11 research outputs found
Mineralogy and Geochemistry of the Guenfouda Clay Deposit, Jerada Province, Northeastern Morocco
peer reviewedThe Guenfouda clay deposit is located at about 36km to the southwest of Oujda city
and 6km to the south of Guenfouda village. It belongs to the Jerada Province of the
northeastern Morocco and hosted within the Upper Visean calc-alkaline dacite lava
interbedded within a schisto-volcanic complex. This deposit is mined for more than 15
years and the product being mainly used for refractories and industrial ceramics.
This clay deposit is funnel or trough-like in form, narrowing downwards and
display a EâW trend, which follows the major dextral strike-slip fault that passes through
the south of the deposit. Based on mineral assemblages, four lateral alteration zones were
defined from the north to south parts of the deposit: the Illite zone, the Pyrophyllite-illite
zone, the Pyrophyllite zone and the Quartz zone.
The presence of high-temperature minerals such as pyrophyllite, diaspore, the
alteration zonation pattern and the chemical characteristics are diagnostic of hypogene
origin. However, the variation diagrams, Zr vs TiO2 and P2O5 vs SO3 as well as the values
of the chemical Index of Weathering (CIW) and the Alteration Index (AI) revealed a mixed type. It seems that the genesis of Guenfouda clay deposit was first controlled by the eastwest
strike-slip faults, which brought ascending hydrothermal solutions that led to clay
formation and finally, the weathering processes have continued and extended the
argillization
The application of proximal visible and near-infrared spectroscopy to estimate soil organic matter on the Triffa Plain of Morocco
Soil organic matter (SOM) is a fundamental soil constituent. The estimation of this parameter in the laboratory using the classical method is complex time-consuming and requires the use of chemical reagents. The objectives of this study were to assess the accuracy of two laboratory measurement setups of the VIS-NIR spectroscopy in estimating SOM content and determine the important spectral bands in the SOM estimation model. A total of 115 soil samples were collected from the non-root zone (0-20 cm) of soil in the study area of the Triffa Plain and then analysed for SOM in the laboratory by the Walkley-Black method. The reflectance spectra of soil samples were measured by two protocols, Contact Probe (CP) and Pistol Grip (PG)) of the ASD spectroradiometer (350-2500 nm) in the laboratory. Partial least squares regression (PLSR) was used to develop the prediction models. The results of coefficient of determination (R-2) and the root mean square error (RMSE) showed that the pistol grip offers reasonable accuracy with an R-2 = 0.93 and RMSE = 0.13 compared to the contact probe protocol with an R-2 = 0.85 and RMSE = 0.19. The near-Infrared range were more accurate than those in the visible range for predicting SOM using the both setups (CP and PG). The significant wavelengths contributing to the prediction of SOM for (PG) setup were at: 424, 597, 1432, 1484, 1830,1920, 2200, 2357 and 2430 nm, while were at 433, 587, 1380, 1431, 1929, 2200 and 2345 nm for (CP) setup
Mineralogical and physicochemical characterization of the Jbel Rhassoul clay deposit (Moulouya Plain, Morocco)
This study aims at the mineralogical and physicochemical characterization of clays of
the Missour region (Boulemane Province, Morocco). For this, three samples were
collected in the Ghassoul deposit. The analyses were carried by X-ray diffraction
(XRD), X-ray fluorescence (XRF) and Scanning Electron Microscopy (SEM). The
thermal analysis from 500 to1100°C was also performed on studied samples, and the
fired samples were characterized by XRD and SEM. The XRD results revealed that raw
Ghassoul clay consists mainly of Mg-rich trioctahedral smectite, stevensite-type clay,
which represents from 89% to 95% of the clay fraction, with a small amount of illite
and kaolinite. The associated minerals are variable amount of quartz, dolomite,
hematite, gypsum and K-feldspars. The chemical analysis confirms the presence of Mgrich
smectite (stevensite) with largest amount in sample containing the highest MgO.
The SEM micrographs revealed the presence of automorphous structures with petalslike
shape typical of smectite. The Thermal transformations determined by X-ray
diffraction indicated that stevensite was transformed to enstatite from 800ÂșC. Diopside
starts to appear from 700°C, which is confirmed by SEM observations, and the quartz is
transformed to cristobalite when the temperature exceeds 1100°C
Golunda aouraghei, sp. nov., the last representative of the genus Golunda in Africa
In this paper, we report a new species of the murid genus Golunda at the Plio-Pleistocene site of GuefaĂŻt-4 (Jerada, Morocco). It is a large-sized murid characterized by the presence of relative good lateral connections between the tubercles. The new species shows affinities with Golunda jaegeri from Oued Athmenia 1. However, some morphological differences become remarkable when compared. We propose the anagenetic lineage Golunda jaegeri ? Golunda aouraghei, marked by a slight increase of the width and the stephanodonty along the Pliocene-Pleistocene transition. Hitherto, Golunda aouraghei represents the youngest Golunda species recorded in Africa. Report of this murid from GuefaĂŻt-4 has significant implications for the biochronological scale of North Africa.Fil: Piñero GarcĂa, Pedro. Universitat Rovira i Virgili. Institut CatalĂ Â de Paleoecologia Humana i EvoluciĂł Social; España. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. DivisiĂłn ZoologĂa de Vertebrados. SecciĂłn de MastozoologĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata; ArgentinaFil: AgustĂ, Jordi. Universitat Rovira i Virgili. Institut CatalĂ Â de Paleoecologia Humana i EvoluciĂł Social; España. InstituciĂł Catalana de Recerca i Estudis Avancats; EspañaFil: Haddoumi, Hamid. Universite Mohammed V. Rabat; Otros paises de ĂfricaFil: El Hammouti, Kamal. Universite Mohammed V. Rabat; Otros paises de ĂfricaFil: ChacĂłn, M. Gema. Universitat Rovira i Virgili. Institut CatalĂ Â de Paleoecologia Humana i EvoluciĂł Social; España. Sorbonne University; FranciaFil: Sala Ramos, Robert. Universitat Rovira i Virgili. Institut CatalĂ Â de Paleoecologia Humana i EvoluciĂł Social; Españ
Le PalĂ©olithique supĂ©rieur de la grotte dâEl Harhoura 2, rĂ©gion de Rabat-TĂ©mara. Contexte stratigraphique, palĂ©oenvironnemental, archĂ©ologique et datations de lâindividu H3
International audienceLâobtention de trois dates AMS sur collagĂšne humain de lâindividu H3 dĂ©couvert en 1996 dans la couche 2 dâEl Harhoura 2 est lâoccasion de faire le bilan sur nos connaissances de cette phase dâoccupation.Ă partir des donnĂ©es des fouilles anciennes et rĂ©centes, le contexte stratigraphique et culturel de lâindividu H3 est discutĂ©. LâĂąge estimĂ©, dâenviron 12 ka, permet de replacer cet individu dans le contexte chronologique plus large du PalĂ©olithique supĂ©rieur de la rĂ©gion de TĂ©mara et du Maroc
Amphibians and squamate reptiles from the late Miocene (Vallesian) of eastern Morocco (GuefaĂŻt-1, Jerada Province)
International audienc
Datation par ESR-U/th combinĂ©es de dents fossiles des grottes dâEl Mnasra et dâEl Harhoura 2, rĂ©gion de Rabat-Temara. Implications chronologiques sur le peuplement du Maroc atlantique au PlĂ©istocĂšne supĂ©rieur et son environnement
La rĂ©gion de TĂ©mara, prĂšs de Rabat, abrite plusieurs sites archĂ©ologiques et palĂ©ontologiques dâune importance majeure pour la PrĂ©histoire du Maroc et du nord de lâAfrique. Les dĂ©couvertes de restes humains palĂ©olithiques associĂ©s Ă des industries atĂ©riennes et du PalĂ©olithique supĂ©rieur Ă Dar es Soltane 2, El Harhoura 1 et aux Contrebandiers, dans les annĂ©es 1970, ont renforcĂ© lâintĂ©rĂȘt des sites de la rĂ©gion de TĂ©mara. Deux grottes ont fait lâobjet de nombreuses recherches et sont en cours de fouilles : El Mnasra depuis 1990 et El Harhoura 2 depuis 2001. Lâapplication de la mĂ©thode de datation ESR-U/Th sur lâĂ©mail dentaire permet de fournir des points de repĂšres gĂ©ochronologiques et de discuter du cadre palĂ©oenvironnemental dans lequel vivait lâHomme palĂ©olithique au Maroc. Les datations ont Ă©tĂ© rĂ©alisĂ©es sur des dents fossiles de bovidĂ©s prĂ©levĂ©es dans des couches attribuĂ©es au PalĂ©olithique moyen (AtĂ©rien). Pour la grotte dâEl Harhoura 2, les Ăąges proposĂ©s sâĂ©chelonnent entre 92 et 44 ka, et pour la grotte dâEl Mnasra, les rĂ©sultats suggĂšrent une occupation comprise entre 66 et 89 ka pour les couches 6 et 7. Ces rĂ©sultats suggĂšrent que les grottes de la rĂ©gion de TĂ©mara ont commencĂ© Ă ĂȘtre frĂ©quentĂ©es par lâHomme moderne dĂšs le stade isotopique marin 5, et ce jusquâĂ environ 40 ka.Lâenregistrement sĂ©dimentaire sâest poursuivi ultĂ©rieurement, comme en tĂ©moignent les vestiges dâoccupations au PalĂ©olithique supĂ©rieur et au NĂ©olithique retrouvĂ©s en stratigraphie.The region of Temara-Rabat yields several archaeological and palaeontological sites of an utmost importance for the prehistory of Morocco and more generally for Northern Africa. During the seventies, the discovery of Palaeolithic human remains associated with Aterian and Upper Palaeolithic artefacts, at Dar es Soltane, El Harhoura 1 and Contrebandiers, have emphasized the interest of the sites in this area. Two caves have been well-studied and are still under excavation: El Mnasra since 1990 and El Harhoura 2 since 2001. The combined ESR-U/Th method applied to fossil herbivorous teeth allows a chronostratigraphical view thanks to guide marks precising the palaeoenvironmental frame in which humans lived during the Palaeolithic period in Morocco. All dated layers are attributed to the Aterian culture. The analyses were performed on bovid fossil teeth unearthed from layers 8, 5 and 4a at El Harhoura 2, and from layers 7, 6a and 6 at El Mnasra. The preliminary results range between 92 and 44 ka for El Haroura2, and between 89 and 62 ka for El Mnasra. These results suggest that caves of TĂ©mara region began to be frequented by modern humans from marine isotope stage 5 until 40 ka. The sedimentary record continued later, as evidenced by remains of occupations during Upper Paleolithic and Neolithic found in stratigraphy