Arabian Journal of Geosciences最新文献

Sorption gas is one of the main components of shale gas and a key parameter for shale gas potential evaluation. Previous studies have shown that the pore structure and organic matter richness of shale are two main controlling factors for methane sorption capacity. However, the effect of organic matter-hosted pore (OM pore) on methane sorption is still ambiguous. To preliminary investigate the role of OM pore played on methane sorption of shale, the methane sorption capacity of eleven Permian coal-bearing shale samples with fewer OM pores were examined. The Langmuir methane sorption volume ranges from 1.15 ml/g to 2.77 ml/g and shows positive correlations with the TOC content and surface area, whereas it shows negative correlation with the pore size. The TOC-normalized Langmuir volume has an overall positive relationship with the total clay and illite content. The Langmuir volume’ correlations with the pore structure parameters are much better than with the TOC content, indicating the methane sorption capacity of the shale is more dependent on pore structure. Compared to the shale from literatures, the Permian shale has lower methane sorption capacity at a same level of TOC content, which is probably a result of the lack of OM pore. As the connection between the bulk pore structure and organic matter richness, the OM pore’s contribution to the whole pore system is as important as the effect of surface area and TOC content on the methane sorption capacity of shale and its effect increases with the TOC content. It is also suggested that a proper model for methane sorption in heterogeneous gas shale should at least contain these three factors: the bulk pore structure, organic matter richness and OM pore characteristic.

This study was conducted in the northern part of the Central African Fold Belt in Cameroon to update the lithological map and understand the geological structure, relief dynamics, and geodynamic implications of dolerite dykes using remote sensing techniques combined with field investigations. The digital surface model derived from SRTM imagery enabled the discrimination of geomorphological units such as hills, plateaus, and alluvial plains. The study area encompasses two distinct relief types with varying altitudes ranging from approximately 220 to 400 m, attributed to recent tectonic activity. The SRTM data also facilitated drainage mapping and the extraction of lineaments, revealing predominant trends of N-S, N30°E, NW–SE, and E-W, which align with regional structural lineaments and fault. To enhance the spatial distribution of lithological units, principal component analysis, color composites, and band ratioing of Landsat 8 OLI bands were applied, supported by ground truthing. These methods effectively delineated areas dominated by gneiss, granite, and amphibolite. These rocks are typically intersected by undeformed doleritic dykes, primarily trending WNW-ESE, with secondary trends including NNE-SSW, NE-SW, and ENE-WSW to E-W. These orientations correspond to Pan-African lineaments and faults (TBF and CASZ), which have influenced the Central African Fold Belt. Microscopic analysis of dolerite thin sections revealed porphyritic-microlithic, intersertal, and ophitic textures, characterized by phenocrysts of plagioclase, clinopyroxene, amphibole, alkaline feldspar, oxides, calcite, and microlites, aligning with observations from similar regional studies. Integration of satellite data, existing geological maps, and field observations suggest that the lithology of the Guebake region may have been significantly influenced by late magmatic events or post-Pan-African tectonic activity affecting the basement. This underscores the value of combining remote sensing techniques with geological mapping and field investigations to enhance the accuracy and efficiency of lithological and tectonic studies, with a gain in time.

This paper presents a summary of the research carried out within the southern terminal of Zuru-Yauri Schist belt, an area enclosed by latitude 10.00⁰ to 10.30⁰ and longitude 4.00⁰ to 5.00⁰ using Aero-magnetic and Aero-radiometric data. Regions that has suffered hydrothermal alterations due to potassium enrichment and Thorium depreciation were mapped and interpreted as regions of orogenic gold mineralization. Nine major fault lines were identified, a major fault labelled F8 trending NE-SW, runs diagonally for about 70 km. Regions of hydrothermal alteration were evaluated from K/Th ratio, K-deviation and F-parameter. Analysis and interpretation of the ternary image indicate that regions where high K/Th values (0.3–0.5) %/ppm, high k-deviation values (7.3–60.6) and high F-Parameter values (0.8–1.3) appears as white on the colour aggregate, an indication of high hydrothermal altered zone. Area with grey colour indicating moderately altered zone. Regions that appears as dark colour indicate low values of K/Th, K-deviation and F-Parameter this occurs within the sedimentary formation of Bida Basin sand stone, located at the Northern end and South Eastern corner of the study area. A comprehensive analysis of these results delineated region of hydrothermal altered zones in white and grey colour that coincides with areas within the faulted and fractured basement. The research concluded by delineating regions in which structures from the magnetic data that coincide with regions of potassium-altered hydrothermal zones are marked as regions for orogenic gold mineralisation haloes. These regions are within Luma, Tungan-Dangaje, New Busa, Ferin Ruwa, Gwagwade, Kinke, and Kado villages, of which part of them harbors artisanal miners.

The marine outcrops of the Rashrashiyah Formation in the Sirhan-Turayf Basin at northern Saudi Arabia was previously assigned to the late Eocene and no detailed marine microfossils have been reported from them. Thus, the lithostratigraphy and planktonic foraminifera of this formation were examined in four lithologic sections: Rash-D1, Rash-D2, Rash-D3 and Section 2. The planktonic foraminifera indicated that the upper part of this formation is early Oligocene in age, which is a new (discovery) record in northern Saudi Arabia, and conformably overlies the upper Eocene deposits without interruption. Therefore, this study primarily aims to establish a time-stratigraphic framework for the studied sections using planktonic foraminiferal biostratigraphy and modify the lithostratigraphy of Rashrashiyah Formation. This formation was divided into lower and upper members, occupying a continental shelf-upper slope and inner neritic environments, respectively. We identified Ninety species of planktonic foraminifera, belonging to twenty one genera, allowing division of successions into five biozones of late middle Eocene-early Oligocene age. They are arranged from older to younger as follows: Morozovelloides crassatus Zone (E13), Globigerinatheka semiinvoluta Zone (E14), Globigerinatheka index Zone (E15), Hantkenina alabamensis Zone (E16), Pseudohastigerina naguewichiensis Zone (O1). These biozones represent the Eocene–Oligocene sequence with several steps of bioevents. Regional correlation of the sections using lithology and foraminiferal assemblages indicated that the region underwent to a major tectonism such as block-faulting after the deposition of lower Oligocene marine sediments. Subsequently, intensive erosion and weathering resulted in deposition of Miocene siliciclastics of the Sirhan Formation unconformably above a peneplained to irregular surface of unequal ages similar or probably synchronous to the syn-rift Miocene sediments in the Red Sea region. These results were correlated with their equivalents worldwide and in the neighbouring countries such as Jordan, Syria, Turkey, and Egypt, which could provide new information about the Eocene–Oligocene transition (EOT), the paleogeography of northern Arabian Plate as well as on paleoceanography of the Neo-Tethys.

The northwest Arabian Gulf, south of Iraq, is considered a strategically important region, especially after the construction of the Grand Faw Port, which possesses the longest breakwater in the world. Numerous scientific, economic, political, and historical studies have been conducted in the region. Holocene deposits contain characteristic mineral assemblages that provide direct evidence of sediment provenance and paleoenvironmental conditions. This research paper focuses on the mineralogy of two cores of sediments 40 m below the seabed. XRD analysis revealed a predominance of quartz, calcite, and albite, with differing ratios of clay minerals, indicating dynamic conversions in the sedimentary environment and salinity regimes over time. In addition, X-ray-oriented clay sections revealed high levels of chlorite, as well as high levels of mixed layers of Mon-Chl, with significant proportions of montmonerlite, illite, and paleokorskite. These proportions indicate that marine conditions primarily influenced the paleoenvironment. The presence of kaolinite at all depths, along with illite, indicates the presence of significant amounts of terrestrial-derived sediments in humid environments, such as riverine or coastal environments. Furthermore, the sand layers indicate the presence of monocrystalline quartz, reflecting sea- level fluctuations in the region, and the grain shapes reflect differences in transport mechanisms and sedimentation energy. In addition, there are high proportions of carbonate rock fragments.

This study explores the complexity of assessing river water quality, a multifaceted process influenced by various water quality parameters (WQPs), inherent uncertainties, and diverse decision-maker judgments. These uncertainties are effectively modeled using fuzzy sets and soft sets. We introduce a novel weighted water pollution score function (WWPSF) on fuzzy soft sets (FSSs) and propose an innovative fuzzy multi-criteria decision-making model (FMCDMM) to derive a weighted water pollution score (WWP-score) for rating river water pollution. We apply this methodology to assess water quality indices for the Manu River, the longest river in Tripura, India, and a crucial drinking water source for North-East Tripura. The FMCDMM and WWP-score are key indicators of the river’s water quality. To assess water quality, we consider ten crucial parameters: pH, calcium, dissolved oxygen, total alkalinity, biochemical oxygen demand, total hardness, total dissolved solids, chloride, total coliform, and fecal coliform, sampled at eight strategic sites along the river during pre-monsoon, monsoon, and post-monsoon seasons of 2021–2022. Guided by waste discharge points, we integrate meteorological data, land-use patterns, and anthropogenic inputs to reveal significant water quality degradation due to seasonal variations and human activities. Factors such as rainfall intensity, temperature fluctuations, industrial discharges, agricultural runoff, and urban waste contribute substantially to pollution levels. This comprehensive approach aids decision-makers in developing strategies for sustainable river management, emphasizing the need to address seasonal changes and anthropogenic impacts to ensure water security for urban ecosystems and dependent communities. Finally, we conduct comparative analyses with existing methodologies to validate and highlight the advantages of our approach.

Groundwater a crucial freshwater source faces growing contamination risks from land use activities. This study examines the effects of urbanization, agriculture, industrial activity, and landfills on groundwater quality in Muscat, Oman. Wells from varied land use zones were sampled twice a year. The study combines PCA DRASTIC modelling and WQI to assess spatial groundwater quality variations in Muscat, Oman. The data show large variability in groundwater quality across land use. Industrial zone wells show extreme degradation (WQI = 2.02) with hazardous nitrate (70 ppm) and TDS levels. Electrical conductivity ranges from 1.78 to 5.84 mS/cm, and total dissolved solids (TDS) exceed 750 ppm, making water unsuitable for domestic use. Nitrate concentrations range from 24–70 ppm, exceeding permissible limits due to agricultural runoff and wastewater discharge. The majority of wells exhibit low-quality water, with the industrial zone exhibiting the worst degradation (WQI = 2.02). Contamination is indicated by high levels of TDS (> 750 ppm), nitrate (24–70 ppm), and sulfate. High groundwater vulnerability is revealed by the DRASTIC model, and significant disparities among land uses are confirmed by PCA and NMDS. Statistical analyses (PERMANOVA p < 0.0001) confirm land use type drives significant quality differences. This study emphasizes the complex relationship between land use and groundwater quality, as well as the critical importance of sustainable practices. Urgent measures like pollution controls and land-use zoning are needed to safeguard groundwater sustainability. In order to preserve groundwater and guarantee its sustainability for future generations, this study emphasizes the necessity of prudent land management.

The crude oil sector in Nigeria continues to be a significant source of income and foreign currency. However, operations related to oil exploration and production have the potential to seriously alter the environment, having an impact on ecosystems, water bodies, and human life. In many cases, pollution indices are viewed as a useful instrument for thoroughly evaluating contamination levels. Additionally, they may have a significant impact when evaluating soil quality and the forecast of long-term ecosystem viability, in the case of farmlands in particular. Atomic absorption spectrometry (AAS) was used to examine the heavy metal contents. Potential ecological risk index, geoaccumulation index, Nemerow pollution, pollution load index, contamination index (CI), and metal pollution index were the seven indicators employed in the study. The concentration of heavy metals such as manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), nickel (Ni), lead (Pb), chromium (Cr), and arsenic (As) ranges from 11.9 to 184.1, 920 to 8870, 1.1 to 9.9, 9.7 to 60.4, 0.001 to 0.001, 2.4 to 34.7, 2.2 to 11.5, and 0.001 to 0.001 mg/kg, respectively. The correlation matrix showed that there were positive correlations between Mn and Ni, Fe and Cu, Zn, Pb, Cr, Cu and Cr, Zn and Pb, Cr, and Pb and Cr, while a negative correlation exists between Cu and Ar. PCA showed that 75% of the samples in PC1 have loadings; in PC2, 50% of the parameters have loadings; in PC3, 25% of the parameters have loadings; and in PC4, 12.5% of the entire parameter has loadings. Findings from the aforementioned indices revealed that the analyzed soil samples are polluted.

This study examines the influence of clear-sky weather conditions on temperature variability in Chefchaouen, a mountainous region in Northern Morocco characterized by a complex interplay of Mediterranean and semi-arid climatic features. Using daily meteorological observations (2015–2020) and upper-air datasets, the research investigates atmospheric circulation patterns at Mean Sea Level Pressure (MSLP) and 500 hPa Geopotential Height (GPH) levels to assess their role in shaping local thermal dynamics under clear skies. To classify synoptic configurations, the study applies Cluster Analysis and Factor Analysis to daily MSLP and GPH data. The Elbow Method identified four distinct atmospheric clusters, which were statistically validated through an Analysis of Variance (ANOVA), confirming significant temperature differences among clusters (F = 131.83, p < 0.001). Factor loadings revealed two key drivers of thermal variability: surface pressure systems (MSLP) and upper-level ridges (500 hPa GPH). Results show that atmospheric ridges and Southerly flows at 500 hPa, along with high-pressure systems and barometric marshes at sea level, stabilize weather conditions and enhance diurnal and seasonal temperature ranges. These findings contribute to understanding localized climatic processes under radiatively dominant conditions and support the refinement of regional climate models and adaptation strategies in Mediterranean mountain regions.

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.