Journal of African Earth Sciences最新文献

{"title":"Zircon U–Pb ages and Sr-Nd isotope ratios for the mafic microgranular enclaves in the sirstan cretaceous granitoids, NE Iraq: Evidence of cogenetic magmatic origin","authors":"Imad Kadhim Abdulzahra ,&nbsp;Yoshihiro Asahara ,&nbsp;Yousif Mohammad ,&nbsp;Irfan Yara","doi":"10.1016/j.jafrearsci.2025.105665","DOIUrl":"10.1016/j.jafrearsci.2025.105665","url":null,"abstract":"<div><div>Mafic microgranular enclaves (MMEs) are observed in the Sirstan granitoid (SG) body in the Shalair Valley area, northeastern Iraq, within the Zagros Orogenic Belt. Zircon U–Pb ages for the MMEs are 110 Ma with an I-type affinity closely resembling the enclosing rocks. The MMEs are gabbroic-diorite to diorite in composition, and the main mineral assemblage are plagioclase, hornblende, and K-feldspar. The MMEs are intermediate in composition and have low SiO₂ (52.0–60.2 wt%) and high Fe₂O₃, Al₂O₃, TiO₂ and CaO contents (Fe₂O₃ = 8.7–13.3 wt%; Al₂O₃ = 14.8–17.2 wt%; TiO₂ = 0.71–1.02 wt%; CaO = 3.4–11.4 wt%). The enclaves have analogous Sr and Nd isotope compositions with positive εNd_(t) values (⁸⁷Sr/⁸⁶Sr(i) = 0.7047 to 0.7058; εNd_(t) = +2.0 to +2.5) as their host granitoids (⁸⁷Sr/⁸⁶Sr(i) = 0.7044 to 0.7057; εNd_(t) = +0.1 to +2.7). The uniform REE patterns and the fractionation trends of major and trace elements of the MMEs with their host rocks indicate simultaneous crystallization by fractionation from the same magma source. According to the geochemical aspects of the MMEs and their host SG rocks with young T_DM ages (676–720 Ma), the low ratios of the Rb/Sr and Nb/Y ratios, in addition to the same ages and Sr-Nd isotope ratios, infer that the same source magma was derived from a young depleted mantle without the contribution of ancient crustal components.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"228 ","pages":"Article 105665"},"PeriodicalIF":2.2,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143854861","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 structure of Precambrian crust in sub-Saharan Africa: An AfricaArray synthesis and review","authors":"Alexandra Sabattier ,&nbsp;Andrew Nyblade ,&nbsp;Raymond Durrheim ,&nbsp;Fenitra Andriampenomanana ,&nbsp;Andriamiranto Raveloson ,&nbsp;Islam Fadel ,&nbsp;Mark van der Meijde ,&nbsp;Amanda Willet","doi":"10.1016/j.jafrearsci.2025.105664","DOIUrl":"10.1016/j.jafrearsci.2025.105664","url":null,"abstract":"<div><div>We combine new estimates of crustal thickness and shear wave velocities from 48 broadband seismic stations in Mozambique, Namibia, South Africa and Uganda with previously published results to review and examine Precambrian crustal structure in sub-Saharan Africa for secular trends. The ensemble of crustal structure estimates used relies heavily on data obtained through the AfricaArray initiative, which is briefly reviewed. Whether or not Precambrian crustal structure exhibits notable changes from the Mesoarchean through the Neoproterozoic places a key constraint on continental crustal genesis and evolution. Our 48 new estimates of Moho depth and crustal shear wave velocity profiles, combined with results from similar previous studies, yield an average crustal thickness for all Precambrian terranes of 39 ± 4 km. We find that average crustal thicknesses are essentially identical for Mesoarchean (38 ± 3 km), Neoarchean (39 ± 4 km), Paleoproterozoic (40 ± 4 km), Mesoproterozoic (40 ± 4 km) and Neoproterozoic (39 ± 4 km) terranes. The average thickness of the mafic lower crust, identified by high velocity layering (Vs &gt; 4.0 km/s), is also almost identical in Archean and Proterozoic terranes (7 ± 4 km and 6 ± 4 km, respectively). Finally, the average crustal shear wave velocities for all terranes fall within 1 standard deviation of a mean velocity of 3.7 km/s. These results are consistent with findings from other studies highlighting a lack of evidence for secular variation in crustal structure or composition within Precambrian terranes in sub-Saharan Africa, suggesting that secular trends, if they existed at the time of crust formation, have been obscured by crustal reworking during later orogenic and/or magmatic events.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"228 ","pages":"Article 105664"},"PeriodicalIF":2.2,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834841","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 first definitive Albian ammonites from the Kribi-Campo sub-basin in Cameroon and biostratigraphic implications for the opening of the South Atlantic","authors":"Elie Fosso Menkem ,&nbsp;Emmanuel Robert ,&nbsp;Paul Gustave Fowe Kwetche ,&nbsp;Marie-Joseph Ntamak Nida ,&nbsp;Jeremy E. Martin","doi":"10.1016/j.jafrearsci.2025.105659","DOIUrl":"10.1016/j.jafrearsci.2025.105659","url":null,"abstract":"<div><div>The timing of the opening of the Equatorial South Atlantic Ocean during the Cretaceous is poorly constrained. Despite previous research carried out along the West African continental margin, the biostratigraphic attribution of the Kribi-Campo sedimentary deposits in Cameroon remain poorly known leading to uncertainties in the ages of the formation and thus leading to incorrect interpretations and correlations of stratigraphic sequences. To date, the deposits are known to correspond to alluvial fan facies from the Lower Mundeck Formation and the assigned age is Barremian?-Aptian. We carried out a prospection in the sedimentary outcrops along the shoreline in the Kribi-Campo sub-Basin where poorly preserved but identifiable ammonite specimens were discovered and collected for analysis in order to determine the age of the formation. The marker bed containing the ammonite fossils consists of thin carbonaceous sandy shale. Our determinations revealed the following ammonites: <em>Douvilleiceras</em> sp. and Uhligellinae that characterize the basal Lower Albian (<em>Douvilleiceras leightonense</em> Zone) interval. This result allows us to suggest a reconsideration of the Kribi-Campo sub-basin deposits to be part of the upper Mundeck Formation. Our results confirm a diachronic separation of South America and Africa and a full connection between the North and South Atlantic Ocean during the Lower Albian.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"228 ","pages":"Article 105659"},"PeriodicalIF":2.2,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143839691","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 geophysical assessment of Miocene Belayim reservoirs in the Tawila West Oil Field, offshore southern Gulf of Suez, Egypt","authors":"Mohammad Abdelfattah Sarhan ,&nbsp;Mu'ayyad Al Hseinat ,&nbsp;Malek AlZidaneen","doi":"10.1016/j.jafrearsci.2025.105661","DOIUrl":"10.1016/j.jafrearsci.2025.105661","url":null,"abstract":"<div><div>This study evaluates the Miocene Belayim reservoirs in the Tawila West Oil Field (TWOF), located offshore in the southern Gulf of Suez Basin, Egypt. By integrating seismic interpretation with petrophysical data from four wells (TW-1, TW-2, TW-5 ST3-A, and TW-6), the research characterizes reservoir properties and evaluates hydrocarbon potential. Seismic data reveal that NW-SE trending fault systems, forming graben structures within the Belayim Formation, significantly influence the distribution and thickness of the reservoirs. Depth-structure maps for key horizons, Belayim #1 and Belayim #4, highlight notable vertical displacements and structural heterogeneity. These faults align with the Early Miocene tectonic activity associated with the Red Sea-Gulf of Suez rift system and play a critical role in shaping reservoir intervals. Petrophysical analysis indicates that Belayim #1 exhibits superior reservoir quality, with low shale volume (∼10 %), low water saturation (∼20 %), high hydrocarbon saturation (∼80 %), and effective porosity ranging from 15 % to 18 %. In contrast, Belayim #4 displays higher shale volume, lower effective porosity (8 %–12 %), and variable hydrocarbon saturation (40 %–55 %). Belayim #1 emerges as the primary target for hydrocarbon extraction, while Belayim #4 requires careful evaluation due to its structural and petrophysical characteristics. This study underscores the value of integrating seismic and petrophysical data to enhance reservoir characterization and optimize hydrocarbon recovery in TWOF.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"228 ","pages":"Article 105661"},"PeriodicalIF":2.2,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143854862","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":"Extreme impact of the Late Cretaceous–Paleocene tectonic events on the evolution of the southern Tethyan margin: a case study from Eastern Desert, Egypt","authors":"Ibrahim Y. El-Mohandes ,&nbsp;Kamel H. Mahfouz ,&nbsp;Jun Shen ,&nbsp;Nageh A. Obaidalla ,&nbsp;Abeer Shreif ,&nbsp;Islam El-Sheikh","doi":"10.1016/j.jafrearsci.2025.105663","DOIUrl":"10.1016/j.jafrearsci.2025.105663","url":null,"abstract":"<div><div>The well-distributed Late Cretaceous–early Paleogene rocks in Egypt are one of the keys to understanding the geologic history of the southern Tethys. Four Late Cretaceous–early Paleogene successions exposed in the Esh-ElMellaha area were investigated. The integrated stratigraphic analyses, including; field, lithostratigraphy and biostratigraphy of these sections within the Esh-ElMellaha ridge showed interesting results. Intensive tectonic processes throughout Paleocene period substantially influenced all rock units, causing differences in their facies and thickness. In addition, these tectonic processes deformed the sedimentary basins. During the Paleocene, Esh-ElMellaha area experienced two significant syn-sedimentary tectonic events (I and II) related to the Syrian Arc Tectonic Event. The evolution of the Esh-ElMellaha basin has been documented for the first time throughout this period which is extremely dependent upon these tectonic events. Four paleo-relief profiles were created to illustrate how these events impacted the history of sedimentary basins, extending from the North Wadi Qena northward to the Gabal Hamadat southward. The strength of tectonic events caused the Esh-ElMellaha area to undergo substantially varied degrees of instability. These profiles demonstrate the stability of the deposition during the Maastrichtian period. However, during the Danian, the basin experienced the deposition of thin strata expanding from north to south. This uplifted the basin into submarine paleohigh and created an erosional surface. During the late Paleocene (Selandian-Thanetian), the basin was deeper in the south (Hamadat) than in the north (North Wadi Qena). In contrast, the basin in the Esh-ElMellaha area became an aerial paleohigh, an event that began at the end of the Danian and continued until the early Eocene (Ypresian). This uplift led to the formation of significant paleosol layers. Moreover, the depocenter's southern sections of Esh-ElMellaha had a less tectonic effect, while the northern regions of Esh-ElMellaha witnessed extreme tectonic activity.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"228 ","pages":"Article 105663"},"PeriodicalIF":2.2,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143820521","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":"2D/3D inversion of geomagnetic data for characterization of the Tulu Moye geothermal reservoir, central main Ethiopian rift, Ethiopia","authors":"Samson Hilemichaeil ,&nbsp;Tigistu Haile ,&nbsp;Gezahegn Yirgu","doi":"10.1016/j.jafrearsci.2025.105667","DOIUrl":"10.1016/j.jafrearsci.2025.105667","url":null,"abstract":"<div><div>Owing to its location in the active parts of the East African Rift System, the Ethiopian Rift System defined by weakening lithosphere, active volcanism, and advanced levels of rifting exhibits geothermal manifestations. As a consequence, the Ethiopian Rift System is one of the promising areas for geothermal resource development and as such roughly 120 locations inside the ERS had their own heating and circulation systems. Seven of these areas have been identified as most promising. One of these geothermal areas is the Tulu Moye geothermal prospect (the subject of this study), found at the eastern margin of the Central Main Ethiopian Rift. Ground-based high density (92000 points) total intensity magnetic data were acquired and analyzed to determine the presence of hydrothermal alteration caused by thermal activity as well as map the extent and geometry of the geothermal reservoir. To minimize the remnant magnetic field effect, the magnetic field was Reduced-to-Equator (RTE) and the results were utilized to produce 2D/3D inversion sections. A number of 2D magnetic anomaly models produced from the RTE anomaly that show a wide range of anomaly values (−424 to 590.2 nT) are used to characterize the geothermal prospect. Further, 3D models were generated to examine the extent and geometry of the reservoir. The highest positive magnetic anomaly (related to strong rock demagnetization in the RTE but depicted in reverse) is focused in the central sector of Tulu Moye inferred caldera. Within the central sector, the northern portion of Tulu Moye with an approximate area of 100 km² is presumed to be the location of the main geothermal reservoir. More specifically, an area west of Salen mount extending from Teru Moye to Giano following the Wonji Fault Belt, and an area east of Salen which extends from Gnaro to Belale are suggested to be appropriate locations for exploratory geothermal boreholes.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"228 ","pages":"Article 105667"},"PeriodicalIF":2.2,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834843","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":"Evidence for triassic salt tectonics in the meridional tellian Atlas: Example from the Ouled H'daïm diapir, Northern-central Algeria","authors":"Metsana-Oussaid Fariza ,&nbsp;Haddoum Hamid ,&nbsp;Maoudj Bouchra ,&nbsp;Takorabt Mebarka ,&nbsp;Menzoul Bouabdellah","doi":"10.1016/j.jafrearsci.2025.105658","DOIUrl":"10.1016/j.jafrearsci.2025.105658","url":null,"abstract":"<div><div>The Ouled H'daïm diapir, located in the southern Tellian Zone, provides new insights into the role of salt tectonics in the structural evolution of the region. This study challenges the hypothesis that the Triassic outcrop was emplaced by thrusting and instead favors a diapiric emplacement. Field investigations reveal a vertical ascension of the Triassic body during extensional phases, followed by lateral migration within the Santonian basin, which persisted from the Santonian to at least the Paleogene. The Santonian-Triassic contact exhibits several geological features that confirm diapiric activity.</div><div>Fracture analysis highlights the inheritance of basement faults, which played a key role in the evolution of the diapir, fluid circulation, and mineralization processes. Intense fracturing facilitated the formation of salt springs and iron-rich mineralized deposits, emphasiz ing the continuous interaction between tectonics and surface processes. During the Miocene, the Triassic salt material acted as a detachment surface, enabling the thrusting of allochthonous Tellian nappes.</div><div>The Ouled H'daïm diapir represents a key example of salt tectonics in the southern Tellian Zone and serves as a crucial case study for understanding diapir evolution in an Alpine compressional setting. This study highlights the need for complementary geophysical investigations to refine regional deformation models related to salt tectonics.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"228 ","pages":"Article 105658"},"PeriodicalIF":2.2,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143839690","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":"A post-ophiolitic plutonism record in the Central-East Iranian Microcontinent: Evidence for Pre-Eocene age of Neo-Tethys subduction","authors":"Marzieh Ghadirpour ,&nbsp;Ghodrat Torabi ,&nbsp;Nargess Shirdashtzadeh ,&nbsp;Thomas C. Meisel ,&nbsp;Tomoaki Morishita","doi":"10.1016/j.jafrearsci.2025.105628","DOIUrl":"10.1016/j.jafrearsci.2025.105628","url":null,"abstract":"<div><div>The Eocene Kalut-e-Ghandehari (KG) pluton, located in the Central Eastern Iranian Microcontinent (CEIM), intrudes the Ashin Mesozoic ophiolite and Middle Eocene volcanic rocks. Petrographic and geochemical analyses reveal a calc-alkaline, metaluminous intermediate to mafic composition ranging from gabbro to monzonite. The rocks exhibit characteristic REE and HFSE patterns indicative of subduction-related magmatism. The KG pluton is composed of plagioclase (An = 34–60 %), Alkali-feldspar (Or = 70.8–96.1 %), diopside (Mg# = 0.71–0.90), phlogopite (Fe# = 0.3), and opaque minerals. Geochemical evidence (e.g., enrichment of LREE, LILE (e.g., Cs, Ba, Rb, Th, U), Zr, and Hf; depletion of HREE, Ti, Nb, and Ta, and Y) suggests partial melting of a lithospheric spinel lherzolite that had been previously enriched by an earlier subduction event. The geochemical similarities of parental magmas of the KG pluton and the Soheyl-e-Pakuh pluton (located in the neighboring ophiolite of Nain) indicate that both derive from a subduction-induced partial melting of a mantle peridotite. However, their magma sources temporality and spatially are in accord with eastern and western Neo-Tethys subduction-related magmatisms, respectively. Thus, the cross-cutting relationships between the pluton and the Ashin ophiolite, combined with geochronological data, support a pre-Upper Eocene closure of the eastern Neotethys oceanic crust. This finding provides valuable insights into the Cenozoic tectonic evolution of the Central Iran.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"228 ","pages":"Article 105628"},"PeriodicalIF":2.2,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143864979","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":"Regional and local structural controls on gold mineralization in the Ngoura-Colomines shear zone, Eastern Cameroon: Implications for gold exploration in shear systems","authors":"Jonas Didero Takodjou Wambo ,&nbsp;Sylvestre Ganno ,&nbsp;Arkadeep Roy ,&nbsp;Jean Paul Nzenti ,&nbsp;Paul D. Asimow","doi":"10.1016/j.jafrearsci.2025.105653","DOIUrl":"10.1016/j.jafrearsci.2025.105653","url":null,"abstract":"<div><div>Several gold occurences have been identified in eastern Cameroon, within the Pan-African-North Equatorial Fold Belt. However, unraveling the complex interplay between deformation history, tectonic setting, and gold mineralization demands further investigation. Collaborative research efforts focused on these aspects are key to unlocking the full potential of this region's gold resources at least from relatively shallow levels (a few kilometers) to deep crustal levels (tens of kilometers). This paper presents a structural analysis of the Ngoura-Colomines ductile-to-brittle shear zone, located within the Boden District. The zone comprises mineralized S-C granitoid plutons and their associated veins emplaced into gneisses. New U-Pb zircon dating constrain the intrusive event to ∼630 Ma. Satellite, field, and petrographic studies reveal evidence of four main deformation events: (1) D<strong>₁</strong> records NNW-SSE ductile shortening with compressional structures in the metamorphic country rocks; (2) D<strong>₂</strong> records an extended period of dominantly ductile shear deformation divided into pre-, syn- and post-gold mineralization sub-events; (3) D₃ records a ductile-to-brittle transition that is superposed on the ductile D₂ structures; and (4) D₄ is a brittle event mainly marked by fractures, aplitic dykes and mineralized quartz veins mostly trending NNE–SSW to ENE–WSW. The tectonic history of the Ngoura-Colomines area is consistent with a protracted history of mostly shear-related Pan-African deformation continuing from mid-crustal to upper crustal levels. Gold genesis is linked to two particular stages of deformation: disseminated gold was formed during ductile shear deformation in the middle of the D₂ stage and lode gold developed during the final D₄ brittle event.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"228 ","pages":"Article 105653"},"PeriodicalIF":2.2,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143825700","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":"Chellata strike-slip fault a transkabyle polyphase fault, contemporary with the Miocene collision (Kabylian “Dorsal”, Algeria): A new kinematic and geodynamic interpretation","authors":"Tiziri Idir ,&nbsp;Mohamed Naak","doi":"10.1016/j.jafrearsci.2025.105636","DOIUrl":"10.1016/j.jafrearsci.2025.105636","url":null,"abstract":"<div><div>The Rif, Kabyle, and Sicilian-Calabrian fronts are primarily manifested by thrust structures on the forelands of African origin. These thrust fronts of the internal zones over the external zones of the Maghreb exhibit variable geometries depending on the transects: the average dip differs from one block to another, as seen between the Djurdjura and Chellata massifs, located on either side of the eponymous pass. The differential tangential block displacement between these two entities creates a decoupling through a strike-slip system, making them relatively autonomous. The Chellata massif retains a coherent paleogeographic organization, while the western Djurdjura shows moderate deformation and thick formations. To the east, deformation gradually decreases, waning near the Chellata massif and concentrating at the Chellata Pass fault. This structure, interpreted in this paper as a sinistral strike-slip, challenges earlier interpretations by Gélard in his thesis, which suggested a dextral motion. The structural analysis reveals two main phases of sliding between the Djurdjura and Chellata blocks. The first phase, sinistral, displaces the Djurdjura by 15–20 km to the south. The second phase, dextral, brings the Chellata block back to its current position. This dynamic is facilitated by a network of conjugate strike-slip faults, notably the Chellata fault to the east and the Thénia-Bouira fault to the west. This phase of late strike-slip and thrusting, dated between the Serravallien-Tortonien is part of the Maghreb collision, synchronized with oceanic opening in the western Mediterranean and the activity of the south Mediterranean transform network.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"228 ","pages":"Article 105636"},"PeriodicalIF":2.2,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143829896","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}