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31.
Martin Thorp Peter Glanville Stephen Stokes Richard Bailey 《Comptes Rendus Geoscience》2002,334(12):903-908
This paper presents the first results of a 14C and optical luminescence dating project on extensive alluvial silt formations in the southern Anti Atlas Mountains in southern Morocco. The silts comprise three members: basal silts, an inter-silt fluvial gravel member and a top silt member and are incised by the rivers. Top silt dates are: 11 340–11 940, 12 670–13 130 cal. yr BP, and 10.6±0.7 ka (OSL). OSL dates for the inter-silt gravels are 29.6±2.0 ka and for the bottom silts is 45.0±3.7 ka. The sediments correlate with Soltanian stratigraphies known elsewhere in Morocco. To cite this article: M. Thorp et al., C. R. Geoscience 334 (2002) 903–908. 相似文献
32.
Abderrahmane Soulaimani Mohammed Jaffal Lhou Maacha Azzouz Kchikach Abdessamad Najine Abdellatif Saidi 《Comptes Rendus Geoscience》2006,338(3):153-160
Aeromagnetic data of the Anti-Atlas Mountains show an important magnetic anomaly along the ‘Major Anti-Atlas Fault’, produced by different mafic and ultramafic rocks of a Neoproterozoic ophiolite complex. The magnetic modelling of Bou Azzer–El Graara ophiolitic suture shows a deep-seated anomaly through the upper continental crust corresponding to a north-dipping subduction. The polarity of the Pan-African subduction in the Anti-Atlas is therefore compatible with the contemporaneous Pan-African orogenic belts, where polarity of subduction dipped away from the West African Craton during the amalgamation of Western Gondwana. To cite this article: A. Soulaimani et al., C. R. Geoscience 338 (2006). 相似文献
33.
Résumé Les rejets sulfurés de la mine abandonnée de Kettara, située à 30 km au Nord-Nord-Ouest de Marrakech, sont directement entreposés sur un substratum schisto-gréseux fracturé. D'une superficie d'environ 16 ha, ils constituent une réelle source de pollution pour l'écosystème local en particulier à cause du Drainage Minier Acide (DMA) vers les eaux de surface et de la nappe phréatique. Le projet de réhabilitation du site minier de Kettara prévoit dans l'un de ses axes de minimiser l'effet DMA par neutralisation à l'aide de dépôts stériles riches en carbonates issus de l'extraction des phosphates de la mine de Youssoufia voisine. Ces derniers seront utilisés à la fois comme amendement des rejets miniers acides et comme couverture évapo-transpirante (barrière capillaire). Notre étude a permis d'une part, de mieux appréhender la nature et la structure du parc à résidus et de son substratum et d'autre part, de caractériser l'impact de ces résidus sur la qualité des ressources en eau souterraine. Les résultats issus de cette étude vont contribuer à la réussite du projet de réhabilitation du site. Editeur Z.W. Kundzewicz Citation Lghoul, M., Kchikach, A., Hakkou, R., Zouhri, L., Guerin, R., Bendjoudi, H., Teíxido, T., Antonio Penã, J., Enriqué, L., Jaffal, M. et Hanich, L., 2012. Etude géophysique et hydrogéologique du site minier abandonné de Kettara (région de Marrakech, Maroc): contribution au projet de réhabilitation. Hydrological Sciences Journal, 57 (2), 370–381. 相似文献
34.
《水文科学杂志》2013,58(6)
Abstract The western reservoirs represent the principal groundwater system in Morocco. Demographic, industrial and agricultural developments during the last decade have markedly altered groundwater quality. The Mamora coastal aquifer system is among the Atlantic systems which are most heavily threatened by pollution. Agricultural and industrial activities, and rapid urban growth contribute to the pollution of the groundwater. Contamination transport is facilitated by a high permeability of the aquifer formations. In order to assess the actual groundwater quality of the Mamora aquifer and to understand the influence of the factors generating the pollution, an extensive multidisciplinary research programme is in progress, with hydrochemistry and microbiology playing essential roles. The present paper concerns the spatial distribution of physico-chemical parameters in the groundwater, subjected to domestic, industrial and agricultural pollution. Fifty-seven samples were analysed for several parameters (Ca2+, Mg2+, Na+, K+, Cl?, SO4 2?, HCO3 ?, NO3 ?, pH, electrical conductivity and temperature). The microbiological analysis of 143 samples reveals the presence of four kinds of indicator bacteria in the groundwater resources: faecal Streptococci, faecal coliform, Escherichia coli and Clostridium. The physico-chemical results and bacteriological monitoring show that the nitrate and bacteria concentrations exceed the maximum admissible levels, notably around pumping stations in the sectors of Sidi Taibi, Sidi Ahmed Taleb and Aïn Sbaâ. Contamination is generated by uncontrolled anthropogenic activities and accentuated by the high intrinsic vulnerability of the aquifer system. Several parameters appeared to exceed admissibility standards. Measures are recommended to prevent groundwater pollution in the region. 相似文献
35.
Christian Montenat Michel Monbaron Ronan Allain Najat Aquesbi Jean Dejax Jean Hernandez Dale Russell et Philippe Taquet 《Eclogae Geologicae Helvetiae》2005,98(2):261-270
Resume. Le gisement de dinosauriens du Jurassique inférieur de Toundoute, à sauropode primitif (Tazoudasaurus naimi), est examiné sous ses aspects stratigraphiques, sédimentologiques et paléoenvironnementaux. Les couches continentales détritiques
à dinosaures, succédant en continuité à des niveaux marins carbonatés trés peu épais du Lias inférieur (Hettangien-Sinémurien
probables), sont rapportées au Lias moyen-supérieur. Les dép?ts continentaux contiennent une part importante de produits volcanoclastiques
différents des basaltes triasiques. Les centres d’émission, non connus, étaient sans doute proches. La sédimentation continentale,
de type chenaux fluviatiles – plaine d’inondation, refléte un climat chaud à périodes alternativement humides et séches, ces
derniéres étant fortement marquées. Les deux niveaux à ossements correspondent à des coulées boueuses ayant charrié des ossements
et portions de carcasses (os en connexion) sur de courtes distances. Ce mode de transport a préservé les ossements de l’érosion
et favorisé un enfouissement rapide permettant leur conservation.
Manuscrit re?u le 16 juillet 2004 Révision acceptée le 17 mars 2005 相似文献
36.
The sedimentological study of Arenig–Llanvirn successions of Aït Lahsen (western High Atlas), Tizi-n-Tichka and Imini (central High Atlas) allow us to recognise two independent epeiric seas. In the western High Atlas, the sedimentation occurred in a wave- and storm-influenced delta, alimented by a source situated at the present-day location of the Argana corridor, under the control of sea-level fluctuations and subsidence. In the central High Atlas, the sedimentation occurred in an influenced tide and episodic storm delta, alimented by sources situated at the present-day location of the Siroua and Ouzellagh Massifs under the control of sea-level fluctuations and tectonics. To cite this article: C. Chacrone, N. Hamoumi, C. R. Geoscience 337 (2005). 相似文献
37.
The aim of this work is the field hydraulic characterisation of Mnasra soils in northern Morocco, which represents an essential step to study the hydraulic and chemical transports through the vadose zone. We have used a tension infiltrometer associated with a transient axisymmetric infiltration method to determine the hydraulic conductivity, which reduces the duration of measurements. This allows us to characterise a large area with many measurements. Parameters of the characteristic functions K(h) and θ(h) are estimated for six different soils belonging to two geomorphologically different domains: a sandy zone and an alluvial plain. To cite this article: K. Tamoh, A. Maslouhi, C. R. Geoscience 336 (2004). 相似文献
38.
Larbi Boudad Lahcen Kabiri Samer Farkh Christophe Falguères Louis Rousseau Jacques Beauchamp Élisabeth Nicot Guillaume Cairanne 《Comptes Rendus Geoscience》2003,335(5):469-478
A large travertine outcrop south of Errachidia, southern Morocco, was studied and U/Th dated. The carbonate fraction was provided by groundwaters then, as now, from the eastern High Atlas percolating through the regional Infra-Cenomanian aquifer. There were two main periods of accumulation at ca 262 kyr BP and 20–11.5 kyr BP separated by a long discontinuity with some limited weathering and erosion and correlated in part with a period of erosion at 30–20 kyr BP further to the west. The two travertine-deposition periods suggest increased rainfall and/or cooler thermal conditions in the eastern High Atlas source regions. Massive travertine accumulation ceased at the end of the Upper Pleistocene. To cite this article: L. Boudad et al., C. R. Geoscience 335 (2003).To cite this article: L. Boudad et al., C. R. Geoscience 335 (2003). 相似文献
39.
The post-collisional Hercynian granitoids crop out in the easternmost part of the Moroccan Hercynian belt. Petrographical and geochemical studies show a composition similarity in the various granitoids. The granitoids belong to per-aluminous and metaluminous magmatic associations. They have evolved according to a scheme similar to high-K calc-alkaline to shoshonitic associations. To cite this article: H. El Hadi et al., C. R. Geoscience 335 (2003). 相似文献
40.
Luc Barbanson Alain Chauvet Aziz Gaouzi Lakhifi Badra Mohamed Mechiche Jean Claude Touray Saı̈d Oukarou 《Comptes Rendus Geoscience》2003,335(14):1021-1029
The Cu ore of Ifri is a chalcopyrite stockwork hosted by Cambrian formations and was until now interpreted as a syngenetic massive sulphide deposit. Textural studies highlight two generations of pyrite early (Py I) and late (Py II) with respect to the regional deformation. The chalcopyrite stockwork overprinted Py II, outlining the epigenetic nature of the Cu mineralization. Regarding the origin of Cu-depositing fluids, the presence in the stockwork paragenesis of an U, W, Sn association and preliminary Pb/Pb dating of a brannerite belonging to this association suggest a contribution of the Tichka granite. To cite this article: L. Barbanson et al., C. R. Geoscience 335 (2003). 相似文献