Journal of African Earth Sciences最新文献

{"title":"Petrographical and geochemical insights into gabbroic rocks in ophiolitic occurrences from Kınık-Kütahya (Türkiye)","authors":"İrem Aksoy,&nbsp;Gürsel Yanık","doi":"10.1016/j.jafrearsci.2025.105686","DOIUrl":"10.1016/j.jafrearsci.2025.105686","url":null,"abstract":"<div><div>The ophiolitic rocks within the Tavşanlı zone offer valuable insights into the closure period of the Neotethys and subsequent geological processes. This study focuses on the petrographic and geochemical characteristics of gabbroic rocks from the Kınık Ophiolite in Kütahya, Turkey. Petrographic observations show that the main constituents of gabbroic rocks are plagioclase (labradorite, bytownite), orthopyroxene, clinopyroxene, and hornblende. Hydrothermal alterations such as uralitization, chloritization, and carbonization are commonly observed in ophiolitic rocks. The mafic rocks are part of a differentiated tholeiitic magma series, emphasizing their co-magmatic evolution within the context of the ophiolitic complex. Despite variations in Large Ion Lithophile Elements (LILEs; K, Sr, Rb, and Ba) due to low-temperature hydrothermal alteration (e.g., saussuritization of plagioclase, uralitization of pyroxene, and chlorite–prehnite vein formation), the geochemical signature of the Kınık gabbroic rocks suggests island arc tholeiitic (IAT) characteristics. Additionally, their rare earth element (REE) patterns strongly indicate a supra-subduction zone (SSZ) affinity. The development of the Kınık ophiolite, involving magmatic crystallization, occurred during the final stages of island arc evolution in the Neotethyan Ocean within a supra-subduction, fore-arc tectonic setting.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"229 ","pages":"Article 105686"},"PeriodicalIF":2.2,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143924535","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}

{"title":"Geochemical approach to depositional setting and organic matter accumulation of lower cretaceous shales of the Mundeck formation, Kribi-Campo sub-basin (South Cameroon)","authors":"Ashukem Ethel Nkongho ,&nbsp;Bokanda Ekoko Eric ,&nbsp;Bisse Salomon Betrant ,&nbsp;Philip Fralick ,&nbsp;Belinga Belinga Cedric ,&nbsp;Daniel Florent Akono ,&nbsp;Ekomane Emile","doi":"10.1016/j.jafrearsci.2025.105685","DOIUrl":"10.1016/j.jafrearsci.2025.105685","url":null,"abstract":"<div><div>In order to deduce the origin, depositional setting and factors of organic matter accumulation, the Kribi Campo shales were examined for total organic carbon and geochemical analysis. The results show that the average total organic carbon concentration in the six studied sites are greater than 1 (3.58–12.26 w. %), suggesting they are good source rocks. The studied shales reveal V/Ni values of 1.88–4.26 indicating that the organic matter in the shales were sourced from marine origin and mixed terrestrial marine origin. The Al, Zr and Zr/Al diagrams, indicate that the terrigenous debris influx was relatively high in the Lower Formation and fluctuates from relatively constant to relatively decreasing and increasing manner in the Upper Formation. The Ni/Co, V/Cr, U/Th ratios range from 1.39 to 3.21, 1.22–1.81, 0.18–0.45 respectively, and an average Y/Ho ratio of 26.37–28.71 ppm, indicate the shales were deposited in a continental environment. The paleoproductivity proxies (P/Ti, Babio, Cu/Al, and Ni/Al), shows that in both Formation the P/Ti average ratio value (0.27 and 0.29), indicates moderate rate of paleoproductivity. Ba_bio average concentration in the studied sites of the Upper Mundeck Formation is higher than that of the Lower Mundeck Formation, indicating the authigenic barium sulfate was stored in variable quantities in the different studied sites of both Formations, its values vary from 322.94 to 2335.22 ppm, indicates a low to moderate paleoproductivity. The organic matter was preserved as a result of rapid deposition, high sedimentation and lesser exposure time.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"229 ","pages":"Article 105685"},"PeriodicalIF":2.2,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144105350","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}

{"title":"Hydrogeochemical properties of Çal Cave and its vicinity: Development and consequences of karstification in Düzköy (Trabzon, NE Türkiye)","authors":"Hilal Alemdağ ,&nbsp;Fatih Köroğlu ,&nbsp;Arzu Fırat Ersoy ,&nbsp;Aysel Şeren ,&nbsp;Zeynep Öğretmen Aydın ,&nbsp;Ali Erden Babacan","doi":"10.1016/j.jafrearsci.2025.105680","DOIUrl":"10.1016/j.jafrearsci.2025.105680","url":null,"abstract":"<div><div>Çal Cave, through which an underground river runs, was formed through the karstification of the neritic limestones that make up the Şahinkaya Formation, located between the neighbouring districts of Çayırbağı and Çalköy in Düzköy (Trabzon). The purpose of this study was to analyse the hydrogeochemical characteristics of samples collected from Çal Cave and the waters believed to supply it to determine their potential origins. Water samples were collected from nine locations during the wet and dry periods. After measuring the physical parameters of the samples, major anion–cation and trace element analyses were performed. When the parameters were compared with both WHO and Turkish standards, it was determined that they were within the limit values specified in the relevant regulations. Schoeller and Piper diagrams suggest that these waters are fed by the same origin and can be classified as a Ca-HCO₃ water type. Water-saturated zones were identified through electrical resistivity tomography sections that analysed the areas around the sampling sites. Finally, a comparison of the water quality data of water samples from Çal Cave during the dry season, published by Ofluoğlu in 1993, and this study's dry season water quality data revealed a decrease in the concentrations of Ca²⁺, Mg²⁺, K⁺, Cl⁻ and SO₄²⁻. The reason for this decrease over the past 29 years is likely the increased number of entryways where surface waters feed the cave.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"229 ","pages":"Article 105680"},"PeriodicalIF":2.2,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143937701","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}

{"title":"Neogene sedimentary evolution and biostratigraphy of the Kasaba and Aksu-Gebiz basins in the eastern Mediterranean: Insights from paleontology and Sr isotope stratigraphy","authors":"Ahmet Can Akıncı ,&nbsp;Nusret Nurlu ,&nbsp;Ulvi Can Ünlügenç ,&nbsp;Deniz İbilioğlu ,&nbsp;Hande Sonsun","doi":"10.1016/j.jafrearsci.2025.105674","DOIUrl":"10.1016/j.jafrearsci.2025.105674","url":null,"abstract":"<div><div>The Kaş-Kasaba and Aksu-Gebiz basins are two important Neogene basins in the Eastern Mediterranean, flanking the Gulf of Antalya in southwestern Anatolia. Comprehensive studies involving sedimentology, paleontology, and Sr isotopes have offered valuable insights into the sedimentary characteristics and depositional environments of these basins during the Neogene period. In the west, the Kasaba Basin features an early to middle Miocene carbonate-clastic succession that developed on the Late Cretaceous Beydağları autochthon, overlain by Paleocene-Eocene neritic carbonates. In contrast, the Aksu-Gebiz Basin in the east presents a transgressive sequence of middle Miocene to Pliocene clastics and carbonates, which developed on different basement units, including the Mesozoic metamorphosed carbonates and the Antalya Complex in the west. Biostratigraphic studies in the Kasaba (Kaş) region revealed 9 genera and 23 species of planktonic foraminifera in the Kasaba Formation, and 12 genera and 29 species in the Sinekçi Fm., marking the lower boundary of the <em>Orbulina suturalis</em> Lineage Subzone (MMi5a) of the middle Miocene. Similarly, in the Gebiz (Aksu) region, the planktonic foraminifera indicate the lower boundary of the MMi12a <em>Globigerinoides obliquus extremus</em>-<em>Globorotalia suterae</em> Interval Subzone of the late Miocene. Benthic foraminifera indicative of shelf environments were identified in both regions. Whole-rock strontium isotope chemostratigraphy revealed ages ranging from 14.3 to 23.7 Ma based on ⁸⁷Sr/⁸⁶Sr ratios from three key samples. Overall, studies in the Kasaba Basin suggest a lower to middle Miocene age with shallow marine environments, consistent with Serravallian to Langhian periods. In the Aksu-Gebiz Basin, detailed investigations of the Karpuzçay Formation identified a mid-Tortonian age. This age, combined with sedimentological and structural data, provides insights into the basin's tectonic evolution and flexural effects. Planktonic and benthic foraminifera within the sequence reflect inner shelf environments throughout. The strontium isotope analysis of samples from the Aksu-Gebiz Basin revealed significant variations in ⁸⁷Sr/⁸⁶Sr ratios, with ages ranging from the Tortonian (9.0 Ma) to the Messinian (5.3 Ma). By integrating biostratigraphy and whole-rock Sr isotope stratigraphy, this study refines the Neogene chronological framework of the Kasaba and Aksu-Gebiz Basins, providing new insights into the Eastern Mediterranean's geological history. These findings also improve stratigraphic correlations with adjacent basins, offering a more comprehensive regional context.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"229 ","pages":"Article 105674"},"PeriodicalIF":2.2,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143924536","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}

{"title":"Zircon and Titanite U-Pb geochronology, petrology and P-T path of garnet-bearing amphibolites from Tadoumet area (Assodé-Issalane terrane, Central Hoggar, Algeria)","authors":"Sofiane Dahmani ,&nbsp;Khadidja Ouzegane ,&nbsp;Amar Drareni ,&nbsp;Carlos J. Garrido ,&nbsp;Manuel J. Román-Alpiste ,&nbsp;Sidali Doukkari ,&nbsp;Amar Arab","doi":"10.1016/j.jafrearsci.2025.105675","DOIUrl":"10.1016/j.jafrearsci.2025.105675","url":null,"abstract":"<div><div>The garnet-bearing amphibolites of the Tadoumet area (Assodé-Issalane terrane, Orosirian Stripe, Hoggar), show three principal metamorphic stages. (i) A pre-peak metamorphic stage, characterized by mineral inclusions of quartz, plagioclase, epidote, rutile, and titanite encapsulated within garnet porphyroblasts (M0); (ii) A relatively high-grade stage, represented by a coarse-grained paragenesis comprising garnet porphyroblasts, amphibole, clinopyroxene, quartz, titanite, and rutile (M1); (iii) A retrograde stage, marked by the development of amphibole‒plagioclase‒K-feldspar coronae assemblages around garnet with titanite (M2).Microprobe analysis indicates that garnet compositions range between X_Alm = 0.47–0.58, X_Gr = 0.25–0.35, and X_Py = 0.06–0.16. Clinopyroxenes exhibit zoning, with cores depleted in Mg relative to the rims (X_Mg core = 0.57, X_Mg rim = 0.65). Furthermore, amphibole associated with the M1 stage displays compositions indicative of magnesio-hornblende, whereas the M2 stage is characterized by magnesian-hastingsite coronae (Si &lt; 6.25 and X_Mg = 0.4–0.6). Tschermakite, with X_Mg values of 0.51–0.60, is found in association with clinopyroxene and plagioclase (X_An = 0.34–0.48).Calculated P-T pseudosections suggest peak P–T conditions of 13.5 ± 1 kbar and 700 ± 50 °C (M1), characterizing a mineral assemblage comprising hornblende, diopside, garnet, K-feldspar, plagioclase, rutile, titanite, and melt, based on garnet core compositions. Additionally, decompression stage corresponds to high temperature conditions (750 ± 50 °C, M2a) followed by cooling (600 ± 50 °C, M2b) at 6.5 ± 1 kbar, using the compositions of garnet rims, secondary diopside, amphibole, and plagioclase isopleths and Ti in amphibole geothermometer. This study constitutes the first geochronological investigation of metamorphism in the Tadoumet area, utilizing in situ U–Pb dating of zircon and titanite. The findings indicate a protolith age of 712 ± 20 Ma (derived from zircons) and an amphibolite-facies metamorphic age of 599 ± 4 Ma (obtained from titanite). The P–T trajectory recorded in the garnet-bearing amphibolites is interpreted as reflecting a distinct sequence of continental collision, in which crustal thickening denotes the peak of metamorphism, followed by decompression driven probably by extensional processes.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"228 ","pages":"Article 105675"},"PeriodicalIF":2.2,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143902428","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}

{"title":"Corrigendum to “Facies and sequence stratigraphy of the Katangan Basin in Zambia” [J. African Earth Sci. 227 (2025) 105617]","authors":"Martin Purkiss","doi":"10.1016/j.jafrearsci.2025.105669","DOIUrl":"10.1016/j.jafrearsci.2025.105669","url":null,"abstract":"","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"228 ","pages":"Article 105669"},"PeriodicalIF":2.2,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143929346","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}

{"title":"Integrated geological and geophysical analysis of the active Sidi–Thabet fault in northeastern Tunisia: insights into recent deformation and seismotectonic implications","authors":"Lassaad Mejri ,&nbsp;Chahreddine Naji ,&nbsp;Nermine Sayah ,&nbsp;Amara Masrouhi ,&nbsp;Olivier Bellier","doi":"10.1016/j.jafrearsci.2025.105672","DOIUrl":"10.1016/j.jafrearsci.2025.105672","url":null,"abstract":"<div><div>The Sidi-Thabet fault, a key structure within the Atlas-Tell orogenic belt in northern Tunisia, illustrates the complex interplay between inherited Tethyan extensional features and subsequent compressional deformation during Tertiary African-Eurasian plate convergence. This study provides insights into the recent activity and seismotectonic significance of the fault by combining geological mapping, shallow geophysical surveys and morphotectonic analysis with seismic and focal mechanism studies. Steeply dipping fault planes, brittle fracture zones and vertical displacements affecting Quaternary and Cretaceous strata are evident from seismic refraction and electrical resistivity tomography. The evidence for recent fault reactivation is further supported by morphotectonic markers. These include displaced calcrete beds, fresh scarps, and disrupted landforms. The focal mechanism analysis indicates a predominantly compressional tectonic regime with secondary normal faulting. This emphasizes that this fault accommodates both transpressional shortening and vertical uplift along its segmented trace. The presence of ductile salt layers enhances deformation complexity, driving differential uplift and influencing the architecture of fault-related folds. These results confirm that the Sidi-Thabet Fault is a major zone of active deformation within the Tunisian Atlas, emphasizing its critical role in seismic hazard assessment, especially given its proximity to Tunis, a city of three million people located just south of the fault.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"228 ","pages":"Article 105672"},"PeriodicalIF":2.2,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143876504","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}

{"title":"The geological and economic legacy of the Pan-african Damara Belt and Lufilian Arc of south-central africa","authors":"Benjamin Siyowi Mapani ,&nbsp;Kabang'u Grace Sakuwaha ,&nbsp;Kawawa Banda","doi":"10.1016/j.jafrearsci.2025.105662","DOIUrl":"10.1016/j.jafrearsci.2025.105662","url":null,"abstract":"<div><div>The Neoproterozoic belts of southern Africa, which include the Damara Belt and the Lufilian Arc, have had a significant impact on the understanding of the geology of Southern Africa and related regions. Above all, both belts are economically important as they host metallic and non-metallic mineral deposits of the Kalahari and Central African Copperbelt which are mined in Namibia, Democratic Republic of Congo (DRC), and Zambia respectively. The Damara Belt continues in a north-easterly direction into Botswana, where it continues below the Phanerozoic cover of the Karoo and Kalahari Supergroups to connect in the subsurface with the Lufilian Arc in western Angola and Zambia. The two belts record a full Wilson cycle and form part of a transcontinental suture zone which resulted from the collision between the Archean Congo and Kalahari cratons. The Damara Belt in Namibia, records a progressive increase in metamorphic grade and deformation intensity from sub-greenschist facies on the northern platform to HT/LP granulite facies in the core of the orogen. Similarly, the Lufilian Arc also records a gradual increase in metamorphic grade from sub-greenschist facies in the north (in the DRC) to amphibolite facies in the in the Domes Region in Zambia. Mineralization in these belts differs in style, shape, and size, which can be attributed to the differences in the nature and characteristics of the original sub-basins that formed during rifting, and subsequent deformation. In the Lufilian Arc, ore reserves for individual mines are in the order of 50–810 Mt of ore at 0.5–3 % Cu. This scale is simply not comparable to that in the Damara Belt with tonnages of up to 35 Mt with grades of 0.1–2 % Cu. Both regions also contain numerous smaller copper deposits. On the other hand, the Damara Belt hosts the world class Rossing and Husab uranium mines of Namibia (with grades of 310–450 ppm U) but no major uranium deposits occur in the Lufilian Arc. The Damara uranium deposits occur associated with syn-to post-tectonic granites in the core of the orogen where granite formation was initiated by anatexis of the metasedimentary rocks of the Swakop Group. In contrast, the associated Pb-Zn ± Cu mineralization in both belts appears to be remarkably similar, with comparable deposit sizes, grades, and estimated reserves. The legacy of these two orogenic belts is significant in that the Lufilian Arc serves as the standard or type locality for understanding sediment-hosted Cu-Co deposits globally, whereas the Damara Belt has been the key to understanding granite melt generation by anatexis and formation of granite-hosted uranium deposits in the world.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"228 ","pages":"Article 105662"},"PeriodicalIF":2.2,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143900095","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}

{"title":"Jurassic tectonic and paleogeographic evolution of the junction zone between the Middle Atlas and High Atlas (Morocco)","authors":"Youssef Ouahzizi,&nbsp;Mohammed Charroud,&nbsp;Driss El Azzab","doi":"10.1016/j.jafrearsci.2025.105673","DOIUrl":"10.1016/j.jafrearsci.2025.105673","url":null,"abstract":"<div><div>The Middle Atlas (MA) and High Atlas (HA) chains are considered intraplate basins developed during the Mesozoic Era. The Jurassic structural evolution of the junction between MA-HA recorded three successive tectonic events beginning with a NE-SW extensional tectonic regime responsible for the differentiation between a nearshore environment to northwest with sandstone and pelite deposits, the platform domain with its metric carbonate marls, and a basin domain filled with black marls and limestones with an euxinic character during the Toarcian. In this episode, the sedimentary thickness is controlled by High Atlas trending faults (N120-N110). The second tectonic event corresponds to a tectonic extension regime with an NW-SE to NNW-SSE directed σ3 axis, causing subsidence towards the southeastern part delimited by the Middle Atlas direction faults (NE-SW). The sedimentary series indicates an evolution from a continental environment in the northwest (conglomerates and sandstones) to platform and basin sedimentation in the southeast, noted by the intercalation of marls and bioclastic limestones of the Aalenian–Bajocian age. During the third tectonic event (Bathonian–Barremian), the sedimentary series becomes continental lagoonal deposits represented by marls with limestones, grading into sandstone and gypsum marl, and conglomerates overlain by marls and sandstones of the \"Red beds\". This evolution associated with by the establishment of a transpressional tectonic regime with NNE-SSW compression σ1 axis responsible for uplift using High Atlas direction faults (E-W to ENE-WSW), caused marine regression; this compression is accompanied by WNW-ESE extension σ3 axis responsible for subsidence towards the southern part with the establishment of basalt lava flows and gabbroic dykes of the Bathonian–Barremian magmatism complex.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"228 ","pages":"Article 105673"},"PeriodicalIF":2.2,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852245","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}

{"title":"Optimizing permeability and porosity prediction with advanced machine learning: A case study unlocking the complexities of late cretaceous reservoirs, gulf of suez, Egypt","authors":"Amer A. Shehata ,&nbsp;Mohamed Ahmed ,&nbsp;Ahmed A. Kassem ,&nbsp;Ramadan Abdelrehim ,&nbsp;Takeshi Tsuji ,&nbsp;Amir Ismail","doi":"10.1016/j.jafrearsci.2025.105670","DOIUrl":"10.1016/j.jafrearsci.2025.105670","url":null,"abstract":"<div><div>Permeability and porosity are critical parameters that influence the evaluation and management of hydrocarbon reservoirs. Conventional permeability and porosity estimation techniques are constrained by data scarcity and geological variability, necessitating advanced predictive models. This study presents a fully automated machine learning (AML) framework that combines four advanced models—Gradient Boosting Machine (GBM), Distributed Random Forest (DRF), Generalized Linear Model (GLM), and Deep Neural Network (DNN)—to predict permeability and porosity based on well log data. The approach integrates twelve well-log responses (i.e. caliper, gamma ray, sonic, density, porosity, water saturation, volume of shale, resistivity) from five wells (inputs), demonstrating enhanced prediction accuracy for permeability and porosity in the Late Cretaceous reservoirs of the Gulf of Suez, Egypt. To ensure robust model training and validation, the dataset was divided into training (60 %), validation (20 %), and testing (20 %) subsets, and model performance was evaluated using Nash-Sutcliffe Efficiency (NSE), correlation coefficient (r), normalized root mean square error (NRMSE), and bias (B). The DNN model excelled in permeability estimation (testing: NRMSE: 0.57 ± 0.09; NSE: 0.68 ± 0.14; r: 0.82 ± 0.10; B: 9.17), while the DRF model outperformed in predicting porosity (testing: NRMSE: 0.72 ± 0.02; r: 0.69 ± 0.03; NSE: 0.47 ± 0.04; B: 0.93) compared to other models, showcasing superior performance metrics such as Nash-Sutcliff efficiency, correlation coefficients, and normalized root mean square error. The GLM model exhibits the least favorable performance when compared to other ML models. Additionally, this study identifies key well log responses, such as sonic, gamma ray, and deep resistivity logs, as major controlling factors for permeability and porosity predictions, highlighting their nonlinear relationships. The developed AML models provide a cost-efficient, computationally effective, and scalable solution for petrophysical property estimation, enhancing reservoir characterization and enabling broader applications in hydrocarbon exploration and beyond.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"228 ","pages":"Article 105670"},"PeriodicalIF":2.2,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143859738","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}