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The dyrosaurids of the lullemmeden Basin (West Africa) are mainly represented by two genera, Hyposaurus and Rhabdognathus. Hyposaurus has been recognized in the Paleocene of Mali and Nigeria with two species, H. nopcsai and H. wil...
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The dyrosaurids of the lullemmeden Basin (West Africa) are mainly represented by two genera, Hyposaurus and Rhabdognathus. Hyposaurus has been recognized in the Paleocene of Mali and Nigeria with two species, H. nopcsai and H. wilsoni. Diagnostic characters given by previous authors for these species do not enable their distinction from each other, nor from North American species. It is therefore reasonable to consider H. nopesai and H. wilsoni as nomina dubia. In 1930, Swinton erected the new genus and species Rhabdognathus rarus on the basis of mandibular remains, and Buffetaut referred a skull to this species in 1980. A new skull was described in 2002 by Brochu et al., and referred to Rhabdognathus sp. Unfortunately, it is impossible to refer either skull to the type species, the mandibular remains having no diagnostic characters at the specific level. Thus, R. rarus is a nomen dubium. and two new names are erected for the two skulls: R. keiniensis n. sp. and R. aslerensis n. sp., all the mandibular remains being referred to Rhabdognathus sp. The species Rhabdognathus compressus is reassigned to the genus Congosaurus, since its mandible is higher than that of Hyposattrus, shorter than that of Rhabdognathus, and the lateromedially compressed teeth demonstrate that C compressus and C. bequaerti are closely related.
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This work presents a new way to prepare cordierite-based ceramics using a raw material abundant in Morocco: rhassoul. Mainly constituted of stevensite (Si4Mg3O10(OH)(2)), rhassoul can substitute talc in cordierite synthesis. Two w...
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This work presents a new way to prepare cordierite-based ceramics using a raw material abundant in Morocco: rhassoul. Mainly constituted of stevensite (Si4Mg3O10(OH)(2)), rhassoul can substitute talc in cordierite synthesis. Two ways were explored : from rhassoul, silica and alumina mixtures ; from rhassoul, and andalousite mixtures ; The progress of the reaction was followed by X-ray diffraction on materials prepared up to 1300degreesC. the cordierite formation is made easier due to rhassoul high specific surface area. The ceramics obtained by reaction sintering at 1250degreesC were characterized by XRD and SEM. Their thermal expansion coefficient was measured. [References: 10]
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This study aims at quantifying soil losses in an agricultural catchment site of 5,2 hectares, located upstream the Nakhla watershed. The evolution of linear erosion both vertically and horizontally was observed by means of a topog...
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This study aims at quantifying soil losses in an agricultural catchment site of 5,2 hectares, located upstream the Nakhla watershed. The evolution of linear erosion both vertically and horizontally was observed by means of a topographic survey. The results of this monitoring show that soil losses reached 187 tons, that is approximately 36 tons per hectare for the period between 28/11/1997 and 19/05/1998 during which a rainfall of 656 mm was recorded. The study of the factors affecting gully development, especially those related to topography and soil structure, shows that in upslope fallow fields, slopes of 20 percent ana more dominantly affect gully activity. The structural stability of these soils developed on marly material is the factor that explains most of soil losses through gullying (R~2=0.50).
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Knowledge on forced magma injection arid magma flow in dykes is crucial for the understanding of how magmas migrate through the crust to the Earth's surface. Because many questions still persist, we used the long, thick, and deep-...
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Knowledge on forced magma injection arid magma flow in dykes is crucial for the understanding of how magmas migrate through the crust to the Earth's surface. Because many questions still persist, we used the long, thick, and deep-seated Foum Zguid dyke (Morocco) to investigate dyke emplacement and internal flow by means of magnetic methods, structural analysis, petrography, and scanning electron microscopy. We also investigated how the host rocks accommodated the intrusion. Regarding internal flow: 1. Important variations of the rock magnetic properties and magnetic fabric occur with distance from dyke wall; 2. anisotropy of anhysteretic remanent magnetization reveals that anisotropy of magnetic susceptibility (AMS) results mainly from the superposition of subfabrics with distinct coercivities and that the imbrication between magnetic foliation and dyke plane is more reliable to deduce flow than the orientation of the AMS maximum principal axis; and 3. a dominant upward flow near the margins can be inferred. The magnetic fabric closest to the dyke wall likely records magma flow best due to fast cooling, whereas in the core the magnetic properties have been affected by high-temperature exsolution and metasomatic effects due to slow cooling. Regarding dyke emplacement, this study shows that the thick forceful intrusion induced deformation by homogeneous flattening and/or folding of the host sedimentary strata. Dewatering related to heat, as recorded by thick quartz veins bordering the dyke in some localities, may have also helped accommodating dyke intrusion. The spatial arrangement of quartz veins and their geometrical relationship with the dyke indicate a preintrusive to synintrusive sinistral component of strike slip.
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The ancient city of Lixus, today situated on a hill on the right bank of the River Loukkos, 4 kmfrom the coast, was founded on the shore of a brackish lagoon that was sheltered from Atlanticstorms. This geographical context provid...
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The ancient city of Lixus, today situated on a hill on the right bank of the River Loukkos, 4 kmfrom the coast, was founded on the shore of a brackish lagoon that was sheltered from Atlanticstorms. This geographical context provided the city with one of the best Phoenician harborsand abundant fishing resources, and allowed access to the Gharb cattle farming resources andcereal production systems. In this study, the historical evolution of the Loukkos estuarineenvironment is reconstructed through geomorphological and sedimentological analyses,combined with cartographic, archaeological, and geographical data. The outcomes reveal theprogressive infilling of the estuarine lagoon of Lixus and its transformation into the currentestuary and floodplain. The recent history of this estuary records four successive stages: (1) aninitial stage associated with the maximum Holocene marine transgression (5500 to 5320 cal.yr B.R) that reached the interior of the estuary; (2) a sheltered brackish tidal lagoon stage inPhoenician and Roman times; (3) a period of progressive infilling of the estuarine lagoon, fromlate Roman times to the Middle Ages (11th tol5th centuries); (4) a period of rapid expansionof intertidal marshes (17th to 19th centuries) that saw the formation of the modern estuarineplain and meandering channel system (20th century).
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We describe the partially preserved femur of a large-bodied theropod dinosaur from the Cenomanian “Kem Kem Compound Assemblage” (KKCA) of Morocco. The fossil is housed in the Museo Geologico e Paleontologico “Gaetano Giorgio Ge...
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We describe the partially preserved femur of a large-bodied theropod dinosaur from the Cenomanian “Kem Kem Compound Assemblage” (KKCA) of Morocco. The fossil is housed in the Museo Geologico e Paleontologico “Gaetano Giorgio Gemmellaro” in Palermo (Italy). The specimen is compared with the theropod fossil record from the KKCA and coeval assemblages from North Africa. The combination of a distally reclined head, a not prominent trochanteric shelf, distally placed lesser trochanter of stout, alariform shape, a stocky shaft with the fourth trochanter placed proximally, and rugose muscular insertion areas in the specimen distinguishes it from Carcharodontosaurus, Deltadromeus and Spinosaurus and supports referral to an abelisaurid. The estimated body size for the individual from which this femur was derived is comparable to Carnotaurus and Ekrixinatosaurus (up to 9 meters in length and 2 tons in body mass). This find confirms that abelisaurids had reached their largest body size in the “middle Cretaceous,” and that large abelisaurids coexisted with other giant theropods in Africa. We review the taxonomic status of the theropods from the Cenomanian of North Africa, and provisionally restrict the Linnean binomina Carcharodontosaurus iguidensis and Spinosaurus aegyptiacus to the type specimens. Based on comparisons among the theropod records from the Aptian-Cenomanian of South America and Africa, a partial explanation for the so-called “Stromer’s riddle” (namely, the coexistence of many large predatory dinosaurs in the “middle Cretaceous” record from North Africa) is offered in term of taphonomic artifacts among lineage records that were ecologically and environmentally non-overlapping. Although morphofunctional and stratigraphic evidence supports an ecological segregation between spinosaurids and the other lineages, the co-occurrence of abelisaurids and carcharodontosaurids, two groups showing several craniodental convergences that suggest direct resource competition, remains to be explained.
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Using a combination of idealized radiative transfer simulations and a case study from the first field campaign of the Saharan Mineral Dust Experiment (SAMUM) in southern Morocco, this paper provides a systematic assessment of the ...
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Using a combination of idealized radiative transfer simulations and a case study from the first field campaign of the Saharan Mineral Dust Experiment (SAMUM) in southern Morocco, this paper provides a systematic assessment of the limitations of the widely used Spinning Enhanced Visible and Infrared Imager (SEVIRI) red-green-blue (RGB) thermal infrared dust product. Both analyses indicate that the ability of the product to identify dust, via its characteristic pink coloring, is strongly dependent on the column water vapor,the lower tropospheric lapse rate, and dust altitude. In particular, when column water vapor exceeds ～20-25 mm, dust presence, even for visible optical depths of the order 0.8, is effectively masked. Variability in dust optical properties also has a marked impact on the imagery, primarily as a result of variability in dust composition. There is a moderate sensitivity to the satellite viewing geometry, particularly in moist conditions. The underlying surface can act to confound the signal seen through variations in spectral emissivity, which are predominantly manifested in the 8.7 μm SEVIRI channel. In addition, if a temperature inversion is present, typical of early morning conditions over the Sahara and Sahel, an increased dust loading can actually reduce the pink coloring of the RGB image compared to pristine conditions. Attempts to match specific SEVIRI observations to simulations using SAMUM measurements are challenging because of high uncertainties in surface skin temperature and emissivity. Recommendations concerning the use and interpretation of the SEVIRI RGB imagery are provided on the basis of these findings.
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Recent research in various Moroccan areas allowed an update and a revision of the Moroccan Ephemeroptera checklist. In this case, 54 species are now listed, belonging to 10 families and 26 genera. The distribution of all studied s...
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Recent research in various Moroccan areas allowed an update and a revision of the Moroccan Ephemeroptera checklist. In this case, 54 species are now listed, belonging to 10 families and 26 genera. The distribution of all studied species is discussed, as well as their biogeographical affinities. Moroccan Mayflies are characterized by a clear dominance of Mediterranean elements with a strong rate of endemism (33.4%).
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Abstract This study examines the role played by remittances in Morocco's spectacular fertility decline over the 1975–2018 period. Using the autoregressive distributed lag (ARDL) bounds approach, we find a significant negative ass...
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Abstract This study examines the role played by remittances in Morocco's spectacular fertility decline over the 1975–2018 period. Using the autoregressive distributed lag (ARDL) bounds approach, we find a significant negative association between remittances to the country and total fertility rate. This relationship is stronger in the long term than in the short term, suggesting that the human capital‐accumulation channel is probably more important than the income effect. Findings of the study highlight the contribution of Morocco's large overseas migrant community to the country's demographic transition.
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