Earth Science Malaysia (ESMY)

The contamination of groundwater by hydrocarbons presents a significant challenge for the residents of the Kegbara Dere community in Ogoniland, Rivers State, Southern Nigeria. The area has been plagued by oil spillage, and the damage done to Ogoniland as a result of oil spillage is so massive that the United Nation (UN) did a report on the extent of pollution in the area. This study aimed to identify and characterize the extent of the groundwater system contamination in the study area. The electrical resistivity imaging and geochemical methods were adopted. 2D electrical resistivity imaging (ERI) along four (4) traverses was processed and analyzed to obtain resistivity-depth sections of the subsurface. Three unique geoelectric zones were delineated, with the intermediate zone identified as the contaminated aquiferous unit. This unit’s resistivity values ranged from 10,804 to 100,000 Ωm along line Lx3, 324 to 23,497 Ωm along line Lx5, 1019 to 10,000 Ωm along line Ly6, and from 1000 to 10,000 Ωm along line Ly5 extending from the surface (0.0 m) to depths between 10 m and 20 m and to a profound depth of approximately 40 m. These high resistivity anomalies are characteristic of hydrocarbon contamination since hydrocarbons have a higher electrical resistivity compared to water. This coincides with the depth of the aquifer that serves as the major origin of edible water exploited by the local population and shows that the aquifer system below the study area, usually exploited for groundwater, has been invaded by hydrocarbon contamination plumes. The groundwater specimens from five boreholes were established to have a common total petroleum hydrocarbon (TPH) amount of 739.51 μg/L, above the DPR target and intervention thresholds of 50 and 600 μg/L, respectively. Groundwater specimens with summed polycyclic aromatic hydrocarbons (ΣPAHs) consist of amounts ranging from 0.36 to 1.89 μg/L in BH-1 to 5, that outweigh the DPR target threshold of 0.15 μg/L. Additionally, BTEX concentration was observed in greater levels in the water specimens above the DPR allowance. These findings explain that the area’s groundwater is heavily contaminated by dissolved-phase contaminants due to hydrocarbon pollution. The groundwater migration flow route at the spill site shows that the dominant flow direction is towards BH4, located northwest (N-W) of the spill site. A broad characterization of the subsurface as obtained from 2D ERI and geochemical results calls for effective remediation planning at the spill site aided by information about the very possible receptor locations at high possibility of contamination, which was defined in the groundwater flow pattern at the spill site.

Sediment deposition poses significant challenges to marine transport, aquatic ecosystems, andhydrogeological exploration. This study investigates the integration of Acoustic Doppler Current Profiler(ADCP) data with grain size analysis to estimate sediment deposition velocities in a lagoonal environment.Data from ten ADCP measurements revealed varying velocities, with the highest at 7.70 ft/s and the lowest at0.99 ft/s. Analysis of ADCP data indicated high velocity zones at depths of 21 to 27 ft and 12 to 19 ft, while lowvelocities were observed at shallow depths (up to 18 ft) and near the bottom at specific locations. Concurrentgrain size analysis identified a predominance of coarse-grained sand, with varying degrees of sorting frommoderately well to poorly sorted sediments. The results demonstrated that areas of high sediment velocityare associated with larger grain sizes, whereas low velocity zones correspond to finer grains. This studysuggests optimal navigation routes for vessels around the lagoon’s middle and recommends dredging edgesto mitigate sediment accumulation. These insights provide valuable guidance for sediment management,coastal engineering, and marine transportation safety.

This research presents an analysis of the estimated solar radiation using maximum and minimum daily temperatures (Tdmax and Tdmin) by applying three models, with calibration using the recently developed CSR model and extensive digital datasets from satellite observations compiled in the Atlas of Solar Radiation for Saudi Arabia, edited by KACST in collaboration with the Center for Renewable Energy Resources of Colorado; the model’s performance was analyzed using four statistical metrics (RMSE, ME, R², MAE), aiming to assess variability and identify the best model for estimating daily solar radiation based on temperature data from 1985 to 2018, relying on a daily dataset of extreme temperatures collected over 34 years (1985–2018) from meteorological stations in Abha (41112), Makkah (41030), Tabouk (40375), Yanbu (40439), Qaysumah (40373), Dammam (40417), Al Jouf (40361), Qasim (40405), and Najran (41118), all supervised by the National Center of Meteorology (NCM); the methodology involves analyzing the statistical distribution of the selected dataset, including maximum daily temperature (Tx), minimum daily temperature (Tm), and daily average temperature (T’), over the period 1985–2018 using the Kolmogorov-Smirnov test, while the statistical significance of temperature trend variations was examined using the semi-averages method and the T-student test, with results visually represented on thematic graphs, revealing spatial variations in daily temperatures and their trends across the selected meteorological stations, showing notable differences in the spatial distribution of daily temperatures, and in the context of trend analysis, the T-student test indicated clear differences between the semi-averages for the two periods 1985–2001 (X’1) and 2002–2018 (X’2), where the temperature differences (X’2–X’1) for minimum and maximum values were generally smaller than (2 SE) across different months in the selected stations, with the mean daily temperature exhibiting an increasing but not statistically significant trend in the studied stations; this study effectively represents the spatial distribution of daily temperature variations using statistical tests to determine the significance of trends from 1985 to 2018, demonstrating that the integrated application of these methods provides more accurate results in identifying climate change indicators across regions of Saudi Arabia.

An overpressure zone is critical in petroleum exploration drilling, leading to potentially dangerous blowouts and other drilling-related hazards. Yet, it often contains significant hydrocarbon reserves in sedimentary basins. This research aims to determine the possible overpressure zones in the Srikail Well-1 of the Srikail Gas Field. The acoustic impedance responses of 2D seismic data for the Srikail Well-1 and its well log responses were examined to find probable overpressure zones at the Srikail Well-1. Seismic inversion is a crucial method in this study for identifying and understanding overpressure zones. Hence, the process involved extracting wavelets, conducting well correlation, determining and picking horizons, followed by model-based seismic inversion, and calibrating pressure to well logs and seismic data using Kerry 2D post-stack seismic data to derive acoustic impedance, a crucial indicator for the presence of potential overpressure. Well-log responses provided evidence for this analysis. The density and sonic log responses of the Srikail-1 well were carefully evaluated. The intervals indicating possible overpressure locations, as identified through a seismic acoustic impedance, exhibited reasonable consistency with the well-log data. The Srikail-1 well does not have enough well-log information, such as density, but it affects the changing trend of well logs. The sonic logs solely follow the rule of an overpressure zone. A cut-off frequency between 4 and 8 Hz was used to build the Srikail-01 well initial model, and the wavelet was created using well logs and seismic data. Very low acoustic impedance values are observed on the model-based inversion map of the Srikail-01 well at a depth range of approximately 3548.58m in the subsurface corresponding to the overpressure zone. Conversely, the identified overpressure zone has encountered the Bhuban formation. Bangladesh’s hydrocarbon reserves are depleting due to high consumption, but unexplored areas and overpressure zones offer untapped potential. Revisiting known structures with robust methods can help to address rising demand.

When assessing the safety of a slope and the environmental impact resulting from open-pit and underground mining activities, it is imperative to consider the ground surface deformation induced by mining operations. Such deformations pose a significant risk to the environment, slope stability, and man-made structures within the mining activity region. Therefore, the monitoring of mining-induced ground surface deformations is crucial, and this study employs C- band Synthetic Aperture Radar (SAR) data to demonstrate the efficacy of the Persistent Scatterer Interferometric SAR (PS-InSAR) method. Specifically, the PS-InSAR method is applied to monitor ground surface deformation in the Midroc Gold Mine Company. The findings reveal that the PS-InSAR technique is capable of effectively tracking ground subsidence time-series, even in areas characterized by dense vegetation and rural landscapes. In the Midroc Lega Dembi open- pit mining region, the highest rate of ground surface deformation is observed at -90 mm per year, with cumulative subsidence values of -200 mm and -100 mm detected for ascending and descending geometries, respectively, through InSAR techniques. Additionally, ground survey data records cumulative subsidence values of -3.99866 m and -0.000122 m for ascending and descending geometries.The discrepancy between datasets is attributed to the thick vegetation cover in the study area. Integration of PS-InSAR results with ground survey data from the Midroc Lega Dembi open-pit mining zone reveals a correlation coefficient of 0.98, validating the accuracy of the PS-InSAR approach in identifying, tracking, and mapping ground surface deformation in the gold mine. This comprehensive methodology utilizes both ground survey data and C-band SAR data for a robust assessment of mining-induced ground surface deformations.

Assessing geotechnical properties of Wetlands Area in Lagos Mainland Western Nigeria. This geotechnical research was conducted at Iyana-Ipaja community in Alimosho Local Government Area of Lagos State. Six soil samples and control samples were collected from seven different sampling points within this region for geotechnical analysis. Geotechnical properties index was carryout on the soil samples. Grain size The analysis, Specific Gravity, Atterberg Limits, Compaction Test, and Triaxial Tests was carried-out on Sample A, Sample B and Sample C. The liquid limit (LL) values for sample A, Sample B, and Sample C were 44.40%, 44.82%, and 45.13% respectively, while the plastic limit values were 28.63%, 33.30%, and 33.46% respectively. The plastic index values for samples A, B, and C were 16.76, 11.53, and 11.67 respectively. These soil samples were classified as inorganic clays of low to medium plasticity (CL) and were considered moderately plastic based on their plasticity index (PI) values being less than 17%. The natural moisture content values for soil samples A, B, and C were 98.02%, 33.22%, and 31.19% respectively. The percentages of fine Sand passing the 200 sieves were 84.35%, 65.29%, and 59.96% for samples A, Sample B and Sample C respectively, leading to their classification as Silty Sand (SM) with uniformly graded sand and silt mixture. The OMC and MDD for Sample A, Sample B and Sample C were found to be 24.4%, 26.3%, 27.5% and .34g/cm3, 1.17g/cm3, 1.27g/cm3 respectively. Wet weight measurements indicated variability but suggested characteristics of clay ranging from Very soft to Firm. The research suggests and concluded that the soil samples from the Iyana-Ipaja area of Alimosho LGA, Lagos, requires chemical stabilization, preferably with cement or lime, to be suitable for construction and geotechnical purposes.

The variability and change in rainfall conditions have become a potential future threat, manifesting several adverse impacts on nature and society. This study examines rainfall variability and change and its impact in the Western Himalaya. Rainfall data, obtained from the Indian Institute of Tropical Meteorology (Pune) for the period 1845-2006, has been analyzed by Mann-Kendall Test and descriptive statistics to describe the evolution of the minimum, maximum, and mean rainfall patterns for monthly, annual, decadal and seasonal periods. The Indian Institute of Tropical Meteorology has divided the Western Himalaya into four rain seasons – (1) January and February; (2) March, April, and May; (3) June, July, August, and September; and (4) October, November, and December. Therefore, the data were analyzed based on these seasons. This study depicts high rainfall variability and change in terms of average decadal, annual, seasonal, and monthly rainfall. Rainfall variability is high in the monsoon and winter seasons. The monsoon season spanning for five months now reduced to three months with high intensity of rain. It can be observed from the data that in 1901, the average annual rainfall was only 1000 mm whereas in 1950 it was 3600 mm. The similar situation was noticed in the recent past. Similarly, the rainfall by western disturbances in December and January has been shifted to February and March with low intensity. This has resulted in low crop production and productivity and high geo-hydrological disasters. Furthermore, it also has an impact on the types and distribution of biodiversity resources.

The modern taxonomical consideration is used for the studied fifty two small porcelaneous benthic foraminiferal species of the Suborder Miliolina throughout the Bartonian-Priabonian belonging to nine genera from seventeen countries in the Norther Tethys (USA, France, Belgium, Germany, Austria, Italy, Hungaria, Slovenia, Turkey) and Southern Tethys (Ecuador, Chile, Argentina, Libya, Egypt, UAE, Pakistan, India). Two of the recorded species are treated here as new: Massilina saidi Anan, n. sp. and Quinqueloculina alaghai Anan, n. sp. Some of the recorded species are distributed outerside its original description in neighbor localities or even far from it, but others are endemic to their original description. The recorded foraminiferal assemblage indicates an open marine environment, and represents favor warm, marginal to deep sheltered environments.

This study uses Geographical Information Systems (GIS) as a support tool for gold exploration to distinguish between true and false soil geochemical anomalies at the northern segment of the Asankragwa gold belt in the Paleoproterozoic Kumasi Basin, Ghana. The main objective of this study is to identify potentially mineralized zones within the northern segment of the Asankragwa gold belt by integrating GIS, structural and soil geochemical datasets. To reduce the probability of delineating false anomalies as true anomalies, diverse graphical threshold determination methods, namely histogram, box plot, QQ plot, mean+2SD, Jenks Natural Break and Probability plot, as well as advanced threshold determination methods like the Mean Absolute Deviation (MAD) and double MAD were employed. The threshold values established from the graphical methods are 175 ppb, 96 ppb, 335ppb, 384 ppb and 100 ppb respectively. However, the MAD and double MAD methods produced threshold values of 74.5ppb and 130ppb respectively. Based on the high variability in the threshold values, anomalous areas were delineated using thresholds values of 100ppb and 130ppb respectively established from the Jenks Natural Break and Probability plot and double MAD method. About 40%, 35% and 20% of the selected anomalous areas are located within soils overlying volcanoclastic, clastic sedimentary and marine volcanoclastic rocks respectively. These anomalies are not lithologically controlled since they are not confined to a particular rock type. Superimposing the selected aanomalies over geological structures and Landsat imagery, 90% of the anomalies can be linked to the NE-SW geological structures. Upon integrating the anomalies with structural data and illegal mining activities and using the Booleon analysis, not all anomalies may be true anomalies. True gold anomalies within the Asankragwa gold belt are consistent with the central> northern> southern portions. Hence, the discovery of gold in the Asankragwa gold belt has been enhanced using GIS as a spatial support tool.

Hydrocarbon reservoir characterization using well log in part of Niger Delta, Nigeria was done in order to examine the potentiality and productivity of the reservoir. A suite of well log data consisting of gamma ray, density, resistivity and neutron logs obtained from two wells within the area of study were used for this research. Gamma ray log was used for lithology identification and differentiation, resistivity log was used to identify the type of fluid present in the reservoir, density log was used to detect gas bearing zones in the reservoir while neutron log was used to distinguish gas from oil in sandstone and shale reservoirs. The results of this study showed sand bodies were delineated and correlated across the wells and were inferred as potential hydrocarbon reservoirs. The result also showed that there is an increase in both porosity and permeability, evaluated petrophysical parameters showed that porosity values range between 0.0391 – 0.3019, water saturation values range from 0.1660 – 1.6740 while hydrocarbon saturation values range from 0.0013 – 0.7296 and net to gross values range from 0.5332 – 0.9674.