Arabian Journal of Geosciences最新文献

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.

In the geotechnical engineering field, the rapid speed of urbanization triggers the need for direct measurements of sub-soil parameters through in situ testing, accompanied by instant results. At this juncture, the cone penetration test (CPT) is selected for this study. Here, an attempt is made to develop a correlation between cone penetration resistance (q_c) and standard penetration blow count (SPT N) in order to predict a reference range of q_c for cohesive (silty clay/clayey silt) sub-soil of different SPT-based consistencies. In this context, 25 CPT were conducted adjacent to conventional boreholes accompanied by SPT tests at eight important locations in West Bengal (WB) and Odisha (OR), India, focusing on infrastructure development. Primarily, sub-soil is characterized by bulk unit weight (γ) along with soil behavior type index (I_C) estimated from the CPT and compared with the sub-soil profile identified from conventional boreholes. Further, a comparison of q_c with SPT N is made to establish a correlation. Also, an attempt is made to tally the established correlation with the earlier correlations established for different regions. This study quantitatively establishes a quadratic correlation (R² = 0.84) between q_c and SPT N, which is found to be in good agreement with the previous correlations. Overall, the key findings of this study, i.e., the predicted range of q_c, reveal a reliable method for assessing the consistency of cohesive sub-soil by virtue of the q_c. However, this correlation is limited to soft to very stiff silty clay/clayey silt sub-soil formation.

Barite is an inorganic mineral mainly constituted by barium sulfate (BaSO4) which finds applications across a variety of industries. Low quality barite can be beneficiated to meet high-purity requirement. Thus, in this work, we developed an optimum beneficiation process for upgrading barite-bearing ore from Azare in Bauchi State, Nigeria. The optimum condition for the beneficiation was established using response surface methodology (RSM) while the beneficiated barite was characterized using standard tests such as scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray fluorescence (XRF) and X-Ray diffraction (XRD). After beneficiation, the specific gravity and other properties, such as moisture content were determined and found within acceptable standards, indicating that impurities were removed. XRD structural patterns revealed highly crystalline peaks after treatment, while XRF analysis indicated BaSO₄ as the primary component with reduced gangue impurities. The presence of barite in the samples was evidenced by the identified absorption peaks from FTIR analysis. Surface morphology characteristics revealed that the barite morphology changed significantly following beneficiation. The results of the beneficiation process showed that for the optimized process using RSM, the maximum yield of BaSO₄ obtained was 99.78%. The properties of the barites obtained under the optimized conditions were all within the API standard. Accordingly, the beneficiated barite sample has prospective applications in drilling mud formulation, pharmaceuticals, medicine, rubber, paint, ceramics and glass industries.

Due to its simple design and cost-effectiveness, Bromhead ring shear apparatus is widely used to assess the drained residual strength through various testing procedures such as single stage, preshearing, and multistage. However, when compared to back-calculated case histories, values obtained through these testing procedures were found to be higher due to wall friction. To address this, Stark and Vettel (Geotech Test J 15:24–32, 1992) have introduced the “Flush testing procedure” which involves adding remolded soil to the specimen and reconsolidate it, in order to minimize the wall friction. Although the procedure yielded satisfactory results, it is more time-consuming. This paper presents a comparison between a proposed preconsolidated presheared flush (P.P.F) and flush testing procedures. The test results showed that this procedure has successfully minimized the effect of wall friction, providing values lower than those obtained using the flush procedure in shorter time.

This study aims to assess the woody species carbon stock in the Munessa dry Afromontane forest and its variations within plant community types, as well as altitudinal, slope, and aspect gradients. A systematic sampling technique was used to acquire vegetation data. At a 100-m altitudinal drop, five transect lines were established. Ten quadrats were laid on each transect line (total 50 quadrants) at 200-m distance intervals. The woody carbon was estimated using an appropriate allometric equation formulated for tropical forests. The data was analyzed using one-way ANOVA in R software. The results show that the total woody carbon stock of the Munessa forest is 210.43 t/ha. The analysis of variance revealed that woody carbon stock varied significantly along altitude, slope, and aspect gradients, whereas community types had no significant effect. Middle elevations (2367–2533 m above sea level (m.a.s.l.)), lower slopes (0–13%), and west-facing aspects had the highest mean carbon stock. The Podocarpus falcatus–Croton macrostachyus community type also contributed a higher woody carbon stock since larger tree size classes and older trees are dominant. Overall, the carbon sequestration potential of woody species in the studied forest is strongly associated with environmental variables. Furthermore, the uneven distribution of species with larger diameter at breast height (DBH) in the studied forest might be linked to anthropogenic factors, as the current forest growth indicates characteristics of a secondary forest. Therefore, the present study suggests developing and implementing a sustainable forest management strategy particularly prioritizing middle elevation, lower slope, and west aspects of the forest to maximize the forest’s carbon sequestration capacity.

This article presents the integrated use of high-resolution satellite remote sensing, GIS, GPS, and geochemical analysis-based observations for mineral targeting in Baragaon area in Jhansi District of Uttar Pradesh in parts of Bundelkhand Craton in Central India. Digital image processing techniques of principal component (PC) transformation have been applied to IRS-P6 LISS-IV satellite data to extract drastic and subtle changes in the disposition, shape, and pattern of the landforms to identify the geomorphic anomalies. PC images have conspicuously highlighted the intersections of lineaments that have been demarcated as structural anomalies. On PC-3 images the geomorphic anomalies have been identified by semicircular to oval-shaped hills in Baragaon area and small circular and elongated hills in the west of Kuraicha. Structural anomalies identified in the area include the intersections of NW–SE and NE-SW trending lineaments in Baragaon, Bukhara, etc. The XRF analysis of rock samples from a geomorphic and structural anomaly zone (with visible host rocks) near Baragaon area has indicated the presence of iron-oxide bearing minerals with 42.13% Fe₂O₃. This study demonstrates that integrated use of geospatial and geochemical techniques can help in quickly zeroing in on the geomorphic and structural anomalies in an area of suitable host rocks. The present approach to mineral targeting helps reduce the area for detailed field investigations particularly in the hinterlands of the country and is time saving and economical.

Geological formations rich in clay tend to undergo expansion upon contact with water-based drilling fluids. The principal mechanism responsible for the disintegration and swelling of these formations is the migration of hydrogen ions into the nano-scale gaps between layers of shale platelets. Effectively mitigating the challenge of clay swelling involves introducing various materials tailored for shale stabilization into water-based drilling mud. In this article, flaxseed mucilage is used as an environmentally friendly drilling fluid additive in a water-based mud system, with the goal of enhancing the rheological, filtration, and hydrophobic characteristics of the water-based mud. The flaxseed extract was added in the mud in four different concentrations (5 mL, 10 mL, 20 mL, and 50 mL). The result of the study reveals that the rheological properties at 38 and 65 degree centigrade after the addition of 10 mL and 20 mL flaxseed extract remained well within the recommended range set by the American Petroleum Institute (API). Both these samples also demonstrated transport index (> 1.5) at both the temperatures. Moreover, the flaxseed extract was also effective in minimizing the fluid loss from the base mud. The 20 mL of flaxseed extract causes only 15 mL of fluid loss from the base mud, which was also three times lower than the base mud. Additionally, the flaxseed extract muds were also tested on the Ranikot shale sample for its stability. According to the immersion test, samples collected from flaxseed mud demonstrated a smooth surface with no cracks and fractures. Furthermore, these immersed shale pellets also revealed high hydrophobic behavior when tested through contact angle measurement. The 20-mL sample showed the highest hydrophobic behavior with contact angle of 56.056 degrees. Besides this, the 20-mL sample also displayed the highest cutting recovery of 70% out of all the samples. In addition, the 20-mL flaxseed sample also showed less shale swelling behavior in linear dynamic swell-meter test. Almost 1.5 times reduction in shale swelling was recorded with the addition of 20 mL flaxseed extract in the base mud. In light of these compelling findings, the study underscores flaxseed’s potential as an eco-friendly and sustainable alternative to traditional clay stabilizers in drilling operations, with the aim of minimizing formation damage.

Microwave treatment is one of the research topics to solve cutting problems of hard rocks such as low cutting rate and high tool wear. Microwave irradiation creates fractures in the rock body and decreases its strength. Numerous studies have been conducted to ascertain how microwaves affect the strength of rocks. Ten carbonate rocks are examined in this paper to see how microwaving affects their strength. First, unconfined compression and tensile strength tests were conducted on unirradiated dry and saturated core specimens. Following that, the two tests were performed again on samples that had been exposed to radiation for varying amounts of time—between 2 and 6 min—at a microwave power of 6 kW. The results showed that the uniaxial compressive strength loss due to microwave irradiation was between 9.0 and 90.0% and 7.3 and 92.0% for the dry and saturated samples, respectively. Tensile strength loss was between 15.6 and 62.7% and 23.2 and 63.1% for the dry and saturated samples, respectively. The efficiency of treating carbonate rocks with microwaves is significantly impacted by density, porosity, and impurities. Multiple regression equations were derived to estimate the strength losses. Concluding remark is that the strength reductions due to microwaves are significant for carbonate rocks.

Soil erosion poses a severe threat to water quality and soil health in semi-arid regions. Assessing soil erosion and sedimentation at the watershed-scale is crucial for managing water resources and soil. In Iran, empirical models, e.g., the erosion potential method (EPM), modified Pacific Southwest Inter-Agency Committee (MPSIAC), and universal soil loss equation (USLE), have drawn more attention than other models, due to the availability of input data and lack of reliable hydrometric station, especially for a long time span. In the present article, we evaluated the soil erosion intensity and sediment yield in the Chehelgazi mountainous watershed (western Iran) utilizing the EPM, MPSIAC, and USLE, combined with the sediment delivery ratio (SDR) module, and then compared them with the observations. The required input data for EPM, MPSIAC, and USLE models all were created in ArcMap 10.8 and ENVI 5.5. The sediment yield amount and soil erosion zonation map were then obtained by the models mentioned and validated by the hydrometric data. According to the results, most portions of the watershed were subject to moderate erosion risk. Moreover, the annual average sediment yield of 196.86, 99.30, and 84.84 kt year⁻¹ assessed by EPM, MPSIAC, and USLE combined with SDR, respectively, suggested the superiority of USLE-SDR and MPSIAC. As compared with the observed amounts of 86.46 kt year ⁻¹, the efficiency of USLE-SDR was astonishing. Overall, we conclude that the USLE model coupled with the Boyce (1975) SDR formula is the best for estimating sediment yield at Chehelgazi mountainous watersheds, while MPSIAC is better suited for mapping soil erosion state.

The geochemistry of Paleogene strata (sandstones and shales) of the N’kapa Formation in part of the western Douala Basin has been studied through major, trace, and rare earth elements (REEs) in order to understand their provenance and tectonic settings. The NF sandstones and shale are clustered around granodiorite with minor contributions from granitic source. The samples show high and fairly constant Th/Sc ratios 0.64–6.9 for sandstone and 1.01–8.7 for shale that strongly indicate provenance from a relatively evolved igneous source (mafic) also different geochemical signatures of Eu/Eu*, La/Sc, La/Co, Th/Sc, Th/Co, Zr/Sc, Cr/V, and Y/Ni ratios, and their plots suggest a mafic igneous provenance with substantial sediment recycling. Geochemical signatures from plots of The La/Th–Hf diagram, La/Sc vs Ti/Zr, and Fe2O3 + MgO vs TiO2 tectonic discrimination diagrams show that the studied rocks were deposited mainly in a passive continental margin setting. The large quantities of alkalis classify the rocks as wackes, Fe-sand, shale, and Fe-shale. The studied lithofacies have been classified based on Al–Fe-Mn enrichment as follows: terrigenous and metalliferous rocks.