Pub Date : 2024-09-07DOI: 10.1016/j.jafrearsci.2024.105415
Luigi Capasso , Sayed Abdel Aziz , Abdel Aziz Tantawy , Mohamed Kamel Mousa , Dalia Gamal Ahmed Wahba , Gebely Abdelmaksoud Abu El-Kheir
An exceptional hypertrophic batoid rostrum of exceptional size (TL = 146 cm) and four fragmentary rostral teeth collected from the marine Maastrichtian of the Dakhla Formation, Egypt. Both the macroscopic aspects (with the presence of a "wood-like" layer that covers the central part of the rostrum and the presence of skin denticles at the bases of the ventral face) and microscopic characters (presence of tessellated cartilage in the central part of the rostrum and of laminated cartilage in the peripheral areas of it) demonstrate that the rostrum belongs to a large specimen of the genus Onchopristis Stromer, 1917. The absence of complete rostral teeth prevents the establishment of a new species. Nonetheless, the described finds demonstrate, for the first time, that the genus Onchopristis persisted in the euryhaline areas of North Africa until the end of the Cretaceous.
{"title":"The first described Onchopristis Stromer, 1917, (Elasmobranchii: †Onchopristidae) from the marine Maastrichtian of Dakhla Formation, Western Desert, Egypt","authors":"Luigi Capasso , Sayed Abdel Aziz , Abdel Aziz Tantawy , Mohamed Kamel Mousa , Dalia Gamal Ahmed Wahba , Gebely Abdelmaksoud Abu El-Kheir","doi":"10.1016/j.jafrearsci.2024.105415","DOIUrl":"10.1016/j.jafrearsci.2024.105415","url":null,"abstract":"<div><p>An exceptional hypertrophic batoid rostrum of exceptional size (TL = 146 cm) and four fragmentary rostral teeth collected from the marine Maastrichtian of the Dakhla Formation, Egypt. Both the macroscopic aspects (with the presence of a \"wood-like\" layer that covers the central part of the rostrum and the presence of skin denticles at the bases of the ventral face) and microscopic characters (presence of tessellated cartilage in the central part of the rostrum and of laminated cartilage in the peripheral areas of it) demonstrate that the rostrum belongs to a large specimen of the genus <em>Onchopristis</em> Stromer, 1917. The absence of complete rostral teeth prevents the establishment of a new species. Nonetheless, the described finds demonstrate, for the first time, that the genus <em>Onchopristis</em> persisted in the euryhaline areas of North Africa until the end of the Cretaceous.</p></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"220 ","pages":"Article 105415"},"PeriodicalIF":2.2,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142241756","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 : 2024-09-05DOI: 10.1016/j.jafrearsci.2024.105412
Mohammad A. Sarhan , Amer A. Shehata , Mohamed I. Abdel-Fattah
This research aims to perform a comprehensive examination encompassing sequence stratigraphy and petrophysical assessment of the Cretaceous meqasequence along the Gulf of Suez region. Through an investigation of eight wells, spanning both offshore and onshore fields in the Gulf of Suez Basin, the sequence stratigraphic analysis reveals a division of the Cretaceous meqasequence into two distinct depositional sequences: Early Cretaceous (SQ-1) and Late Cretaceous megasequence. The Early Cretaceous megasequence comprises the Nubia Sandstones, while the Late Cretaceous megasequence includes the siliciclastic/carbonate sediments found within the Raha, Abu Qada, Wata, and Matulla Formations (SQ-2, SQ-3, and SQ-4). The distribution of the Cretaceous megasequences across the study area highlights a significant variation in thickness from the onshore to the offshore regions of the Gulf of Suez. This variation is primarily attributed to tectonic forces that governed both the deposition and erosion of sediments over time. The lowstand systems tracts (LSTs) and highstand systems tracts (HSTs) within both Cretaceous megasequences are characterized by sufficient sand content, making them favorable reservoirs.
Conversely, the transgressive systems tracts (TSTs) are identified as potential reservoir rocks. The analysis of petrophysical properties across different Cretaceous reservoirs reveals that the Early Cretaceous fluvial megasequence exhibits superior reservoir qualities compared to its Late Cretaceous counterpart. However, the Late Cretaceous megasequence comprises reservoirs with multiple levels and diverse petrophysical characteristics. The study offers valuable insights into how petrophysical properties and sequence stratigraphy influence Cretaceous reservoir architecture. Examining the depositional environments and petrophysical evaluation enhances our understanding of reservoir quality and distribution. Furthermore, it guides future exploration activities in the mixed siliciclastic and carbonate multi-level intervals of the Gulf of Suez and nearby basins, aiding in identifying potential hydrocarbon zones and optimizing drilling strategies.
{"title":"Sequence stratigraphic and petrophysical controls on the oil-reservoirs architecture: A case study from the Cretaceous meqasequence, Gulf of Suez region, Egypt","authors":"Mohammad A. Sarhan , Amer A. Shehata , Mohamed I. Abdel-Fattah","doi":"10.1016/j.jafrearsci.2024.105412","DOIUrl":"10.1016/j.jafrearsci.2024.105412","url":null,"abstract":"<div><p>This research aims to perform a comprehensive examination encompassing sequence stratigraphy and petrophysical assessment of the Cretaceous meqasequence along the Gulf of Suez region. Through an investigation of eight wells, spanning both offshore and onshore fields in the Gulf of Suez Basin, the sequence stratigraphic analysis reveals a division of the Cretaceous meqasequence into two distinct depositional sequences: Early Cretaceous (SQ-1) and Late Cretaceous megasequence. The Early Cretaceous megasequence comprises the Nubia Sandstones, while the Late Cretaceous megasequence includes the siliciclastic/carbonate sediments found within the Raha, Abu Qada, Wata, and Matulla Formations (SQ-2, SQ-3, and SQ-4). The distribution of the Cretaceous megasequences across the study area highlights a significant variation in thickness from the onshore to the offshore regions of the Gulf of Suez. This variation is primarily attributed to tectonic forces that governed both the deposition and erosion of sediments over time. The lowstand systems tracts (LSTs) and highstand systems tracts (HSTs) within both Cretaceous megasequences are characterized by sufficient sand content, making them favorable reservoirs.</p><p>Conversely, the transgressive systems tracts (TSTs) are identified as potential reservoir rocks. The analysis of petrophysical properties across different Cretaceous reservoirs reveals that the Early Cretaceous fluvial megasequence exhibits superior reservoir qualities compared to its Late Cretaceous counterpart. However, the Late Cretaceous megasequence comprises reservoirs with multiple levels and diverse petrophysical characteristics. The study offers valuable insights into how petrophysical properties and sequence stratigraphy influence Cretaceous reservoir architecture. Examining the depositional environments and petrophysical evaluation enhances our understanding of reservoir quality and distribution. Furthermore, it guides future exploration activities in the mixed siliciclastic and carbonate multi-level intervals of the Gulf of Suez and nearby basins, aiding in identifying potential hydrocarbon zones and optimizing drilling strategies.</p></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"219 ","pages":"Article 105412"},"PeriodicalIF":2.2,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142164967","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 : 2024-09-05DOI: 10.1016/j.jafrearsci.2024.105410
Younesse EL Cheikh , Ahmed Attou , Lahsen Achkouch , Younes Mamouch , Toufik Khouya , Adama Sangare , Abdelhalim Miftah
This research paper introduces a comprehensive methodology for assessing hydrothermal alteration zones and structural complexity in the Ezzhiliga region, situated in the Hercynian Central Massif of Morocco. The approach utilizes ASTER imagery as the primary data source. The main objectives were to identify and analyze these geological features and then create a potential map for mineral exploration by integrating fuzzy logic and fractal concentration area analysis. Band ratios (RBD) and principal component analysis (PCA) were employed to detect and map argillic, phyllic, propylitic, and iron oxide alteration zones. Additionally, structural lineaments were extracted from the PC1 imagery to understand the structural pattern of the survey area. The incorporation of hydrothermal alteration zones and structural lineaments was achieved through the application of a fuzzy logic model, resulting in the generation of a mineral favorability map. The fuzzy logic model was customized to combine hydrothermal alteration and lineaments density maps, effectively eliminating false spectral anomalies induced by various interference factors. This map was then analyzed using the fractal concentration-area (C-A) model, which separated the anomaly from the geological background and generated a final mineral potential map. Analysis of fractal concentration-area was employed to define thresholds with greater precision, enhancing the reliability of mineral prospectivity assessments. Furthermore, laboratory analyses were performed to verify the outcomes of the mineral potential map. The obtained results revealed a significant affinity with the field data and indicated that the highly prospective zones are perfectly limited in spatial extent and generally associated with the contact of the Zaër granitic pluton with the metamorphic host rock, except for the anomaly identified to the southeast of the study area, along a major NE-SW trending fault.
{"title":"Targeting high-potential mineral prospects in the Ezzhiliga region, Moroccan central massif, using spectral data from the ASTER sensor","authors":"Younesse EL Cheikh , Ahmed Attou , Lahsen Achkouch , Younes Mamouch , Toufik Khouya , Adama Sangare , Abdelhalim Miftah","doi":"10.1016/j.jafrearsci.2024.105410","DOIUrl":"10.1016/j.jafrearsci.2024.105410","url":null,"abstract":"<div><p>This research paper introduces a comprehensive methodology for assessing hydrothermal alteration zones and structural complexity in the Ezzhiliga region, situated in the Hercynian Central Massif of Morocco. The approach utilizes ASTER imagery as the primary data source. The main objectives were to identify and analyze these geological features and then create a potential map for mineral exploration by integrating fuzzy logic and fractal concentration area analysis. Band ratios (RBD) and principal component analysis (PCA) were employed to detect and map argillic, phyllic, propylitic, and iron oxide alteration zones. Additionally, structural lineaments were extracted from the PC1 imagery to understand the structural pattern of the survey area. The incorporation of hydrothermal alteration zones and structural lineaments was achieved through the application of a fuzzy logic model, resulting in the generation of a mineral favorability map. The fuzzy logic model was customized to combine hydrothermal alteration and lineaments density maps, effectively eliminating false spectral anomalies induced by various interference factors. This map was then analyzed using the fractal concentration-area (C-A) model, which separated the anomaly from the geological background and generated a final mineral potential map. Analysis of fractal concentration-area was employed to define thresholds with greater precision, enhancing the reliability of mineral prospectivity assessments. Furthermore, laboratory analyses were performed to verify the outcomes of the mineral potential map. The obtained results revealed a significant affinity with the field data and indicated that the highly prospective zones are perfectly limited in spatial extent and generally associated with the contact of the Zaër granitic pluton with the metamorphic host rock, except for the anomaly identified to the southeast of the study area, along a major NE-SW trending fault.</p></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"219 ","pages":"Article 105410"},"PeriodicalIF":2.2,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142147894","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 : 2024-09-04DOI: 10.1016/j.jafrearsci.2024.105414
Pascal Mambwe , Damien Delvaux , Stijn Dewaele , Louis Kipata , Philippe Muchez
<div><p>The metasedimentary rock succession of the Neoproterozoic-Cambrian Katanga Supergroup in the Central Africa Copperbelt shows evidence of several complex tectonic events. The deformation of this supergroup started from the tectonic inversion at about 570 Ma and lasted up to today, but reached paroxysm at ∼550 Ma. This long period was characterized by folding and faulting throughout multiple compressive and extensional events, which controlled the regional fluid flow on the one hand, and played an important role during formation of the stratiform to stratabound Cu-Co (Ni, U) deposits and the polymetallic Cu-Zn-Pb (Ag, Ge, Mo, Cd) vein type deposits on the other hand. Based on the structural analysis and paleostress reconstruction, coupled with fluid inclusion characterization from mineralized structures in rocks from the Nguba, Kundelungu and Biano Groups, this study demonstrates that the composition of hydrothermal fluids changed during brittle tectonic deformation during the Lufilian orogeny and subsequent uplift and post-Lufilian faulting.</p><p>During early brittle tectonic deformation along strike slip faults with sinistral and dextral movement related to a NE-SW transpression, the Cu-mineralizing fluid was hypersaline (27.9–31.1 eq. wt% NaCl) with moderate temperatures (Th = 128–216 °C). The subsequent Cu or Cu (Zn, Pb) mineralization formed within an E-W extensional stress regime, related to the late Lufilian orogenic collapse. The fluid inclusions present in the gangue minerals associated with this latter mineralization show a large range in Th (50–264 °C) and salinity (26.7–36.0 eq. wt% NaCl). The decrease in temperature is interpreted to be due to migration of the fluids at shallower depth in the subsurface after uplift and erosion of the orogen. The increased salinity of the fluid is related to the dissolution of evaporites, mainly NaCl. A second H<sub>2</sub>O-NaCl-CaCl<sub>2</sub> fluid with a homogenization temperature below 55 °C has also been found associated with this brittle stage and mineralization phase, but only in rocks belonging to the Kundelungu Group. A third mineralization phase, also characterized by Cu or Cu (Zn, Pb), formed during the post-Lufilian period within a NW-SE transpressional inversion regime. The fluid inclusion in the gangue minerals of this mineralization phase have a smaller range in homogenization temperature (Th = 37–172 °C) and the largest range in salinity (0.71–30 eq. wt% NaCl), compared to the earlier fluid inclusions generations. This large range in salinity may be explained by the mixing of a high salinity fluid, already present during the earlier tectonic stages in the sedimentary basin, with meteoric water. During the more recent rift-related extension, a fluid with again a large and higher range in homogenization temperatures (Th = 47–257 °C) and with a typical low salinity (<10 eq. wt% NaCl) has been recognized in minerals filling NNE-SSW to NE-SW oriented faults and fractures. The u
{"title":"Fluid flow in the Katanga Supergroup: From Lufilian brittle tectonic stages to the post-Lufilian period (Democratic Republic of Congo)","authors":"Pascal Mambwe , Damien Delvaux , Stijn Dewaele , Louis Kipata , Philippe Muchez","doi":"10.1016/j.jafrearsci.2024.105414","DOIUrl":"10.1016/j.jafrearsci.2024.105414","url":null,"abstract":"<div><p>The metasedimentary rock succession of the Neoproterozoic-Cambrian Katanga Supergroup in the Central Africa Copperbelt shows evidence of several complex tectonic events. The deformation of this supergroup started from the tectonic inversion at about 570 Ma and lasted up to today, but reached paroxysm at ∼550 Ma. This long period was characterized by folding and faulting throughout multiple compressive and extensional events, which controlled the regional fluid flow on the one hand, and played an important role during formation of the stratiform to stratabound Cu-Co (Ni, U) deposits and the polymetallic Cu-Zn-Pb (Ag, Ge, Mo, Cd) vein type deposits on the other hand. Based on the structural analysis and paleostress reconstruction, coupled with fluid inclusion characterization from mineralized structures in rocks from the Nguba, Kundelungu and Biano Groups, this study demonstrates that the composition of hydrothermal fluids changed during brittle tectonic deformation during the Lufilian orogeny and subsequent uplift and post-Lufilian faulting.</p><p>During early brittle tectonic deformation along strike slip faults with sinistral and dextral movement related to a NE-SW transpression, the Cu-mineralizing fluid was hypersaline (27.9–31.1 eq. wt% NaCl) with moderate temperatures (Th = 128–216 °C). The subsequent Cu or Cu (Zn, Pb) mineralization formed within an E-W extensional stress regime, related to the late Lufilian orogenic collapse. The fluid inclusions present in the gangue minerals associated with this latter mineralization show a large range in Th (50–264 °C) and salinity (26.7–36.0 eq. wt% NaCl). The decrease in temperature is interpreted to be due to migration of the fluids at shallower depth in the subsurface after uplift and erosion of the orogen. The increased salinity of the fluid is related to the dissolution of evaporites, mainly NaCl. A second H<sub>2</sub>O-NaCl-CaCl<sub>2</sub> fluid with a homogenization temperature below 55 °C has also been found associated with this brittle stage and mineralization phase, but only in rocks belonging to the Kundelungu Group. A third mineralization phase, also characterized by Cu or Cu (Zn, Pb), formed during the post-Lufilian period within a NW-SE transpressional inversion regime. The fluid inclusion in the gangue minerals of this mineralization phase have a smaller range in homogenization temperature (Th = 37–172 °C) and the largest range in salinity (0.71–30 eq. wt% NaCl), compared to the earlier fluid inclusions generations. This large range in salinity may be explained by the mixing of a high salinity fluid, already present during the earlier tectonic stages in the sedimentary basin, with meteoric water. During the more recent rift-related extension, a fluid with again a large and higher range in homogenization temperatures (Th = 47–257 °C) and with a typical low salinity (<10 eq. wt% NaCl) has been recognized in minerals filling NNE-SSW to NE-SW oriented faults and fractures. The u","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"220 ","pages":"Article 105414"},"PeriodicalIF":2.2,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142172452","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 GIS-based geomorphological and morphometric approaches were combined with field- and tephrostratigraphic analyses to reconstruct the history of the Mt Manengouba volcano including the Eboga maars in the southwestern part of the Cameroon Volcanic Line (CVL). The elevation, slope, relative relief, topographic position and terrain ruggedness indexes from the Digital Elevation Model (DEM, 12.5 m) were determined to constrain two main geomorphic units corresponding to the Elengoum and Eboga nested stratovolcanoes which were affected by differential erosional processes. The studied grain size, shape, vesicularity, structure, degree of lithification, sorting, thickness, grading patterns, sedimentary features, spatial distribution revealed three tephrostratigraphic units: U1 (U1-1, lithic and juvenile; U1-2 dominantly juvenile), U2 (U2-1 ash- and juvenile rich-deposits; U2-2, juvenile-scoria with few lithic) and U3 (scoria cone deposits). The total volume of ∼0.199 km3 of tephra deposits ranges the Eboga maars volcanoes within the small-volume monogenetic types. These results revealed dry/wet phreatomagmatism and strombolian activity as a contribution to the seven phases-eruptive history of the Mt Manengouba volcano: the pre-Manengouba; emplacement of Elengoum stratovolcano; collapse of Elengoum summit and formation of Elengoum caldera; emplacement of Eboga stratovolcano; the collapse of Eboga summit and formation of Eboga caldera; a phreatomagmatic phase and emplacement of Female and Male maars ending with an explosive stage associated with the formation of scoria and parasitic cones.
{"title":"Morphometry of the Mt Manengouba volcano: Insights into tephrostratigraphy of Eboga maars (South West Cameroon)","authors":"Amad Samir Mounpen Njiemessa , Moussa Nsangou Ngapna , Monespérance Germain Marie Mboudou , Moïse Christian Balla Ateba , Pascal Landry Wabo Defo , Dieudonné Youmen , Sébastien Owona","doi":"10.1016/j.jafrearsci.2024.105411","DOIUrl":"10.1016/j.jafrearsci.2024.105411","url":null,"abstract":"<div><p>The GIS-based geomorphological and morphometric approaches were combined with field- and tephrostratigraphic analyses to reconstruct the history of the Mt Manengouba volcano including the Eboga maars in the southwestern part of the Cameroon Volcanic Line (CVL). The elevation, slope, relative relief, topographic position and terrain ruggedness indexes from the Digital Elevation Model (DEM, 12.5 m) were determined to constrain two main geomorphic units corresponding to the Elengoum and Eboga nested stratovolcanoes which were affected by differential erosional processes. The studied grain size, shape, vesicularity, structure, degree of lithification, sorting, thickness, grading patterns, sedimentary features, spatial distribution revealed three tephrostratigraphic units: U1 (U<sub>1-1</sub>, lithic and juvenile; U<sub>1-2</sub> dominantly juvenile), U2 (U<sub>2-1</sub> ash- and juvenile rich-deposits; U<sub>2-2</sub>, juvenile-scoria with few lithic) and U3 (scoria cone deposits). The total volume of ∼0.199 km<sup>3</sup> of tephra deposits ranges the Eboga maars volcanoes within the small-volume monogenetic types. These results revealed dry/wet phreatomagmatism and strombolian activity as a contribution to the seven phases-eruptive history of the Mt Manengouba volcano: the pre-Manengouba; emplacement of Elengoum stratovolcano; collapse of Elengoum summit and formation of Elengoum caldera; emplacement of Eboga stratovolcano; the collapse of Eboga summit and formation of Eboga caldera; a phreatomagmatic phase and emplacement of Female and Male maars ending with an explosive stage associated with the formation of scoria and parasitic cones.</p></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"220 ","pages":"Article 105411"},"PeriodicalIF":2.2,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1464343X24002449/pdfft?md5=cddc54edcbceda16270840a00e77c8f5&pid=1-s2.0-S1464343X24002449-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142162902","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 : 2024-09-01DOI: 10.1016/j.jafrearsci.2024.105413
Neamat Aboelhassan , Elhamy Tarabees , Mohamed El Bastawesy , Saad Mogren , Bassem S. Nabawy , Elkhedr Ibrahim , S.M. Talha Qadri
The main aim of this study is to delineate the hydrocarbon potential and evaluate the petroleum system elements of the Cenomanian Abu Roash G (AR/G) and the Upper Bahariya Members in the Karama Field. It lies at the southeast borders of the Abu Gharadig Basin, a well-known basin in the W.D. to the NE of Africa. We accomplish this study by analyzing a total of thirty 2D seismic profiles, a complete data set of well logs for five wells, and their geochemical data. The workflow starts with illustrating the dominant subsurface structural features, defining the main potential reservoirs and their parameters, and checking the maturity of the probable source rocks. The seismic interpretation indicated that the research area had been influenced by a NE-SW anticlinal structure accompanied by a set of WNW-ESE and NW-SE normal faults that are controlled by the positive compression inversion process that dominated during the Late Cretaceous. Analyzing and processing the well log data sets suggest that the reservoirs of the Abu Roash G (AR/G) and the Upper Bahariya Members are characterized by poor to good reservoir settings with net-pay thickness reaching up to 13–50 feet in the different wells (av. Effective porosity (∅eff) = 17.7 % and 15.6% for the AR/G and the Upper Bahariya Members, av. Shale volume (Vsh) = 17.4 % and 13.6 %, av. Water saturation (Sw) = 38.9 % and 39.8 %, while av. Hydrocarbon saturation values (So) = 60.2 % and 61.1%, respectively). The geochemical and maturity analyses assisted in determining the potential mature source rocks of the Jurassic Khatatba Shale (TOC = 0.70–5.67%; S1+S2 = 0.43–5.97 mg/g, Ro = 0.54–1.06 %) with some contribution from the Cretaceous sources (Alam El-Bueib and Bahariya Formations). Studying elements of the petroleum regime of the Karama Field indicates that the trapped hydrocarbons are structurally controlled by three-way dip closures, horst blocks, sealing faults, and vertical sealing by impervious shale and limestone beds. This case study could be applied to similar analogs in other oil fields in the Egyptian Western Desert to delineate their hydrocarbon potential and structural setting.
{"title":"Integrated seismic, petrophysical, and geochemical studies for evaluating the petroleum system of the Upper Bahariya-Abu Roash G sequence in the Karama Field, Abu Gharadig Basin, North Western Desert, Egypt","authors":"Neamat Aboelhassan , Elhamy Tarabees , Mohamed El Bastawesy , Saad Mogren , Bassem S. Nabawy , Elkhedr Ibrahim , S.M. Talha Qadri","doi":"10.1016/j.jafrearsci.2024.105413","DOIUrl":"10.1016/j.jafrearsci.2024.105413","url":null,"abstract":"<div><p>The main aim of this study is to delineate the hydrocarbon potential and evaluate the petroleum system elements of the Cenomanian Abu Roash G (AR/G) and the Upper Bahariya Members in the Karama Field. It lies at the southeast borders of the Abu Gharadig Basin, a well-known basin in the W.D. to the NE of Africa. We accomplish this study by analyzing a total of thirty 2D seismic profiles, a complete data set of well logs for five wells, and their geochemical data. The workflow starts with illustrating the dominant subsurface structural features, defining the main potential reservoirs and their parameters, and checking the maturity of the probable source rocks. The seismic interpretation indicated that the research area had been influenced by a NE-SW anticlinal structure accompanied by a set of WNW-ESE and NW-SE normal faults that are controlled by the positive compression inversion process that dominated during the Late Cretaceous. Analyzing and processing the well log data sets suggest that the reservoirs of the Abu Roash G (AR/G) and the Upper Bahariya Members are characterized by poor to good reservoir settings with net-pay thickness reaching up to 13–50 feet in the different wells (av. Effective porosity (<em>∅</em><sub><em>eff</em></sub>) = 17.7 % and 15.6% for the AR/G and the Upper Bahariya Members, av. Shale volume (<em>Vsh</em>) = 17.4 % and 13.6 %, av. Water saturation (<em>Sw</em>) = 38.9 % and 39.8 %, while av. Hydrocarbon saturation values (<em>So</em>) = 60.2 % and 61.1%, respectively). The geochemical and maturity analyses assisted in determining the potential mature source rocks of the Jurassic Khatatba Shale (<em>TOC</em> = 0.70–5.67%; <em>S</em><sub><em>1</em></sub><em>+S</em><sub><em>2</em></sub> = 0.43–5.97 mg/g, <em>Ro</em> = 0.54–1.06 %) with some contribution from the Cretaceous sources (Alam El-Bueib and Bahariya Formations). Studying elements of the petroleum regime of the Karama Field indicates that the trapped hydrocarbons are structurally controlled by three-way dip closures, horst blocks, sealing faults, and vertical sealing by impervious shale and limestone beds. This case study could be applied to similar analogs in other oil fields in the Egyptian Western Desert to delineate their hydrocarbon potential and structural setting.</p></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"219 ","pages":"Article 105413"},"PeriodicalIF":2.2,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142129305","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 : 2024-09-01DOI: 10.1016/j.jafrearsci.2024.105406
R. Leprêtre , M. El Houicha , A. Schito , R. Ouchaou , F. Chopin , P. Cózar
Within the Variscan Belt of Morocco, the Central Massif preserves Early Carboniferous rift basins. The Lower Carboniferous Khenifra and Qasbat-Tadla basins are aborted rifts, developed just before the Variscan orogenesis in Morocco that occurred during the Pennsylvanian-Cisuralian in NW Africa. Due to both weak inversion of these basins during the Variscan orogeny and limited burial afterwards, these basins offer the opportunity to study the Early Carboniferous pre-orogenic thermal regimes. In the Khenifra basin, 77 samples collected across the basin and its basement's boundaries, allowed the determination of the maximal temperature reached during the rocks burial by means of Raman spectroscopic analyses. The Ordovician basement shows mean temperatures between 230 and 300 °C whereas the upper Visean/Serpukhovian infill has a wide range, from temperatures <160 °C to 250–260 °C. This thermal variation within the basinal series has been evidenced from west to east and cannot have been acquired during the Variscan events. The acquisition of these maximal temperatures occurred between Late Devonian to Upper Visean/Serpukhovian and is thought to result from the formation of an extended rift. In the Qasbat-Tadla basin, Rock-Eval data from Ordovician to Devonian source-rocks indicate significantly lower maximal temperatures reached by pre-Carboniferous samples that are within the oil window. Our results are in favor of a heterodox model for the Variscan belt in Morocco and NW African in general, suggesting that no pre-Variscan compressional events are needed. Instead, the development of the intraplate Variscan belt in NW Africa was permitted through the development of hot and weak Lower Carboniferous basins, subsequently inverted in a far-field stress field. The striking thermal differences between the Khenifra and Qasbat-Tadla basins suggest that important tectonic segmentation must have shaped the area during the Early Carboniferous extensional phase.
在摩洛哥的瓦利斯坎带,中央丘保留了早石炭世裂谷盆地。下石炭统 Khenifra 和 Qasbat-Tadla 盆地是中止的裂谷,是在西北非宾夕法尼亚-志留纪期间发生的摩洛哥瓦里斯坎造山运动之前形成的。由于这些盆地在瓦里肯造山运动期间的反转作用较弱,而造山运动之后的埋藏作用有限,因此这些盆地为研究早石炭世前造山运动的热机制提供了机会。在 Khenifra 盆地,通过对盆地及其基底边界采集的 77 个样本进行拉曼光谱分析,确定了岩石埋藏期间达到的最高温度。奥陶纪基底的平均温度在 230 ° C 到 300 ° C 之间,而上维谢安/塞普霍夫页岩的填充温度范围很广,从 160 ° C 到 250-260 ° C 不等。基底系列内的这种热量变化是自西向东的,不可能是在瓦利斯坎时期获得的。这些最高温度的获得发生在晚泥盆世至上维西期/上塞普霍夫期,被认为是延伸裂谷形成的结果。在卡斯巴特-塔德拉盆地,来自奥陶纪至泥盆纪源岩的岩石-评价数据表明,石炭纪以前的样本所达到的最高温度要低得多,而这些样本都在石油窗口之内。我们的研究结果表明,摩洛哥和整个西北非洲的瓦利斯坎带采用的是一种非正统模型,即不需要发生瓦利斯坎前的压缩事件。相反,西北非洲板内瓦里斯坎带的发展是通过下石炭纪热而弱的盆地的发展实现的,这些盆地随后在远场应力场中发生了倒转。Khenifra盆地和Qasbat-Tadla盆地之间显著的热差异表明,在早石炭世的伸展阶段,该地区一定发生了重要的构造分段。
{"title":"Thermal studies on the lower Carboniferous basins of Khenifra and Qasbat-Tadla, Morocco: What do they teach us about the pre-Variscan stages in NW Africa?","authors":"R. Leprêtre , M. El Houicha , A. Schito , R. Ouchaou , F. Chopin , P. Cózar","doi":"10.1016/j.jafrearsci.2024.105406","DOIUrl":"10.1016/j.jafrearsci.2024.105406","url":null,"abstract":"<div><p>Within the Variscan Belt of Morocco, the Central Massif preserves Early Carboniferous rift basins. The Lower Carboniferous Khenifra and Qasbat-Tadla basins are aborted rifts, developed just before the Variscan orogenesis in Morocco that occurred during the Pennsylvanian-Cisuralian in NW Africa. Due to both weak inversion of these basins during the Variscan orogeny and limited burial afterwards, these basins offer the opportunity to study the Early Carboniferous pre-orogenic thermal regimes. In the Khenifra basin, 77 samples collected across the basin and its basement's boundaries, allowed the determination of the maximal temperature reached during the rocks burial by means of Raman spectroscopic analyses. The Ordovician basement shows mean temperatures between 230 and 300 °C whereas the upper Visean/Serpukhovian infill has a wide range, from temperatures <160 °C to 250–260 °C. This thermal variation within the basinal series has been evidenced from west to east and cannot have been acquired during the Variscan events. The acquisition of these maximal temperatures occurred between Late Devonian to Upper Visean/Serpukhovian and is thought to result from the formation of an extended rift. In the Qasbat-Tadla basin, Rock-Eval data from Ordovician to Devonian source-rocks indicate significantly lower maximal temperatures reached by pre-Carboniferous samples that are within the oil window. Our results are in favor of a heterodox model for the Variscan belt in Morocco and NW African in general, suggesting that no pre-Variscan compressional events are needed. Instead, the development of the intraplate Variscan belt in NW Africa was permitted through the development of hot and weak Lower Carboniferous basins, subsequently inverted in a far-field stress field. The striking thermal differences between the Khenifra and Qasbat-Tadla basins suggest that important tectonic segmentation must have shaped the area during the Early Carboniferous extensional phase.</p></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"219 ","pages":"Article 105406"},"PeriodicalIF":2.2,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1464343X24002395/pdfft?md5=86b392077930dd25ae2e2e61ee1778a3&pid=1-s2.0-S1464343X24002395-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142136322","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 : 2024-08-30DOI: 10.1016/j.jafrearsci.2024.105409
Mohamed Alkhuzamy Aziz , Ahmed El-Zeiny , Fayrouz M. Hassan , Doaa M. Naguib
The Red Sea coastal environment of Halayeb and Shalateen area is renowned for its abundant marine flora and fauna. It also holds significant economic and cultural importance for local communities. However, this region is currently confronted with various challenges, including climate change and habitat destruction. To effectively address and mitigate these issues, advanced technologies that offer a holistic understanding of the area's environmental conditions are required. This paper applies the integration of Geospatial Artificial Intelligence (GeoAI) and ChatGPT to study the Red Sea Coastal water quality dynamics of Halayeb and Shalateen Area. Landsat imagery and Copernicus Marine Service were used to retrieve area boundaries and monitor the physicochemical characteristics of the coastal water respectively. ChatGPT was utilized to generate Python code that facilitates the creation of optimal distribution maps for each physical and chemical property criterion. The Python codes were incorporated into the Python program within the ArcGIS 10.7.1 and executed to generate the desired maps representing the dynamics of physical and chemical properties. It was found an observed fluctuation in chemical properties next to the coastline around the mouth of two main wadies; Wadi Hudain, and Wadi Da'eb. The degree of stability increased away from the coast toward the deep water. That proved the effect of the runoff on the seawater, as the runoff plays an essential role in the water state, especially in such semi-closed water bodies like the Red Sea where the flashfloods are the main source that can enrich water with sediment and nutrients. The state of seawater in terms of physical properties was not characterized by a specific pattern. The distribution of physical parameters in the Red Sea is influenced by factors such as regional climate variations, monsoonal winds, and local topography. This paper serves as a stepping stone for future research endeavors, exploring the full potential of this integrated approach. It can be concluded that the fusion of GeoAI and ChatGPT technologies has the potential to revolutionize our approach to studying and managing the coastal environment.
{"title":"Coastal water quality dynamics of the Red Sea, southeast coast of Egypt using GeoAI and ChatGPT","authors":"Mohamed Alkhuzamy Aziz , Ahmed El-Zeiny , Fayrouz M. Hassan , Doaa M. Naguib","doi":"10.1016/j.jafrearsci.2024.105409","DOIUrl":"10.1016/j.jafrearsci.2024.105409","url":null,"abstract":"<div><p>The Red Sea coastal environment of Halayeb and Shalateen area is renowned for its abundant marine flora and fauna. It also holds significant economic and cultural importance for local communities. However, this region is currently confronted with various challenges, including climate change and habitat destruction. To effectively address and mitigate these issues, advanced technologies that offer a holistic understanding of the area's environmental conditions are required. This paper applies the integration of Geospatial Artificial Intelligence (GeoAI) and ChatGPT to study the Red Sea Coastal water quality dynamics of Halayeb and Shalateen Area. Landsat imagery and Copernicus Marine Service were used to retrieve area boundaries and monitor the physicochemical characteristics of the coastal water respectively. ChatGPT was utilized to generate Python code that facilitates the creation of optimal distribution maps for each physical and chemical property criterion. The Python codes were incorporated into the Python program within the ArcGIS 10.7.1 and executed to generate the desired maps representing the dynamics of physical and chemical properties. It was found an observed fluctuation in chemical properties next to the coastline around the mouth of two main wadies; Wadi Hudain, and Wadi Da'eb. The degree of stability increased away from the coast toward the deep water. That proved the effect of the runoff on the seawater, as the runoff plays an essential role in the water state, especially in such semi-closed water bodies like the Red Sea where the flashfloods are the main source that can enrich water with sediment and nutrients. The state of seawater in terms of physical properties was not characterized by a specific pattern. The distribution of physical parameters in the Red Sea is influenced by factors such as regional climate variations, monsoonal winds, and local topography. This paper serves as a stepping stone for future research endeavors, exploring the full potential of this integrated approach. It can be concluded that the fusion of GeoAI and ChatGPT technologies has the potential to revolutionize our approach to studying and managing the coastal environment.</p></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"219 ","pages":"Article 105409"},"PeriodicalIF":2.2,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142147895","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 : 2024-08-30DOI: 10.1016/j.jafrearsci.2024.105408
Ali Abedini , Ali Asghar Calagari
The Yengejeh diasporic karst bauxite deposit (NW Iran) was developed as discontinuous layers and lenses along the contact of dolomitic limestone of the Ruteh Formation (middle-upper Permian) and dolomite of the Elika Formation (Triassic). This deposit is constituted by two conspicuous subset layers, (1) green bauxite (GB) and (2) red bauxite (RB). The XRD analytic data revealed that diaspore is accompanied by chlorite and anatase in the GB subset and by hematite in the RB subset. Minerals such as pyrophyllite, kaolinite, illite, and rutile are present within the both subsets. The antithetical distributions of Al with Fe and Al with Ti in the deposit are indicative of the controlling role of climatic changes of the depositional environment and the function of post-formation diagenetic processes. The increment in certain geochemical ratios like La/Y, (La/Yb)N, and (LREE/HREE)N from the top toward the bottom of the horizon is designative of pH increase in depositional milieu by buffering of the percolating solutions, and of preferential scavenging of LREE by hematite. The positive Ce anomaly in the GB subset took place as the result of change in the oxidation state of this element from Ce3+ to Ce4+. However, the positive Ce anomalies in the RB subset implicates preferential scavenging of Ce onto hematite. The marked variation range in anomaly values of Eu/Eu* (0.38–1.01) at Yengejeh reveals that this index acted as non-conservative during the evolution of this deposit, and this behavior is related most likely to influences of post-formation diagenetic processes.
Yengejeh散居岩溶铝土矿(伊朗西北部)沿鲁特地层(中-上二叠统)白云质灰岩和埃利卡地层(三叠统)白云岩的接触面发育为不连续的层和透镜体。该矿床由两个明显的子集层构成:(1)绿色铝土矿(GB)和(2)红色铝土矿(RB)。XRD 分析数据显示,在 GB 亚层中,绿泥石和锐钛矿与斜长石伴生,而在 RB 亚层中,赤铁矿与斜长石伴生。在这两个子集中还存在辉石、高岭石、伊利石和金红石等矿物。矿床中 Al 与 Fe 和 Al 与 Ti 的反向分布表明了沉积环境气候变化的控制作用和成岩后成岩过程的作用。某些地球化学比率,如 La/Y、(La/Yb)N 和 (LREE/HREE)N 从地层顶部向地层底部的递增,表明沉积环境中的 pH 值因渗流溶液的缓冲作用而升高,以及赤铁矿对 LREE 的优先清除作用。GB 子集中的正 Ce 异常是由于该元素的氧化态从 Ce3+ 变为 Ce4+ 的结果。然而,RB 子集中的正 Ce 异常表明赤铁矿优先清除了 Ce。在 Yengejeh,Eu/Eu*异常值(0.38-1.01)的明显变化范围表明,在该矿床的演化过程中,该指标是非保守的,这种行为很可能与成岩后成岩过程的影响有关。
{"title":"The yengejeh diasporic karst bauxite deposit, NW Iran: Constraints on distribution and fractionation of major and rare earth elements","authors":"Ali Abedini , Ali Asghar Calagari","doi":"10.1016/j.jafrearsci.2024.105408","DOIUrl":"10.1016/j.jafrearsci.2024.105408","url":null,"abstract":"<div><p>The Yengejeh diasporic karst bauxite deposit (NW Iran) was developed as discontinuous layers and lenses along the contact of dolomitic limestone of the Ruteh Formation (middle-upper Permian) and dolomite of the Elika Formation (Triassic). This deposit is constituted by two conspicuous subset layers, (1) green bauxite (GB) and (2) red bauxite (RB). The XRD analytic data revealed that diaspore is accompanied by chlorite and anatase in the GB subset and by hematite in the RB subset. Minerals such as pyrophyllite, kaolinite, illite, and rutile are present within the both subsets. The antithetical distributions of Al with Fe and Al with Ti in the deposit are indicative of the controlling role of climatic changes of the depositional environment and the function of post-formation diagenetic processes. The increment in certain geochemical ratios like La/Y, (La/Yb)<sub>N</sub>, and (LREE/HREE)<sub>N</sub> from the top toward the bottom of the horizon is designative of pH increase in depositional milieu by buffering of the percolating solutions, and of preferential scavenging of LREE by hematite. The positive Ce anomaly in the GB subset took place as the result of change in the oxidation state of this element from Ce<sup>3+</sup> to Ce<sup>4+</sup>. However, the positive Ce anomalies in the RB subset implicates preferential scavenging of Ce onto hematite. The marked variation range in anomaly values of Eu/Eu* (0.38–1.01) at Yengejeh reveals that this index acted as non-conservative during the evolution of this deposit, and this behavior is related most likely to influences of post-formation diagenetic processes.</p></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"219 ","pages":"Article 105408"},"PeriodicalIF":2.2,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142098878","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 : 2024-08-29DOI: 10.1016/j.jafrearsci.2024.105407
Burcu Karataş , Mustafa Akyildiz , Nail Yildirim , Tolga Oyman
The Tütün Tepeleri Fe-Oxide-Cu-Au (IOCG) mineralization is located in the Eastern Taurus Mountains (Baskil-Elazığ/Turkey) and it is associated with Baskil magmatites (diorite, gabbro and tonalite) cut by Late Cretaceous Bilaser Tepe magmatites (quartized diorite, granite, granodiorite, tonalite porphyry, monzosyenite, monzonite, aplite and diorite porphyry). Baskil Magmatites are Coniacian-Santonian (82–86 Ma), calc-alkaline in character and I-type. Bilaser Tepe Magmatics are Campanian (73–74 Ma) and represent an extensional environment after the collision of oceanic arc and the Taurus platform. In this study, the Sodic-calcic alteration zone in the Tütün Tepeleri region, which was determined as Porphyry type mineralization by different researchers, was determined for the first time and the mineralizations were evaluated in terms of Fe-Oxide-Cu-Au (IOCG) deposits. Three types of alteration zones have been identified in the region, including the sodic-calcic alteration zone. These are sodic-calcic (tremolite-actinolite, albite, epidote, chlorite, magnetite), potassic (biotite, quartz, chlorite, K-feldspar, anhydrite) and sericitic (sericite, carbonate, quartz, chlorite, illite) alterations. Sodic-calcic alteration is more widespread in the region than >1 km2, reaches thicknesses of 500 m, and is occasionally overlain by potassic alterations, just like similar Fe-Oxide-Cu-Au (IOCG) deposits in the world. Tütün Tepeleri mineralizations are in the form of rare magnetite veins with intense magnetite dispersion within the sodic-calcic alteration developed in diorites. Mineral paragenesis is in the form of magnetite, molybdenite, pyrite, arsenopyrite, chalcopyrite, sphalerite, galena, hematite, malachite and azurite, and Ti content in magnetites is determined as 0.13–0.64%. Fe content is 20.13% on average. Formation temperatures in fluid inclusions measured in ore-bearing quartz veins are 320.3 °C on average and salinity is 11.32% NaCl equivalent on average. Isotope analysis results of these mineralizations show δ34Spyrite = 6–8.9; δ34Sc.pyrite = 3.8–5.5; δ18Oquartz was determined in the range of 10.8–13.2 and δD = (−37) – (−53). When the alteration types determined with isotope analysis results showing that the mineralization occurred in a magmatic-hydrothermal system, the low Ti content in the magnetites, the formation temperature and salinity values are evaluated together, it was anticipated that Tütün Tepeleri mineralization is an example of Fe-Oxide-Cu-Au (IOCG) deposits formed in a hydrothermal-magmatic system.
{"title":"Formation conditions and geochemistry of the Tütün Tepeleri (Baskil-Elazig/Türkiye) Fe-oxide-Cu-Au (IOCG) mineralization","authors":"Burcu Karataş , Mustafa Akyildiz , Nail Yildirim , Tolga Oyman","doi":"10.1016/j.jafrearsci.2024.105407","DOIUrl":"10.1016/j.jafrearsci.2024.105407","url":null,"abstract":"<div><div>The Tütün Tepeleri Fe-Oxide-Cu-Au (IOCG) mineralization is located in the Eastern Taurus Mountains (Baskil-Elazığ/Turkey) and it is associated with Baskil magmatites (diorite, gabbro and tonalite) cut by Late Cretaceous Bilaser Tepe magmatites (quartized diorite, granite, granodiorite, tonalite porphyry, monzosyenite, monzonite, aplite and diorite porphyry). Baskil Magmatites are Coniacian-Santonian (82–86 Ma), calc-alkaline in character and I-type. Bilaser Tepe Magmatics are Campanian (73–74 Ma) and represent an extensional environment after the collision of oceanic arc and the Taurus platform. In this study, the Sodic-calcic alteration zone in the Tütün Tepeleri region, which was determined as Porphyry type mineralization by different researchers, was determined for the first time and the mineralizations were evaluated in terms of Fe-Oxide-Cu-Au (IOCG) deposits. Three types of alteration zones have been identified in the region, including the sodic-calcic alteration zone. These are sodic-calcic (tremolite-actinolite, albite, epidote, chlorite, magnetite), potassic (biotite, quartz, chlorite, K-feldspar, anhydrite) and sericitic (sericite, carbonate, quartz, chlorite, illite) alterations. Sodic-calcic alteration is more widespread in the region than >1 km<sup>2</sup>, reaches thicknesses of 500 m, and is occasionally overlain by potassic alterations, just like similar Fe-Oxide-Cu-Au (IOCG) deposits in the world. Tütün Tepeleri mineralizations are in the form of rare magnetite veins with intense magnetite dispersion within the sodic-calcic alteration developed in diorites. Mineral paragenesis is in the form of magnetite, molybdenite, pyrite, arsenopyrite, chalcopyrite, sphalerite, galena, hematite, malachite and azurite, and Ti content in magnetites is determined as 0.13–0.64%. Fe content is 20.13% on average. Formation temperatures in fluid inclusions measured in ore-bearing quartz veins are 320.3 °C on average and salinity is 11.32% NaCl equivalent on average. Isotope analysis results of these mineralizations show δ<sup>34</sup>S<sub>pyrite</sub> = 6–8.9; δ<sup>34</sup>S<sub>c.pyrite</sub> = 3.8–5.5; δ<sup>18</sup>O<sub>quartz</sub> was determined in the range of 10.8–13.2 and δD = (−37) – (−53). When the alteration types determined with isotope analysis results showing that the mineralization occurred in a magmatic-hydrothermal system, the low Ti content in the magnetites, the formation temperature and salinity values are evaluated together, it was anticipated that Tütün Tepeleri mineralization is an example of Fe-Oxide-Cu-Au (IOCG) deposits formed in a hydrothermal-magmatic system.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"220 ","pages":"Article 105407"},"PeriodicalIF":2.2,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142322392","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}