Search

This study presents a comprehensive account of geochemical data on the granitoids of Ambaji-Sendra Terrain and associated mafic dykes. These granitoids, interpreted as S–type, I-type and A-type, lack a consensual interpretation probably due to the study of only those rocks which are exposed in Sendra region. We identified that these granitoids are A-type (A2- subtype) granites. There are two petrogenetic groups of the granitoids having exclusive crustal and crust-mantle interactive origins which are supported by their mineralogy and structure. The associated dykes also display two distinct geochemical groups one with within-plate character and other with typical arc signatures. Whole body of evidence suggests that magma for the granitoids and dykes was generated during the closure of Delhi Ocean. The simultaneous emplacement of granitoids started during subduction process and culminated after the collision or/ accretion of Delhi arc with eastern crustal block, consequent to the Rodinian assembly mechanism.

Detrital and volcanic-detrital rocks from the Ifni Buttonhole and Lakhssas Plateau were analyzed to determine their provenance, compositional maturity, and alteration source. Geochemically, the sediments were classified as arkoses, lithic arenites, grauwackes, sandstones, lithic arenites, and Fe-rich sands, indicating low compositional and mineralogical maturity. A high average SiO2 concentration and low Al2O3 were consistent with a low abundance of shale and clay components. The geochemical signatures of the detrital and volcano-detrital (RDVD) rocks indicate that they have undergone a moderate to low degree of chemical alteration. The CIA study also suggests that the granitic, granodioritic rocks represent the source provenance which, during weathering and transport, supplied the detritus to the supra-crustal units. The major trace element data suggest that these rocks are largely derived from felsic igneous rocks, namely granitoids, with a minor contribution from intermediate sources. The carbonate rocks do not represent a wide variety of facies: dolomitic limestone, calcareous limestone, and calcaro-dolomitic chert. Calcitic and dolomitic samples show a linear increase in SiO2, regardless of their CaO/LOI ratio values, which remain relatively constant. The highest SiO2 contents are observed in the calc-dolomitic chert. Geochemical analysis of RDVD from the Ifni buttonhole determined their origin, maturity, and alteration. Major oxides decreased with higher silica content, indicating quartz control. Samples, formed under semi-arid conditions, show maturity under stable deposition. They suggest a felsic, recycled source, with moderate alteration and zircon enrichment during recycling. In the study area, limestones and dolomites serve as materials applicable in the building sector, suitable for all types of concrete. The Taliwine Formation harbors Lower Cambrian dolomites and limestones, ideal for mosaic aggregates. Described as variable in color, compact, homogeneous, very hard, and resistant to alteration, the plutonic rocks form prominent peaks. They exhibit both subalkaline characteristics in granitoids and an alkaline trend in dolerite dykes. Most samples display minimal alteration, indicating the reliability of their major element compositions for geochemical analyses. These granitoids constitute valuable deposits for ornamental and building rock purposes.

The concept of ecotourism has experienced a significant surge in popularity over the past two decades, primarily driven by the multitude of adverse impacts associated with mass tourism. The objective of the study was to develop a comprehensive ecotourism suitability index to guide policymakers in implementing tourism development policies. Given the considerable appeal of the study area to both local and international tourists, it is essential to conduct a systematic evaluation to pinpoint suitable areas for ecotourism development. This necessity arises from the study area's placement within a fragile ecosystem and its proximity to a UNESCO World Heritage site. We employed a Geographic Information Systems (GIS) integrated environment coupled with a fuzzy Multi-Criteria Decision Analysis (MCDA) methodology. The GIS-MCDA integrated framework leverages the Analytic Hierarchy Process (AHP) and a weighted linear combination that seeks to amalgamate many features and criteria to assess ecotourism potential by integrating 20 criteria into six separate categories: landscape, topography, accessibility, climate, forest and wildlife, and negative factors. Weights were allocated to each criterion and factor based on the expert's opinions of their impact on the development of ecotourism. The final ecotourism suitability index comprised five unique classes: very high, high, moderate, less, and not suitable. Results reveal that out of the total areas, 45.4 % (259 km2) are within the high and very high suitable classes. The sensitivity analysis suggested that ecotourism potentials are more favorable to forest and accessibility variables. The generated index can be utilized as a road map since validation verified a 64 % accuracy. Given the dearth of earlier research, this study provides vital support for the development of sustainable ecotourism projects in the study area.

In this study, we have applied a stable downward continuation technique to magnetic anomalies from the global geomagnetic field model MAG2V3 to improve the resolution of magnetic data of the west central Arabian Shield, Saudi Arabia. Then, advanced interpretation methods such as the tilt angle of the horizontal gradient (TAHG), horizontal gradient of a modified tilt angle (HGSTDR), and enhanced horizontal gradient (EHGA) have been applied to downward continued magnetic dataset to highlight the main structural features in the region. The observed geologic structures from the magnetic analysis revealed NW-SE, NE-SW, and ENE-WSW orientations in the west central Arabian Shield. The depths of these structures were computed by the analytic signal (AS) technique and the obtained result shows depths varying from 1.2 to 9.2 km. This study provided a new map of the subsurface geological structures for a better understanding of the tectonic evolution of the west central Arabian Shield.

Conceptual Framework: Coastal decrepitude is the loss of topographical resources along the coast as a result of silt, temperature fluctuations, tidal shifts, and wave breaking. Hydraulic activity, scraping, abrasion, and erosion are the major causes of erosion; other factors that affect it include the condition of the shore, rocks, joints, fissures, marine chemical reactions, and wave force. Objectives: The primary objectives of this study are to analyze the coastline changes between 1972 and 2022 utilizing remote sensing and GIS data and forecast the changes in the shoreline in 2032. Methods: The study examined coastal areas from 1972 to 2022 using multi-temporal satellite data from Landsat TM and Landsat OLI/TIRS. Shoreline change and the calculations related to it were examined using the Digital Shoreline Analysis System using near-infrared bands and tasseled cap transformation, to determine the rate of change in the shoreline, the study also employed Shoreline Change Envelope and End Point Rate techniques. Results: Coastal erosion caused substantial damage to the island between 1972 and 2022. The northern, southeastern, and western regions of the coast are seeing the highest levels of coastal erosion. The south coast experiences considerable erosion, whereas the west and southeast coasts experience the least. The EPR of Ghoramara Island has mean, minimum, and maximum changes of −10.59, −4.13, and −35.93, respectively. A notable inshore shift has occurred in the northern portion of Ghoramara, extending from 676 m to 855 m. The study also uses tidal gauge records and Revised Local Reference data from the Haldia Gauge Station to track long-term sea level variations. According to the study, Ghoramara Island's shoreline will change by 2032, with the greatest negative changes expected to occur around the island's western and southern borders. Conclusion: The study shows a significant decrease in Ghoramara's shoreline regions between 1972 and 2022, with a 3,000-population shifted from the place in 2016 due to Lohachara's submergence. Changes in the island's morphology and human activities have reduced cultivation. The study suggests increasing mangrove vegetation to combat coastal erosion and prevent further displacement of people to neighboring islands.

This study predicts sediment yield on various landuse surfaces within the Calabar River Catchment, Nigeria. Five experimental plots of 31 by 23 cm (representing urban, farm, grass, bare, and forest surfaces) were established on a convex slope series with a 20% gradient, oriented along the slope strike. Rainfall, morphological, and hydraulic stations were derived for each plot. Multiple regressions and Factor analysis were employed to analyse the collected data. The research identifies critical factors influencing sediment yield, such as rainfall amount, rainfall intensity, slope gradient, slope length, sand, silt, clay, vegetation cover, and infiltration capacity. The results (p

Aeromagnetic data of the Agadir Melloul region (Morocco) has been previously interpreted to delineate structural lineaments using the tilt angle method. In this study, we show the limitations of the tilt angle method in extracting the boundaries of magnetic sources and reinterpret aeromagnetic data of the Agadir Melloul region using the improved logistic method. Initially, the tilt angle and improved logistic methods are tested on 3D synthetic magnetic models where the results obtained from the improved logistic method show improvements in the delineation of the actual edges of sources compared to the tilt angle method. Then, aeromagnetic data from the Agadir Melloul region has been enhanced by the improved logistic method for delineating structural features. The obtained result provides a new look at the structural lineaments of the study area.

Lineament detector and depth estimation method involving modern aeromagnetic data were employed to study parts of the Obudu Plateau and Lower Benue Trough (southeast Nigeria) with the aim of mapping thermo-tectonic geologic structures and estimating sediment thicknesses. In this investigation, the enhanced horizontal gradient amplitude (EHGA) (applied to both simulated and real data) and tilt depth approaches were operated. The simulated magnetic model employing the EHGA detector generated sharp and properly defined edges of magnetic bodies with the capacity to place peaks over source borders. The tilt depth technique showed thin and thick sedimentations that vary from ∼ 500 to ∼ 1000 m and ∼ 1500 to ∼ 2500 m, respectively. The observed geologic structures trend mainly in the NW and NE, as well as minor NS directions. These structures, generated by the Younger Mesozoic Granitic intrusions of calc alkaline ring complexes, and the Santonian Abakaliki Anticlinorium serve as paths for super enriched hydrothermal fluids migration and deposition. The applied methods can be used to decipher the geologic structures in alike zones around the world.

This work aims to utilize oxygen and hydrogen stable isotopes as tracers for determining the groundwater sources of recharge in the central Nile delta. The analyzed water samples were collected from canals and drains as surface water, soil water and shallow, intermediate and deep zones of the groundwater. The isotopic data indicated that surface water samples have higher isotopic content than recent Nile river water (δ 18O = 2.39‰ and δ2H = 22‰) which reflect the influence of an evaporation process that takes place in surface water bodies during its flow. Soil water samples were affected by evaporation process during water infiltration via soil. It was estimated that soil water samples have higher enrichment isotopic contents than groundwater and less than surface and recent Nile water. Studied groundwater is composed of mixed source from groundwater recharged before and that recharged after High Dam construction. Few groundwater samples have depleted isotopic content which suggested a mixing source between the rainwater and the Nile River water before High Dam construction. The evaporation is indicated in the shallow groundwater by the deviation away from the global meteoric line. In the deep groundwater, more deviation from global meteoric line was noticed which reflects the effect of mixing between freshwater and seawater. The intermediate groundwater samples average line showed an intermediate deviation indicating the effect of both evaporation and seawater intrusion.

The LTHG and EHGA methods are enhancement versions of the gradient amplitude and can outline the edges of shallow and deep anomalous bodies simultaneously. Recently, these techniques have been used in approximating the edges of gravity and magnetic data. In this paper, we apply the LTHG and EHGA methods to the gravity dataset from the global gravity model WGM2012 to extract structural features of Northeastern Laos that appear as lineaments on transformed data maps. We also apply the tilt depth method to this dataset to estimate the depth of these lineaments. The findings showed that most of structures identified in Northeastern Laos are trending in the ENE-WSW, NE-SW, E-W, WNW-ESE and N-S directions with the depth ranging from 1.3 to 2.1 km.

The existing work deals with the structural analysis and detecting basement depth of G. Shilman area, South Eastern Desert (SED), Egypt. This work includes interpreting aeromagnetic data to map out structures within the study area and determine the depth of the magnetic basement which can be an aide to advance exploratory study. The first vertical derivative (1st VD) enhanced the short-wavelength and high-frequency features of the data. The analytic signal (AS) and horizontal gradient magnitude (HGM) maps well the structures of G. Shilman area. Statistical analysis of the delineated structures indicated that the NW, N_S, NNE and NE are the main structural trends controlling the study area. This suggests that the area was dominated by various stress regimes. The source parameter imaging (SPI) method which acts strongly at all magnetic latitudes was applied to the data to map the basement topography of G. Shilman area. The basement depths vary from about 0.1 km to about 1.5 km at the deepest part of the study area. The depth examination indicates that the recent deposits are not thick and reflect the shallow nature of the basement in G. Shilman area. The results of our study gives more accurate interpretation for the structural regime of the study area and can be applied for alike areas.

One major purpose of interpretation of magnetic data is to highlight edges of geology structures. In this paper, we applied the edge methods such as the enhancement of total gradient (ETG), normalized horizontal gradient (TDX), theta map (TM) and fast sigmoid (FSED) methods to delineate geological structures that appear as lineaments in transformed magnetic anomaly maps. Initially, these methods were estimated on a magnetic model for understanding their capability. Further, we applied these methods to real aeromagnetic data for determining lineaments of the Wadi Umm Dulfah area. Additionally, the depths of the magnetic sources in the area were also computed by the tilt depth method. The obtained results indicate the presence in the study area of three major lineament trends in NW–SE, N-S, and NE–SW directions, and most of the lineaments are in the depth range of 0.1 km to 1 km. These results bring a better understanding of the edge methods capability, as well as the geology structures of the Wadi Umm Dulfah area.

Determining the main structures that control sedimentary basins from magnetic and gravity data is an important step for hydrocarbon exploration. In this study, the structural features of the area, east of the Qattara Depression, was deduced utilizing the gravity and magnetic data. Regional-residual separation, lineament analysis, tilt derivative and spectral analysis techniques were utilized to realize this main goal. Fast Fourier transform (FFT) was used for regional and residual separation. The structural patterns of the area were outlined by lineament analysis. The bedrock depth was calculated by applying the spectral analysis method on twenty gravity and magnetic profiles. The coupled 2D and 2.5D modeling along the three gravity and magnetic profiles indicated that the region consists of horsts and grabens blocks, consisting of both acidic and basic rocks. Consequently, a structural map was made to identify the main basins and highs. Besides, it was observed that the thickness of the sedimentary cover varies between 2.5 and 5.5 km in the study area.

Identification of lateral boundaries for the subsurface structures is a popular topic in many applications of geoscience. For this purpose, many edge detection and enhancement methods have been introduced to determine the lineaments of subsurface structures. In this study, the improved parabola-based method has been applied to reveal the lineaments of subsurface structures of Nam Dinh province. The obtained results have shown that there are NW–SE trending structures in this region and most of the lineaments are in the depth range of 2 km to 8 km. These results provide a new perspective to help us better understand the structural framework and tectonic settings of the study area.

Extensive geophysical and geodetic measurements were carried out to evaluate the groundwater aquifer, trace the basement relief, as well as detect the igneous intrusions and structural elements (mainly faults) that affect the occurrence of groundwater in the study area. The fieldwork included resistivity sounding, a geomagnetic survey, and Global Positioning System measurements. The magnetic results showed the presence of a group of main faults in East-west trend at the western part of the area and major fault at the northern part of the area of NW-SW trend. The findings also showed the presence of two igneous rock intrusions located in the middle of the eastern part of the valley. Pronounced differences in the depths of basement rocks have been identified, ranging between 0 and 900 m from the surface. Both high horizontal movements and high shear strain rates have been found to be concentrated at the southeast of the study area and it was noted that high stress was accumulated along the main observed faults and at the main groundwater aquifers. The geoelectrical results confirmed the presence of two aquifers; a shallow aquifer (Quaternary aquifer) that narrows northwards and a Nubian sandstone aquifer, which considered the main aquifer. The Nubian sandstone aquifer carries groundwater in the region, which overlies the last geoelectric unit represented by the basement complex layer and geological structures affecting the potential availability of groundwater in the study area, as proved by the geomagnetic survey and stress accumulation.

India is a land of rivers and Narmada is one of the principal river systems and is ascribed as the lifeline of Central India. Freshwater ecosystems such as rivers across the globe are facing degradation due to multitude of anthropogenic stress factors. Holistic and sustainable approach is prerequisite for monitoring, risk assessment and management of such multitude of problems and critical challenges. Geographical Information System (GIS) has emerged as a powerful tool for carrying out scientific and unbiased monitoring and assessment studies as well as understanding the degradation of ecosystems. The present study focuses on decadal land use changes along the upper catchment area of Narmada river basin. Vegetation was spatially analyzed for digitally classifying numerous imageries using the maximum likelihood algorithm (MLA). Six land cover types were identified which includes dense mixed forest, Sal dominated forests, barren landscapes, agricultural fields, water bodies as well as habitation and commercial spaces. The vegetation structure and species composition are important ecological attributes of the ecosystem. Our study area has faced intensification in anthropogenic stress factors, which is observable in our temporal variations study as well. Increasing urbanization and deforestation in river valley regions is alarming and testimony of the fact. Therefore, in order to maintain the river health advocacy at policy level is needed. The current study is an attempt in that direction. It is therefore essential in developing a road-map for sustainable development of this important riparian ecosystem.

The Chichali Formation encountered in Chanda 01 well, located in the Shakardara Kohat, Khyber Pakhtunkhwa Province of Pakistan has been studied in detail as a source for hydrocarbon. Nine drill cuttings of the formation were subjected to geochemical analyses and organic petrography. Various screening techniques including TOC analysis by using Leco-CS analyzer, Rock Eval pyrolysis and organic petrography were used to determine the quality, quantity, maturity and depositional environment of the organic matter. The total organic carbon (TOC) of samples from Chichali Formation ranging from 0.47 to 2.76 wt% indicate fair to very good source rock. Pyrolysis parameters resulted in S1values ranging from 0.21 to 0.83 mg/g of rock, S2 0.44 to 0.61 mg/g rock, PI 0.32–0.51 and Tmax 442–448 °C. The Tmax and vitrinite reflectance data (0.72–0.84 Ro %) indicate that Chichali Formation is effective source rock and is in the process of generating hydrocarbons and falls within oil window. Geochemical parameters Hydrogen index (HI), Oxygen index (OI), Tmax along with organic petrography analyses (maceral) are used for kerogen type evaluation. The calculated HI ranges between 31 and 54 mg HC/g TOC and OI 30–96 mg O2/g TOC. Using modified Van Krevlen diagram between HI vs OI of Rock Eval pyrolysis and maceral analyses, kerogen type II/III and transition between anoxic to oxic depositional environments is interpreted for the studied Chichali Formation.