Journal of African Earth Sciences最新文献

{"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":"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":"Corrigendum to “Sequence stratigraphic architecture and depositional evolution of the early Eocene-early Miocene Al Jabal Al Akhdar carbonate successions, N Cyrenaica Promontory, NE Libya – Interplay of tectonics and eustasy” [J. Afr. Earth Sci. 220 (2024) 1–24 105438]","authors":"Muneer Abdalla,&nbsp;Salah Hassan,&nbsp;Akram Zafir,&nbsp;Abdlsaid Ibrahem,&nbsp;Ahmad Issa","doi":"10.1016/j.jafrearsci.2024.105450","DOIUrl":"10.1016/j.jafrearsci.2024.105450","url":null,"abstract":"","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"220 ","pages":"Article 105450"},"PeriodicalIF":2.2,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mohamed G. Abdelsalam, An obituary by friends and family","authors":"Jean-Paul Liégeois,&nbsp;Robert J. Stern,&nbsp;Mahasin Idris,&nbsp;Hiam Abdelsalam,&nbsp;Francisca Oboh Ikuenobe,&nbsp;Estella A. Atekwana","doi":"10.1016/j.jafrearsci.2024.105430","DOIUrl":"10.1016/j.jafrearsci.2024.105430","url":null,"abstract":"","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"220 ","pages":"Article 105430"},"PeriodicalIF":2.2,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660296","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":"Integration of multivariate statistical analysis, geochemical modeling, and irrigation water quality assessment in the aquifers of the South-Atlas Tinghir-Errachidia-Boudenib basin (Pre-African Trough, Morocco)","authors":"Fadoua Laghrib ,&nbsp;Sahar Elkasmi ,&nbsp;Tarik Bahaj ,&nbsp;Azddine Barbot ,&nbsp;Mostapha Bouzekraoui ,&nbsp;Mohamed Hilali ,&nbsp;Youssef Touiss ,&nbsp;Mohamed Draoui ,&nbsp;Othmane Hammani ,&nbsp;Fatima Benammi ,&nbsp;Rachid Ben Aakame ,&nbsp;Myrieme Walid","doi":"10.1016/j.jafrearsci.2024.105444","DOIUrl":"10.1016/j.jafrearsci.2024.105444","url":null,"abstract":"<div><div>Irrigation development commonly results in the onset of salinization and soil alkalinization, to different degrees, and the irrigation water quality index (IWQI) is the main method utilized globally to assess water quality. This study aims to investigate the hydrogeochemical characteristics and irrigation suitability of groundwater in the South-Atlas region, one of the arid regions in the southeastern part of Morocco, using Principal Component Analysis (PCA) was applied to identify the main factors influencing groundwater quality and Hierarchical Cluster Analysis (HCA) was then used to classify the water samples into distinct groups based on their hydrogeochemical properties. The research also evaluates groundwater suitability for irrigation using several irrigation water quality indices (IWQIs) such as irrigation water quality index (IWQI), Sodium Adsorption Ratio (SAR), Percent Sodium (Na%), Permeability Index (PI), magnesium hazard (MH), and Potential salinity (PS) assisted by geochemical modeling and the Piper trilinear diagram. Fifty groundwater samples were systematically collected in February 2023 from various aquifers (Senonian, Infracenomanian, Quaternary, and Paleozoic) based on their geographical distribution and hydrogeological significance. The Piper diagram reflecting Ca-Mg-Cl-SO4 followed by Na-K-Cl-SO4 and Ca-Mg-HCO3 water facies under the stress of evaporation, saltwater intrusion and reverse ion exchange processes.</div><div>The results of the IWQI indicated that, roughly speaking, 0% of the samples fell into the unrestricted category, 46% had leaching restrictions ranging from low to moderate, and 54% of the samples were classified as high to severely limited, meaning that only high salt tolerance plants can be irrigated with groundwater.</div><div>The Senonian samples demonstrated excellent SAR, Na%, and PI, values, whereas most groundwater samples from other aquifers showed good to permissible suitability for irrigation. The study identified water-rock interactions, particularly in the Infracenomanian aquifer, and the use of agricultural fertilizers as significant factors affecting groundwater composition.</div></div>","PeriodicalId":14874,"journal":{"name":"Journal of African Earth Sciences","volume":"221 ","pages":"Article 105444"},"PeriodicalIF":2.2,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651972","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}