Processes of water–rock interaction in the Turonian aquifer of Oum Er-Rabia Basin, Morocco

Possible water–rock interaction processes, in the Moroccan basin of Oum Er-Rabia, were discussed by a geochemical study of groundwater from the Turonian limestone aquifer, the most important water resource in the region. Different types of water according to the classification of Piper were defined. Waters have shown an evolution from dominant CHO₃–Ca–Mg type through mixed to SO₄–Cl–Ca–Mg type. The use of geochemical diagrams and chemical speciation modeling method has shown that water–rock interaction is mainly controlled by carbonate and anhydrite dissolution, ion exchange and reverse ion exchange processes. Water–rock equilibrium conditions are favorable for the precipitation of calcite, dolomite, kaolinite and magnesian smectite.     

Groundwater pollution risk mapping for the Eocene aquifer of the Oum Er-Rabia basin, Morocco

Sustainable development requires the management and preservation of water resources indispensable for all human activities. When groundwater constitutes the main water resource, vulnerability maps therefore are an important tool for identifying zones of high pollution risk and taking preventive measures in potential pollution sites. The vulnerability assessment for the Eocene aquifer in the Moroccan basin of Oum Er-Rabia is based on the DRASTIC method that uses seven parameters summarizing climatic, geological, and hydrogeological conditions controlling the seepage of pollutant substances to groundwater. Vulnerability maps were produced by using GIS techniques and applying the “generic” and “agricultural” models according to the DRASTIC charter. Resulting maps revealed that the aquifer is highly vulnerable in the western part of the basin and areas being under high contamination risk are more extensive when the “agricultural” model was applied.     

Incidences of water-rock interaction on natural resources characters,Oum Er-Rabia Basin (Morocco)

The Oum Er-Rabia Basin provides important water resources from a multi-layer aquifer system of which the Turonian limestone aquifer constitutes the main potential resource. The same basin is also known by its wealth in phosphates and comprises the Ouled Abdoun Series, the largest Moroccan phosphate occurrence. The present work attempts to characterize the interaction of natural resources with their impacts on water and phosphates quality. Hydrogeochemical data on waters of the Turonian and the Eocene aquifers, as well as their petrographical analyses, by optical and electronic microscopes and by the X-ray diffraction method on weathered and non-weathered rocks of relative aquifers, have shown that water-rock interaction has a large influence on the quality of water and phosphate resources in the Oum Er-Rabia Basin.     

Vulnerability mapping of the Turonian limestone aquifer in the Phosphates Plateau (Morocco)

Turonian limestones are an important source of water indispensable for industrial, urban and agricultural development in the Phosphates Plateau. This is an elaboration of a vulnerability map of the aquifer, based on a multicriterion approach according to the DRASTIC charter that serves as a tool for assessment, management and protection of the groundwater quality.     

Modelling groundwater flow of the Trifa aquifer, Morocco

Trifa is the most productive agricultural plain of north-eastern Morocco. The development of agricultural activities during the last few decades has been mainly based on imported water for irrigation. However, irrigation requirements have become so large that groundwater is used as a secondary source to supply the agricultural and domestic water needs, causing a depletion of the groundwater resources, especially during dry periods. A hydrological and a hydrogeological model for the Trifa plain have been developed, which yield information on relevant parameters such as groundwater recharge, and estimate the amount of pumped groundwater needed to meet the irrigation needs. The models (MODFLOW and WetSpass) provide insight into the status and evolution of the groundwater reserves. The results of the study are useful to predict the sustainability of the groundwater resources in the Trifa plain and to evaluate possible management actions. A reduction in groundwater abstraction by at least 25% may be necessary to achieve sustainable conditions.

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Resumen Trifa es la planicie agrícola más productiva del noreste de Marruecos. El desarrollo de las actividades agrícolas durante las últimas décadas se ha basado principalmente en agua importada para riego. Sin embargo, los requerimientos de riego han llegado a ser tan grandes ocasionando que se utilice el agua subterránea como una fuente secundaria para abastecer las necesidades de agua para uso doméstico y agrícola, lo que causa un agotamiento de los recursos de agua subterránea, especialmente durante periodos secos. Se ha desarrollado un modelo hidrogeológico e hidrológico para la planicie Trifa el cual aporta información de parámetros relevantes tal como recarga de agua subterránea y estima la cantidad de agua subterránea que necesita bombearse para satisfacer las necesidades de riego. Los modelos (MODFLOW y WetSpass) aportan una idea acerca del estado actual y la evolución de las reservas de agua subterránea. Los resultados de este estudio son útiles para predecir la sostenibilidad de los recursos de agua subterránea en la planicie Trifa y para evaluar posibles acciones de gestión. Puede ser necesario reducir la explotación de agua subterránea en por lo menos 25% para alcanzar condiciones sostenibles.

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Résumé Trifa est la plaine agricole la plus productive du Nord-Est marocain. Le développement de l’activité agricole durant ces dernières décennies a essentiellement reposé sur l’irrigation. Néanmoins les besoins de l’irrigation sont devenus tels que l’eau souterraine est utilisée comme ressource secondaire, pour combler la demande en eau domestique et agricole, induisant un rabattement d’autant plus important durant les périodes sèches. Un modèle hydrologique et hydrogéologique de la plaine de Trifa a été développé sur base des paramètres les plus importants, tels la recharge, et permet d’estimer le pompage nécessaire des eaux souterraines pour combler les besoins de l’irrigation. Les modèles (MODFLOW et WetSpass) apportent une bonne connaissance de l’état et de l’évolution des réserves souterraines. Les résultats de l’étude sont utiles pour prédire la longévité des ressources et pour évaluer différents scénarios de gestion. Une réduction de l’extraction de 25% serait nécessaire pour atteindre un état durable.

     

Evolution of groundwater salinity in the unconfined aquifer of Bou-Areg, Northeastern Mediterranean coast, Morocco

The Bou-Areg plain in the Mediterranean coast at the North-eastern of Morocco is characterized by a semi-arid climate. The aquifer consists of two sedimentary formations of Plio-quaternary age: the upper formation of fine silts and the lower one of coarse silts with sand and gravels. The aquifer is underlain by marly bedrock of Miocene age that dips toward the coastal lagoon of Bou-Areg. The hydrodynamic characteristics vary between 10⁻⁴ and 10⁻³ m/s; and transmissivities range between 10⁻⁴ and 10⁻¹ m²/s. The general direction of flow is SW to NE, toward the lagoon. The aquifer is crossed by the river Selouane, which also ends in the lagoon. The groundwater is characterized by a high salinity that can reach 7.5 g/l. The highest values are observed in the upstream and in the downstream sectors of the aquifer. The temporal evolution of the physico-chemical parameters depends on the climatic conditions and piezometric variations. The analysis of the spatio-temporal distribution of the physico-chemical parameters suggests different sources of groundwater salinization: the seawater intrusion, the influence of marly gypsum-bearing terrains, and the influence of anthropogenic products as the agricultural fertilizers, which cause great nitrate concentrations that vary between 80 and 140 mg/l.     

Hydrochemical and isotopic characteristics of groundwater in the Souss Upstream Basin, southwestern Morocco

Heterogeneous shallow Plio-Quaternary formations of the Souss Plain represent the most important aquifer in southern High Atlas Mountains in Morocco. The present work was conducted in the Souss Upstream Basin to identify the chemical characteristics and the origin of groundwater in an aquifer under semi-arid climate. Isotopic and hydrochemical compositions combined with geological and hydrogeological data were used for this purpose. The total dissolved solids vary from 239 to 997 mg l⁻¹, and the following groundwater types are recognized: Ca²⁺–Mg²⁺–HCO₃⁻, Ca²⁺–Mg²⁺–SO₄²⁻ and Ca²⁺–Mg²⁺–Cl⁻. The groundwater is saturated and slightly supersaturated with respect to carbonate minerals and undersaturated with respect to evaporite minerals, which means that the groundwater composition is largely controlled by the dissolution of carbonate rocks known in the basin. The isotopic contents of groundwaters ranged from −8‰ to −5.2‰ for δ¹⁸O, from −52‰ to −34‰ for δD, and from 0 to 5.5 TU for tritium. The hydrogen (δD) and oxygen (δ¹⁸O) isotope signatures reveal a significant infiltration before evaporation takes place, indicating a major recharge directly from fractures in the crystalline and limestone formations of Atlas Mountains (above 800 m a.s.l.) and infiltration of surface water in the alluvial cones at the border of the Atlas basins. The very low tritium values suggest that the groundwater recharge follows a long flow path and a mixing between old and modern water is shown. However, a slight evaporation effect is noted in the southern part of the basin close to the Anti-Atlas Mountains.     

Methodology for mapping shallow groundwater quality in urbanized areas: A case study from Lithuania

Cities have a negative impact on the quality of shallow groundwater. Many of Lithuania's urban residents drink water from dug wells. Moreover, polluted shallow groundwater contaminates deeper aquifers of fresh drinking water. Therefore, this situation should be controlled and managed, as far as possible. In order to evaluate the quality of shallow groundwater in an urban area and to create an optimal monitoring system, an original methodology for groundwater mapping has been proposed. It resembles the GIS (geographical information system) technologies. The set of maps, laid one over another, consists of the following: (1) urbanization map, (2) geological-hydrogeological map, (3) groundwater chemistry map, (4) resulting groundwater chemistry factorial analysis map, and (5) pollution and pollutant transport map. The data obtained from studies on dug and geotechnical wells have been used for compilation of the maps. The system for shallow groundwater monitoring in the city with an area of 70 sq km and a population of 140,000 is proposed to consist of about 30 monitoring wells and several dug wells.     

An extension to the DRASTIC model to assess groundwater vulnerability to pollution: application to the Haouz aquifer of Marrakech (Morocco)

An extension to the DRASTIC model is proposed in order to assess aquifer vulnerability to pollution. In contrast to the DRASTIC model, which considers the unsaturated and saturated zones together and computes a global intrinsic vulnerability index, the suggested approach discriminates between the aquifer vertical vulnerability (a concept related to the pollutant percolation) and the groundwater susceptibility (a concept that depends on the behaviour and uses of the groundwater). This approach is applied to the Haouz aquifer (Morocco) that supplies water to the Marrakech area. This aquifer is widely overexploited and there is evidence that the groundwater quality is threatened by various sources of pollution. Evaluation of the vertical vulnerability indicates that the aquifer mainly presents a moderate-to-weak vertical vulnerability. The zones potentially most favourable to pollutant percolation are mainly located in Central Haouz, along or near the surface wadis. The aquifer susceptibility is high in places located near the N’Fis, Baaja and Issil wadis. Everywhere else, low-to-moderate susceptibility is observed. This new approach therefore enables areas of vertical vulnerability and areas of susceptibility to be delineated separately. As a result, it constitutes a valuable decision-making tool for optimising the management of aquifer water resources and land-use planning.     

Geographic Information System and groundwater quality mapping in Panvel Basin,Maharashtra, India

Panvel Basin of Raigarh district, Maharashtra, India is the study area for groundwater quality mapping using the Geographic Information System (GIS). The study area is typically covered by Deccan basaltic rock types of Cretaceous to Eocene age. Though the basin receives heavy rainfall, it frequently faces water scarcity problems as well as water quality problems in some specific areas. Hence, a GIS based groundwater quality mapping has been carried out in the region with the help of data generated from chemical analysis of water samples collected from the basin. Groundwater samples show quality exceedence in terms of chloride, hardness, TDS and salinity. These parameters indicate the level of quality of groundwater for drinking and irrigation purposes. Idrisi 32 GIS software was used for generation of various thematic maps and for spatial analysis and integration to produce the final groundwater quality map. The groundwater quality map shows fragments pictorially representing groundwater zones that are desirable and undesirable for drinking and irrigation purposes.     

Present recharge of an aquifer in a semi-arid region: an example from the Turonian limestones of the Errachidia basin, Morocco

 The Errachidia basin is composed of three superposed aquifers (Senonian, Turonian limestones and Infracenomanian). The Liassic limestone of the upper Atlas borders the northern part of the basin. The piezometric map of the Turonian aquifer displays a north-south flow, with an inflow area from the Atlas. This recharge hypothesis is demontrated by a discriminant analysis performed on chemical data: the majority of the spots are of sodium choride and hydrogenocarbonate types, while several boreholes are assigned to a calcium hydrogenocarbonate type Jurassic component. ¹⁸O measurements, using the Atlasic gradient δ¹⁸O=–4.18–0.0027 x elevation to estimate the recharge areas, confirm that the recharge area is the basin itself (<1100 m) on the Turonian outcrops, while in the confined part, the Turonian is recharged higher than 1400 m (corresponding to the Atlas). This contribution ranges from 56 to 85%, according to the situation versus the piezometric inflow area. The remainder represents infiltration and vertical leakage from the Senonian layers.     

Environmental impact of an urban landfill on a coastal aquifer (El Jadida, Morocco)

The El Jadida landfill is one among many uncontrolled dumping sites in Morocco with no bottom liner. About 150 tons/day of solid wastes from mixed urban and industrial origins are placed directly on the ground. At the site of this landfill, the groundwaters circulate deeply (10–15 m) in the Cenomanian rock (calcareous–marl), which is characterised by an important permeability from cracks. The soil is sand–clay characterized by a weak coefficient of retention.The phreatic water ascends to the bottom of three quarries, which are located within the landfill. These circumstances, along with the lack of a leachate collection system, worsen the risks for a potential deterioration of the aquifer.To evaluate groundwater pollution due to this urban landfill, piezometric level and geochemical analyses have been monitored since 1999 on 60 wells. The landfill leachate has been collected from the three quarries that are located within the landfill. The average results of geochemical analyses show an important polluant charge vehiculed by landfill leachate (chloride = 5680 mg l⁻¹, chemical oxygen demand = 1000 mg l⁻¹, iron = 23 000 μg l⁻¹). They show also an important qualitative degradation of the groundwater, especially in the parts situated in the down gradient area and in direct proximity to the landfill. In these polluted zones, we have observed the following values: higher than 4.5 mS cm⁻¹ in electric conductivity, 1620 and 1000 mg l⁻¹ respectively in chlorides and sulfate (), 15–25 μg l⁻¹ in cadmium, and 60–100 μg l⁻¹ in chromium. These concentrations widely exceed the standard values for potable water.Several determining factors in the evolution of groundwater contamination have been highlighted, such as (1) depth of the water table, (2) permeability of soil and unsaturated zone, (3) effective infiltration, (4) humidity and (5) absence of a system for leachate drainage. So, to reduce the pollution risks of the groundwater, it is necessary to set a system of collection, drainage and treatment of landfill leachates and to emplace an impermeable surface at the site of landfill, in order to limit the infiltration of leachate.     

Sustainability analysis of groundwater resources in a coastal aquifer, Alabama

Fort Morgan Peninsula is an attached portion of a dynamic barrier complex in the northern Gulf of Mexico and is a large tourist area that brings in a significant amount of revenue for Alabama. Many of the hotels and tourist attractions depend on the groundwater as their water supply. The over-withdrawal of groundwater and saltwater intrustion will have a negative impact on the ecology, tourism and economy if groundwater resources are not properly monitored and managed. In this study a calibrated groundwater flow model was used to analyze the sustainability of groundwater resources at Fort Morgan Peninsula. Detailed flow budgets were prepared to check the various components of inflow and outflow under different water use and climatic conditions. The results indicated the locations where groundwater was over-pumped and subjected to saltwater intrusion, or will be subjected to saltwater intrusion under a range of projected water use and climatic conditions.     

Calcareous nannofossil biostratigraphy and paleoecology of the Cenomanian – Turonian transition in the Tarfaya Basin, southern Morocco

An abundant and diverse nannoflora occurs across the Cenomanian/Turonian (C/T) boundary at Tazra in the Tarfaya Basin of southern Morocco. The nannoflora of this sequence permits recognition of three biozones (CC10-CC12), three subzones (CC10a, CC10b and CC10c), and thirteen important nannolith bioevents previously reported from this interval elsewhere. The floral record shows erratic species abundance fluctuations that clearly vary with lithology and reflect at least in part preservational bias and diagenetic processes. In general, four dissolution resistant taxa are dominant: Watznaueria barnesae, Eiffellithus turriseiffelii, Eprolithus floralis, and Zeugrhabdotus spp. The late Cenomanian Zone CC10 marks a rapid excursion in ∂¹³C and is characterized by the successive extinction of four taxa, which are widely recognized as reliable biomarkers: Corollithion kennedyi, Axopodorhabdus albianus, Lithraphidites acutus, and Helenea chiastia. This interval is also marked by high species richness and high abundance of the tropical species Watznaueria barnesae, suggesting warm tropical waters. The subsequent ∂¹³C plateau and organic carbon-rich black shale deposition of the oceanic anoxic event (OAE2) is characterized by low species richness, but high nannofossil abundance, and peak abundance of the cool water and high productivity indicator Zeugrhabdotus spp., followed by the first peak abundance of cool water Eprolithus floralis. This interval correlates with the planktic foraminiferal diversity minimum and the Heterohelix shift, which marks the expansion of the oxygen minimum zone (OMZ). The C/T boundary is identified based on the FO of Quadrum gartneri, which is <1 m below the FO of the planktic foraminifer C/T marker Helvetoglobotruncana helvetica. In the early and middle Turonian, the two dominant species, tropical W. barnesae and cool water E. floralis, alternate in abundance and suggest fluctuating climatic conditions.     

Spatial and statistical assessment of nitrate contamination in groundwater:Case of Sais Basin,Morocco

The objective of this study is to evaluate the nitrate contamination in the plioquaternary aquifer of Sais Basin based on a statistical approach. A total of 98 samples were collected in the cultivated area during the spring and autumn period of 2018. The results show that 55% and 57% of the samples in spring and autumn respectively exceed the threshold fixed by WHO(50 mg/L). However, nitrate concentrations do not show seasonal and spatial variation(p0.05). The results of the correlation matrix, principal component analysis(PCA), and hierarchical cluster analysis(HCA) suggest that nitrate pollution is related to anthropogenic source. Moreover, multiple linear regression results show that NO_3 is more positively explained in the spring period by Ca and SO_4 and negatively explained by pH and HCO_3. Regarding the autumn period, nitrate pollution is positively explained by Ca and negatively by pH. This study proposes a useful statistical platform for assessing nitrate pollution in groundwater.     

Identifying trends in groundwater quality using residence time indicators: an example from the Permian aquifer of Dumfries, Scotland

The Permian sandstone and breccia aquifer of Dumfries has an important role in supplying water to the principal town in southwest Scotland. The area comprises mainly pastoral farmland with some industry and fish farming. Ongoing development of the aquifer has revealed the existence of complex groundwater flow through fractures and increasing nitrate concentrations. To further investigate these issues, the age and quality of groundwater throughout the aquifer has now been assessed using standard hydrogeochemical techniques together with CFCs and SF₆ as residence time indicators. The aquifer consists of sandstone- and breccia-dominated units: the Locharbriggs Sandstone in the east and the Doweel Breccia in the west. Groundwater throughout the aquifer is of Ca–Mg–HCO₃ type and moderately mineralised; pH is near neutral. The observed groundwater chemistry is the product of maritime rainfall modified by the dissolution of carbonate material in the breccia, sandstone and surficial deposits. CFC and SF₆ concentrations are interpreted on the basis of mixing between older (>50 years) and recent (1990s) components. Although there is generally a higher proportion of older water within the Locharbriggs Sandstone compared to the Doweel Breccia, stable isotope evidence suggests that the older water component in the interbedded sandstones of the breccia is of much greater antiquity, possibly containing an element of palaeowater. Concentrations of nitrate across the aquifer can be directly related to the amount of recent recharge. Modern groundwater contains approximately 9 mg l^–1 NO₃-N and pre-1950s groundwater has approximately 2 mg l^–1 NO₃-N. Nitrate concentrations measured at individual boreholes are explained by the relative proportions of modern and pre-1950s groundwater. If current practices continue, the concentrations of nitrate measured across the Dumfries Basin will rise as the proportion of pre-1950s groundwater diminishes.

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Resumen El acuífero de areniscas y brechas Pérmicas de Dumfries desempeña un papel importante en el abastecimiento a la ciudad principal del Sudoeste de Escocia. El área comprende sobretodo tierras de pastoreo y granjas, junto con algunas industrias y piscifactorías. El desarrollo iniciado en el acuífero ha revelado la existencia de un complicado flujo subterráneo a través de las fracturas y de un aumento progresivo en la concentración de nitrato. Con el fin de profundizar en el conocimiento de estos temas, se ha determinado la edad y calidad de las aguas subterráneas en todo el acuífero por medio de técnicas hidrogeoquímicas estándar y de indicadores del tiempo de residencia como los clorofluorcarbonados (CFCs) y el fluoruro de azufre (SF₆). El acuífero está formado por las areniscas de Locharbriggs, al Este, y las brechas de Doweel, hacia el Oeste. Las aguas subterráneas son de tipo bicarbonatadas cálcico-magnésicas y presentan una mineralización moderada, mientras que el pH es prácticamente neutro. La química de las aguas subterráneas es el resultado del aerosol marino modificado por la disolución de materiales carbonatados en las brechas, areniscas y depósitos superficiales. Las concentraciones de CFCs y SF₆ se interpretan a partir de una mezcla de aguas entre una componente antigua (más de 50 años) y una reciente (de la década de 1990). Aunque en general se da una mayor proporción de aguas antiguas en las areniscas de Locharbriggs que en las Brechas de Doweel, los isótopos estables sugieren que la componente de aguas antiguas en las intercalaciones de areniscas que aparecen en la formación de brechas es mucho más antigua, y que, posiblemente, se trate de paleoaguas. Las concentraciones de nitrato en el acuífero pueden ser relacionadas directamente con la aportación de recarga reciente. Las aguas subterráneas modernas contienen aproximadamente 9 mg l^–1 de nitrato, mientras que las aguas subterráneas anteriores a 1950 tienen unos 2 mg l^–1. Se puede explicar las concentraciones de nitrato en pozos individuales por las proporciones relativas de aguas subterráneas modernas y anteriores a 1950. Si las prácticas actuales continúan, se producirá un aumento de las concentraciones de nitrato en la cuenca de Dumfries debido a la disminución de la proporción de aguas antiguas.

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Résumé L'aquifère des grès et brèches du Permien de Dumfries joue un rôle important dans l'alimentation en eau de la principale ville du sud-ouest de l'Écosse. La région est principalement soumise à de l'élevage pastoral avec quelques industries et des piscicultures. La progression de l'exploitation de cet aquifère a révélé l'existence d'un écoulement souterrain complexe en fractures et des concentrations en nitrate croissantes. Dans le but d'étudier ces deux points plus en détail, l'âge et la qualité de l'eau souterraine dans tout l'aquifère ont été évalués en utilisant des techniques hydrogéochimiques conventionnelles avec les CFC et SF₆ comme marqueurs du temps de séjour. L'aquifère est constitué par des unités dominées par des brèches et des grès: les grès de Locharbriggs à l'est et les brèches de Doweel à l'ouest. L'eau souterraine dans tout l'aquifère a un faciès bicarbonaté calcique et magnésien et est moyennement minéralisée; le pH est proche de la neutralité. Le chimisme observé de l'eau souterraine résulte des apports marins par la pluie modifiés par la dissolution du matériau carbonaté des brèches, des grès et des formations superficielles. Les concentrations en CFC et SF₆ sont interprétées sur la base d'un mélange entre des composantes ancienne (>50 ans) et récente (années 1990). Bien qu'il y ait en général une plus forte proportion d'eau ancienne dans les grès de Locharbriggs que dans la brèche de Doweel, les isotopes stables suggèrent que la composante d'eau ancienne dans les grès interstratifiés des brèches est beaucoup plus ancienne, contenant probablement un élément d'eau fossile. Les concentrations en nitrate dans l'aquifère peuvent être directement reliées au taux de recharge récente. L'eau souterraine moderne contient approximativement 9 mg l^–1 en NO₃-N et l'eau souterraine d'avant 1950 environ 2 mg l^–1 en NO₃-N. Les concentrations en nitrate mesurées dans des forages individuels sont expliquées par des proportions relatives d'eaux souterraines moderne et antérieure à 1950. Si les pratiques actuelles continuent, les concentrations en nitrate mesurées dans le bassin de Dumfries augmenteront alors que la part de l'eau souterraine d'avant 1950 diminuera.

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Mapping potential areas for groundwater storage in the High Guir Basin (Morocco):Contribution of remote sensing and geographic information system

Identification of water potential areas in arid regions is a crucial element for the enhancement of their water resources and socio-economic development. In fact, water resources system-planning can be used to make various decisions and implement management of water resources policies. The purpose of this study is to identify groundwater storage areas in the high Guir Basin by implementing Geographic Information System (GIS) and Remote Sensing methods. The required data for this study can be summarized into five critical factors: Topography (slope), lithology, rainfall, rock fracture and drainage. These critical factors have been converted by the GIS into thematic maps. For each critical parameter, a coefficient with weight was attributed according to its importance. The map of potential groundwater storage areas is obtained by adding the products (coefficient × weight) of the five parameters. The results show that 50% to 64% of the total area of the High Guir Basin is potentially rich in groundwater, where most of fracture systems are intensely developed. The obtained results are validated with specific yield of the aquifer in the study area. It is noted that there is a strong positive correlation between excellent groundwater potential zones with high flows of water points and it diminishes with low specific yield with poor potential zones.     

A baby mosasauroid (Reptilia,Squamata) from the Turonian of Morocco – Tethysaurus ‘junior’ discovered?

New Middle Turonian mosasauroid remains were discovered in the same large-sized nodule that yielded a specimen referred to Tethysaurus nopcsai Bardet et al., 2003, from the Goulmima region (southern Morocco). They comprise isolated, fragmentary cranial elements (skull and mandible) and some vertebrae. Their very small size suggests a juvenile condition, an observation supported also by anatomical (spongious nature of numerous bone parts), micro-anatomical (loose inner spongiosa) and histological (numerous remains of calcified cartilage deep into the centrum; radial vascular canals) data. These bones belonged to a basal mosasauroid that cannot be distinguished from Tethysaurus nopcsai to which taxon we tentatively assign the material.