Journal of African Earth Sciences最新文献

{"title":"A novel approach for integrating spatial data in gold prospectivity mapping using a modified TODIM method, a case study: Basiran-Mokhtaran - Eastern Iran","authors":"Hosein Ferdowsi,&nbsp;Abbas Bahroudi,&nbsp;Ali Moradzadeh,&nbsp;Maysam Abedi","doi":"10.1016/j.jafrearsci.2024.105482","DOIUrl":"10.1016/j.jafrearsci.2024.105482","url":null,"abstract":"<div><div>To address the significant challenges posed by varying methodologies across diverse environments, it is imperative to enhance innovative approaches for Mineral Prospectivity Mapping (MPM). A significant issue arises in greenfield regions, where determining the appropriate weights for various geospatial layers in MPM leads to a considerable difficulty. Given the scarcity of known deposits of similar types in these areas, relying on experienced geologists for layer weighting often results in biased outcomes that reflect the subjective views of the experts. This study utilized available geological, airborne geophysical, geochemical, and remote sensing datasets to develop reliable evidence layers for gold exploration, despite the fact that much of the study area is covered by alluvial deposits and has only a few known occurrences of gold and copper. The prediction-area (P-A) method was used to assess the weight of each geospatial layer, independent of the geologist's subjective evaluations. This data-driven approach quantifies the significance of each layer by analyzing the ratio of known deposits to their respective areas. Ultimately, these calculated weights were utilized to create a gold prospectivity map for the region through a modified TODIM and multi-index overlay (MIO) method. The TODIM method, a sophisticated pairwise comparison technique that accommodates preferences for either profit or loss, was refined through subtle adjustments to its calculation algorithm, enhancing its efficiency in managing a multitude of alternatives. In our approach, we employ a classification procedure rather than a ranking system to determine the final outputs of TODIM. To assess the efficacy of the modified TODIM, we utilized the index overlay method as a benchmark for performance evaluation.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"222 ","pages":"Article 105482"},"PeriodicalIF":2.2,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745628","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":"Petrology and geochemistry of the Suhum Basin granitoid complex, Ghana: Implications for crustal growth during the Rhyacian orogeny of the West African Craton","authors":"Daniel Kwayisi ,&nbsp;Prince Ofori Amponsah ,&nbsp;Emmanuel Kwaku Awunyo ,&nbsp;Marian Selorm Sapah ,&nbsp;Patrick Asamoah Sakyi ,&nbsp;Ben-Xun Su ,&nbsp;Prosper M. Nude ,&nbsp;Abigail Enyonam Ayikwei ,&nbsp;Eric Dominic Forson","doi":"10.1016/j.jafrearsci.2024.105475","DOIUrl":"10.1016/j.jafrearsci.2024.105475","url":null,"abstract":"<div><div>The Suhum Basin granitoid complex is an important granitoid complex of the Birimian terrane of Ghana for unravelling the crustal growth and evolution of the West African Craton (WAC) during the Rhyacian Eburnean orogeny. Almost the entire Suhum Basin is occupied by an extensive granitoid complex, which contains useful information for constraining debatable plate tectonic issues, especially during the Archean-Paleoproterozoic transition period. We present petrography, whole-rock geochemistry, and mineral chemistry data of biotite, amphibole, and plagioclase to constrain the temperature-pressure conditions of emplacement, petrogenesis, tectonic setting, the evolution of the granitoids complex of the Suhum Basin, and its implications for the crustal growth and evolution of the WAC. Four lithological types; granite gneiss, migmatites, leucogranites, and mafic enclaves, characterise the granitoid complex of the Suhum Basin. Biotites from the granitoid complex have an annite-siderophyllite composition, and that, coupled with their calc-alkaline and I-type signatures, indicates crystallisation of the granitoid complex of the Suhum Basin under oxidised conditions. The medium-to high-K character of the rocks, together with the calc-alkaline nature, may be a reflection of the generation of magma in regions where the mantle wedge might have interacted with enriched fluids from the underlying plate during dehydration. The enrichment of LILE and LREE relative to HREE and HFSE and the negative Eu, Nb-Ta, and Ti anomalies of the granitoids complex may indicate derivation from enriched magma sources with varying degrees of fractionation in an arc environment. Amphibole-plagioclase thermobarometry indicates that the granitoid complex formed at P-T conditions of 600–712 °C and 5.2–7.2 kbar, signifying a deeper depth (19–27 km) of emplacement. The overall geochemical data suggest that the rocks formed during a single orogenic event related to a volcanic arc environment where subduction zone components played a role in the generation of their parental magmas. This finding is therefore consistent with the onset of “modern-style” subduction-related processes during the Archean-Paleoproterozoic transitional period.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"222 ","pages":"Article 105475"},"PeriodicalIF":2.2,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723086","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":"Spatio-temporal land use/land cover change analysis and assessment of urban heat island in Ghana: A focus on the Greater Accra Region","authors":"Abraham Aidoo Borsah ,&nbsp;Evans Annan Boah ,&nbsp;Eric Thompson Brantson","doi":"10.1016/j.jafrearsci.2024.105474","DOIUrl":"10.1016/j.jafrearsci.2024.105474","url":null,"abstract":"<div><div>The expansion of cities coupled with economic development over the years has transformed many locations into hotspots for massive urban populace. The Greater Accra Region which is the capital city of Ghana is no exception. The urban population growth rate in the region has expanded extensively at the expense of increasingly vegetation cover. As a result, there is an increasing need to investigate urban resilience, land use/land cover (LULC) change, and urban heat islands (UHI) dynamics in the region. The aim of this study is to analyze multi-spectral Landsat images of 2000 and 2020 to examine the LULC change and the UHI trend across the Greater Accra Region of Ghana. The results from the analysis show a significant change in the spatial trend of land surface temperature (LST) and UHI between the years 2000 and 2020. Spatial distribution of LST from 0 °C to 28 °C and 17 °C–33 °C in the years 2000 and 2020 respectively were observed. Urban areas dominated more than half of the study area in 2020, covering 85% (equivalent to 3160 sq. km), and reflecting a 20% increase from the year 2000–2020. During the same period, sparse and dense forested areas decreased by 10% (373 sq. km) and 4% (146 sq. km) with a 5% reduction in bare land (equivalent to 177 sq. km). The spatio-temporal analysis revealed a significant surge in the population of urban areas within the study area. The UHI areas also increased from 13.20% in 2000 to 18.20% in 2020. On the other hand, non-UHI areas decreased from 86.80% to 81.80% during the same period. The successful contribution of this research demonstrates the usefulness of spatial models as tools in generating LULC maps for assessing UHI to facilitate future sustainable city planning.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"221 ","pages":"Article 105474"},"PeriodicalIF":2.2,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651973","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":"Using archive hydrogeological data to enhance the hydrodynamic knowledge of hardrock aquifers in Western Africa","authors":"Mozimwè Ani ,&nbsp;Jessy Jaunat ,&nbsp;Béatrice Marin ,&nbsp;Frederic Huneau ,&nbsp;Kissao Gnandi","doi":"10.1016/j.jafrearsci.2024.105477","DOIUrl":"10.1016/j.jafrearsci.2024.105477","url":null,"abstract":"<div><div>In the Kara River Watershed (KRW, northern Togo), drinking water is mainly supplied by groundwater flowing through fissures in the metamorphic formations of the Dahomeyides belt. The study was based on the use and valorisation of hydrogeological archive dataset from 1970s to 2021. The database comprises 1389 boreholes, but only 710 are considered after pre-treatment, and provides information mainly on total depth, weathering thickness, discharge at drilling, piezometric level, specific discharge, transmissivity, and the nature of the lithology tapped. The methodological approach involved statistical analysis of data, characterization of the fissured horizon, establishment of relationships between hydrodynamic parameters and satellite image processing. The results showed that the aquifers structure is close to those observed worldwide in hardrock context and they provide operational details on the hydrogeological functioning of these environments in the West African particular context. From the surface downwards, aquifers show a layer of saprolite (thickness between 0.2 and 37.3 m) acting as a storage level, a fissured layer whose permeability depends on the number and connectivity of the fissures, and then a level of very low permeability, unfissured bedrock. In the study area, the depth of the useful fissured medium is 52 m with an average useful discharge of 7.1 m³ h⁻¹. The coefficients of variation for specific discharge and transmissivity are greater than 100%, reflecting the structural heterogeneity of the study area. Analysis of the discharges measured in the boreholes as a function of lithology shows that the metasediments are more productive than other geological formations. Finally, all the geological, hydrogeological, and hydrodynamical data have been used to propose a preliminary conceptual model of the watershed's hardrock aquifers. These results will serve as decision-making tools for water managers and will facilitate the policy of integrated management of groundwater resources at the scale of the KRW. The developed methodology also shows how archive data should be used to achieve optimized management of aquifers without major investments.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"221 ","pages":"Article 105477"},"PeriodicalIF":2.2,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651974","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":"Analyzing seismic impact across regions: A comprehensive study of the Pazarcık and Elbistan earthquakes in Türkiye (February 6, 2023)","authors":"Özgür Yıldız ,&nbsp;Ali Fırat Çabalar","doi":"10.1016/j.jafrearsci.2024.105463","DOIUrl":"10.1016/j.jafrearsci.2024.105463","url":null,"abstract":"<div><div>The seismic events in Pazarcık (Mw 7.7) and Elbistan (Mw 7.6) on February 6, 2023, caused widespread damage and destruction across 11 provinces and districts in eastern Türkiye. Despite similarities in construction quality and structural stock characteristics, notable differences in the patterns of destruction between the affected cities have highlighted the need for a more detailed investigation. This study focuses on examining local site effects and seismic behavior in residential areas within the impacted zone to better understand the structural damage caused by these earthquakes. Geotechnical data from the affected cities were used as the basis for conducting nonlinear seismic site response analyses. These analyses, using real earthquake records measured in city centers, explored factors such as liquefaction potential, amplification capacity, and the dynamic behavior of soil profiles under seismic loads. Simulations based on actual earthquake records and soil data provided insights into the causes of structural damage in the affected areas during both seismic events. Finally, an evaluation of site effects on structural damage resulting from both major earthquakes was conducted, offering valuable insights through a comprehensive analysis of the results.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"223 ","pages":"Article 105463"},"PeriodicalIF":2.2,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142759002","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":"Petrography and geochemistry of volcanic rocks of the Kulf-Amba area, in the Northwestern Ethiopian plateau: Implication for petrogenesis of felsic volcanic suites","authors":"Dejen Teka ,&nbsp;Minyahl Teferi Desta","doi":"10.1016/j.jafrearsci.2024.105465","DOIUrl":"10.1016/j.jafrearsci.2024.105465","url":null,"abstract":"<div><div>The Kulf-Amba area, located on the Northwestern Ethiopian plateau, is primarily composed of Cenozoic volcanic rocks with minor intertrappean sediments. To understand the petrogenesis of these rocks, we conducted field investigations, petrographic studies, and geochemical analyses. The main volcanic products include basalt (upper and lower), rhyolite lava flows, rhyolitic ignimbrite, volcanic glass, and agglomeratic tuff. Basalts exhibit aphanitic, porphyritic, and glomerophyric textures, with phenocryst of olivine, Ca-rich plagioclase, clinopyroxene, and Fe-Ti oxides. Felsic rocks display porphyritic, aphyric, and glassy textures, with phenocryst of quartz, alkali feldspar, and Fe-Ti oxides. Geochemical data reveal a bimodal composition. The mafic rocks resemble high titaniferous (HT2) basalts of Northwestern Ethiopia and are classified as transitional to tholeiitic. Felsic rocks are primarily peralkaline comendites. The mafic rocks exhibit a depleted heavy rare earth element (HREE) pattern with (Dy/Yb)_N = 1.75–2.02 and enriched light rare earth element (LREE) values with (Ce/Yb)_N = 7.16–9.26, without a significant negative Eu anomaly. Enrichment in LREE with (Ce/Yb)_N = 6.27–15.03 and flat HREE with (Dy/Yb)_N = 1.23–1.79, with varying Eu negative anomaly are characteristics of the felsic volcanic rocks, indicating removal of plagioclase throughout their evolutionary process. The consistent Nb/Ta (17.29–23.67 ppm) and Zr/Hf (37.53–45.08 ppm) ratios in both mafic and felsic rocks suggest that fractional crystallization was the dominant process in their formation, with small crystal contamination. The primitive mantle-normalized variation diagram for the mafic rocks reveals LREE enrichment and HREE depletion, indicating garnet in the source. Melting models using primitive mantle normalized values of Sm/Yb vs. La/Sm ratios further confirm garnet's presence and suggest a low degree (2%) of partial melting a source with less than 2% of garnet. The trace element signatures and geochemical modelling of the mafic lavas indicate a plume-related origin, potentially related to the Afar mantle plume.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"221 ","pages":"Article 105465"},"PeriodicalIF":2.2,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651409","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}

{"title":"Seismotectonic map of the Sinai Triple Junction","authors":"Mona Hamada ,&nbsp;Hanan Gaber ,&nbsp;Mohamed Saleh ,&nbsp;Hazem Badreldin ,&nbsp;Shimaa H. ElKhouly ,&nbsp;Amr El-Sharkawy ,&nbsp;Abdelbaset M. Abudeif ,&nbsp;Essam A. Mohamed ,&nbsp;Hatem S. Ramadan","doi":"10.1016/j.jafrearsci.2024.105464","DOIUrl":"10.1016/j.jafrearsci.2024.105464","url":null,"abstract":"<div><div>The geodynamic evolution of the Sinai Triple Junction, a highly deformed and seismically active area, is controlled by the Red Sea rift, Gulf of Suez and Aqaba-Dead Sea conjunctions. However, the driving forces for the focusing deformation at crustal depths beneath this area are still ambiguous. Here, we provide an updated seismotectonic map of the area relying on updated seismological and geodetic datasets. A homogenized earthquake catalog has been compiled from well-located earthquakes (&gt; Mw 2.0) by the Egyptian Seismic Network and International Seismological Center in the period between 1990 and 2020. We calculated the average b-value along three seismogenic zones including Gulf of Aqaba, northern Red Sea and Gulf of Suez that amount to 1.1, 0.99 and 0.97, respectively. Additionally, we complied and updated a comprehensive P-wave-based database for the fault plane solutions in the area for events with Mw &gt; 3.5 till 2023. Furthermore, a unified velocity field for the region as well as slip-rate and locking-depth at the active fault segments were estimated from a consistent geodetic dataset from peer-reviewed GPS velocities between 1999 and 2018. Results indicate a dominant NNE left-lateral strike-slip fault with normal component along the Gulf of Aqaba. Pure NW-SE to WNW-ESE dip-slip normal faulting, associated with a strike-slip component in some cases, is dominating the northern and central parts of the Gulf of Suez, whereas pure normal dip-slip movement with an NNE–SSW extension in a horizontal direction is observed in the southern part of the gulf. The estimated slip-rate and locking-depths at the Aqaba fault segments falls between 4.8 and 4.9 mm/yr and 8–12 km, respectively.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"221 ","pages":"Article 105464"},"PeriodicalIF":2.2,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rutile U-Pb ages and implications for the extension of the timing of the Eburnean overprint in the Ntem Complex (southern Cameroon) portion of the Congo Craton","authors":"Nzesseu Nandjou Valentino ,&nbsp;Bineli Betsi Thierry ,&nbsp;Belinga Belinga Cédric ,&nbsp;Ekomane Emile ,&nbsp;Kelepile Tebogo","doi":"10.1016/j.jafrearsci.2024.105459","DOIUrl":"10.1016/j.jafrearsci.2024.105459","url":null,"abstract":"<div><div>To gain an understanding of the tectono-metamorphic evolution of the Congo Craton in the southern Cameroonian Ntem Complex, alluvial rutile EPMA geochemistry and LA-ICP-MS U-Pb geochronology were carried out, and for the first time, robust rutile ages are obtained in that section of the Congo Craton. Concentrations of Nb vary from 287 to 7074 ppm and those of Zr and Cr from 7 to 592 ppm, and from 75 to 5836 ppm, respectively. These data suggest Minto alluvial rutile was sourced from mainly metapelitic and accessorily metamafic rocks. The Zr-in-rutile thermometer indicates a range of temperatures between 430 and 720 °C, with an average temperature of 613 °C. This suggests that the alluvial rutile rock sources were formed under conditions of amphibolite facies metamorphism. Five alluvial rutile grains yield overlapping and concordant ages of 1974 ± 8.8 Ma, 1987 ± 13 Ma, 1992.2 ± 8.4 Ma, 1989.1 ± 8.3 Ma, 1985.1 ± 12.1 Ma, respectively. These results are all consistent with a single Paleoproterozoic metamorphic growth event. The rutile ages suggest that Minto, in the southern part of the Ntem Complex, was subjected to Eburnean thermal rejuvenation. Therefore, our findings extend the timing and location of the Eburnean overprint in the Cameroonian Congo Craton portion beyond the previously recognised spatiotemporal window.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"221 ","pages":"Article 105459"},"PeriodicalIF":2.2,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterizing groundwater contamination flow-paths and heavy metal mobilization near a waste site in Southwestern Nigeria","authors":"AbdulGaniyu Isah ,&nbsp;Etido Nsukhoridem Bassey ,&nbsp;Olukole Adedeji Akinbiyi ,&nbsp;Rasaq Adebayo Azeez ,&nbsp;Andrew Sunday Oji ,&nbsp;Tijjani El-Badawy","doi":"10.1016/j.jafrearsci.2024.105460","DOIUrl":"10.1016/j.jafrearsci.2024.105460","url":null,"abstract":"<div><div>This study investigates potential groundwater contamination near a waste disposal site in southwestern Nigeria. The area's complex geological setting, characterized by fractured rock formations, posed significant challenges for traditional monitoring methods. To address these challenges and comprehensively assess groundwater conditions, we employed a combined approach utilizing Electrical Resistivity Tomography (ERT), Ground Penetrating Radar (GPR), and geochemical analysis of heavy metals and water conductivity. This approach enabled the investigation of groundwater levels, identification of potential contamination zones, and delineation of contaminant flow paths. GPR identified a shallow zone, termed the “shadow zone,” with conductive residues indicating contaminants with anomalous conductivity ranging from 1 to 1.5 m. An intermittent reflection zone at a depth of 1.5–3.5 m suggested the potential presence of leachate-impacted groundwater. ERT confirmed a shallow resistive layer at depths of 0–2 m, attributed to compacted waste and topsoil, around the abandoned main dumpsite. Below this layer, a zone of low resistivity, decreasing downward through a porous weathered zone, was observed. This corresponded to high water conductivity in well data, ranging from 21 to 147 mS/m (equivalent to 6.80 to 47.62 Ω-m), indicating a high conductive anomaly suspected to be a leachate plume at depths of 2–10 m in a sandy-gravelly weathered zone. Validation against ground truth data confirmed the correlation between radar signatures, geoelectrical imaging, and subsurface lithology. Analysis of well and soil samples revealed concerningly elevated concentrations of cadmium, mercury, lead, arsenic, and cobalt, ranging from 641 to 1175 ppb, exceeding established safety limits for drinking water. Additionally, soil samples showed elevated levels of nickel and chromium, generally ranging from &lt;0 to &lt;1 ppb. These findings highlight the significant risk of groundwater contamination due to the proximity of the leachate zone to the groundwater table in the weathered basement complex. This study demonstrates the effective integration of geophysical and geochemical methods for comprehensive mapping of contaminated zones and identification of preferential pathways for contaminant migration. The findings underscore the critical need for implementing comprehensive risk assessment methodologies in similar complex geological settings.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"221 ","pages":"Article 105460"},"PeriodicalIF":2.2,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142592615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Miocene bioerosion in a Cretaceous metamorphic basement from the Arzew Mountains (Oran, northwestern Algeria): First evidence of a Tortonian rocky shore in the southwestern Mediterranean area","authors":"Mohammed Nadir Naimi ,&nbsp;Ahmed Zeghari ,&nbsp;Chikh Younes Mahboubi","doi":"10.1016/j.jafrearsci.2024.105462","DOIUrl":"10.1016/j.jafrearsci.2024.105462","url":null,"abstract":"<div><div>Bioerosive trace fossils at the Guessiba Valley (Arzew Mountains) document an ancient Tortonian shoreline cut into Barremian calcschists at the lowermost part of the Tortonian Balanid Marl Formation. Four ichnogenera produced by endolithic bivalves (<em>Gastrochaenolites</em>) and polychaete annelids (<em>Caulostrepsis</em>, <em>Maeandropolydora</em>, <em>Trypanites</em>) have been identified. The four traces consist of dwelling structures (domichnia). The encrusting epifauna on the rockground include acorn barnacles of the genus <em>Balanus</em> and scarce, poorly preserved bivalves. These epibionts exhibit <em>Trypanites</em> and <em>Entobia</em>, respectively. This ichnoassociation identifies the <em>Entobia</em> ichnosubfacies as part of the <em>Trypanites</em> ichnofacies. The fossil rocky shore described in this paper is related to a transgression that occurred during the Tortonian, characterising a stratigraphic surface corresponding to a sequence boundary. The Guessiba Valley succession marks the first Mediterranean marine transgression affecting the southern flank of the Arzew Mountains, characterised by three distinct phases. The calcschists reported here are among the rare examples of non-carbonate rocky substrates colonised by endolithic boring organisms.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"220 ","pages":"Article 105462"},"PeriodicalIF":2.2,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}