Arabian Journal of Geosciences最新文献

Groundwater is extensively utilized for drinking, irrigation, and industrial activities globally. However, its quality is deteriorating significantly, particularly in coastal regions where saline water infiltration is a major issue. This study investigates the coastal aquifer of Udupi district in Karnataka, India, covering approximately 80 km², through hydro-geochemical analysis of groundwater samples from 57 spatially distributed locations, pre- and post-monsoon. The major anion and cation parameters analyzed include Cl⁻, HCO₃⁻, SO₄²⁻, NO₃⁻, Na⁺, Ca²⁺, K⁺, and Mg²⁺. The analysis revealed a pH range of 2.9 to 8.3, indicating acidic to slightly alkaline conditions, and total dissolved solids (TDS) concentrations ranging from 110 to 6683 mg/L, predominantly showing saline characteristics toward the coastline. Hydrogeochemical assessment, including Chadha’s plot, identified Na-Cl type water in most samples, indicating the influence of salinity. Approximately 21% of pre-monsoon and 67% of post-monsoon samples were deemed unsuitable for irrigation based on permeability index values, with 2 to 3% exhibiting high salinity hazards. The variation in correlation coefficients between pre-monsoon and post-monsoon periods suggests that saline water intrusion, freshwater recharge, and geochemical interactions influence the coastal groundwater system. The molar ratio of Na⁺ to Cl⁻ suggested a reverse cation exchange process, highlighting the complex interactions between saline and freshwater. Overall, 79% of pre-monsoon and 80% of post-monsoon samples were deemed suitable for irrigation, while 21% and 20% were classified as completely unsuitable, respectively.

This study critically examines the spatial dynamics of urban sprawl and land use changes in Bhilwara, Rajasthan, over the past three decades, utilizing advanced remote sensing and GIS methodologies. The primary objective is to elucidate the patterns of urban expansion and its consequential impacts on green infrastructure. The findings reveal a pronounced increase in built-up areas, with the most significant growth observed towards the north-northwest (NNW) and west-southwest (WSW) directions, driven by the presence of major transportation corridors and proximate urban centers. The LULC classification achieved high accuracy, with Producer’s accuracy ranging from 81 to 94.4%, User’s accuracy from 73.7 to 100%, and Overall accuracy between 84.5 and 93.8%, accompanied by a Kappa coefficient of 0.78 to 0.83. These results underscore the robust methodology employed and highlight the critical need for integrated urban planning approaches that prioritize sustainable development and green infrastructure preservation. The study’s conclusions offer substantial contributions to the academic discourse on urbanization, providing actionable insights for policymakers and urban planners to manage urban growth effectively and sustainably.

A synthesis of field geological and archaeological surveying, as well as near-surface stratigraphy, provides new insights into the late Quaternary history of this region. We find a long series of alluvial, colluvial, playa, and aeolian deposits that show a complicated history of changes in the late Quaternary climate and environment. In the current study, we summarize the results of a geoarchaeological study that focused on the entire range of landscapes and associated landforms along the fringe of the Libyan Plateau at Umm Dabadib, Kharga Oasis, in the Western Desert of Egypt. We also determined the distribution of the cultural materials of prehistoric sites in different geomorphic settings, including playas, wadis, and dune fields.

The purpose of this study is to locate groundwater-saturated aquifers in the Vindhyan fringe belt in the Mirzapur district of Uttar Pradesh, India, and evaluate their protection using geoelectrical indices. The Schlumberger electrode layout, with a maximum half-current distance between electrodes of 300 m, was used to perform three gradient profilings and six geoelectrical soundings. The inversion IPI2win program and the traditional partial curve matching approach were used for geoelectrical sounding data interpretation. Four to five geologic units are identified in the research region based on the interpretation of the geoelectrical sounding data. These are the top-surface soil, clay, kankar/laterite and sand, weathered sandstone, and compact sandstone. The research region is characterized by HA-type sounding curves, and the obtained findings suggest the presence of groundwater-saturated zones and cracks in the area. The weathered sandstone saturated with water shows resistivity ranges between 375.4 and 407.1 Ω-m and depth ranges from 96.8 to 97.6 m. Thematic maps were prepared for total longitudinal conductance, transverse resistance, overburden thickness, and electrical anisotropy. The protective capacity of the aquifer is measured using the transverse resistance (Tr) and longitudinal conductance (Lc) of the Dar Zarrouk parameters. Based on the longitudinal conductance of the aquifers, the results obtained indicate that the research region is dominated by a good aquifer protective capacity rating.

The urban population of India has increased fivefold during the last five decades. Monitoring and estimation of urban sprawl are crucial for urban planning, land and water resource management, facility allocation, etc. The present study is aimed at making an in-depth analysis of urban dynamics in the Bengaluru Urban District by using three different indices: the built-up density index (BUDI), the annual urban spatial expansion index (AUSEI), and the annual built-up change index (ABCI), along with temporal satellite data and GIS. The study reveals that an exponential outward urban expansion has taken place in the study area from 1993 to 2020, mainly due to the development of the co-working industry, migration of people from cities to outer areas, high population growth, rapid and significant growth in the IT field, economic growth, and developments of road networks. The analysis shows that about 21.08% of growth was taken in terms of the urban area during the period from 1993 to 2020, and such changes led to the irreversible conversion of rural land into urban land. The analysis of BUDI shows that the density of the study area increases periodically and densifies toward its outer parts. The AUSEI shows that the minimum changes in respect of annual urban expansion were observed during 2003–2013 and the maximum were noted during 2013–2020. The ABUCI illustrates that the speed of urban growth is increasing from period to period and drastically increasing outward. It was also observed that by the latest period (2013 to 2020), the ABUCI value reached its maximum (> 120), especially from the distance of 10th to 24th in the study area.

The increasing demand for water resources has resulted in environmental degradation and conflicting interests among diverse users. This research aimed to scrutinize the causes and repercussions of land use exploitation and degradation within the Samambaia River Basin (SRB), focusing on potential environmental impacts linked to the management of irrigated agriculture. The study encompassed the entire SRB. Adopting climatological data from 1981 to 2010, distinct dry and wet seasons in the SRB were delineated. A precise slope map has been produced based on an elevation dataset, while vegetation indices like the Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI) have been computed. Indices such as the Woody Vegetation Biomass Index (WVBI), Vegetation Vulnerability Index (VVI), and Land Vulnerability Index (LVI) were derived from the NDVI. The dataset underwent descriptive statistical analysis, incorporating adjustment and validation factors. The root mean square error (RMSE) values for the daily rainfall data were notably low (7.0711 and 7.9223 mm). The years 2015, 2016, and 2018 experienced heightened rainfall during the dry season, while 2015 and 2018 recorded significant rainfall in the wet season. NDWI ranged from − 0.41 to 0.24, with positive values indicating the presence of water bodies in the SRB. During the dry season, regions with denser vegetation are largely associated to areas with central pivot irrigation. The WVBI revealed intensified vegetation in the wet seasons of 2014 and 2019. The LVI during the dry season varied from moderate to very low, with limited high-risk areas predominantly along water body boundaries.

This work permitted the understanding of processes in continental environments through the conditions of formation and deposition of alluvial clay materials in the Mbam Riverbanks (Central Africa). The Mbam River is the main tributary of the Sanaga River, one of the largest rivers in Central Africa. Twelve clay samples were collected from six wells, exhibiting different facies, and characterized using the Robinson-Köln pipetting, infrared spectroscopy, X-ray diffraction, and X-ray fluorescence. All the materials were classified as sandy clays. Their mineralogical assemblage is made of quartz, kaolinite, orthoclase, hematite/goethite, rutile, anorthite, and augite. The values for chemical, plagioclase, and mafic indices of alteration combined with those for Ba, Sr, and Rb/Sr ratio show that primary minerals like orthoclase, anorthite, and augite in source rocks are moderately altered. The studied materials are arkoses, wackes, shales, and Fe-Shales. Based on the index of compositional variability and on the SiO₂/Al₂O₃ ratio, the associated sediments are considered immature. They are, according to Cr, Ni, and SiO₂ contents, Al₂O₃/TiO₂, Th/Sc, Th/Cr, and Cr/Ni ratios, and some binary provenance diagrams, from mafic, intermediate, and felsic sources. Values of the authigenic uranium, U/Th, V/Cr, and Ni/Co ratios permit to infer that they were deposited in an oxic environment.

This paper presents the findings regarding the displacement-load behavior of both plane strain model experiments’ ultimate load and numerical analyses conducted on unreinforced and reinforced sand slopes loaded with strip footing. The investigated parameters include the impact of the reinforcement and varying eccentricity on the ultimate load and displacement of the strip footing. A group of finite element analyses was performed with the 3D plane strain model and the computer code ANSYS software to validate the results of the model experiments on a slope. The results from both the numerical analyses and model experiments suggested that the use of reinforcement could enhance the load–displacement behavior of the central and eccentrically loaded footings. The load–displacement curves demonstrated that a higher load eccentricity leads to a reduction in the ultimate load of the strip footing. The concordance between the computed and observed results was reasonably satisfactory for the load displacement and the overall behavioral trend.

This case study evaluated the liquefaction risk and application of vibro-compaction for soil improvement in a construction project site on Saadiyat Island, Abu Dhabi, UAE. Abu Dhabi is designated as Zone 0 according to the Uniform Building Code (UBC-97), and we discuss the design criteria for vibro-compaction that were adopted to mitigate the liquefaction risk, the trials conducted to establish the application criteria for vibro-compaction, and the general practices related to vibro-compaction. Specific studies conducted in Abu Dhabi Emirate indicate that the seismicity in the region is low, and the probability of liquefaction is very limited. However, during the pre-project soil investigation phase, the analysis of potential soil liquefaction indicated that certain examined areas have the potential to undergo liquefaction. The liquefaction potential was assessed based on a combination of safety factors obtained for an earthquake with a magnitude Mw = 6 and the corrected cone tip resistance (qc). The acceptability criteria for improved soil are based on cone penetration test (CPT) results. The target qc is accepted as 2.7 MPa and the treatment depth would be a minimum of − 3.5 m. A field trial was conducted to determine the optimal compaction grid spacing that meets the specified acceptance criteria and aligns with the project’s design criteria. Based on the trial evaluation, a vibro-compaction grid spacing of 4 × 4 m was appropriate. Consequently, a total of 4125 points at the construction site underwent vibro-compaction.

Navigation channels provide a vital link in the supply chain of inland transport. Excavation of sediment from the river bed and fluvial islands is necessary to make the large braided river navigable for transportation. Present research work investigates the feasibility of dredging operations in the mid-sand bars of the Brahmaputra River (Assam, India) for navigation purposes. Pernicious metal (Cu, Zn, Fe, Mn, Ni, Co, Cr, Pb, Cd) concentrations were assessed at 42 sampling locations, covering a reach length of approx. 600 km (reaches 1 and 2). Vertical samples were obtained from 0 cm, 50 cm, and 100 cm of the mid-sand bar. Various indices were evaluated to quantify the contamination level in the mid-sand bars. Based on the enrichment factor (EF), reach 2 was highly enriched with toxic metal-limiting dredging operation. Conversely, reach 1 was found suitable for dredging operations, owing to the low EF value. Various anthropogenic activities are likely to be the causative factor for the heavy metal enrichment in reach 2, including effluents from pharmaceutical industries, oil refineries, and industrial and domestic runoff. Statistical analysis also endorsed those heavy metals possess similar anthropogenic origins. Overall, the dredging can be feasible for reach 1 and at localized zones for reach 2 across the Brahmaputra River. Further, the study tries to present a suitable mitigation measure to carry out dredging operations and manage contaminated dredged sediment for reach 2.