of the identified facies units with conventional method of interpretation showed that the k-means algorithm was able to cluster the data and correlate them with depth.

This study investigates the morphology of ancient fluvial systems in the Ganga–Yamuna interfluve and examines the potential influence of basement topography, specifically the Delhi–Haridwar Ridge (DHR), on their evolution. Using LANDSAT-8 false-colour composite imagery, Topographic Wetness Index (TWI) maps, SRTM DEM, and borehole lithological data, two distinct types of paleochannels were identified: type 1, characterized by anastomosing patterns and type 2, exhibiting meandering forms. These paleochannels, with an average width of approximately 2.1 km, indicate the presence of a larger river system that was abandoned likely during a halted megafan-building event between the Late Pleistocene-Holocene. The borehole lithology analyses reveal four lithofacies associations (LA-1 to LA-4) indicating different depositional environments under different tectonic and climatic conditions. LA-1 may represent the basal depositional unit consisting of coarse sand and gravel, indicating high-energy braided river system, and may imply the lateral migration of the major rivers across the megafan surface and likely interpreted as relict channel deposits. Orientation analysis using azimuthal extraction techniques revealed that both the paleochannels and the DHR share a predominant NNE–SSW trend. Statistical correlation using the chi-square test yielded values between 9 and 18, below the critical threshold of 28, thereby supporting the hypothesis that the basement topography significantly influenced paleochannel development. This study underscores the importance of subsurface structural features in shaping ancient drainage systems and offers new insights into the tectonic and geomorphic evolution of the Ganga Plain.

This paper presents a comparative study on under-reamed and helical piles under compressive and tensile loads. The study includes single-bulb, single-helix, double-bulb, double-helix, triple-bulb, triple-helix, and conventional pile types. The diameter and length for all the piles were 16 mm and 400 mm, respectively. Experimental studies were performed on the pile models under compressive loads using a tank of size 0.5 m × 0.5 m × 0.5 m. A numerical analysis was also conducted under compressive and tensile loading. The presence of bulbs and helices influenced the compressive and tensile behaviour of the piles. Under compressive loading conditions, it was observed that the triple bulb had a load-carrying capacity 5.5 times higher than the conventional pile and 4.7 times higher than the triple helix for the same settlement values. Comparing the load-carrying capacity of triple-bulb and triple helix piles under tensile loading, it was found that the former increased by 674% and 577%, respectively, over conventional piles. It has been observed that as the number of bulbs or helices increases, the pile’s settlement is reduced.

The study is carried out in selected vulnerable localities in terms of shortage in water supply in the White Nile State, Sudan, which include El Salam, Guli, and El Gabalain localities. These locations are either situated on basement rocks or dominated by thick clayey deposits within the NW-trending isolated sedimentary rift basins. The primary goal of this study is to explore the groundwater potential zones in the selected areas. The methods of investigations are based on the integration of the processed satellite gravity data with the ground electrical resistivity survey using winner and Schlumberger configurations. The interpretation of satellite gravity data were done through the Residual Bouguer Anomaly (RBA) and second vertical derivatives (SVD) to define the configuration of the sedimentary basins as water-bearing formations. The high-density rocks are attributed to the basement rocks, where the low-density rocks are related to the sedimentary sequences in the (RBA) maps. The faults, plains, and deep fractures are delineated as sharp boundaries between different gravity anomalies in (VSD) maps. The conducted geo-electrical surveys were done on the gravity data findings, detecting the lateral and vertical variations of sub-surface geology that help to highlight the groundwater occurrences. The high resistivity values ≥ 200 Ώ m refer to the occurrences of basement rocks; the medium resistivity values 20–200 Ώ m refer to the aquifer zones, while the low resistivity values of ≤ 20 Ώ m refer to clayey sediments or to saline water in the region.