Pub Date : 2024-11-06DOI: 10.1016/j.jafrearsci.2024.105464
Mona Hamada , Hanan Gaber , Mohamed Saleh , Hazem Badreldin , Shimaa H. ElKhouly , Amr El-Sharkawy , Abdelbaset M. Abudeif , Essam A. Mohamed , Hatem S. Ramadan
The geodynamic evolution of the Sinai Triple Junction, a highly deformed and seismically active area, is controlled by the Red Sea rift, Gulf of Suez and Aqaba-Dead Sea conjunctions. However, the driving forces for the focusing deformation at crustal depths beneath this area are still ambiguous. Here, we provide an updated seismotectonic map of the area relying on updated seismological and geodetic datasets. A homogenized earthquake catalog has been compiled from well-located earthquakes (> Mw 2.0) by the Egyptian Seismic Network and International Seismological Center in the period between 1990 and 2020. We calculated the average b-value along three seismogenic zones including Gulf of Aqaba, northern Red Sea and Gulf of Suez that amount to 1.1, 0.99 and 0.97, respectively. Additionally, we complied and updated a comprehensive P-wave-based database for the fault plane solutions in the area for events with Mw > 3.5 till 2023. Furthermore, a unified velocity field for the region as well as slip-rate and locking-depth at the active fault segments were estimated from a consistent geodetic dataset from peer-reviewed GPS velocities between 1999 and 2018. Results indicate a dominant NNE left-lateral strike-slip fault with normal component along the Gulf of Aqaba. Pure NW-SE to WNW-ESE dip-slip normal faulting, associated with a strike-slip component in some cases, is dominating the northern and central parts of the Gulf of Suez, whereas pure normal dip-slip movement with an NNE–SSW extension in a horizontal direction is observed in the southern part of the gulf. The estimated slip-rate and locking-depths at the Aqaba fault segments falls between 4.8 and 4.9 mm/yr and 8–12 km, respectively.
{"title":"Seismotectonic map of the Sinai Triple Junction","authors":"Mona Hamada , Hanan Gaber , Mohamed Saleh , Hazem Badreldin , Shimaa H. ElKhouly , Amr El-Sharkawy , Abdelbaset M. Abudeif , Essam A. Mohamed , Hatem S. Ramadan","doi":"10.1016/j.jafrearsci.2024.105464","DOIUrl":"10.1016/j.jafrearsci.2024.105464","url":null,"abstract":"<div><div>The geodynamic evolution of the Sinai Triple Junction, a highly deformed and seismically active area, is controlled by the Red Sea rift, Gulf of Suez and Aqaba-Dead Sea conjunctions. However, the driving forces for the focusing deformation at crustal depths beneath this area are still ambiguous. Here, we provide an updated seismotectonic map of the area relying on updated seismological and geodetic datasets. A homogenized earthquake catalog has been compiled from well-located earthquakes (> Mw 2.0) by the Egyptian Seismic Network and International Seismological Center in the period between 1990 and 2020. We calculated the average b-value along three seismogenic zones including Gulf of Aqaba, northern Red Sea and Gulf of Suez that amount to 1.1, 0.99 and 0.97, respectively. Additionally, we complied and updated a comprehensive P-wave-based database for the fault plane solutions in the area for events with Mw > 3.5 till 2023. Furthermore, a unified velocity field for the region as well as slip-rate and locking-depth at the active fault segments were estimated from a consistent geodetic dataset from peer-reviewed GPS velocities between 1999 and 2018. Results indicate a dominant NNE left-lateral strike-slip fault with normal component along the Gulf of Aqaba. Pure NW-SE to WNW-ESE dip-slip normal faulting, associated with a strike-slip component in some cases, is dominating the northern and central parts of the Gulf of Suez, whereas pure normal dip-slip movement with an NNE–SSW extension in a horizontal direction is observed in the southern part of the gulf. The estimated slip-rate and locking-depths at the Aqaba fault segments falls between 4.8 and 4.9 mm/yr and 8–12 km, respectively.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"221 ","pages":"Article 105464"},"PeriodicalIF":2.2,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651971","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}
To gain an understanding of the tectono-metamorphic evolution of the Congo Craton in the southern Cameroonian Ntem Complex, alluvial rutile EPMA geochemistry and LA-ICP-MS U-Pb geochronology were carried out, and for the first time, robust rutile ages are obtained in that section of the Congo Craton. Concentrations of Nb vary from 287 to 7074 ppm and those of Zr and Cr from 7 to 592 ppm, and from 75 to 5836 ppm, respectively. These data suggest Minto alluvial rutile was sourced from mainly metapelitic and accessorily metamafic rocks. The Zr-in-rutile thermometer indicates a range of temperatures between 430 and 720 °C, with an average temperature of 613 °C. This suggests that the alluvial rutile rock sources were formed under conditions of amphibolite facies metamorphism. Five alluvial rutile grains yield overlapping and concordant ages of 1974 ± 8.8 Ma, 1987 ± 13 Ma, 1992.2 ± 8.4 Ma, 1989.1 ± 8.3 Ma, 1985.1 ± 12.1 Ma, respectively. These results are all consistent with a single Paleoproterozoic metamorphic growth event. The rutile ages suggest that Minto, in the southern part of the Ntem Complex, was subjected to Eburnean thermal rejuvenation. Therefore, our findings extend the timing and location of the Eburnean overprint in the Cameroonian Congo Craton portion beyond the previously recognised spatiotemporal window.
{"title":"Rutile U-Pb ages and implications for the extension of the timing of the Eburnean overprint in the Ntem Complex (southern Cameroon) portion of the Congo Craton","authors":"Nzesseu Nandjou Valentino , Bineli Betsi Thierry , Belinga Belinga Cédric , Ekomane Emile , Kelepile Tebogo","doi":"10.1016/j.jafrearsci.2024.105459","DOIUrl":"10.1016/j.jafrearsci.2024.105459","url":null,"abstract":"<div><div>To gain an understanding of the tectono-metamorphic evolution of the Congo Craton in the southern Cameroonian Ntem Complex, alluvial rutile EPMA geochemistry and LA-ICP-MS U-Pb geochronology were carried out, and for the first time, robust rutile ages are obtained in that section of the Congo Craton. Concentrations of Nb vary from 287 to 7074 ppm and those of Zr and Cr from 7 to 592 ppm, and from 75 to 5836 ppm, respectively. These data suggest Minto alluvial rutile was sourced from mainly metapelitic and accessorily metamafic rocks. The Zr-in-rutile thermometer indicates a range of temperatures between 430 and 720 °C, with an average temperature of 613 °C. This suggests that the alluvial rutile rock sources were formed under conditions of amphibolite facies metamorphism. Five alluvial rutile grains yield overlapping and concordant ages of 1974 ± 8.8 Ma, 1987 ± 13 Ma, 1992.2 ± 8.4 Ma, 1989.1 ± 8.3 Ma, 1985.1 ± 12.1 Ma, respectively. These results are all consistent with a single Paleoproterozoic metamorphic growth event. The rutile ages suggest that Minto, in the southern part of the Ntem Complex, was subjected to Eburnean thermal rejuvenation. Therefore, our findings extend the timing and location of the Eburnean overprint in the Cameroonian Congo Craton portion beyond the previously recognised spatiotemporal window.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"221 ","pages":"Article 105459"},"PeriodicalIF":2.2,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651407","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 investigates potential groundwater contamination near a waste disposal site in southwestern Nigeria. The area's complex geological setting, characterized by fractured rock formations, posed significant challenges for traditional monitoring methods. To address these challenges and comprehensively assess groundwater conditions, we employed a combined approach utilizing Electrical Resistivity Tomography (ERT), Ground Penetrating Radar (GPR), and geochemical analysis of heavy metals and water conductivity. This approach enabled the investigation of groundwater levels, identification of potential contamination zones, and delineation of contaminant flow paths. GPR identified a shallow zone, termed the “shadow zone,” with conductive residues indicating contaminants with anomalous conductivity ranging from 1 to 1.5 m. An intermittent reflection zone at a depth of 1.5–3.5 m suggested the potential presence of leachate-impacted groundwater. ERT confirmed a shallow resistive layer at depths of 0–2 m, attributed to compacted waste and topsoil, around the abandoned main dumpsite. Below this layer, a zone of low resistivity, decreasing downward through a porous weathered zone, was observed. This corresponded to high water conductivity in well data, ranging from 21 to 147 mS/m (equivalent to 6.80 to 47.62 Ω-m), indicating a high conductive anomaly suspected to be a leachate plume at depths of 2–10 m in a sandy-gravelly weathered zone. Validation against ground truth data confirmed the correlation between radar signatures, geoelectrical imaging, and subsurface lithology. Analysis of well and soil samples revealed concerningly elevated concentrations of cadmium, mercury, lead, arsenic, and cobalt, ranging from 641 to 1175 ppb, exceeding established safety limits for drinking water. Additionally, soil samples showed elevated levels of nickel and chromium, generally ranging from <0 to <1 ppb. These findings highlight the significant risk of groundwater contamination due to the proximity of the leachate zone to the groundwater table in the weathered basement complex. This study demonstrates the effective integration of geophysical and geochemical methods for comprehensive mapping of contaminated zones and identification of preferential pathways for contaminant migration. The findings underscore the critical need for implementing comprehensive risk assessment methodologies in similar complex geological settings.
{"title":"Characterizing groundwater contamination flow-paths and heavy metal mobilization near a waste site in Southwestern Nigeria","authors":"AbdulGaniyu Isah , Etido Nsukhoridem Bassey , Olukole Adedeji Akinbiyi , Rasaq Adebayo Azeez , Andrew Sunday Oji , Tijjani El-Badawy","doi":"10.1016/j.jafrearsci.2024.105460","DOIUrl":"10.1016/j.jafrearsci.2024.105460","url":null,"abstract":"<div><div>This study investigates potential groundwater contamination near a waste disposal site in southwestern Nigeria. The area's complex geological setting, characterized by fractured rock formations, posed significant challenges for traditional monitoring methods. To address these challenges and comprehensively assess groundwater conditions, we employed a combined approach utilizing Electrical Resistivity Tomography (ERT), Ground Penetrating Radar (GPR), and geochemical analysis of heavy metals and water conductivity. This approach enabled the investigation of groundwater levels, identification of potential contamination zones, and delineation of contaminant flow paths. GPR identified a shallow zone, termed the “shadow zone,” with conductive residues indicating contaminants with anomalous conductivity ranging from 1 to 1.5 m. An intermittent reflection zone at a depth of 1.5–3.5 m suggested the potential presence of leachate-impacted groundwater. ERT confirmed a shallow resistive layer at depths of 0–2 m, attributed to compacted waste and topsoil, around the abandoned main dumpsite. Below this layer, a zone of low resistivity, decreasing downward through a porous weathered zone, was observed. This corresponded to high water conductivity in well data, ranging from 21 to 147 mS/m (equivalent to 6.80 to 47.62 Ω-m), indicating a high conductive anomaly suspected to be a leachate plume at depths of 2–10 m in a sandy-gravelly weathered zone. Validation against ground truth data confirmed the correlation between radar signatures, geoelectrical imaging, and subsurface lithology. Analysis of well and soil samples revealed concerningly elevated concentrations of cadmium, mercury, lead, arsenic, and cobalt, ranging from 641 to 1175 ppb, exceeding established safety limits for drinking water. Additionally, soil samples showed elevated levels of nickel and chromium, generally ranging from <0 to <1 ppb. These findings highlight the significant risk of groundwater contamination due to the proximity of the leachate zone to the groundwater table in the weathered basement complex. This study demonstrates the effective integration of geophysical and geochemical methods for comprehensive mapping of contaminated zones and identification of preferential pathways for contaminant migration. The findings underscore the critical need for implementing comprehensive risk assessment methodologies in similar complex geological settings.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"221 ","pages":"Article 105460"},"PeriodicalIF":2.2,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142592615","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 : 2024-10-29DOI: 10.1016/j.jafrearsci.2024.105462
Mohammed Nadir Naimi , Ahmed Zeghari , Chikh Younes Mahboubi
Bioerosive trace fossils at the Guessiba Valley (Arzew Mountains) document an ancient Tortonian shoreline cut into Barremian calcschists at the lowermost part of the Tortonian Balanid Marl Formation. Four ichnogenera produced by endolithic bivalves (Gastrochaenolites) and polychaete annelids (Caulostrepsis, Maeandropolydora, Trypanites) have been identified. The four traces consist of dwelling structures (domichnia). The encrusting epifauna on the rockground include acorn barnacles of the genus Balanus and scarce, poorly preserved bivalves. These epibionts exhibit Trypanites and Entobia, respectively. This ichnoassociation identifies the Entobia ichnosubfacies as part of the Trypanites ichnofacies. The fossil rocky shore described in this paper is related to a transgression that occurred during the Tortonian, characterising a stratigraphic surface corresponding to a sequence boundary. The Guessiba Valley succession marks the first Mediterranean marine transgression affecting the southern flank of the Arzew Mountains, characterised by three distinct phases. The calcschists reported here are among the rare examples of non-carbonate rocky substrates colonised by endolithic boring organisms.
{"title":"Miocene bioerosion in a Cretaceous metamorphic basement from the Arzew Mountains (Oran, northwestern Algeria): First evidence of a Tortonian rocky shore in the southwestern Mediterranean area","authors":"Mohammed Nadir Naimi , Ahmed Zeghari , Chikh Younes Mahboubi","doi":"10.1016/j.jafrearsci.2024.105462","DOIUrl":"10.1016/j.jafrearsci.2024.105462","url":null,"abstract":"<div><div>Bioerosive trace fossils at the Guessiba Valley (Arzew Mountains) document an ancient Tortonian shoreline cut into Barremian calcschists at the lowermost part of the Tortonian Balanid Marl Formation. Four ichnogenera produced by endolithic bivalves (<em>Gastrochaenolites</em>) and polychaete annelids (<em>Caulostrepsis</em>, <em>Maeandropolydora</em>, <em>Trypanites</em>) have been identified. The four traces consist of dwelling structures (domichnia). The encrusting epifauna on the rockground include acorn barnacles of the genus <em>Balanus</em> and scarce, poorly preserved bivalves. These epibionts exhibit <em>Trypanites</em> and <em>Entobia</em>, respectively. This ichnoassociation identifies the <em>Entobia</em> ichnosubfacies as part of the <em>Trypanites</em> ichnofacies. The fossil rocky shore described in this paper is related to a transgression that occurred during the Tortonian, characterising a stratigraphic surface corresponding to a sequence boundary. The Guessiba Valley succession marks the first Mediterranean marine transgression affecting the southern flank of the Arzew Mountains, characterised by three distinct phases. The calcschists reported here are among the rare examples of non-carbonate rocky substrates colonised by endolithic boring organisms.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"220 ","pages":"Article 105462"},"PeriodicalIF":2.2,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572190","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 : 2024-10-26DOI: 10.1016/j.jafrearsci.2024.105458
Paulo Fernandes , Raul C.G.S. Jorge , Luís Albardeiro , David Chew , Foteini Drakou , Zélia Pereira , João Marques
Detrital zircon U-Pb geochronology of the Moatize and N'Condédzi coalfields in the Zambezi Karoo Basin of Mozambique provides key insights into the regional provenance, sediment dispersal pathways and basin evolution. Borehole cores from the two coalfields reveal a stratigraphy spanning the early Roadian (middle Permian) to the Carnian (Upper Triassic). The Permian sandstones of the Moatize Coalfield (MC) yield three detrital zircon populations, with ages ranging from 1150 to 950 Ma, 900–780 Ma and 650–490 Ma. In contrast, the Permian sandstones of the N'Condédzi Coalfield (NC) have only one population, which ranges from 1150 to 950 Ma. During the Permian, the provenance area for the NC was the Tete-Chipata Terrane and Malawi Complex (1150–950 Ma) to the north-northeast. In the MC, the detrital zircon populations of the early lake delta depositional setting (Roadian to Wordian) indicate a main provenance in the Zambezi Belt (900–780 Ma) located to the south of the MC, with minor sourcing from the Nampula Block (1150–950 Ma and 650–490 Ma) to the east. The transition from a lake delta to an alluvial depositional setting is attributed to a major tectonic event in the MC, which involved the formation of a braided channel belt. Sandstones from this braided channel belt yield three detrital zircons populations (650–490 Ma, 900–780 Ma and 1150–950 Ma), indicating provenance from both the Zambezi Belt and the Nampula Block. The overlying sandstones in the MC show only a minor population from the Zambezi Belt (900–780 Ma), implying a shift in provenance to the Nampula Block that was likely induced by tectonics. The absence of detrital zircon populations of 900–780 Ma and 650–490 in the Permian sandstones of NC implies that the two coalfields were not connected during the mid to late Permian. It is likely that an intra-rift horst (the Mesoproterozoic Gabbro-Anorthosite Tete Suite) separated the two coalfields. The Lower Triassic sandstones of the NC yield a main detrital zircon population indicating provenance from the Tete-Chipata Terrane and Malawi Complex (1150–950 Ma). A minor population at 650–490 Ma is linked to increased aridity at the Permian – Triassic boundary, which caused expansion of the watershed across the Tete-Chipata Terrane and the Malawi Complex. The Upper Triassic sandstones in the NC yield a 1150–950 Ma detrital zircon population, indicating provenance from the Tete-Chipata Terrane and Malawi Complex and a return to the source-to-sink conditions seen in the mid to late Permian.
莫桑比克赞比西河卡鲁盆地 Moatize 和 N'Condédzi 煤田的碎屑锆石 U-Pb 地质年代学提供了有关区域来源、沉积物扩散途径和盆地演化的重要信息。这两个煤田的钻孔岩心揭示的地层跨越了早期路德安（中二叠统）至卡尼安（上三叠统）。Moatize煤田（MC）的二叠纪砂岩产生了三个锆英石碎片群，年龄分别为1150-950Ma、900-780Ma和650-490Ma。相比之下，N'Condédzi 煤田（NC）的二叠纪砂岩只有一个族群，年龄在 1150 至 950 Ma 之间。在二叠纪期间，NC 的产地是东北偏北的 Tete-Chipata Terrane 和马拉维复合体（1150-950 Ma）。在MC地区，早期湖泊三角洲沉积环境（Roadian至Wordian）的锆英石碎片群表明，其主要产地位于MC南部的赞比西河带（900-780 Ma），东部的楠普拉区块（1150-950 Ma和650-490 Ma）是其次要产地。从湖泊三角洲到冲积沉积环境的转变归因于管委会的一次重大构造事件，其中涉及辫状河道带的形成。来自该辫状河道带的砂岩产生了三个碎片锆石群（650-490 Ma、900-780 Ma 和 1150-950 Ma），表明其来源于赞比西河带和楠普拉区块。MC上覆砂岩仅有少量来自赞比西河带（900-780 Ma）的锆石，这意味着其产地可能因构造作用而转移到了楠普拉地块。在 NC 的二叠纪砂岩中没有 900-780 Ma 和 650-490 Ma 的碎屑锆石群，这意味着这两个煤田在二叠纪中晚期并不相连。很可能是一个裂谷内的地角（中新生代加布罗-正长岩泰特组）将两个煤田分隔开来。北卡罗来纳州的下三叠统砂岩产生了一个主要的锆英石碎片群，表明其来源于泰特-奇帕塔地层和马拉维复合体（1150-950 Ma）。650-490Ma的少量锆石与二叠纪-三叠纪交界处干旱加剧有关，干旱加剧导致了Tete-Chipata Terrane和马拉维复合体流域的扩展。北卡罗来纳州的上三叠世砂岩产生了 1150-950 Ma 的锆石碎片群，表明其来源于 Tete-Chipata Terrane 和马拉维复合体，并恢复了二叠纪中晚期的源-汇条件。
{"title":"Detrital zircon U-Pb geochronology of the Moatize and N'Condédzi coalfields, Zambezi Karoo Basin of Mozambique: Implications for provenance, sediment dispersal and basin evolution","authors":"Paulo Fernandes , Raul C.G.S. Jorge , Luís Albardeiro , David Chew , Foteini Drakou , Zélia Pereira , João Marques","doi":"10.1016/j.jafrearsci.2024.105458","DOIUrl":"10.1016/j.jafrearsci.2024.105458","url":null,"abstract":"<div><div>Detrital zircon U-Pb geochronology of the Moatize and N'Condédzi coalfields in the Zambezi Karoo Basin of Mozambique provides key insights into the regional provenance, sediment dispersal pathways and basin evolution. Borehole cores from the two coalfields reveal a stratigraphy spanning the early Roadian (middle Permian) to the Carnian (Upper Triassic). The Permian sandstones of the Moatize Coalfield (MC) yield three detrital zircon populations, with ages ranging from 1150 to 950 Ma, 900–780 Ma and 650–490 Ma. In contrast, the Permian sandstones of the N'Condédzi Coalfield (NC) have only one population, which ranges from 1150 to 950 Ma. During the Permian, the provenance area for the NC was the Tete-Chipata Terrane and Malawi Complex (1150–950 Ma) to the north-northeast. In the MC, the detrital zircon populations of the early lake delta depositional setting (Roadian to Wordian) indicate a main provenance in the Zambezi Belt (900–780 Ma) located to the south of the MC, with minor sourcing from the Nampula Block (1150–950 Ma and 650–490 Ma) to the east. The transition from a lake delta to an alluvial depositional setting is attributed to a major tectonic event in the MC, which involved the formation of a braided channel belt. Sandstones from this braided channel belt yield three detrital zircons populations (650–490 Ma, 900–780 Ma and 1150–950 Ma), indicating provenance from both the Zambezi Belt and the Nampula Block. The overlying sandstones in the MC show only a minor population from the Zambezi Belt (900–780 Ma), implying a shift in provenance to the Nampula Block that was likely induced by tectonics. The absence of detrital zircon populations of 900–780 Ma and 650–490 in the Permian sandstones of NC implies that the two coalfields were not connected during the mid to late Permian. It is likely that an intra-rift horst (the Mesoproterozoic Gabbro-Anorthosite Tete Suite) separated the two coalfields. The Lower Triassic sandstones of the NC yield a main detrital zircon population indicating provenance from the Tete-Chipata Terrane and Malawi Complex (1150–950 Ma). A minor population at 650–490 Ma is linked to increased aridity at the Permian – Triassic boundary, which caused expansion of the watershed across the Tete-Chipata Terrane and the Malawi Complex. The Upper Triassic sandstones in the NC yield a 1150–950 Ma detrital zircon population, indicating provenance from the Tete-Chipata Terrane and Malawi Complex and a return to the source-to-sink conditions seen in the mid to late Permian.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"220 ","pages":"Article 105458"},"PeriodicalIF":2.2,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-26DOI: 10.1016/j.jafrearsci.2024.105461
Mario Iglesias-Martínez , Francisco J. Alcalá , Marina Rull
In western African cratonic regions, fractured crystalline bedrock, Neoproterozoic sedimentary covers, and regolith deposits constitute the most productive aquifer systems. Structural lineaments derived from remote sensing data and weathered cover thickness from borehole interpretations provide cost-effective methods for evaluating well productivity in regions with limited economic resources and hydrogeological knowledge, such as Houet province in Western Burkina Faso. Structural lineaments were interpreted using 1:200,000 Landsat TM images and 1:50,000 aerial photographs, revealing NE and NW as the most significant directions. An analysis of 101 borehole stratigraphic profiles from rural water supply program reports revealed the weathering depth and cover thickness. Borehole productivity exhibited a strong correlation with increased weathered cover thickness. Negative well results were concentrated in areas with less than 5 m of cover. In contrast, significant differences in specific yield rates were observed with greater thicknesses, ranging from 2.5 m³/d for 20 m of saturated thickness to 7.6 m³/d when the regolith reached a depth of 40 m. These preliminary groundwater exploration tools effectively target successful well sites by accounting for differing lithologies, regional tectonics, and regolith development. This approach is particularly relevant for cratonic regions with limited resources and hydrogeological knowledge, aiding in sustainable groundwater development and land-use planning.
{"title":"Predicting well productivity in cratonic regions using remote sensing lineaments and weathered cover thickness: A case study from Bobo Dioulasso, Burkina Faso","authors":"Mario Iglesias-Martínez , Francisco J. Alcalá , Marina Rull","doi":"10.1016/j.jafrearsci.2024.105461","DOIUrl":"10.1016/j.jafrearsci.2024.105461","url":null,"abstract":"<div><div>In western African cratonic regions, fractured crystalline bedrock, Neoproterozoic sedimentary covers, and regolith deposits constitute the most productive aquifer systems. Structural lineaments derived from remote sensing data and weathered cover thickness from borehole interpretations provide cost-effective methods for evaluating well productivity in regions with limited economic resources and hydrogeological knowledge, such as Houet province in Western Burkina Faso. Structural lineaments were interpreted using 1:200,000 Landsat TM images and 1:50,000 aerial photographs, revealing NE and NW as the most significant directions. An analysis of 101 borehole stratigraphic profiles from rural water supply program reports revealed the weathering depth and cover thickness. Borehole productivity exhibited a strong correlation with increased weathered cover thickness. Negative well results were concentrated in areas with less than 5 m of cover. In contrast, significant differences in specific yield rates were observed with greater thicknesses, ranging from 2.5 m³/d for 20 m of saturated thickness to 7.6 m³/d when the regolith reached a depth of 40 m. These preliminary groundwater exploration tools effectively target successful well sites by accounting for differing lithologies, regional tectonics, and regolith development. This approach is particularly relevant for cratonic regions with limited resources and hydrogeological knowledge, aiding in sustainable groundwater development and land-use planning.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"220 ","pages":"Article 105461"},"PeriodicalIF":2.2,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142539500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-23DOI: 10.1016/j.jafrearsci.2024.105450
Muneer Abdalla, Salah Hassan, Akram Zafir, Abdlsaid Ibrahem, Ahmad Issa
{"title":"Corrigendum to “Sequence stratigraphic architecture and depositional evolution of the early Eocene-early Miocene Al Jabal Al Akhdar carbonate successions, N Cyrenaica Promontory, NE Libya – Interplay of tectonics and eustasy” [J. Afr. Earth Sci. 220 (2024) 1–24 105438]","authors":"Muneer Abdalla, Salah Hassan, Akram Zafir, Abdlsaid Ibrahem, Ahmad Issa","doi":"10.1016/j.jafrearsci.2024.105450","DOIUrl":"10.1016/j.jafrearsci.2024.105450","url":null,"abstract":"","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"220 ","pages":"Article 105450"},"PeriodicalIF":2.2,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660297","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 Azzel-Matti circular structure (25°51′ N, 0°35’ E) is located on the Tanezrouft plateau at the boundary between the West African Craton and the Bled El Mass compartment. Its morphology exhibits a diameter of about 6.5 km, with a raised rim that stands above the surrounding terrain. This study is based on a combination of remote sensing data (Landsat-8-OLI images and Shuttle Radar Topography Mission (SRTM) images), aeromagnetic and seismic data, and field investigations in and around the Azzel-Matti circular structure to analyze its morphology and ascertain its origin. The investigation of the area surrounding the structure did not reveal any evidence of magmatism, diapirism or impact. However, it did confirm the presence of new faults of a deeper character, as highlighted by remote sensing, aeromagnetic, and seismic analysis. This suggests that tectonic deformation is a probable factor contributing to the formation of this circular structure. The morphology of the structure is explained by the counter-clockwise rotation of the strata, likely resulting from the interplay between movements along the sub-meridian faults marking the eastern and western boundaries and the ESE-WNW oblique reverse fault marking the northern boundary. These faults are coherently arranged to facilitate the counter-clockwise rotation of the strata. The movement of the faults and their depth indicate an NE-SW compressional event corresponding to the Late Paleozoic Variscan (Hercynian) orogeny. This is supported by the presence of horizontal lacustrine carbonate formations, presumably of Jurassic age, which are discordant with the Carboniferous strata, thus providing evidence for the age of the Azzel-Matti circular structure between the Moscovian and the Jurassic.
{"title":"On the origin of the Azzel-Matti circular structure (southern Algeria): Insights from remote sensing, geological and geophysical data","authors":"Mohamed Hassani , Moulley Charaf Chabou , Hamid Haddoum , Mohamed Hamoudi , Saci Kermani , Mohamed Said Guettouche , Sofiane Bellabiod","doi":"10.1016/j.jafrearsci.2024.105457","DOIUrl":"10.1016/j.jafrearsci.2024.105457","url":null,"abstract":"<div><div>The Azzel-Matti circular structure (25°51′ N, 0°35’ E) is located on the Tanezrouft plateau at the boundary between the West African Craton and the Bled El Mass compartment. Its morphology exhibits a diameter of about 6.5 km, with a raised rim that stands above the surrounding terrain. This study is based on a combination of remote sensing data (Landsat-8-OLI images and Shuttle Radar Topography Mission (SRTM) images), aeromagnetic and seismic data, and field investigations in and around the Azzel-Matti circular structure to analyze its morphology and ascertain its origin. The investigation of the area surrounding the structure did not reveal any evidence of magmatism, diapirism or impact. However, it did confirm the presence of new faults of a deeper character, as highlighted by remote sensing, aeromagnetic, and seismic analysis. This suggests that tectonic deformation is a probable factor contributing to the formation of this circular structure. The morphology of the structure is explained by the counter-clockwise rotation of the strata, likely resulting from the interplay between movements along the sub-meridian faults marking the eastern and western boundaries and the ESE-WNW oblique reverse fault marking the northern boundary. These faults are coherently arranged to facilitate the counter-clockwise rotation of the strata. The movement of the faults and their depth indicate an NE-SW compressional event corresponding to the Late Paleozoic Variscan (Hercynian) orogeny. This is supported by the presence of horizontal lacustrine carbonate formations, presumably of Jurassic age, which are discordant with the Carboniferous strata, thus providing evidence for the age of the Azzel-Matti circular structure between the Moscovian and the Jurassic.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"220 ","pages":"Article 105457"},"PeriodicalIF":2.2,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532554","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 : 2024-10-19DOI: 10.1016/j.jafrearsci.2024.105456
Sherif Mansour , Noriko Hasebe , Akihiro Tamura , Kamal Abdelrahman , Mohammed S. Fnais , Mohamed A. Gharib , Mohamed Zaki Khedr
The ophiolitic mélange and granitic intrusions along the Qift‒Quseir transect in the Central Eastern Desert (CED) of Egypt are parts of the Egyptian Nubian Shield (ENS), which is the northern segment of the East African Orogeny (EAO). The Arabian-Nubian Shield (ANS) is the longest Neoproterozoic belt on Earth, and it was formed during the East and West Gondwanaland collisions within the framework of the EAO. The ANS basement rocks were developed during three distinct phases of magmatic activity: the island arc and syn-collisional phases, identifying a compressional tectonic regime, and a post-collisional phase that identifies changing the tectonic regime into an extensional type. The geochronological assessment of these magmatic activities is essential for understanding the regional geology and tectonic development of the ANS. In our study, we dated different rock units along the Qift‒Quseir transect and revealed ages ranging from the Late Tonian (820 ± 8 Ma) to the Late Ediacaran (563 ± 4 Ma). These ages were associated with three different magmatic pulses: (1) a seafloor spreading and island arc phase (ophiolite and related rocks), represented by sample QQ05, which was dated from 820 ± 8 Ma; (2) a syn-collisional phase, represented by samples QQ08 and QQ10, dated from 733 ± 10 Ma and 729 ± 10 Ma, respectively; and (3) a post-collisional phase, represented by all the other samples, dated from the Ediacaran at 603 ± 9 Ma to 563 ± 5 Ma. These results showed that the post-collisional phase was dominant, especially in terms of the alkali-feldspar granites, relative to ophiolitic rocks, and the syn-collisional granites in the CED. Initiation of the Dokhan Volcanic eruptions at 639 ± 2 Ma gave us the date of the compressional-to-extensional tectonic transition setting, and the post-collisional tensional regime was activated at 603 ± 9 Ma. Additionally, we identified evidence of local magmatic sources by dating 11 grains of Paleo-to Meso-Proterozoic xenocrysts with ages ranging from 1876 ± 18 to 1070 ± 13 Ma (i.e., components of the pre-Arabian-Nubian Shield).
{"title":"Geochronological assessment of the Arabian-Nubian Shield plutonic intrusions in the arc assemblages along the Qift-Quseir transect, Central Eastern Desert of Egypt","authors":"Sherif Mansour , Noriko Hasebe , Akihiro Tamura , Kamal Abdelrahman , Mohammed S. Fnais , Mohamed A. Gharib , Mohamed Zaki Khedr","doi":"10.1016/j.jafrearsci.2024.105456","DOIUrl":"10.1016/j.jafrearsci.2024.105456","url":null,"abstract":"<div><div>The ophiolitic mélange and granitic intrusions along the Qift<strong>‒</strong>Quseir transect in the Central Eastern Desert (CED) of Egypt are parts of the Egyptian Nubian Shield (ENS), which is the northern segment of the East African Orogeny (EAO). The Arabian-Nubian Shield (ANS) is the longest Neoproterozoic belt on Earth, and it was formed during the East and West Gondwanaland collisions within the framework of the EAO. The ANS basement rocks were developed during three distinct phases of magmatic activity: the island arc and syn-collisional phases, identifying a compressional tectonic regime, and a post-collisional phase that identifies changing the tectonic regime into an extensional type. The geochronological assessment of these magmatic activities is essential for understanding the regional geology and tectonic development of the ANS. In our study, we dated different rock units along the Qift<strong>‒</strong>Quseir transect and revealed ages ranging from the Late Tonian (820 ± 8 Ma) to the Late Ediacaran (563 ± 4 Ma). These ages were associated with three different magmatic pulses: (1) a seafloor spreading and island arc phase (ophiolite and related rocks), represented by sample QQ05, which was dated from 820 ± 8 Ma; (2) a syn-collisional phase, represented by samples QQ08 and QQ10, dated from 733 ± 10 Ma and 729 ± 10 Ma, respectively; and (3) a post-collisional phase, represented by all the other samples, dated from the Ediacaran at 603 ± 9 Ma to 563 ± 5 Ma. These results showed that the post-collisional phase was dominant, especially in terms of the alkali-feldspar granites, relative to ophiolitic rocks, and the syn-collisional granites in the CED. Initiation of the Dokhan Volcanic eruptions at 639 ± 2 Ma gave us the date of the compressional-to-extensional tectonic transition setting, and the post-collisional tensional regime was activated at 603 ± 9 Ma. Additionally, we identified evidence of local magmatic sources by dating 11 grains of Paleo-to Meso-Proterozoic xenocrysts with ages ranging from 1876 ± 18 to 1070 ± 13 Ma (i.e., components of the pre-Arabian-Nubian Shield).</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"220 ","pages":"Article 105456"},"PeriodicalIF":2.2,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533127","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 : 2024-10-19DOI: 10.1016/j.jafrearsci.2024.105455
Mohamed Amine Zaidi , Marcin Krajewski , Caner Kaya Özer , Mariusz A. Salamon , W. James Kennedy , Madani Benyoucef
The stratigraphical features and palaeoenvironmental conditions of the uppermost Albian-lower Turonian succession of the eastern Algerian Saharan Atlas domain are described for the first time. Two formations have been recognised, called the Ouled Serradj and the Chemla, respectively. Ammonites and calcareous nannofossils enable us to assign the Ouled Serradj Formation to the upper Albian-Cenomanian and the Chemla Formation to the uppermost Cenomanian-lower Turonian. Based on the field data and microfacies studies, the strata of these formations are arranged into eight microfacies types (MT 1 to MT 8) that are described in terms of depositional environments and grouped into three main facies associations (FA-1 to FA-3): FA-1 (MT 1–4), deep-water outer platform marl-dominated facies association 1 with limestone intercalations; FA-2 (MT 5 and 6), mid-platform marl-dominated facies association 2; and FA-3 (MT 7 and 8), mid- and inner platform limestone-marl facies association 3.
{"title":"Stratigraphy and sedimentology of the uppermost Albian-lower Turonian of the Morsott area (Algero-Tunisian Atlasic Basin)","authors":"Mohamed Amine Zaidi , Marcin Krajewski , Caner Kaya Özer , Mariusz A. Salamon , W. James Kennedy , Madani Benyoucef","doi":"10.1016/j.jafrearsci.2024.105455","DOIUrl":"10.1016/j.jafrearsci.2024.105455","url":null,"abstract":"<div><div>The stratigraphical features and palaeoenvironmental conditions of the uppermost Albian-lower Turonian succession of the eastern Algerian Saharan Atlas domain are described for the first time. Two formations have been recognised, called the Ouled Serradj and the Chemla, respectively. Ammonites and calcareous nannofossils enable us to assign the Ouled Serradj Formation to the upper Albian-Cenomanian and the Chemla Formation to the uppermost Cenomanian-lower Turonian. Based on the field data and microfacies studies, the strata of these formations are arranged into eight microfacies types (MT 1 to MT 8) that are described in terms of depositional environments and grouped into three main facies associations (FA-1 to FA-3): FA-1 (MT 1–4), deep-water outer platform marl-dominated facies association 1 with limestone intercalations; FA-2 (MT 5 and 6), mid-platform marl-dominated facies association 2; and FA-3 (MT 7 and 8), mid- and inner platform limestone-marl facies association 3.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"220 ","pages":"Article 105455"},"PeriodicalIF":2.2,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552736","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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