In the Saharian domain, the Tarfaya-Laayoune coastal basin developed in a stable passive margin, where asymmetrical sedimentation increase from East to West and reach a sediment stack of about 14 kilometers. However, ...In the Saharian domain, the Tarfaya-Laayoune coastal basin developed in a stable passive margin, where asymmetrical sedimentation increase from East to West and reach a sediment stack of about 14 kilometers. However, the morphology of the studied area corresponds to a vast plateau (hamada) presenting occasional major reliefs. For this purpose, remote sensing approach has been applied to find the best approaches for truthful lithological mapping. The two supervised classification methods by machine learning (Artificial Neural Network and Spectral Information Divergence) have been evaluated for a most accurate classification to be used for our lithofacies mapping. The latest geological maps and RGB images were used for pseudo-color groups to identify important areas and collect the ROIs that will serve as facilities samples for the classifications. The results obtained showed a clear distinction between the various formation units, and very close results to the field reality in the ANN classification of the studied area. Thus, the ANN method is more accurate with an overall accuracy of 92.56% and a Kappa coefficient is 0.9143.展开更多
This work aims first to characterize the Maastrichtian and Paleogene clays of the Ouled Bou Sbaa phosphate deposit located in the northern part of the Meskala Basin;and as a second goal, the most efficient clay fracti...This work aims first to characterize the Maastrichtian and Paleogene clays of the Ouled Bou Sbaa phosphate deposit located in the northern part of the Meskala Basin;and as a second goal, the most efficient clay fractions are tested and identified for organic dyes removal. Several techniques and methods have been adopted for the characterization of clays: X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence (XRF), Scanning electron microscope (SEM), and thermogravimetric analysis (TGA). Tests for the removal of methylene blue from clays were carried out by adsorption. The XRD study shows that the clays of the Ouled Bou Sbaa deposit contain fibrous clay types of palygorskite and sepiolite, and phyllite clays such as montmorillonite and illite. Stratigraphically, the Maastrichtian sample yielded, mainly aluminous clays dominated by montmorillonites, while in the Paleogene clays, the palygorskite-types clays, also rich in magnesium, are more common. The results of FTIR, XRF and SEM analyses confirm the mineralogical data, respectively, by the presence of characteristic bands and the dominance of oxides of silica, aluminum, magnesium, and the large dominance of palygorskite which is presented in the form of bundles or platelets of long fibers and montmorillonite which is presented in the form of a stack of sheets. The adsorption of methylene blue (MB) on these clays showed very fast fixation kinetics and a very efficient purifying power for this organic pollutant. The equilibrium isotherms were determined using the Langmuir, Freundlich and Elovich models. The results show that the Freundlich isotherm had better agreement with the methylene blue on clay with a correlation coefficient of 0.959.展开更多
Globally, the Paleogene period experienced several events marking the Paleocene-Eocene transition which is especially to one of the hottest periods that the Earth has ever known (Paleocene-Eocene Thermal Maximum, PETM...Globally, the Paleogene period experienced several events marking the Paleocene-Eocene transition which is especially to one of the hottest periods that the Earth has ever known (Paleocene-Eocene Thermal Maximum, PETM), followed by the biological crisis that affected benthic foraminifera. The Bekrit Syncline, subject of this study, shows three Formations of range from the Cretaceous to the Eocene ages (the El Koubbat, Irbzer and Bekrit-Timahdite Formations). Sedimentological, palynological and geochemical analyses of collected samples, in the Bekrit syncline, were studied to determine the paleogeographic and paleoenvironmental conditions of the Middle Atlas. The carbonate rocks were analyzed by microscopic study and geochemical analysis by X-ray Fluorescence (XF) and Inductively Coupled Plasma Spectrometry (ICP). The results obtained highlight the sedimentary events that took place during the Paleogene. Thus, the Maastrichtian is characterized by a closed euxinic marine environment shared by a more open and oxidizing environment. On the other hand, the Paleocene was a restricted marine environment with evaporitic sedimentation, while the Eocene sees the installation of a carbonate platform with a bioclastic Shoal.展开更多
Located in the North-West of the African continent, the Moroccan Middle Atlas constitutes an intra-continental chain within the Atlas domain. It is known by several global geological events such as the Paleocene-Eocen...Located in the North-West of the African continent, the Moroccan Middle Atlas constitutes an intra-continental chain within the Atlas domain. It is known by several global geological events such as the Paleocene-Eocene crisis during the Paleogene, which corresponds to one of the hottest periods on earth with Paleocene-Eocene thermal maximum (PETM). A taxonomic study carried out on the carbonate deposits of the Bekrit-Timahdite Formation from three sections of the Bekrit syncline allowed the identification of 5 species of the Cheilostome and Cyclostome Bryozoans (<em>Cellaria rigida</em>, <em>Cellaria sinuosa</em>, <em>Aimulosia lamellosa</em>, <em>Heteropora</em> and <em>Osthimosia</em>) in bioclastic limestones, nodular limestones, marly and sandy limestones. The interest of Bryozoans as indicators of paleoenvironments and paleoclimates was assessed by examining current communities, in terms of depth evolution as richness and abundance, distribution of taxonomic categories zoarium types, and zooidal morphology. The depositional environment analysis of Bryozoans showed a shallow marine carbonate platform with low sedimentation energy where is registered a relatively warm paleoclimate.展开更多
文摘In the Saharian domain, the Tarfaya-Laayoune coastal basin developed in a stable passive margin, where asymmetrical sedimentation increase from East to West and reach a sediment stack of about 14 kilometers. However, the morphology of the studied area corresponds to a vast plateau (hamada) presenting occasional major reliefs. For this purpose, remote sensing approach has been applied to find the best approaches for truthful lithological mapping. The two supervised classification methods by machine learning (Artificial Neural Network and Spectral Information Divergence) have been evaluated for a most accurate classification to be used for our lithofacies mapping. The latest geological maps and RGB images were used for pseudo-color groups to identify important areas and collect the ROIs that will serve as facilities samples for the classifications. The results obtained showed a clear distinction between the various formation units, and very close results to the field reality in the ANN classification of the studied area. Thus, the ANN method is more accurate with an overall accuracy of 92.56% and a Kappa coefficient is 0.9143.
文摘This work aims first to characterize the Maastrichtian and Paleogene clays of the Ouled Bou Sbaa phosphate deposit located in the northern part of the Meskala Basin;and as a second goal, the most efficient clay fractions are tested and identified for organic dyes removal. Several techniques and methods have been adopted for the characterization of clays: X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence (XRF), Scanning electron microscope (SEM), and thermogravimetric analysis (TGA). Tests for the removal of methylene blue from clays were carried out by adsorption. The XRD study shows that the clays of the Ouled Bou Sbaa deposit contain fibrous clay types of palygorskite and sepiolite, and phyllite clays such as montmorillonite and illite. Stratigraphically, the Maastrichtian sample yielded, mainly aluminous clays dominated by montmorillonites, while in the Paleogene clays, the palygorskite-types clays, also rich in magnesium, are more common. The results of FTIR, XRF and SEM analyses confirm the mineralogical data, respectively, by the presence of characteristic bands and the dominance of oxides of silica, aluminum, magnesium, and the large dominance of palygorskite which is presented in the form of bundles or platelets of long fibers and montmorillonite which is presented in the form of a stack of sheets. The adsorption of methylene blue (MB) on these clays showed very fast fixation kinetics and a very efficient purifying power for this organic pollutant. The equilibrium isotherms were determined using the Langmuir, Freundlich and Elovich models. The results show that the Freundlich isotherm had better agreement with the methylene blue on clay with a correlation coefficient of 0.959.
文摘Globally, the Paleogene period experienced several events marking the Paleocene-Eocene transition which is especially to one of the hottest periods that the Earth has ever known (Paleocene-Eocene Thermal Maximum, PETM), followed by the biological crisis that affected benthic foraminifera. The Bekrit Syncline, subject of this study, shows three Formations of range from the Cretaceous to the Eocene ages (the El Koubbat, Irbzer and Bekrit-Timahdite Formations). Sedimentological, palynological and geochemical analyses of collected samples, in the Bekrit syncline, were studied to determine the paleogeographic and paleoenvironmental conditions of the Middle Atlas. The carbonate rocks were analyzed by microscopic study and geochemical analysis by X-ray Fluorescence (XF) and Inductively Coupled Plasma Spectrometry (ICP). The results obtained highlight the sedimentary events that took place during the Paleogene. Thus, the Maastrichtian is characterized by a closed euxinic marine environment shared by a more open and oxidizing environment. On the other hand, the Paleocene was a restricted marine environment with evaporitic sedimentation, while the Eocene sees the installation of a carbonate platform with a bioclastic Shoal.
文摘Located in the North-West of the African continent, the Moroccan Middle Atlas constitutes an intra-continental chain within the Atlas domain. It is known by several global geological events such as the Paleocene-Eocene crisis during the Paleogene, which corresponds to one of the hottest periods on earth with Paleocene-Eocene thermal maximum (PETM). A taxonomic study carried out on the carbonate deposits of the Bekrit-Timahdite Formation from three sections of the Bekrit syncline allowed the identification of 5 species of the Cheilostome and Cyclostome Bryozoans (<em>Cellaria rigida</em>, <em>Cellaria sinuosa</em>, <em>Aimulosia lamellosa</em>, <em>Heteropora</em> and <em>Osthimosia</em>) in bioclastic limestones, nodular limestones, marly and sandy limestones. The interest of Bryozoans as indicators of paleoenvironments and paleoclimates was assessed by examining current communities, in terms of depth evolution as richness and abundance, distribution of taxonomic categories zoarium types, and zooidal morphology. The depositional environment analysis of Bryozoans showed a shallow marine carbonate platform with low sedimentation energy where is registered a relatively warm paleoclimate.
