Pub Date : 2026-01-27DOI: 10.1016/j.jafrearsci.2026.106044
Effiom E. Antia
Knowledge of longevity of sediment-borne contaminants in estuaries is central to contingency planning of coastal regions worldwide. Inter-comparison of the response patterns of estuarine hydrodynamic and water quality parameters to tidal forcing at time scale of semidiurnal and lunar tidal cycle is crucial to this effort. Results of above parameters at two contiguous mesotidal estuaries (Imo River and Qua Iboe River) on the southeastern coast of Nigeria are presented based on synoptic monitoring of 50 successive semidiurnal tidal cycles. The time-series patterns of studied parameters in the estuaries showed considerable compatibility. Both estuaries displayed increased velocities (tidal peak, tidal stage-averaged and tidal cycle residual) and tidal cycle net excursion lengths with increase in tidal amplitude. Their transparency depths were shallowest at spring tides while water colour, pH and salinity were lowest at neap tides. The estuaries are prone to export sediment-borne contaminants on a long term, but at a faster rate at spring than neap tide. This is based on > 80 % frequency of ebb-asymmetric net excursion length and averaged spring to neap tide net excursion length ratios of 2.1–2.4. Of wider application is the prospect of utilizing the predictive relations on contaminant import-export drivers to rank longevity of contaminants in comparable estuaries.
{"title":"Lunar tidal cycle forcing on estuarine hydrodynamics and water quality patterns and implications for suspended sediment-borne contaminant transport: Case study of SE coast of Nigeria","authors":"Effiom E. Antia","doi":"10.1016/j.jafrearsci.2026.106044","DOIUrl":"10.1016/j.jafrearsci.2026.106044","url":null,"abstract":"<div><div>Knowledge of longevity of sediment-borne contaminants in estuaries is central to contingency planning of coastal regions worldwide. Inter-comparison of the response patterns of estuarine hydrodynamic and water quality parameters to tidal forcing at time scale of semidiurnal and lunar tidal cycle is crucial to this effort. Results of above parameters at two contiguous mesotidal estuaries (Imo River and Qua Iboe River) on the southeastern coast of Nigeria are presented based on synoptic monitoring of 50 successive semidiurnal tidal cycles. The time-series patterns of studied parameters in the estuaries showed considerable compatibility. Both estuaries displayed increased velocities (tidal peak, tidal stage-averaged and tidal cycle residual) and tidal cycle net excursion lengths with increase in tidal amplitude. Their transparency depths were shallowest at spring tides while water colour, pH and salinity were lowest at neap tides. The estuaries are prone to export sediment-borne contaminants on a long term, but at a faster rate at spring than neap tide. This is based on > 80 % frequency of ebb-asymmetric net excursion length and averaged spring to neap tide net excursion length ratios of 2.1–2.4. Of wider application is the prospect of utilizing the predictive relations on contaminant import-export drivers to rank longevity of contaminants in comparable estuaries.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"237 ","pages":"Article 106044"},"PeriodicalIF":2.2,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090368","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}
This study presents the first integrated interregional correlation of the upper Albian–lower Turonian stratigraphic record of the Aurès Basin (northeast Algeria) within a broad Tethyan–Atlantic framework, integrating lithostratigraphy, ammonite biostratigraphy, and palaeogeography based on three stratigraphically logged and sampled sections along a southwest–northeast transect. Four successive formations were identified: Grès Rouges, Taghrout Ameur Gray Marls, Zeouei, and Yabous formations, representing a continuous upper Albian to lower Turonian record. Eight ammonite biozones were identified and correlated: StoliczkaiaInterval Zone (upper Albian), Mantelliceras cf. mantelli Partial Range Zone (lower Cenomanian), Mantelliceras dixoni Interval Zone (upper-lower Cenomanian), Cunnigtoniceras inerme Interval Zone (Lower-middle Cenomanian), Acanthoceras cf. rhotomagense Interval Zone (middle Cenomanian), Acanthoceras amphibolum Total Range Zone (upper-middle Cenomanian), Neolobites vibrayeanus/Eucalycoceras pentagonum Total Range Zone (early upper Cenomanian), and Pseudaspidoceras flexuosum Interval Zone (lower Turonian). Comparative analysis of twelve biozones in Northwest Europe and nineteen in Western Interior reveals broad synchrony in zonal development, but also highlights palaeobiogeographic differentiation driven by climatic gradients, provincialism and marine barriers. The Cunningtoniceras inerme and Conlinoceras tarrantense Zones establish robust links with the Western Interior, whereas the absence of P. flexuosum in Boreal Europe marks a persistent Tethyan–Boreal faunal divide. Transgressive events and the opening of the South Atlantic broadened marine corridors along the Tethyan edge, facilitating ammonite dispersal and promoting both endemism and cosmopolitanism. The Oceanic Anoxic Event 2 (OAE2) had divergent biotic impacts, diminishing variety in Boreal Europe while preserving or enhancing it in North Africa and the Western Interior. Overall, the Aurès ammonite record demonstrates that the basin functioned as a key southern Tethyan palaeogeographic corridor, providing critical constraints for refining global ammonite biostratigraphic frameworks and understanding upper Albian-lower Turonian transcontinental marine connectivity.
{"title":"Toward a refined framework for upper Albian-lower Turonian ammonite biostratigraphy: case study from the Aurès Basin (NE Algeria), and regional correlation with Western Europe, central Tunisia, and the Western Interior Seaway","authors":"Aida Bensekhria , Mhammed Abdeldjalil , Rabah Bouhata , Meriem Khelali","doi":"10.1016/j.jafrearsci.2026.106046","DOIUrl":"10.1016/j.jafrearsci.2026.106046","url":null,"abstract":"<div><div>This study presents the first integrated interregional correlation of the upper Albian–lower Turonian stratigraphic record of the Aurès Basin (northeast Algeria) within a broad Tethyan–Atlantic framework, integrating lithostratigraphy, ammonite biostratigraphy, and palaeogeography based on three stratigraphically logged and sampled sections along a southwest–northeast transect. Four successive formations were identified: Grès Rouges, Taghrout Ameur Gray Marls, Zeouei, and Yabous formations, representing a continuous upper Albian to lower Turonian record. Eight ammonite biozones were identified and correlated: <em>Stoliczkaia</em>Interval Zone (upper Albian), <em>Mantelliceras</em> cf. <em>mantelli</em> Partial Range Zone (lower Cenomanian), <em>Mantelliceras dixoni</em> Interval Zone (upper-lower Cenomanian), <em>Cunnigtoniceras inerme</em> Interval Zone (Lower-middle Cenomanian), <em>Acanthoceras</em> cf. <em>rhotomagense</em> Interval Zone (middle Cenomanian), <em>Acanthoceras amphibolum</em> Total Range Zone (upper-middle Cenomanian), <em>Neolobites vibrayeanus/Eucalycoceras pentagonum</em> Total Range Zone (early upper Cenomanian), and <em>Pseudaspidoceras flexuosum</em> Interval Zone (lower Turonian). Comparative analysis of twelve biozones in Northwest Europe and nineteen in Western Interior reveals broad synchrony in zonal development, but also highlights palaeobiogeographic differentiation driven by climatic gradients, provincialism and marine barriers. The <em>Cunningtoniceras inerme</em> and <em>Conlinoceras tarrantense</em> Zones establish robust links with the Western Interior, whereas the absence of <em>P. flexuosum</em> in Boreal Europe marks a persistent Tethyan–Boreal faunal divide. Transgressive events and the opening of the South Atlantic broadened marine corridors along the Tethyan edge, facilitating ammonite dispersal and promoting both endemism and cosmopolitanism. The Oceanic Anoxic Event 2 (OAE2) had divergent biotic impacts, diminishing variety in Boreal Europe while preserving or enhancing it in North Africa and the Western Interior. Overall, the Aurès ammonite record demonstrates that the basin functioned as a key southern Tethyan palaeogeographic corridor, providing critical constraints for refining global ammonite biostratigraphic frameworks and understanding upper Albian-lower Turonian transcontinental marine connectivity.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"237 ","pages":"Article 106046"},"PeriodicalIF":2.2,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090369","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 : 2026-01-24DOI: 10.1016/j.jafrearsci.2026.106040
Ahmed Ismail Mahmoud , Xiaodong Ma , Shib Sankar Ganguli , Ahmed Shakkar , Ahmed M. Metwally , Walid M. Mabrouk , Mahmoud Leila
The Paleozoic reservoirs of Shifa Formation sandstones in Egypt's Western Desert are deeply buried (>3500 m) and poorly explored, with significant uncertainties concerning the controls of depositional and diagenetic attributes on their hydraulic flow properties. In this regard, we integrate geophysical, petrographical, petrophysical and machine learning results to investigate spatiotemporal evolution of different reservoir rock types (RRTs) and hydraulic flow zones. We found that eodiagenetic infiltration of clays, kaolinite cementation, and mesogenetic quartz overgrowth are the key burial modifications controlling the evolution of the pore network of the Shifa sandstones. Two sandstone microfacies were reported: quartz arenite and kaolinitic quartz arenite. Petrographic analysis demonstrates that early diagenesis significantly degraded the reservoir quality of the kaolinite-rich sandstones, while mesodiagenesis has a mild impact on the sandstones' pore system. Lithofacies analysis reveals that the lower part of the Shifa succession consists mainly of mudstones and kaolinitic quartz arenites, which exhibit lower porosity and permeability compared to quartz arenite sandstones. The stratigraphic modified Lorenz plot (SMLP) and 3D property models demonstrate that the spatial distribution of quartz arenite sandstones predominantly controls fluid flow conduits. Bayesian neural network (BNN) models demonstrated their effectiveness in estimating the permeability of the Shifa sandstones microfacies, thereby improving the predictability of the best RRTs. These findings showcase the promising potential of BNN and integrated reservoir characterization analyses for developing reliable hydrocarbon exploration strategies in the region, thereby offering economic benefits.
{"title":"Diagenesis and hydraulic flow characteristics of the Paleozoic Shifa sandstones in the western desert, Egypt: Implications for new prospective reservoir targets","authors":"Ahmed Ismail Mahmoud , Xiaodong Ma , Shib Sankar Ganguli , Ahmed Shakkar , Ahmed M. Metwally , Walid M. Mabrouk , Mahmoud Leila","doi":"10.1016/j.jafrearsci.2026.106040","DOIUrl":"10.1016/j.jafrearsci.2026.106040","url":null,"abstract":"<div><div>The Paleozoic reservoirs of Shifa Formation sandstones in Egypt's Western Desert are deeply buried (>3500 m) and poorly explored, with significant uncertainties concerning the controls of depositional and diagenetic attributes on their hydraulic flow properties. In this regard, we integrate geophysical, petrographical, petrophysical and machine learning results to investigate spatiotemporal evolution of different reservoir rock types (RRTs) and hydraulic flow zones. We found that eodiagenetic infiltration of clays, kaolinite cementation, and mesogenetic quartz overgrowth are the key burial modifications controlling the evolution of the pore network of the Shifa sandstones. Two sandstone microfacies were reported: quartz arenite and kaolinitic quartz arenite. Petrographic analysis demonstrates that early diagenesis significantly degraded the reservoir quality of the kaolinite-rich sandstones, while mesodiagenesis has a mild impact on the sandstones' pore system. Lithofacies analysis reveals that the lower part of the Shifa succession consists mainly of mudstones and kaolinitic quartz arenites, which exhibit lower porosity and permeability compared to quartz arenite sandstones. The stratigraphic modified Lorenz plot (SMLP) and 3D property models demonstrate that the spatial distribution of quartz arenite sandstones predominantly controls fluid flow conduits. Bayesian neural network (BNN) models demonstrated their effectiveness in estimating the permeability of the Shifa sandstones microfacies, thereby improving the predictability of the best RRTs. These findings showcase the promising potential of BNN and integrated reservoir characterization analyses for developing reliable hydrocarbon exploration strategies in the region, thereby offering economic benefits.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"236 ","pages":"Article 106040"},"PeriodicalIF":2.2,"publicationDate":"2026-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090711","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 : 2026-01-22DOI: 10.1016/j.jafrearsci.2026.106031
Heba S. Mubarak , Mokhles K. Azer , Adel A. Surour , Hilmy E. Moussa , Paul D. Asimow , Mona Kabesh , Faris A. Abanumay
The granitic rocks in Wadi Hangaliya, in the south Eastern Desert of Egypt, represent an offshoot of the Gebel Nugrus intrusion. They include alkali feldspar granite, syenogranite, sheared granite, and highly mineralized granite in the vicinity of the well-known Hangaliya gold mine. Geochemically, the suite has peraluminous, calc-alkaline, and highly fractionated characteristics. Whole-rock geochemical data indicate overall enrichment in rare-earth elements; light rare earth elements are enriched compared to heavy rare earth elements and there are prominent negative Eu anomalies. Heterogeneity is noted in ratios of elements that are similarly incompatible during fractionation (K/Rb, Zr/Rb and Ba/Nb). Field relations and geochemical characteristics of the granite suite are consistent with generation of parental magma in a post-collisional tectonic setting through partial melting of a juvenile igneous crustal source, followed by extensive fractional crystallization with some upper crustal contamination. Some samples are garnet-bearing, with an almandine-dominated composition often associated with magmatic garnets crystallized from I-type magma at low pressure. Two arsenic-bearing phases were found and studied in the Hangaliya gold mine samples: scorodite [FeAsO4 2H2O] and arsenosiderite [Ca2Fe3(AsO4)3O2 3H2O], which is considered to have formed by alteration of arsenopyrite and scorodite. Gold alloys were readily detected in Hangaliya gold mine samples and are characterized by variable Au contents (31–83 wt%).
{"title":"Mineral chemistry and whole-rock geochemistry of highly fractionated post-collisional granites in the Hangaliya gold mine area, Arabian-Nubian Shield, Egypt","authors":"Heba S. Mubarak , Mokhles K. Azer , Adel A. Surour , Hilmy E. Moussa , Paul D. Asimow , Mona Kabesh , Faris A. Abanumay","doi":"10.1016/j.jafrearsci.2026.106031","DOIUrl":"10.1016/j.jafrearsci.2026.106031","url":null,"abstract":"<div><div>The granitic rocks in Wadi Hangaliya, in the south Eastern Desert of Egypt, represent an offshoot of the Gebel Nugrus intrusion. They include alkali feldspar granite, syenogranite, sheared granite, and highly mineralized granite in the vicinity of the well-known Hangaliya gold mine. Geochemically, the suite has peraluminous, calc-alkaline, and highly fractionated characteristics. Whole-rock geochemical data indicate overall enrichment in rare-earth elements; light rare earth elements are enriched compared to heavy rare earth elements and there are prominent negative Eu anomalies. Heterogeneity is noted in ratios of elements that are similarly incompatible during fractionation (K/Rb, Zr/Rb and Ba/Nb). Field relations and geochemical characteristics of the granite suite are consistent with generation of parental magma in a post-collisional tectonic setting through partial melting of a juvenile igneous crustal source, followed by extensive fractional crystallization with some upper crustal contamination. Some samples are garnet-bearing, with an almandine-dominated composition often associated with magmatic garnets crystallized from I-type magma at low pressure. Two arsenic-bearing phases were found and studied in the Hangaliya gold mine samples: scorodite [FeAsO<sub>4</sub> <span><math><mrow><mo>·</mo></mrow></math></span> 2H<sub>2</sub>O] and arsenosiderite [Ca<sub>2</sub>Fe<sub>3</sub>(AsO<sub>4</sub>)<sub>3</sub>O<sub>2</sub> <span><math><mrow><mo>·</mo></mrow></math></span> 3H<sub>2</sub>O], which is considered to have formed by alteration of arsenopyrite and scorodite. Gold alloys were readily detected in Hangaliya gold mine samples and are characterized by variable Au contents (31–83 wt%).</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"236 ","pages":"Article 106031"},"PeriodicalIF":2.2,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090712","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 : 2026-01-21DOI: 10.1016/j.jafrearsci.2026.106037
Suleyman Demir
This study presents the effect of zeolite (NZ) and pumice powder (PP) on some engineering properties of an organic soil. Organic soil treated with NZ and PP separately, with 10, 20, 30, and 40 % additive ratios, was investigated with compaction, fall cone, and unconfined compression (UC) tests, and a model. The axial stress values from UC tests were fitted using a second-order polynomial response surface model (RSM). The sensitivity of the model was investigated with partial derivative plots. The findings showed that the liquid limit and optimum water content (wopt) values of organic soil decreased with both NZ and PP additions. 40 % PP and NZ improved the maximum dry density (γdmax) value of organic soil by 16 % and 7.2 %, respectively. Unconfined compressive strength (qu) value of organic soil increased by 18 %, with 40 % PP additions. 10 % NZ and PP additions increased the energy absorption capacity value of clean organic soil by 36 % and 13 %, respectively. At a given content, PP-treated organic soil exhibited a greater qu than NZ-treated organic soil. SEM photos of treated specimens showed some interparticle contacts between additives, which contributed to the strength improvement of the mixtures. The RSM revealed the coefficients of determination (R2) values of 0.93 and 0.97 for PP and NZ-treated mixtures, respectively. Sensitivity analysis showed that the stress is governed by strain at small deformation levels, while the additive content decreased the strain softening at large strain levels. Consequently, this study presents important insights into the macro and micro-mechanics of PP and NZ-stabilized organic soils.
{"title":"Geotechnical behaviour of organic soil modified with natural pumice and zeolite: Implications for sustainable use of volcanic raw materials for soil stabilization","authors":"Suleyman Demir","doi":"10.1016/j.jafrearsci.2026.106037","DOIUrl":"10.1016/j.jafrearsci.2026.106037","url":null,"abstract":"<div><div>This study presents the effect of zeolite (NZ) and pumice powder (PP) on some engineering properties of an organic soil. Organic soil treated with NZ and PP separately, with 10, 20, 30, and 40 % additive ratios, was investigated with compaction, fall cone, and unconfined compression (UC) tests, and a model. The axial stress values from UC tests were fitted using a second-order polynomial response surface model (RSM). The sensitivity of the model was investigated with partial derivative plots. The findings showed that the liquid limit and optimum water content (w<sub>opt</sub>) values of organic soil decreased with both NZ and PP additions. 40 % PP and NZ improved the maximum dry density (γ<sub>dmax</sub>) value of organic soil by 16 % and 7.2 %, respectively. Unconfined compressive strength (q<sub>u</sub>) value of organic soil increased by 18 %, with 40 % PP additions. 10 % NZ and PP additions increased the energy absorption capacity value of clean organic soil by 36 % and 13 %, respectively. At a given content, PP-treated organic soil exhibited a greater q<sub>u</sub> than NZ-treated organic soil. SEM photos of treated specimens showed some interparticle contacts between additives, which contributed to the strength improvement of the mixtures. The RSM revealed the coefficients of determination (R<sup>2</sup>) values of 0.93 and 0.97 for PP and NZ-treated mixtures, respectively. Sensitivity analysis showed that the stress is governed by strain at small deformation levels, while the additive content decreased the strain softening at large strain levels. Consequently, this study presents important insights into the macro and micro-mechanics of PP and NZ-stabilized organic soils.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"237 ","pages":"Article 106037"},"PeriodicalIF":2.2,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090428","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}
This study provides a comprehensive analysis of airborne gamma-ray spectrometry (GRS) data from the Bou Azzer–El Graara inlier in the central Anti-Atlas Mountains of Morocco. This region is geologically complex, renowned for its Pan-African suture zone and abundant cobalt, copper, and uranium mineralization. High-resolution GRS data, acquired during helicopter surveys in 1998 and 1999, were processed to map the distribution and ratios of naturally occurring radioactive elements (uranium, thorium, and potassium) and to delineate anomalous areas associated with hydrothermal alteration and mineralization. The integration of geological and remote sensing data revealed significant spatial correlations. Cobalt mineralization exhibited a high eU/K ratio, indicating the presence of uranium-rich hydrothermal fluids during cobalt deposit formation. The occurrence of copper mineralization correlates with typical eTh/K anomalies in felsic volcanic systems. Radiometric dating data also identified uranium-rich mineralization zones, primarily located within the Ediacaran volcanic rocks. Tectonic analysis revealed major fault activity controlling fluid flow and alteration patterns, thus aiding in orebody localization. Ternary K-eU-eTh maps further distinguished lithological units and alteration halos. These results highlight the value of gamma-ray spectrometry (GRS) in rapid and efficient mineral exploration, particularly in the exploration of cobalt deposits associated with uranium anomalies. The study recommends further ground-based radiometric surveys in the Bou Azzer mining area to optimize target locations and highlights the potential of uranium-focused gamma-ray spectrometry for cobalt exploration in complex Pan-African geological contexts.
{"title":"Airborne gamma-ray spectrometry survey over the Bou Azzer-El Graara Inlier (Central Anti-Atlas, Morocco): implications for mineral exploration","authors":"Fouzia Anzar , Saïd Ilmen , Mohammed Jaffal , Abderrahmane Soulaimani","doi":"10.1016/j.jafrearsci.2026.106038","DOIUrl":"10.1016/j.jafrearsci.2026.106038","url":null,"abstract":"<div><div>This study provides a comprehensive analysis of airborne gamma-ray spectrometry (GRS) data from the Bou Azzer–El Graara inlier in the central Anti-Atlas Mountains of Morocco. This region is geologically complex, renowned for its Pan-African suture zone and abundant cobalt, copper, and uranium mineralization. High-resolution GRS data, acquired during helicopter surveys in 1998 and 1999, were processed to map the distribution and ratios of naturally occurring radioactive elements (uranium, thorium, and potassium) and to delineate anomalous areas associated with hydrothermal alteration and mineralization. The integration of geological and remote sensing data revealed significant spatial correlations. Cobalt mineralization exhibited a high eU/K ratio, indicating the presence of uranium-rich hydrothermal fluids during cobalt deposit formation. The occurrence of copper mineralization correlates with typical eTh/K anomalies in felsic volcanic systems. Radiometric dating data also identified uranium-rich mineralization zones, primarily located within the Ediacaran volcanic rocks. Tectonic analysis revealed major fault activity controlling fluid flow and alteration patterns, thus aiding in orebody localization. Ternary K-eU-eTh maps further distinguished lithological units and alteration halos. These results highlight the value of gamma-ray spectrometry (GRS) in rapid and efficient mineral exploration, particularly in the exploration of cobalt deposits associated with uranium anomalies. The study recommends further ground-based radiometric surveys in the Bou Azzer mining area to optimize target locations and highlights the potential of uranium-focused gamma-ray spectrometry for cobalt exploration in complex Pan-African geological contexts.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"237 ","pages":"Article 106038"},"PeriodicalIF":2.2,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146049143","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 : 2026-01-21DOI: 10.1016/j.jafrearsci.2026.106025
Mohamed Outiskt , Soufiane Tichli , Maria Ana Baptista , Said El Moussaoui , Khadija Aboumaria
Tsunamis have historically affected the Moroccan Atlantic coast, resulting in significant human and socio-economic consequences. This study presents the first tsunami risk assessment specifically focused on the city of Agadir, a major urban and economic hub in southwestern Morocco. By simulating the 1755 Lisbon tsunami and evaluating its potential impact on Agadir, we fill a critical gap in the existing literature, which has largely overlooked this vulnerable coastal city. Agadir's dense urban fabric, thriving tourism sector, and strategic harbor make it particularly susceptible to tsunami-induced disruptions. We analyze four credible earthquake scenarios, previously identified in scientific literature as potential triggers of the 1755 event, using the NSWING (Nonlinear Shallow Water with Nested Grids) numerical simulation model. The results, visualized through high-resolution maps of maximum wave heights and inundation distances, reveal significant vulnerability, with wave heights ranging from 0.1 to 5.3 m and inundation distances reaching up to 310 m inland. These findings offer vital insight for local authorities and policymakers, providing a scientific foundation for enhancing tsunami preparedness, resilience strategies, and public awareness initiatives in Agadir.
{"title":"Predictive study of tsunami impact on the southwestern Atlantic coast of Morocco","authors":"Mohamed Outiskt , Soufiane Tichli , Maria Ana Baptista , Said El Moussaoui , Khadija Aboumaria","doi":"10.1016/j.jafrearsci.2026.106025","DOIUrl":"10.1016/j.jafrearsci.2026.106025","url":null,"abstract":"<div><div>Tsunamis have historically affected the Moroccan Atlantic coast, resulting in significant human and socio-economic consequences. This study presents the first tsunami risk assessment specifically focused on the city of Agadir, a major urban and economic hub in southwestern Morocco. By simulating the 1755 Lisbon tsunami and evaluating its potential impact on Agadir, we fill a critical gap in the existing literature, which has largely overlooked this vulnerable coastal city. Agadir's dense urban fabric, thriving tourism sector, and strategic harbor make it particularly susceptible to tsunami-induced disruptions. We analyze four credible earthquake scenarios, previously identified in scientific literature as potential triggers of the 1755 event, using the NSWING (Nonlinear Shallow Water with Nested Grids) numerical simulation model. The results, visualized through high-resolution maps of maximum wave heights and inundation distances, reveal significant vulnerability, with wave heights ranging from 0.1 to 5.3 m and inundation distances reaching up to 310 m inland. These findings offer vital insight for local authorities and policymakers, providing a scientific foundation for enhancing tsunami preparedness, resilience strategies, and public awareness initiatives in Agadir.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"236 ","pages":"Article 106025"},"PeriodicalIF":2.2,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090710","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 : 2026-01-21DOI: 10.1016/j.jafrearsci.2026.106029
Roland Asare , Raymond Webrah Kazapoe , Obed Fiifi Fynn , Samuel Dzidefo Sagoe , Joseph Turkson , Kwabina Ibrahim , Patrick Asamoah Sakyi , Frank Kwakye Nyame
This study examined groundwater hydrogeochemistry, pollution sources, and health risks in the mining-dominated Atiwa West District of Ghana using 56 borehole and well samples collected in dry and wet seasons. Electrical conductivity and total dissolved solids ranged from 67.2 to 692 μS/cm and 33.6–389 mg/L, respectively, classifying the water as fresh. Iron (mean 2.05 mg/L, wet) and manganese (mean 0.33 mg/L, wet) exceeded WHO aesthetic limits, while arsenic (max 0.006 mg/L) and mercury (max 0.002 mg/L) approached guideline values. Principal Component Analysis explained over 80 % of variance, linking carbonate weathering, redox mobilization of Fe–Mn, and sulphide oxidation as key geochemical controls, with anthropogenic contributions evident in wet-season recharge. Saturation index modeling showed persistent undersaturation of evaporite minerals (gypsum, halite, sylvite), indicating active dissolution, while carbonate minerals (calcite, aragonite, dolomite) were near equilibrium to supersaturated, reflecting their buffering role in aquifers. Water Quality Index (WQI) ranged from excellent (<25) to very poor (>200), with deteriorated quality more common near mining and agricultural zones in the wet season. HHRA results indicate that most risks remain within acceptable limits, though non-carcinogenic HI exceedances reached 3.97 percent in adults and 7.66 percent in children during the dry season, declining to 2.43 percent and 4.83 percent in the wet season. Cancer risk exceedances affected 8.02 percent of adults and 12.69 percent of children in the dry season, reducing to 5.60 percent and 9.26 percent in the wet season, with Mn and Cu as the dominant contributors to non-carcinogenic risk.
{"title":"Groundwater quality, pollution sources, and health risk assessment in a mining-dominated district: A case study from Atiwa West, Ghana","authors":"Roland Asare , Raymond Webrah Kazapoe , Obed Fiifi Fynn , Samuel Dzidefo Sagoe , Joseph Turkson , Kwabina Ibrahim , Patrick Asamoah Sakyi , Frank Kwakye Nyame","doi":"10.1016/j.jafrearsci.2026.106029","DOIUrl":"10.1016/j.jafrearsci.2026.106029","url":null,"abstract":"<div><div>This study examined groundwater hydrogeochemistry, pollution sources, and health risks in the mining-dominated Atiwa West District of Ghana using 56 borehole and well samples collected in dry and wet seasons. Electrical conductivity and total dissolved solids ranged from 67.2 to 692 μS/cm and 33.6–389 mg/L, respectively, classifying the water as fresh. Iron (mean 2.05 mg/L, wet) and manganese (mean 0.33 mg/L, wet) exceeded WHO aesthetic limits, while arsenic (max 0.006 mg/L) and mercury (max 0.002 mg/L) approached guideline values. Principal Component Analysis explained over 80 % of variance, linking carbonate weathering, redox mobilization of Fe–Mn, and sulphide oxidation as key geochemical controls, with anthropogenic contributions evident in wet-season recharge. Saturation index modeling showed persistent undersaturation of evaporite minerals (gypsum, halite, sylvite), indicating active dissolution, while carbonate minerals (calcite, aragonite, dolomite) were near equilibrium to supersaturated, reflecting their buffering role in aquifers. Water Quality Index (WQI) ranged from excellent (<25) to very poor (>200), with deteriorated quality more common near mining and agricultural zones in the wet season. HHRA results indicate that most risks remain within acceptable limits, though non-carcinogenic HI exceedances reached 3.97 percent in adults and 7.66 percent in children during the dry season, declining to 2.43 percent and 4.83 percent in the wet season. Cancer risk exceedances affected 8.02 percent of adults and 12.69 percent of children in the dry season, reducing to 5.60 percent and 9.26 percent in the wet season, with Mn and Cu as the dominant contributors to non-carcinogenic risk.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"236 ","pages":"Article 106029"},"PeriodicalIF":2.2,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146034960","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 : 2026-01-20DOI: 10.1016/j.jafrearsci.2026.106036
Mohamed A. Agamy , Mahmoud Y. Zein El Din , Mohamed M. El Nady , Walid A. Makled
This study presents a comprehensive geochemical assessment of rock samples and natural gas data to evaluate the petroleum system of the Abu El Gharadig Basin. The investigation focuses on the Upper Cretaceous Abu Roash (C –G) members and Middle Jurassic Khatatba Formation which represent the principal source rocks in the basin. Total organic carbon (TOC) and Rock-Eval pyrolysis analyses reveal significant organic richness, with TOC values reaching up to 3.14 wt%, and hydrogen index (HI) values peaking at 489 mg HC/g TOC indicative of Type II kerogen. This indicates a strong potential for liquid hydrocarbon generation. Thermal maturity parameters including Tmax (430–448 °C) and vitrinite reflectance (Ro = 0.50–0.92 %) confirm that these source rocks lie within the oil window, with deeper intervals approaching peak maturity. Geochemical characterization of natural gas from the Apollonia reservoir further supports this interpretation. The gases are gas associated with oil generation with elevated wetness and high ethane concentrations, indicating an association with condensates derived from the thermal cracking of liquid hydrocarbons. The absence of isotopic alteration suggests efficient migration and preservation. Basin modeling shows that hydrocarbon generation in the Abu El Gharadig basin began in the Early Cretaceous, with major oil-to-gas conversion occurring much later, and structural traps forming beforehand to secure these accumulations. Collectively, the results confirm a dynamic and effective petroleum system within the Abu El Gharadig Basin, with the Abu Roash and Khatatba formations as key hydrocarbon sources driving both generation and expulsion processes. Collectively, the results confirm a dynamic and effective petroleum system within the Abu El Gharadig Basin, where the Abu Roash and Khatatba formations as key hydrocarbon sources driving both generation and expulsion processes.
通过岩石样品和天然气资料的综合地球化学评价，对Abu El Gharadig盆地的含油气系统进行了评价。以上白垩统Abu Roash （C -G）段和中侏罗统Khatatba组为主要烃源岩。总有机碳（TOC）和岩石热解分析显示有机质丰度显著，TOC值高达3.14 wt%，氢指数（HI）峰值为489 mg HC/g TOC，为ⅱ型干酪根。这表明该区具有强大的生烃潜力。热成熟度参数Tmax（430 ~ 448℃）和镜质组反射率（Ro = 0.50 ~ 0.92%）证实这些烃源岩位于油窗内，层段越深，成熟度越接近峰值。来自Apollonia储层的天然气地球化学特征进一步支持了这一解释。这些气体是与产油有关的气体，具有较高的湿度和较高的乙烷浓度，表明与液态烃热裂解产生的凝析油有关。同位素变化的缺失表明了有效的迁移和保存。盆地模拟表明，Abu El Gharadig盆地的生烃始于早白垩世，主要的油气转化发生在晚得多的时间，构造圈闭的形成提前确保了这些聚集。总的来说，研究结果证实了Abu El Gharadig盆地内存在一个动态而有效的石油系统，Abu Roash和Khatatba组是驱动生排过程的关键烃源。总的来说，这些结果证实了Abu El Gharadig盆地内存在一个动态和有效的石油系统，其中Abu Roash和Khatatba组是驱动生排过程的关键烃源。
{"title":"Geochemical evidence for a thermogenic oil-associated gas petroleum system for JDT field in Abu El Gharadig basin, Egypt","authors":"Mohamed A. Agamy , Mahmoud Y. Zein El Din , Mohamed M. El Nady , Walid A. Makled","doi":"10.1016/j.jafrearsci.2026.106036","DOIUrl":"10.1016/j.jafrearsci.2026.106036","url":null,"abstract":"<div><div>This study presents a comprehensive geochemical assessment of rock samples and natural gas data to evaluate the petroleum system of the Abu El Gharadig Basin. The investigation focuses on the Upper Cretaceous Abu Roash (C –G) members and Middle Jurassic Khatatba Formation which represent the principal source rocks in the basin. Total organic carbon (TOC) and Rock-Eval pyrolysis analyses reveal significant organic richness, with TOC values reaching up to 3.14 wt%, and hydrogen index (HI) values peaking at 489 mg HC/g TOC indicative of Type II kerogen. This indicates a strong potential for liquid hydrocarbon generation. Thermal maturity parameters including Tmax (430–448 °C) and vitrinite reflectance (R<sub>o</sub> = 0.50–0.92 %) confirm that these source rocks lie within the oil window, with deeper intervals approaching peak maturity. Geochemical characterization of natural gas from the Apollonia reservoir further supports this interpretation. The gases are gas associated with oil generation with elevated wetness and high ethane concentrations, indicating an association with condensates derived from the thermal cracking of liquid hydrocarbons. The absence of isotopic alteration suggests efficient migration and preservation. Basin modeling shows that hydrocarbon generation in the Abu El Gharadig basin began in the Early Cretaceous, with major oil-to-gas conversion occurring much later, and structural traps forming beforehand to secure these accumulations. Collectively, the results confirm a dynamic and effective petroleum system within the Abu El Gharadig Basin, with the Abu Roash and Khatatba formations as key hydrocarbon sources driving both generation and expulsion processes. Collectively, the results confirm a dynamic and effective petroleum system within the Abu El Gharadig Basin, where the Abu Roash and Khatatba formations as key hydrocarbon sources driving both generation and expulsion processes.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"237 ","pages":"Article 106036"},"PeriodicalIF":2.2,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090370","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 : 2026-01-20DOI: 10.1016/j.jafrearsci.2026.106024
Jihede Haj Messaoud , Hela Fakhfakh Ben Jemai , Chokri Yaich , Hanen Kamoun , Sameh Khaled , Zied Chikhaoui
Magnetic susceptibility is recognized as a predictive tool in reservoir identification, mineral exploration, and sequence stratigraphy; however, its controlling factors in mixed carbonate–siliclastic systems remain insufficiently understood. This study aims to elucidate the primary drivers of magnetic susceptibility variability by examining carbonate and siliciclastic systems from central and northeastern Tunisia. We specifically assess the relationships between magnetic susceptibility, lithology, facies, and mineralogy, with attention to the modifying effects of diagenetic processes and the occurrence of phosphate and organic matter enrichment. Our methodological approach integrates high-resolution magnetic susceptibility measurements with detailed sedimentological logging, facies analysis, carbonate content, and mineralogical characterization. In siliciclastic-dominated systems, distal fine-grained sediments yield elevated magnetic susceptibility values due to higher concentrations of magnetic minerals. At the same time, coarser facies tend to exhibit lower or negative magnetic susceptibility values. In carbonate settings, elevated magnetic susceptibility values are typically associated with regressive phases, while reduced values are observed during transgressions. Diagenetic modifications exert a substantial impact on the magnetic susceptibility signal. Dolomitization typically reduces magnetic susceptibility by replacing magnetic-bearing carbonate mud with less magnetic dolomite crystals, diluting the original signal. Intervals with phosphate are often marked by enhanced magnetic susceptibility values, reflecting the concentration of iron-bearing phases associated with phosphate mineralization. Organic-rich layers exhibit a mixed magnetic susceptibility response: in some cases, magnetic susceptibility increases due to the formation or preservation of authigenic magnetite under reducing early diagenetic conditions, whereas in other cases, magnetic susceptibility decreases, likely reflecting the absence of magnetic mineral formation or their dissolution under highly anoxic conditions. These findings emphasize the complex interplay of factors influencing magnetic susceptibility and demonstrate its potential as a valuable tool for sequence stratigraphy and mineralogical exploration in both siliciclastic and carbonate settings.
{"title":"Magnetic susceptibility records and sequence stratigraphy in shallow-water carbonates, fluvial-deltaic, and organic / phosphatic-rich deposits: Insights from the Paleogene-Neogene of Central and NE Tunisia","authors":"Jihede Haj Messaoud , Hela Fakhfakh Ben Jemai , Chokri Yaich , Hanen Kamoun , Sameh Khaled , Zied Chikhaoui","doi":"10.1016/j.jafrearsci.2026.106024","DOIUrl":"10.1016/j.jafrearsci.2026.106024","url":null,"abstract":"<div><div>Magnetic susceptibility is recognized as a predictive tool in reservoir identification, mineral exploration, and sequence stratigraphy; however, its controlling factors in mixed carbonate–siliclastic systems remain insufficiently understood. This study aims to elucidate the primary drivers of magnetic susceptibility variability by examining carbonate and siliciclastic systems from central and northeastern Tunisia. We specifically assess the relationships between magnetic susceptibility, lithology, facies, and mineralogy, with attention to the modifying effects of diagenetic processes and the occurrence of phosphate and organic matter enrichment. Our methodological approach integrates high-resolution magnetic susceptibility measurements with detailed sedimentological logging, facies analysis, carbonate content, and mineralogical characterization. In siliciclastic-dominated systems, distal fine-grained sediments yield elevated magnetic susceptibility values due to higher concentrations of magnetic minerals. At the same time, coarser facies tend to exhibit lower or negative magnetic susceptibility values. In carbonate settings, elevated magnetic susceptibility values are typically associated with regressive phases, while reduced values are observed during transgressions. Diagenetic modifications exert a substantial impact on the magnetic susceptibility signal. Dolomitization typically reduces magnetic susceptibility by replacing magnetic-bearing carbonate mud with less magnetic dolomite crystals, diluting the original signal. Intervals with phosphate are often marked by enhanced magnetic susceptibility values, reflecting the concentration of iron-bearing phases associated with phosphate mineralization. Organic-rich layers exhibit a mixed magnetic susceptibility response: in some cases, magnetic susceptibility increases due to the formation or preservation of authigenic magnetite under reducing early diagenetic conditions, whereas in other cases, magnetic susceptibility decreases, likely reflecting the absence of magnetic mineral formation or their dissolution under highly anoxic conditions. These findings emphasize the complex interplay of factors influencing magnetic susceptibility and demonstrate its potential as a valuable tool for sequence stratigraphy and mineralogical exploration in both siliciclastic and carbonate settings.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"237 ","pages":"Article 106024"},"PeriodicalIF":2.2,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090513","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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