Accurate prediction of near-surface air temperature (NST) is crucial for addressing climate variability and its impacts, particularly in climate-vulnerable regions such as Ghana. Traditional methods, although reliable, face limitations in spatial coverage and measurement consistency, which hinder effective climate adaptation planning. This study utilizes multiple machine learning (ML) algorithms to enhance temperature prediction accuracy, leveraging 40 years of data from 23 synoptic stations across Ghana. We employ six advanced ML models: Support Vector Regressor (SVR), Gradient Boosting Regressor (GBR), Light Gradient Boosting Machine (LGBM), Random Forest (RF), and Extreme Gradient Boosting (XGB), to predict monthly mean temperatures. The models were rigorously trained, validated, and tested, with the SVR model demonstrating superior performance (R2 = 0.93; mean squared error [MSE] = 0.04; mean absolute error [MAE] = 0.14). Our findings highlight the transformative potential of ML in generating high-resolution, accurate climate data, which is essential for developing targeted climate adaptation strategies in Ghana and similar regions. By improving temperature prediction, this study contributes to the realization of key Sustainable Development Goals (SDGs), including SDG 13 (Climate Action), SDG 2 (Zero Hunger), and SDG 7 (Affordable and Clean Energy), by enabling informed decision-making for agriculture, disaster management, and energy planning. This scalable ML approach provides a robust framework for addressing climate challenges globally, particularly in data-sparse regions.
{"title":"Leveraging machine learning for accurate near-surface air temperature prediction to enhance climate adaptation in Ghana","authors":"Collins Oduro , Benjamin Kwapong Osibo , Solomon Obiri Yeboah Amankwah , Sangar Khan , Emmanuel Adu Gyamfi Kedjanyi , Oscar Famous Darteh , Yiting Geng , Augustine O.K.N. Mensah , Naicheng Wu","doi":"10.1016/j.jafrearsci.2025.105877","DOIUrl":"10.1016/j.jafrearsci.2025.105877","url":null,"abstract":"<div><div>Accurate prediction of near-surface air temperature (NST) is crucial for addressing climate variability and its impacts, particularly in climate-vulnerable regions such as Ghana. Traditional methods, although reliable, face limitations in spatial coverage and measurement consistency, which hinder effective climate adaptation planning. This study utilizes multiple machine learning (ML) algorithms to enhance temperature prediction accuracy, leveraging 40 years of data from 23 synoptic stations across Ghana. We employ six advanced ML models: Support Vector Regressor (SVR), Gradient Boosting Regressor (GBR), Light Gradient Boosting Machine (LGBM), Random Forest (RF), and Extreme Gradient Boosting (XGB), to predict monthly mean temperatures. The models were rigorously trained, validated, and tested, with the SVR model demonstrating superior performance (R<sup>2</sup> = 0.93; mean squared error [MSE] = 0.04; mean absolute error [MAE] = 0.14). Our findings highlight the transformative potential of ML in generating high-resolution, accurate climate data, which is essential for developing targeted climate adaptation strategies in Ghana and similar regions. By improving temperature prediction, this study contributes to the realization of key Sustainable Development Goals (SDGs), including SDG 13 (Climate Action), SDG 2 (Zero Hunger), and SDG 7 (Affordable and Clean Energy), by enabling informed decision-making for agriculture, disaster management, and energy planning. This scalable ML approach provides a robust framework for addressing climate challenges globally, particularly in data-sparse regions.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"233 ","pages":"Article 105877"},"PeriodicalIF":2.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145268207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Although advanced machine learning models have demonstrated considerable potential for environmental monitoring, their application to assessing groundwater contamination in Ghana's peri-urban areas remains inadequately explored and poorly understood. To bridge this gap, this study aimed to apply advanced non-linear machine learning techniques, specifically Variational Autoencoders (VAEs) and Self-Organising Maps (SOMs), to analyse groundwater contaminants in south-eastern Ghana. The study examines intricate relationships and patterns among various pollutants to provide a comprehensive evaluation of groundwater quality. All the physicochemical parameters evaluated fell within the WHO guideline values. The VAE and SOM analyses confirm dual-source controls on groundwater chemistry in the Birimian terrains, involving both natural geogenic inputs from silicate and mafic lithologies and anthropogenic impacts from settlements. Inverse loadings across latent dimensions captured spatial heterogeneity, separating lithology-driven variables (e.g., Na+, Ca2+, EC) from pollution markers (e.g., NO3−, Cl−). SOM clustering further distinguished zones of minimal human influence from areas with localised contamination, such as Pb hotspots and elevated EC and salinity linked to mineralisation or saline intrusion. Scattered peaks in F− and Cl− suggested episodic anthropogenic inputs. The results reveal notable disparities in machine learning model performance based on target variable features; the Nitrate Pollution Index (NPI) yielded a Test R2 of 0.983, indicating superior predictive accuracy. Conversely, challenges with the Fluoride Pollution Index (FPI) and Pollution Index of Groundwater (PIG) exposed limitations due to unmeasured geological factors and low variability. We propose a data-driven, scalable diagnostic tool for monitoring water quality that can be integrated into national frameworks. This tool has implications for Sub-Saharan Africa and other regions similarly affected.
{"title":"Harnessing Variational Autoencoders and self-organising maps for groundwater contamination assessment in peri-urban Ghana","authors":"Portia Annabelle Opoku , Raymond Webrah Kazapoe , Noah Kwaku Baah , Abass Gibrilla , Geophrey K. Anornu , Nana Kobea Bonso","doi":"10.1016/j.jafrearsci.2025.105866","DOIUrl":"10.1016/j.jafrearsci.2025.105866","url":null,"abstract":"<div><div>Although advanced machine learning models have demonstrated considerable potential for environmental monitoring, their application to assessing groundwater contamination in Ghana's peri-urban areas remains inadequately explored and poorly understood. To bridge this gap, this study aimed to apply advanced non-linear machine learning techniques, specifically Variational Autoencoders (VAEs) and Self-Organising Maps (SOMs), to analyse groundwater contaminants in south-eastern Ghana. The study examines intricate relationships and patterns among various pollutants to provide a comprehensive evaluation of groundwater quality. All the physicochemical parameters evaluated fell within the WHO guideline values. The VAE and SOM analyses confirm dual-source controls on groundwater chemistry in the Birimian terrains, involving both natural geogenic inputs from silicate and mafic lithologies and anthropogenic impacts from settlements. Inverse loadings across latent dimensions captured spatial heterogeneity, separating lithology-driven variables (e.g., Na<sup>+</sup>, Ca<sup>2+</sup>, EC) from pollution markers (e.g., NO<sub>3</sub><sup>−</sup>, Cl<sup>−</sup>). SOM clustering further distinguished zones of minimal human influence from areas with localised contamination, such as Pb hotspots and elevated EC and salinity linked to mineralisation or saline intrusion. Scattered peaks in F<sup>−</sup> and Cl<sup>−</sup> suggested episodic anthropogenic inputs. The results reveal notable disparities in machine learning model performance based on target variable features; the Nitrate Pollution Index (NPI) yielded a Test R<sup>2</sup> of 0.983, indicating superior predictive accuracy. Conversely, challenges with the Fluoride Pollution Index (FPI) and Pollution Index of Groundwater (PIG) exposed limitations due to unmeasured geological factors and low variability. We propose a data-driven, scalable diagnostic tool for monitoring water quality that can be integrated into national frameworks. This tool has implications for Sub-Saharan Africa and other regions similarly affected.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"233 ","pages":"Article 105866"},"PeriodicalIF":2.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145222098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01Epub Date: 2025-10-01DOI: 10.1016/j.jafrearsci.2025.105869
Asbar Abbasi , Ali Kadkhodaie , Rahim Mahari , Reza Moussavi-Harami
Carbonate Sarvak Formation is considered as one of the productive oil reservoir units in Dezful embayment of the Zagros Basin. The current study focuses on the cyclostratigraphic analysis of the Sarvak Formation by using evolutionary spectral analysis approaches of fast Fourier transform (FFT) spectrogram combined with wavelet transform (WT) scalogram and multi-Taper Method (MTM) periodogram. The Multi-Taper Method (MTM) periodogram utilized in this study to detect the Milankovitch cycles in the Sarvak Formation. In addition, the power spectrum of spectral gamma-ray and formation density (RHOB) logs, based on evolutionary FFT and WT Scalograms indicate strong astronomical signals of the Milankovitch cycles (E, e, O, P) in three wells of the Anaran block. Using the new approaches of evolutionary correlation coefficient and evolutionary significance levels, variations in sediment accumulation rates during deposition of the Sarvak Formation were compared in wells A-C. The minimum and maximum amount of sediment accumulation in the upper Sarvak Formation in the studied wells are estimated to be approximately 2 cm/kyr and 5.2 cm/kyr, respectively. According to spectral powers observed in the evolutionary correlation coefficient spectrogram, the sedimentation of the upper Sarvak Formation in well C was mostly influenced by the long-eccentricity cycle (E); on the contrary and based on the observed spectral powers, the sedimentation of the upper Sarvak Formation in wells A and B is mostly influenced by Obliquity (O) and long-eccentricity cycle (E). The contribution of other cycles is insignificant compared to E and O.
{"title":"Analyzing sediment accumulation rates of the upper cretaceous Sarvak Formation based on well logging data in a cyclostratigraphic framework, southwestern Zagros Basin, Iran","authors":"Asbar Abbasi , Ali Kadkhodaie , Rahim Mahari , Reza Moussavi-Harami","doi":"10.1016/j.jafrearsci.2025.105869","DOIUrl":"10.1016/j.jafrearsci.2025.105869","url":null,"abstract":"<div><div>Carbonate Sarvak Formation is considered as one of the productive oil reservoir units in Dezful embayment of the Zagros Basin. The current study focuses on the cyclostratigraphic analysis of the Sarvak Formation by using evolutionary spectral analysis approaches of fast Fourier transform (FFT) spectrogram combined with wavelet transform (WT) scalogram and multi-Taper Method (MTM) periodogram. The Multi-Taper Method (MTM) periodogram utilized in this study to detect the Milankovitch cycles in the Sarvak Formation. In addition, the power spectrum of spectral gamma-ray and formation density (RHOB) logs, based on evolutionary FFT and WT Scalograms indicate strong astronomical signals of the Milankovitch cycles (E, e, O, P) in three wells of the Anaran block. Using the new approaches of evolutionary correlation coefficient and evolutionary significance levels, variations in sediment accumulation rates during deposition of the Sarvak Formation were compared in wells A-C. The minimum and maximum amount of sediment accumulation in the upper Sarvak Formation in the studied wells are estimated to be approximately 2 cm/kyr and 5.2 cm/kyr, respectively. According to spectral powers observed in the evolutionary correlation coefficient spectrogram, the sedimentation of the upper Sarvak Formation in well C was mostly influenced by the long-eccentricity cycle (E); on the contrary and based on the observed spectral powers, the sedimentation of the upper Sarvak Formation in wells A and B is mostly influenced by Obliquity (O) and long-eccentricity cycle (E). The contribution of other cycles is insignificant compared to E and O.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"233 ","pages":"Article 105869"},"PeriodicalIF":2.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145222097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01Epub Date: 2025-09-28DOI: 10.1016/j.jafrearsci.2025.105867
Ali Hagras
Reliable forecasts of rainfall-runoff are crucial for reducing flood risks. Furthermore, the risk of such floods can be prevented and reduced with the use of appropriate modeling. So, accurate runoff calculation is regarded as necessary for rainfall-runoff modeling. However, the lack of runoff measurements in watersheds is considered a big obstacle in many developing countries. So, this study uses an uncalibrated model based on established physical parameters. In Egypt, there are no monitoring field measurements for every watershed. Hence, the statistical distributions were adopted for the approximate estimation of rainfall depth at the meteorological station that affects the research area for various return periods and created an intensity duration frequency curve (IDF) in the return periods (25-50-100 years) in the Safaga Valley Basin. In the present study, the HEC-HMS model was used to create a runoff simulation in the Safaga Valley Basin. Also, the SCS curve number method, SCS unit hydrograph method, as a transform method was applied to simulate the hydrological processes. Also, assessing the study's findings by carrying out a field visit in the Safaga Valley Basin. The primary goal of this study is hydrological modeling of rainfall-runoff and Flooding in the Safaga Valley Basin applied the HEC-HMS Model through GIS environment to calculate the peak discharges, direct runoff volume and create hydrographs in the return periods of the sub-basins in the Safaga Valley Basin. Results showed result of the modeling in the return periods of the sub-basins in the Safaga Valley Basin where the total peak discharge in return period 100 years is 698.4 (m3/s) and sub-basin 7 is the largest peak discharge in return period 100 years where reached 137.5 (m3/s) and the total discharge volume in return period 100 years is 12288.5 (1000m3) and sub-basin 7 is the largest discharge volume in return period 100 years where reached 3050.2 (1000m3). In this regard, a flash flood risk assessment of the Safaga Valley sub-basins identified five possible hazards: very low, low, moderate, high, and very high. In addition, the finding shows that the hydrodynamic hazard is largest (High and Very high) in the SB2, SB3, SB4, and SB6 subbasins. In recent decades, the study area has seen devastating flash floods, which have had a significant impact on infrastructure, livelihoods, and human lives. So, this study recommended emphasizing these regions as top objectives for future flood mitigation strategies. The results demonstrate that the developed HEC-HMS model provides a crucial tool for sustainable land use planning and the design of flood protection infrastructure in the Safaga Valley Basin.
{"title":"Modeling of rainfall-runoff and flooding using HEC-HMS model through GIS in an arid environment: A case study in the Safaga Valley basin, West Safaga city, Egypt","authors":"Ali Hagras","doi":"10.1016/j.jafrearsci.2025.105867","DOIUrl":"10.1016/j.jafrearsci.2025.105867","url":null,"abstract":"<div><div>Reliable forecasts of rainfall-runoff are crucial for reducing flood risks. Furthermore, the risk of such floods can be prevented and reduced with the use of appropriate modeling. So, accurate runoff calculation is regarded as necessary for rainfall-runoff modeling. However, the lack of runoff measurements in watersheds is considered a big obstacle in many developing countries. So, this study uses an uncalibrated model based on established physical parameters. In Egypt, there are no monitoring field measurements for every watershed. Hence, the statistical distributions were adopted for the approximate estimation of rainfall depth at the meteorological station that affects the research area for various return periods and created an intensity duration frequency curve (IDF) in the return periods (25-50-100 years) in the Safaga Valley Basin. In the present study, the HEC-HMS model was used to create a runoff simulation in the Safaga Valley Basin. Also, the SCS curve number method, SCS unit hydrograph method, as a transform method was applied to simulate the hydrological processes. Also, assessing the study's findings by carrying out a field visit in the Safaga Valley Basin. The primary goal of this study is hydrological modeling of rainfall-runoff and Flooding in the Safaga Valley Basin applied the HEC-HMS Model through GIS environment to calculate the peak discharges, direct runoff volume and create hydrographs in the return periods of the sub-basins in the Safaga Valley Basin. Results showed result of the modeling in the return periods of the sub-basins in the Safaga Valley Basin where the total peak discharge in return period 100 years is 698.4 (m<sup>3</sup>/s) and sub-basin 7 is the largest peak discharge in return period 100 years where reached 137.5 (m<sup>3</sup>/s) and the total discharge volume in return period 100 years is 12288.5 (1000m<sup>3</sup>) and sub-basin 7 is the largest discharge volume in return period 100 years where reached 3050.2 (1000m<sup>3</sup>). In this regard, a flash flood risk assessment of the Safaga Valley sub-basins identified five possible hazards: very low, low, moderate, high, and very high. In addition, the finding shows that the hydrodynamic hazard is largest (High and Very high) in the SB2, SB3, SB4, and SB6 subbasins. In recent decades, the study area has seen devastating flash floods, which have had a significant impact on infrastructure, livelihoods, and human lives. So, this study recommended emphasizing these regions as top objectives for future flood mitigation strategies. The results demonstrate that the developed HEC-HMS model provides a crucial tool for sustainable land use planning and the design of flood protection infrastructure in the Safaga Valley Basin.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"233 ","pages":"Article 105867"},"PeriodicalIF":2.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145222096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01Epub Date: 2025-10-24DOI: 10.1016/j.jafrearsci.2025.105885
Harzali Makrem , Troudi Habib
The Albian succession of West-Central Tunisia records a complex interaction of tectonic extension, eustatic sea-level changes, and sedimentary dynamics that shape its stratigraphic architecture and hydrocarbon prospectivity. This study integrates seismic interpretation, well log correlation, and geochemical characterization to construct a high-resolution sequence stratigraphic framework, revealing significant exploration potential within the region. Structural mapping through isochron, depth, and isopach analyses delineates a heterogeneous fault network trending NW-SE, NE-SW, and E-W, with salt diapirism influencing thickness variations and controlling subsidence in fault-bounded depocenters. Seismic data recognize five distinct Albian sequences (Alb-1 to Alb-5) exhibiting diverse reflection patterns and depositional facies, indicative of syn-sedimentary fault activity, halokinesis, and global sea-level fluctuations. Wireline logs corroborate third-order depositional sequences characterized by progradational to aggradational stacking, interrupted by regional unconformities linked to tectonic uplift and eustatic events. Geochemical results from the Lower Fahdène Formation demonstrate Type II kerogen with TOC values up to 2.3 % and Hydrogen Index ranging 400–800 mg HC/g TOC, confirming oil-prone source rock potential. Biomarker and isotopic signatures from oil seeps confirm a marine origin and active petroleum systems, with δ13C data indicating deposition under dysoxic to anoxic conditions. The depositional environment was governed by extensional tectonics associated with Atlantic rifting and halokinesis activity, while global anoxic events enhanced organic matter preservation. This comprehensive model elucidates the distribution and quality of Albian source rocks, providing critical insights for hydrocarbon exploration in analogous rifted passive margin settings.
{"title":"Geophysical characterization of Albian source rocks in West-Central Tunisia: Implications for hydrocarbon exploration","authors":"Harzali Makrem , Troudi Habib","doi":"10.1016/j.jafrearsci.2025.105885","DOIUrl":"10.1016/j.jafrearsci.2025.105885","url":null,"abstract":"<div><div>The Albian succession of West-Central Tunisia records a complex interaction of tectonic extension, eustatic sea-level changes, and sedimentary dynamics that shape its stratigraphic architecture and hydrocarbon prospectivity. This study integrates seismic interpretation, well log correlation, and geochemical characterization to construct a high-resolution sequence stratigraphic framework, revealing significant exploration potential within the region. Structural mapping through isochron, depth, and isopach analyses delineates a heterogeneous fault network trending NW-SE, NE-SW, and E-W, with salt diapirism influencing thickness variations and controlling subsidence in fault-bounded depocenters. Seismic data recognize five distinct Albian sequences (Alb-1 to Alb-5) exhibiting diverse reflection patterns and depositional facies, indicative of syn-sedimentary fault activity, halokinesis, and global sea-level fluctuations. Wireline logs corroborate third-order depositional sequences characterized by progradational to aggradational stacking, interrupted by regional unconformities linked to tectonic uplift and eustatic events. Geochemical results from the Lower Fahdène Formation demonstrate Type II kerogen with TOC values up to 2.3 % and Hydrogen Index ranging 400–800 mg HC/g TOC, confirming oil-prone source rock potential. Biomarker and isotopic signatures from oil seeps confirm a marine origin and active petroleum systems, with δ13C data indicating deposition under dysoxic to anoxic conditions. The depositional environment was governed by extensional tectonics associated with Atlantic rifting and halokinesis activity, while global anoxic events enhanced organic matter preservation. This comprehensive model elucidates the distribution and quality of Albian source rocks, providing critical insights for hydrocarbon exploration in analogous rifted passive margin settings.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"233 ","pages":"Article 105885"},"PeriodicalIF":2.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145416923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
‘Primary Karst Deposits'’ represented by Mediterranean Bauxite Belt in Milas-Muğla, Türkiye were being deposited by in-situ process within the karstic caves of the Late Cretaceous (Cenomanian-Campanian) meta-dolomitic carbonates and are composed of diaspore, hematite, chloritoid, muscovite with minor amounts of quartz, chlorite, paragonite, kaolinite/dickite and dickite/chlorite. Deposits are made up of three structural members as pizolitic bauxites, oolitic bauxites ans pelitomorphic bauxites with irregularly distributed clay-rich bauxites. Pizolitic bauxites representing upper parts of the deposits display nodular to massive dark red colors and continue with highly indurated massive and dense oolitic bauxite layers. The lower parts of the deposits are mainly composed of breccia-baring eroded bauxite layers. Geochemical classification of the meta-bauxite deposits suggests ‘‘bauxite/ferritic bauxite’’ indicating strong laterization. Bauxitophile elemental imprints show that deposits might have been derived from dominantly basaltic rocks mixing with argillaceous parent rocks by extensive weathering and leaching processes during the bauxitization. New 40Ar-39Ar (41.17 ± 0.20 Ma) age evaluated together with the depositional age of the Kızılağaç Formation suggest that Late Cretaceous successions might have been uplifted and imbricated with northerly derived Neotethian ophiolitic slices that were emplaced onto the upper part of the Late Cretaceous carbonate platform after closure of the northern branch of the Neotethys ocean. Deformational structures within macro-crystallized diaspore zones generated along the tectonic zones of the bauxite deposits indicate that metamorphism might be underwent between 37 and 30 Ma. Thus, deposits were generated between latest Maastrichtian (latest Cretaceous) and latest Lutetian (Middle Eocene) interval in a humid and tropical climate on the surface under the dry conditions on the continental margin. Mediterranean Bauxite Belt type these deposits paleogeographically and genetically correlate well with similar peri-Gondwanan areas in the southern Turkey, Spain, France, Italy and Greece and are partly different than those deposits in Iran areas.
{"title":"Petrogenetic characteristics of karstic meta-bauxite deposits in Milas area, SW Türkiye: Insights on chemical fractionations and parental affinities","authors":"Semih Gürsu , Emirhan Ki̇raz , Gülcan Bozkaya , Ömer Bozkaya , Muhittin Yiğmatepe","doi":"10.1016/j.jafrearsci.2025.105893","DOIUrl":"10.1016/j.jafrearsci.2025.105893","url":null,"abstract":"<div><div>‘Primary Karst Deposits'’ represented by Mediterranean Bauxite Belt in Milas-Muğla, Türkiye were being deposited by in-situ process within the karstic caves of the Late Cretaceous (Cenomanian-Campanian) meta-dolomitic carbonates and are composed of diaspore, hematite, chloritoid, muscovite with minor amounts of quartz, chlorite, paragonite, kaolinite/dickite and dickite/chlorite. Deposits are made up of three structural members as pizolitic bauxites, oolitic bauxites ans pelitomorphic bauxites with irregularly distributed clay-rich bauxites. Pizolitic bauxites representing upper parts of the deposits display nodular to massive dark red colors and continue with highly indurated massive and dense oolitic bauxite layers. The lower parts of the deposits are mainly composed of breccia-baring eroded bauxite layers. Geochemical classification of the meta-bauxite deposits suggests ‘‘bauxite/ferritic bauxite’’ indicating strong laterization. Bauxitophile elemental imprints show that deposits might have been derived from dominantly basaltic rocks mixing with argillaceous parent rocks by extensive weathering and leaching processes during the bauxitization. New <sup>40</sup>Ar-<sup>39</sup>Ar (41.17 ± 0.20 Ma) age evaluated together with the depositional age of the Kızılağaç Formation suggest that Late Cretaceous successions might have been uplifted and imbricated with northerly derived Neotethian ophiolitic slices that were emplaced onto the upper part of the Late Cretaceous carbonate platform after closure of the northern branch of the Neotethys ocean. Deformational structures within macro-crystallized diaspore zones generated along the tectonic zones of the bauxite deposits indicate that metamorphism might be underwent between 37 and 30 Ma. Thus, deposits were generated between latest Maastrichtian (latest Cretaceous) and latest Lutetian (Middle Eocene) interval in a humid and tropical climate on the surface under the dry conditions on the continental margin. Mediterranean Bauxite Belt type these deposits paleogeographically and genetically correlate well with similar peri-Gondwanan areas in the southern Turkey, Spain, France, Italy and Greece and are partly different than those deposits in Iran areas.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"234 ","pages":"Article 105893"},"PeriodicalIF":2.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01Epub Date: 2025-11-14DOI: 10.1016/j.jafrearsci.2025.105933
Nouhaila Elbakhouch , Ahmed Touil , John S. Armstrong-Altrin , Hassan Ibouh , Driss Chafiki
The paleoweathering, paleoclimate, and paleoenvironment of the clastic sediments from the Ediacaran and Cambrian Tighardine Formation in the Western High Atlas have been evaluated based on geochemical data. According to their geochemical characteristics, the sediments of Ediacaran age (Ed-S) are ranged as shale and wacke types, while those of the Cambrian age are classified as shales (Ca-S). The Chemical Index of Alteration (CIA) varies from 43.58 to 74.59 in the Ed-S (average: 58 %), and from 65.81 to 79.22 in the Ca-S (average: 75.97 %). The Compositional Maturity Index (ICV) varies from 0.81 to 1.92 in the Ed-S (average: 1.21), and from 0.66 to 1.07 in the Ca-S (average: 0.74). The Chemical Index of Weathering (CIW) varies from 49 to 98 in the Ed-S (average: 78.71), and from 79.18 to 92.71 in the Ca-S (average: 87.73). The Plagioclase Index of Alteration (PIA) varies from 31.61 to 95.29 in the Ed-S (average: 71.05), and from 75.57 to 91.21 in the Ca-S (average: 85.31). The Al2O3–CaO + Na2O–K2O and Al2O3–CaO + Na2O–FeOT + MgO ternary diagrams indicate that the Ed-S shows an immature composition and low to moderate weathering. While the Ca-S have a mature composition, high sediment recycling and moderate weathering intensity, during a predominantly semi-arid climate. Redox indicators such as V/Cr ratios, suggest that the Ed-S were deposited under anoxic condition, as evidenced by the presence of a graphitized zone within the Ediacaran Formation in the study area, while the Ca-S were formed in an oxic condition.
{"title":"Geochemical composition of the Ediacaran and Cambrian shales from the Tighardine region, Western High-Atlas, Morocco: implications for depositional environments, paleoclimate, and paleoweathering","authors":"Nouhaila Elbakhouch , Ahmed Touil , John S. Armstrong-Altrin , Hassan Ibouh , Driss Chafiki","doi":"10.1016/j.jafrearsci.2025.105933","DOIUrl":"10.1016/j.jafrearsci.2025.105933","url":null,"abstract":"<div><div>The paleoweathering, paleoclimate, and paleoenvironment of the clastic sediments from the Ediacaran and Cambrian Tighardine Formation in the Western High Atlas have been evaluated based on geochemical data. According to their geochemical characteristics, the sediments of Ediacaran age (Ed-S) are ranged as shale and wacke types, while those of the Cambrian age are classified as shales (Ca-S). The Chemical Index of Alteration (CIA) varies from 43.58 to 74.59 in the Ed-S (average: 58 %), and from 65.81 to 79.22 in the Ca-S (average: 75.97 %). The Compositional Maturity Index (ICV) varies from 0.81 to 1.92 in the Ed-S (average: 1.21), and from 0.66 to 1.07 in the Ca-S (average: 0.74). The Chemical Index of Weathering (CIW) varies from 49 to 98 in the Ed-S (average: 78.71), and from 79.18 to 92.71 in the Ca-S (average: 87.73). The Plagioclase Index of Alteration (PIA) varies from 31.61 to 95.29 in the Ed-S (average: 71.05), and from 75.57 to 91.21 in the Ca-S (average: 85.31). The Al<sub>2</sub>O<sub>3</sub>–CaO + Na<sub>2</sub>O–K<sub>2</sub>O and Al<sub>2</sub>O<sub>3</sub>–CaO + Na<sub>2</sub>O–FeO<sub>T</sub> + MgO ternary diagrams indicate that the Ed-S shows an immature composition and low to moderate weathering. While the Ca-S have a mature composition, high sediment recycling and moderate weathering intensity, during a predominantly semi-arid climate. Redox indicators such as V/Cr ratios, suggest that the Ed-S were deposited under anoxic condition, as evidenced by the presence of a graphitized zone within the Ediacaran Formation in the study area, while the Ca-S were formed in an oxic condition.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"234 ","pages":"Article 105933"},"PeriodicalIF":2.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01Epub Date: 2025-11-27DOI: 10.1016/j.jafrearsci.2025.105948
Alsir A.A. Alkhaleefa , Talha M. Yousif , Musab A.A. Hassan , Khalid A. Elsayed Zeinelabdein
Talc deposits found in the southwestern Fodikwan area of northeastern Sudan exhibit potential economic significance; nevertheless, their geological context, geochemical characteristics, and genesis remain inadequately defined. This study aims to elucidate the origin and formation mechanisms of these deposits, thereby facilitating the development of more effective exploration strategies. An integrated methodology was employed, comprising detailed geological mapping, petrographic investigations, and mineralogical and geochemical assessments utilizing X-ray diffraction (XRD) and X-ray fluorescence (XRF). The study area is characterized by basement rocks comprising a volcanic-sedimentary sequence that has been metamorphosed in the greenschist facies and intruded by syn-to late-orogenic microgranodiorite. Field and petrographic observations indicate that unaltered dolomitic marble predominates in areas distant from microgranodiorite contacts. Conversely, the contact zone between dolomitic marble and microgranodiorite presents a conducive environment for talc mineralization. Geochemical analyses reveal that SiO2 and MgO are the dominant constituents, whereas CaO exhibits a decreasing trend as SiO2 increases, reflecting the metamorphism of dolomitic marble into talc. Additionally, a noteworthy depletion of Al, La, Th, Cr, Ni, and Co in talc ores is inconsistent with a mafic or ultramafic protolith. The results suggest that the silica necessary for talc formation was derived from the adjacent microgranodiorite, with dolomitic marble acting as the primary protolith. Furthermore, the presence of quartz within the dolomitic marble may have provided the necessary silica for the formation of talc. This evidence supports a genetic model of contact metasomatism and has significant implications for regional talc exploration, particularly targeting the marble-microgranodiorite contact zones.
{"title":"Talc mineralization in the SW Fodikwan area, Red Sea Hills, NE Sudan: Geological and geochemical constraints","authors":"Alsir A.A. Alkhaleefa , Talha M. Yousif , Musab A.A. Hassan , Khalid A. Elsayed Zeinelabdein","doi":"10.1016/j.jafrearsci.2025.105948","DOIUrl":"10.1016/j.jafrearsci.2025.105948","url":null,"abstract":"<div><div>Talc deposits found in the southwestern Fodikwan area of northeastern Sudan exhibit potential economic significance; nevertheless, their geological context, geochemical characteristics, and genesis remain inadequately defined. This study aims to elucidate the origin and formation mechanisms of these deposits, thereby facilitating the development of more effective exploration strategies. An integrated methodology was employed, comprising detailed geological mapping, petrographic investigations, and mineralogical and geochemical assessments utilizing X-ray diffraction (XRD) and X-ray fluorescence (XRF). The study area is characterized by basement rocks comprising a volcanic-sedimentary sequence that has been metamorphosed in the greenschist facies and intruded by syn-to late-orogenic microgranodiorite. Field and petrographic observations indicate that unaltered dolomitic marble predominates in areas distant from microgranodiorite contacts. Conversely, the contact zone between dolomitic marble and microgranodiorite presents a conducive environment for talc mineralization. Geochemical analyses reveal that SiO<sub>2</sub> and MgO are the dominant constituents, whereas CaO exhibits a decreasing trend as SiO<sub>2</sub> increases, reflecting the metamorphism of dolomitic marble into talc. Additionally, a noteworthy depletion of Al, La, Th, Cr, Ni, and Co in talc ores is inconsistent with a mafic or ultramafic protolith. The results suggest that the silica necessary for talc formation was derived from the adjacent microgranodiorite, with dolomitic marble acting as the primary protolith. Furthermore, the presence of quartz within the dolomitic marble may have provided the necessary silica for the formation of talc. This evidence supports a genetic model of contact metasomatism and has significant implications for regional talc exploration, particularly targeting the marble-microgranodiorite contact zones.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"234 ","pages":"Article 105948"},"PeriodicalIF":2.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145690725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01Epub Date: 2025-09-23DOI: 10.1016/j.jafrearsci.2025.105860
Mohamed Fathy , Hatem E. Semary , Mohamed Mosaad , Anis Ben Ghorbal , Amer A. Shehata
This study integrates seismic interpretation and 3D structural and petrophysical modeling to characterize the Pliocene siliciclastic reservoirs of the Denise Field in the offshore Eastern Nile Delta, focusing on reservoir geometry, spatial distribution, and quality assessment. Seismic interpretation reveals a complex structural framework dominated by E-W trending growth faults (F1–F6) linked to Jurassic crustal extension, alongside NNE-SSW trending Rosetta faults associated with transpressional movement. A prominent rollover anticline and gas chimneys further influence hydrocarbon migration and accumulation. Petrophysical evaluation of the Kafr El Sheikh Formation identifies three key reservoir units: Pre U. Denise S.S., U. Denise S.S., and L. Denise S.S. The U. Denise S.S. unit, the primary reservoir, exhibits high porosity (15–30 %) and variable water saturation (20–42 %), with net pay thicknesses ranging from 52 to 130 m. The L. Denise S.S. unit shows consistent high porosity (17–32 %) but higher water saturation (30–40 %), while the Pre U. Denise S.S. unit is limited in distribution, with moderate porosity (15–35 %). 3D structural modeling highlights fault-controlled horst and graben structures, with sealing faults (F2, F3, F5) potentially compartmentalizing the reservoir. Facies modeling indicates NW-SE trending sand bodies, with the U. Denise S.S. unit exhibiting the highest sand content. Petrophysical modeling reveals strong porosity-permeability correlations, with gas-bearing zones concentrated in high-porosity regions. The study identifies the northwestern channel trend as the most favorable reservoir zone, while increased shale content and water saturation degrade reservoir quality in the central basin trend. These findings provide critical insights for reservoir development and future exploration in the Denise Field. Moreover, these results underscore the critical control of seismic interpretation and reservoir modelling on reservoir distribution and quality. These methodologies and findings provide a transferable framework with broad international significance, offering essential insights for future exploration targeting in analogous settings worldwide.
{"title":"Interpretation of seismic data and 3D structural and property modeling of siliciclastic Pliocene reservoirs in the Denise Field (eastern Nile delta Offshore): Insights for reservoir architecture and assessment","authors":"Mohamed Fathy , Hatem E. Semary , Mohamed Mosaad , Anis Ben Ghorbal , Amer A. Shehata","doi":"10.1016/j.jafrearsci.2025.105860","DOIUrl":"10.1016/j.jafrearsci.2025.105860","url":null,"abstract":"<div><div>This study integrates seismic interpretation and 3D structural and petrophysical modeling to characterize the Pliocene siliciclastic reservoirs of the Denise Field in the offshore Eastern Nile Delta, focusing on reservoir geometry, spatial distribution, and quality assessment. Seismic interpretation reveals a complex structural framework dominated by E-W trending growth faults (F1–F6) linked to Jurassic crustal extension, alongside NNE-SSW trending Rosetta faults associated with transpressional movement. A prominent rollover anticline and gas chimneys further influence hydrocarbon migration and accumulation. Petrophysical evaluation of the Kafr El Sheikh Formation identifies three key reservoir units: Pre U. Denise S.S., U. Denise S.S., and L. Denise S.S. The U. Denise S.S. unit, the primary reservoir, exhibits high porosity (15–30 %) and variable water saturation (20–42 %), with net pay thicknesses ranging from 52 to 130 m. The L. Denise S.S. unit shows consistent high porosity (17–32 %) but higher water saturation (30–40 %), while the Pre U. Denise S.S. unit is limited in distribution, with moderate porosity (15–35 %). 3D structural modeling highlights fault-controlled horst and graben structures, with sealing faults (F2, F3, F5) potentially compartmentalizing the reservoir. Facies modeling indicates NW-SE trending sand bodies, with the U. Denise S.S. unit exhibiting the highest sand content. Petrophysical modeling reveals strong porosity-permeability correlations, with gas-bearing zones concentrated in high-porosity regions. The study identifies the northwestern channel trend as the most favorable reservoir zone, while increased shale content and water saturation degrade reservoir quality in the central basin trend. These findings provide critical insights for reservoir development and future exploration in the Denise Field. Moreover, these results underscore the critical control of seismic interpretation and reservoir modelling on reservoir distribution and quality. These methodologies and findings provide a transferable framework with broad international significance, offering essential insights for future exploration targeting in analogous settings worldwide.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"233 ","pages":"Article 105860"},"PeriodicalIF":2.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Rovuma Basin, situated in northern Mozambique, was formed by the rifting of the African and Madagascar tectonic plates approximately 165 million years ago. In the present study, topographic, gravity and magnetic data are utilized to comprehend the geology of the basin, recognized for its intricate geological characteristics. Initially, a 3D gravimetric inversion was conducted to develop a density-contrast model and estimate the depth of the sediment in the basin. This process involved data processing and the selection of three specific areas (RVB1, RVB2, and RVB3) for inversion. The inversion results revealed variations in density contrast and sediment thickness in these areas. Furthermore, edge detection techniques and source estimation methods were utilized to improve the identification of geological boundaries and evaluate the distribution of subsurface density sources. The analysis of magnetic data included the use of vertical derivatives, horizontal gradient, tilt derivative, analytic signal (ASTA), and Euler deconvolution, which consistently emphasized prominent NE–SW structural trends. These trends indicate the persistent impact of regional shear zones and deep-seated faults that have influenced crustal deformation within the basin. The combination of gravity, magnetic, and forward modeling data was crucial in deciphering the subsurface architecture of the study area. The relationship between gravity lows and thick sedimentary sequences, bolstered by structural modeling, underscores areas of significant crustal thinning likely governed by extensional tectonic processes. Moreover, the alignment of these gravity anomalies with low magnetic responses in sediment-filled depressions corroborates the existence of non-magnetic or weakly magnetic lithologies, which aligns with the interpreted stratigraphy. Subsequently, 2D forward modeling was carried out along three profiles (A-A′, B-B′, and C-C′) traversing these areas, which provided information about the geometric configuration of the basin and calculated the depth of the sediment. Our results show that the thickness of the Rovuma Basin varies between 4 and 6 km, potentially reaching up to 7 km, with the maximum depth observed in area RVB2 and along profile B-B’, indicating potential for hydrocarbon accumulation in this region. This highlights its importance for future investigations and exploration efforts.
{"title":"Geophysical study of the onshore Rovuma Basin in northern Mozambique using gravity and magnetic data","authors":"Onofre H.D.J. das Flores , Vinicius A.R. Oliveira , Caisse Amisse , Harini Guruhappa , Ivenso da S.V. Sualehe , Gilda A.B. Jorge","doi":"10.1016/j.jafrearsci.2025.105906","DOIUrl":"10.1016/j.jafrearsci.2025.105906","url":null,"abstract":"<div><div>The Rovuma Basin, situated in northern Mozambique, was formed by the rifting of the African and Madagascar tectonic plates approximately 165 million years ago. In the present study, topographic, gravity and magnetic data are utilized to comprehend the geology of the basin, recognized for its intricate geological characteristics. Initially, a 3D gravimetric inversion was conducted to develop a density-contrast model and estimate the depth of the sediment in the basin. This process involved data processing and the selection of three specific areas (RVB1, RVB2, and RVB3) for inversion. The inversion results revealed variations in density contrast and sediment thickness in these areas. Furthermore, edge detection techniques and source estimation methods were utilized to improve the identification of geological boundaries and evaluate the distribution of subsurface density sources. The analysis of magnetic data included the use of vertical derivatives, horizontal gradient, tilt derivative, analytic signal (ASTA), and Euler deconvolution, which consistently emphasized prominent NE–SW structural trends. These trends indicate the persistent impact of regional shear zones and deep-seated faults that have influenced crustal deformation within the basin. The combination of gravity, magnetic, and forward modeling data was crucial in deciphering the subsurface architecture of the study area. The relationship between gravity lows and thick sedimentary sequences, bolstered by structural modeling, underscores areas of significant crustal thinning likely governed by extensional tectonic processes. Moreover, the alignment of these gravity anomalies with low magnetic responses in sediment-filled depressions corroborates the existence of non-magnetic or weakly magnetic lithologies, which aligns with the interpreted stratigraphy. Subsequently, 2D forward modeling was carried out along three profiles (A-A′, B-B′, and C-C′) traversing these areas, which provided information about the geometric configuration of the basin and calculated the depth of the sediment. Our results show that the thickness of the Rovuma Basin varies between 4 and 6 km, potentially reaching up to 7 km, with the maximum depth observed in area RVB2 and along profile B-B’, indicating potential for hydrocarbon accumulation in this region. This highlights its importance for future investigations and exploration efforts.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"233 ","pages":"Article 105906"},"PeriodicalIF":2.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145416920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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