Arabian Journal of Geosciences最新文献

Oke-Ere, part of Isanlu Sheet 225 SW, is known for occurrence of pegmatite veins, quartz schist, talc schist, and marble out crops. Consequently, weathered soil (top soil (pedolith) and saprolite) and these fresh rock samples were collected from different areas within the study area and subjected to geochemical analyses to possibly understand rare-metal concentration trend associated with the weathered soils and overlying rocks. Geochemically, the trace metal distribution shows similar patterns for the top soil zone (pedolith) and saprolite units with bedrocks. This suggest a positive link between the trace metals in the weathered units and the respective bedrocks. This is possibly due to a lithogenic release of the respective trace metals through the weathering process. This is confirmed by the Enrichment Ratio > 1 for the trace elements (Pb, Ni, Zn, Cr, Co, Sr, Ta, Sc, Nb, and Ba) obtained for pedolith and saprolite samples. The high concentration of Zn (avg. 93 ppm) Nb (avg. 36), Sn (avg. 145 ppm), and Li (avg. 142 ppm) in the pegmatite samples compared to the pedolith and saprolite also confirms this assertion. Plots of A = Al-(K + Na + 2Ca) vs. B = Fe + Mg + Ti, and Ta vs. Ga revealed that the investigated pegmatite and schistose samples are associated with magmatic differentiation of peraluminous melts with all the investigated samples barren in Ta. Tectonically, all the representative samples plot within the field of WPG (Within Plate Granite), implying their origin from a plume or a hotspot and probable genetic relationship between them. The study shows significant enrichment of Zn, Nb, and Sn in Oke-Ere pegmatites, pedolite and saprolite, highlighting promising economic potential thus proving saprolith and pedolith with associated host rock in any given area can supply an exploration guide for rare-metal mineralization.

To elucidate the instability mechanisms of surrounding rock in water-rich tunnels under construction disturbances, this study conducted triaxial graded cyclic loading–unloading seepage coupling tests to systematically investigate the mechanical response and permeability evolution characteristics of saturated sandstone. The results demonstrate that cyclic loading induces multi-crack failure patterns, distinct from the conventional single shear plane failure. Increasing confining pressure promotes a transition from tensile cracking to shear-dominated failure, while elevated seepage pressure induces tension-shear composite failure. The morphological evolution of hysteresis loops characterizes the damage transition from primary fracture closure to new crack propagation. Under cyclic loading–unloading, the post-peak permeability increases by one order of magnitude on average compared to the initial permeability. The crack volumetric strain transitions continuously from compression to dilation during loading, with its critical zero-crossing point under high confining pressure synchronously corresponding to the peak total volumetric strain and the inflection point of accelerated permeability increase. Elevated confining pressure transforms the loading permeability curve from “spoon-shaped” to “U-shaped” and delays the permeability inflection point. Under rapid loading rates, permeability is comprehensively reduced due to delayed seepage response. Increased seepage pressure enhances permeability by reducing effective stress and intensifying hydraulic gradients, resulting in significant permeability enhancement and accelerated post-peak fracture propagation. This research reveals the synergistic evolution mechanism of damage and permeability in sandstone under coupled graded cyclic loading-seepage effects, providing a theoretical basis for stability control of surrounding rock in water-rich tunnels.

This study integrates organic and inorganic geochemical analyses to evaluate the hydrocarbon generative potential of Upper Jurassic-Lower Cretaceous (UJLC) sediments in the Senegalo-Mauritanian (SM) Basin. Representative limestone and shale have been characterized using Rock-Eval pyrolysis and LECO, as well as Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The Total Organic Carbon (TOC) values of Jurassic, Neocomian, Aptian, and Albian sediments range, respectively, between 0.11 and 0.438 wt%; 0.10 and 0.76 wt%; 0.12 and 0.86 wt%; and 0.2 and 2.43 wt%. Based on the HI values, the UJLC samples of the SM Basin suggest a higher terrigenous contribution, indicating type III kerogen. However, 15.38% of the Albian samples and 33% of Neocomian samples show the presence of type II/type I kerogen. Cross plots of Hydrogen Index (HI) versus Tmax show that the majority of Albian samples are within the mature zone with the potential to generate oil and little gas. The Aptian sediments are present in equal proportion between immature and mature zones, while Neocomian and Jurassic sediments are partly within the immature zone. Additionally, the calculated Vitrinite Reflectance (Ro) values indicate that the majority of Jurassic and Neocomian samples are immature, whereas Albian and Aptian samples have Ro values exceeding 0.6% or even 0.8%. The Production Index (PI) observed in the samples increased with lithology and depth with high value in limestones of the Neocomian and Upper Jurassic sequence. Compared to the Jurassic and Neocomian samples, Albian and Aptian samples present fair hydrocarbon generative potential. The Low HC generative potential of the UJLC sequence may be related to the moderate-to-low primary productivity observed from Ba/Al, Cu/Al, and Ni/Al proxies, or to the oxic environment of deposition, which does not favor organic matter preservation. Incorporating organic matter proxies into source rock evaluation is highly beneficial to the assessment of the petroleum potential of the studied basin. It reduces exploration uncertainty and provides guidance for future resource development in this underexplored margin.

The Gulf of Aqaba coast is witnessing an increase in constructing tourism development facilities, especially focused on South Sinai governorate. The need to protect these investments and ensure sustainable tourism development has led to the investigation of associated risks with geological processes in and around the study area. The current manuscript focused on applying near-surface geophysical techniques for evaluating the subsurface geologic setting of the Napq area for construction purposes, to provide an ample foundation for future planning. The geological mapping was utilized, as well as geophysical techniques (geoelectric resistivity, ground penetrating radar GPR, and seismic hazard analysis), which were applied for optimal land-use planning. The findings of the geophysical survey revealed a subsurface model consisting of four distinctive layers: the first layer ranged in resistivity from 133 to 3600 Ohm.m and was 0.5–1.3 m thick, which was represented by weathered alluvial deposits; the second layer had a resistivity ranging from 36 to 744 Ohm.m and was 3.1–8.2 m thick, equivalent to gravelly sand deposits; the third layer had a resistivity ranging from 10 to 24 Ohm.m and a thickness of 7.2–22.3 m, equivalent to saline saturated gravelly sand deposits, and ended with the fourth layer of fractured basement granite rocks with a resistivity > 200 Ohm.m. The GPR survey supported and confirmed the gained results of geoelectric resistivity. The seismic hazard analysis indicated the levels of peak ground acceleration (PGA) that ranged between 0.15 and 0.17 g for an exposure period of 50 years, and as normally expected, PGA values increase to a value between 0.2 and 0.25 g for an exposure period of 100 years. Finally, all the acquired geophysical surveys were integrated and fitted together to generate an optimal land use plan for the Napq area for construction purposes. The study area can be classified into four distinctive main units: the first unit that can be the most suitable unit for construction and engineering purposes, which is represented by Quaternary wadi-fill deposits of sand and gravel horizontal layers; the second unit that can be suitable for construction purposes after checking the possibility of the presence of subsurface cavities; the third unit, which is avoided for any constructions, is bounded by the tracks of the flood plains and active faults, which can be used as open areas such as gardens and playgrounds; and the fourth unit, which is avoided for any engineering purposes, is represented by the western mountainous areas of the study area.

The long-term performance of infrastructure, such as bridges, buildings, and dams, depends on the durability of the materials used in construction. Metal-organic frameworks (MOFs) play a critical role in enhancing material resilience, particularly against corrosion, a significant factor in structural degradation. This review attempts to systematically evaluate recent studies that assess the integration of MOFs with traditional materials under varying environmental stressors, including temperature extremes, chemical exposure, and soil conditions. The review combines exploratory information gained through referenced experimental and computational findings on MOF-based coatings applied to construction substrates, such as steel and concrete. Key parameters analyzed include porosity, thermal stability, ion-exchange capacity, and corrosion inhibition efficiency. Comparative studies with traditional anti-corrosive systems have reported cases where electrochemical impedance spectroscopy showed an approximately threefold increase in charge transfer resistance, indicating superior barrier properties. Additionally, surface analysis studies demonstrated up to 50% less mass loss and improved morphological stability after thermal cycling and chemical exposure. Research has proven that structures built with MOF-enhanced materials demonstrate up to 65% increased resistance to corrosion in adverse conditions, such as chloride-rich environments. Reports on electrochemical tests revealed a 40–60% reduction in corrosion rate, while surface analysis showed improved retention of the morphological features under thermal cycling. Further, qualitative findings suggest that the mode of protection offered by MOFs is mainly mediated through selective adsorption and barrier formation. These results highlight the potential of MOFs as sustainable additives for extending the lifespan of infrastructure in the modern construction industry.

The subject of this research deals with the study of inscriptions and rock drawings found in Jabal At-Tais Mountain located at the type locality of the Saq Formation west of Al-Qassim. In this research, two inscriptions in the Thamudic language, an elaborate drawing of a lion in a clicked manner, and drawings of wild goats and hounds were identified. These inscriptions and drawings indicate the early development of the Arabic alphabetic and the possibility of the passage of ancient trade routes near Jabal At-Tais Mountain.

Soils are exposed to various environmental pressures resulting from human activities, which can impact their physical properties, chemical composition, and microbial populations. Soil samples from cassava processing mills (Double Crown, Ekueme, Olorungbogo, Olalandu, and Akewe) in Ilaro metropolis, Ogun State, Nigeria, were assessed through physicochemical, heavy metal, and microbial analyses, as well as evaluations of contamination indices and human health risks. Twenty-two soil samples were collected from four points at a depth of 0.5 m on each of the five selected mills, and two control samples were obtained from unpolluted sites. About 5 g post-sieved samples was prepared and taken for the contamination assessments. The increased soil pH, textural content, cations, cation exchange capacity, organic matter, and organic carbon altered the toxic metal levels and microbial populations in the study samples. High mean heavy metal concentrations (Ni, Pb, Cd, Mn, Cu, Fe, and Zn) were observed in all the samples except Mn in Double Crown samples. The contamination indices indicated anthropogenic origins of the toxins, except for Mn in Double Crown, which revealed crustal sources. These suggested that the cassava mills significantly contributed to bioaccumulating toxins in the soil. The Double Crown, Ekueme, and Olorungbogo samples indicated moderate contamination, while the Akewe and Olanlandu samples showed severe contamination. The microbial counts of the soils (total coliforms, E. coli, fungi, and total bacteria) were relatively high and play crucial roles in soil and crop health. The total potential non-carcinogenic and carcinogenic health risks for both children and adults through inhalation, ingestion, and dermal pathways were within the permissible limits.

This research paper presents a scientific analysis of the land use and land cover changes in Old Dhaka over a 20-year period from 2003 to 2023. Data have been collected from the United States Geological Survey (USGS) for utilizing Landsat satellite imagery by using Remote sensing (RS) and GIS techniques. Despite numerous studies on urban expansion in Dhaka, limited research has focused specifically on the historic core of Old Dhaka, which is uniquely constrained by heritage structures, high population density, and informal land use practices. The research aims to fill this gap by systematically analyzing spatial and temporal LULC dynamics to understand how urban growth has impacted green spaces, bare land, and water bodies within this context. The study reveals a dramatic expansion of built-up areas rising from 41.89% in 2003 to 63.16% in 2023 accompanied by a sharp decline in vegetation and water bodies. In 2003, 33.81% of the land was covered with vegetation; by 2023, that percentage had dropped to 12.63%. The water body’s proportion decreased to 0.95% in 2023 from 3.56% in 2003. These changes highlight urgent environmental challenges and underscore the need for integrated, heritage-sensitive urban planning. The objective of this research is to generate evidence-based insights that can inform sustainable urban management strategies tailored to the unique characteristics of Old Dhaka. This research highlights the need for sustainable urban planning and conservation efforts to safeguard the city’s green spaces and maintain ecological balance amid rapid urbanization trends.

This study presents a comprehensive assessment of groundwater quality in Madurai North Taluk, Tamil Nadu, with a focus on its seasonal variation and irrigation suitability. Groundwater samples were collected during the pre- and post-monsoon seasons of 2022 and analyzed for physicochemical parameters including pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS), major cations (Ca²⁺, Mg²⁺, Na⁺, K⁺) and anions (Cl⁻, HCO₃⁻, SO₄²⁻, NO₃⁻), as well as Sodium Adsorption Ratio (SAR) and Sodium Percentage (Na%). The pre-monsoon season exhibited higher concentrations of salts, TDS, and Hardness, attributed to limited recharge and evaporation. Post-monsoon samples showed increased variability due to dilution, leaching, and anthropogenic return flows. Piper Trilinear Diagram interpretations revealed that CaHCO₃ and mixed CaMgCl types were dominant, indicating rock-water interactions and the influence of domestic and agricultural effluents. The USSL Diagram showed that a majority of the samples fall within C2–S1 and C3–S1 fields, reflecting medium to high Salinity with low Sodium hazard. However, a few samples shifted toward C4 salinity classes, particularly in the post-monsoon season, indicates that the need for caution in irrigation usage. The Wilcox classification further supported these findings, with most samples falling into the “excellent to good” and “good to permissible” categories, though several were “doubtful to unsuitable” due to elevated Na%. Overall, the findings suggest that groundwater in the region is generally suitable for irrigation, but localized management strategies like adopting micro-irrigation, introducing salt-tolerant crops, and improving recharge through percolation ponds are required to mitigate increasing salinity and sodium hazards.