Biostratigraphie des foraminifères du Toarcien du Moyen Atlas Central, Maroc Biostratigraphy of the Toarcian foraminifera of the Central Middle Atlas, Morocco

International audienceLes dépôts toarciens du Moyen Atlas central, généralement de type hémipélagiques, indiquent des conditions de plate-forme et de bassin ; ils sont marneux et confinés dans les dépocentres, calcaro-marneux et condensés dans les dépoaxes. L'étude micropaléontologique des foraminifères benthiques a permis de suivre l'extension biostratigraphique des dif-férentes espèces rencontrées. Quatre biozones sont établies (biozone à Lingulina gr. tenera et Marginulina gr. Prima ; biozone à Lenticulina obonensis mg P. ; biozone à Lenticulina pennensis mg. M., Ichtyolaria hauffi, Dentalina utriculata, Citharina longuemari et spectre Lenticulina chicheryi ; biozone à Lenticulina d'orbignyi mg L. et Nodosaria pulchra). Les associations ou les espèces indicatrices de paléoenvironnements particuliers sont soulignées. Pour répondre aux conditions des milieux de vie, ces espèces adoptent généralement des stratégies exprimées par des tendances mor-phologiques particulières concernant, entre autres, la taille du test, son aplatissement et son déroulement. The Toarcian sediments of the Central Middle Atlas show hemipelagic facies deposited in platform to basinal envi-ronments. They are represented by marly thick sections which accumulated in troughs under restricted conditions and by condensed sections of marly limestones encountered rather on high ridges. The micropalaeontological study of benthic foraminifera allowed us to establish the biostratigraphic extension of the different encountered species. Four biozones were thus established (biozone with Lingulina gr. tenera and Marginu-lina gr. Prima; biozone with Lenticulina obonensis mg P.; biozone with Lenticulina pennensis mg. M., Ichtyolaria hauffi, Dentalina utriculata, Citharina longuemari and spectre Lenticulina chicheryi; biozone with Lenticulina d'orbignyi mg L. and Nodosaria pulchra). Both typical associations and paleoenvironmental marker species are described. In response to envi-ronmental change, significant morphological variations have evolved in these species (e.g. size, flattening and uncoiling of the test)

Stratégies adaptatives des foraminifères benthiques toarciens du Moyen Atlas (Maroc) : implications paléoécologiques. Adaptive strategies of the Toarcian Benthic Foraminifera of the Middle Atlas (Morocco) : paleoecological implications

International audienceAu Toarcien, dans le Moyen Atlas, l'analyse quantitative et qualitative des associations de foraminifères benthiques montre une adaptation aux conditions du milieu qui influent sur la diversité, la fréquence et les modifications morphologiques (forme et taille). Plusieurs taxons appartenant essentiellement aux Nodosariidés, aux Cératobuliminidés et aux Agglutinés adoptent des formes et des tailles particulières qui leur permettent de subsister et parfois de proliférer dans des niches où les conditions écologiques sont difficiles (déficit en oxygène, fonds vaseux, etc.). Quantitative and qualitative analysis show that, as a whole, associations of Foraminifera adapt with the conditions of the envi-ronment which influence diversity, frequency fluctuations and morphological modifications (form and size). Several species belonging primarily to Nodosariidea, Ceratobuliminidea and Agglutinea adopt particular forms and sizes which enable them to remain and sometimes to proliferate in niches where the ecological conditions are difficult (e.g. oxygen deficit, muddy funds, ...)

Approche Méthodologique D’évaluation De Susceptibilité Des Versants Aux Glissements De Terrain Par Un Modèle Volumique De L’aléa ; Application Au Secteur De Boujibar Al Hoceima (Rif, Maroc)

This paper presents a new assessment technique of slopes landslide susceptibility, through a geometrical solid model of hazard in reliance on application and comparison of two different approaches (probability and determinist). Here we present a complete methodology for resolving all the technical difficulties encountered during the application of deterministic approach on a catchment basin scale, and to generate an estimating model of hazard not only on the ground surface but also in depth. Indeed, the application of this approach in the area of Boujibar in the south of Al Hoceima city has allowed to specify that, the deterministic method based on factor of safety (Fs) calculation for hazard evaluation of catchment basin is the most adapted and most suitable method on a local and regional scale

Potential-field geophysical data inversion for 3D modelling and reserve estimation (Example of the Hajjar mine, Guemassa massif, Morocco): magnetic and gravity data case

Geophysical data inversion is a tool, which can be used to recover the subsurface distribution of physical properties from field data. Each type of geophysical data can be inverted using one or more inversion algorithms. In this paper, a set of geophysical magnetic and gravity data of the Hajjar area in Morocco, covering an extent of $3.2\times 1.6~\mathrm{km}^{2}$, were used to make a 3D model of an orebody and to estimate the mineral reserve by potential-field geophysical data inversion and excess mass estimation. We thus promote the development and application of potential-field geophysical data inversion using the softwares Geosoft Oasis Montaj and Voxi Earth Modelling™ and the evaluation of its power compared to the excess mass estimation method. The process of inversion begins with data processing, then moves to analysis and interpretation, and ends with unconstrained Cartesian cut cell inversion. The results show a variation of $-$0.22 mGal to 1.59 mGal for the gravity residual anomaly map, leading to have density variations from $2.45~\mathrm{g}/\mathrm{cm}^{3}$ to $4.22~\mathrm{g}/\mathrm{cm}^{3}$, and a variation of $-$232 nT to 1018 nT for the reduced magnetic anomaly map.Moreover, data inversion allowed us to create a 3D model of the orebody and of the adjacent geological formation, and to estimate the different parameters that characterize the orebody derived from the inversion results, which have been confirmed from survey data: (depth $\approx 160$ m; maximum density $\approx 4.22~\mathrm{g}/\mathrm{cm}^{3}$; minimum density $\approx 3~\mathrm{g}/\mathrm{cm}^{3}$; mean density $\approx 3.61~\mathrm{g}/\mathrm{cm}^{3}$; thickness of the overburden $\approx$120 m; dip $\approx 45^{\circ }$; morphology ${\approx }$ lens; volume $\approx 4.8 \times 10^{6}~\mathrm{m}^{3}$).It was therefore possible to evaluate the reserve, and to validate the reliability of the inversion by having a root mean square error between the exploited reserve and the calculated reserve of 13.5%, i.e. an insignificant difference between the real and calculated magnetic and gravity orebody responses, which support the validity of the results

Potential-field geophysical data inversion for 3D modelling and reserve estimation (Example of the Hajjar mine, Guemassa massif, Morocco): magnetic and gravity data case

Geophysical data inversion is a tool, which can be used to recover the subsurface distribution of physical properties from field data. Each type of geophysical data can be inverted using one or more inversion algorithms. In this paper, a set of geophysical magnetic and gravity data of the Hajjar area in Morocco, covering an extent of $3.2\times 1.6~\mathrm{km}^{2}$, were used to make a 3D model of an orebody and to estimate the mineral reserve by potential-field geophysical data inversion and excess mass estimation. We thus promote the development and application of potential-field geophysical data inversion using the softwares Geosoft Oasis Montaj and Voxi Earth Modelling™ and the evaluation of its power compared to the excess mass estimation method. The process of inversion begins with data processing, then moves to analysis and interpretation, and ends with unconstrained Cartesian cut cell inversion. The results show a variation of $-$0.22 mGal to 1.59 mGal for the gravity residual anomaly map, leading to have density variations from $2.45~\mathrm{g}/\mathrm{cm}^{3}$ to $4.22~\mathrm{g}/\mathrm{cm}^{3}$, and a variation of $-$232 nT to 1018 nT for the reduced magnetic anomaly map.Moreover, data inversion allowed us to create a 3D model of the orebody and of the adjacent geological formation, and to estimate the different parameters that characterize the orebody derived from the inversion results, which have been confirmed from survey data: (depth $\approx 160$ m; maximum density $\approx 4.22~\mathrm{g}/\mathrm{cm}^{3}$; minimum density $\approx 3~\mathrm{g}/\mathrm{cm}^{3}$; mean density $\approx 3.61~\mathrm{g}/\mathrm{cm}^{3}$; thickness of the overburden $\approx$120 m; dip $\approx 45^{\circ }$; morphology ${\approx }$ lens; volume $\approx 4.8 \times 10^{6}~\mathrm{m}^{3}$).It was therefore possible to evaluate the reserve, and to validate the reliability of the inversion by having a root mean square error between the exploited reserve and the calculated reserve of 13.5%, i.e. an insignificant difference between the real and calculated magnetic and gravity orebody responses, which support the validity of the results

Metodología para un inventario y evaluación de sitios geológicos en Marruecos: propuesta para su aplicación a otras regiones africanas

Officially, there is no exhaustive inventory of Sites of Geological Interest (SGI) in Morocco. Nonetheless, the Geological Service of Morocco started identification of these sites a few years ago, and published 9 volumes on the subject as geological and mining guides of Morocco. This was only limited to identification of SGI without their characterization and assessment, or identification of the threats that could affect them. In the last few years several PhD Thesis and research papers have dealed with this subject. Unfortunately, these initiatives are sporadic and far from establishing a global strategy for geoconservation and valorization of the Moroccan geological heritage. This paper proposes a global methodology for the inventory of geoheritage in Morocco by: i) providing a detailed synthesis of the research work on geoheritage in the world; ii) proposing the ways for assessing the Moroccan geoheritage at different scales (scientific education, geotourism, sustainable development, etc.); and iii) applying them to a wide variety of landscapes in Morocco. The obtained results and conclusions can be further extended to other African regions.No existe un inventario exhaustivo oficial de Sitios de Interés Geológico (SGI) en Marruecos. El Servicio Geológico de Marruecos ha promovido en los últimos años iniciativas para identificar estos sitios y las ha publicado, en 9 volúmenes, en forma de guías geológicas y mineras de Marruecos. Esta iniciativa sólo se limitaba a identificar los SGI sin caracterizarlos, evaluarlos o reconocer las amenazas que pudieran afectarles. En los últimos años varias tesis doctorales y trabajos de investigación han abordado esta cuestión. Desafortunadamente, han sido iniciativas esporádicas que no pueden cumplir el ambicioso reto de establecer una estrategia global de geoconservación y valorización del patrimonio geológico marroquí. En este trabajo se propone una metodología global para inventariar el geopatrimonio marroquí mediante: i) una síntesis detallada de trabajos de investigación llevados a cabo sobre geopatrimonio en el mundo; ii) la propuesta de criterios para evaluar estos resultados a diferentes escalas (educación científica, geoturismo, desarrollo sostenible, etc.); y iii) su aplicación a una gran variedad de paisajes de Marruecos. Los principales resultados y conclusiones obtenidos se pueden aplicar a otras regiones africanas.The present work has been funded by the Research Project reference PID2020-114381GB-I00 (Spanish Ministry of Education and Science), the Research Group reference VIGROV-53 (Alicante University, CTMA-IGA), both coordinated by M. Martín-Martín; and the Research Project “Identification, conservation et valorisation du Patrimoine Géologique de la région Tanger-Tétouan-Al Hoceima pour un développement durable” (Abdelmalek Essaadi University, Morocco) coordinated by R. Hlila

Data Conditioning Modes for the Study of Groundwater Resource Quality Using a Large Physico-Chemical and Bacteriological Database, Occitanie Region, France

International audienceWhen studying large multiparametric databases with very heterogeneous parameters (microbiological, chemical, and physicochemical), covering a wide and heterogeneous area, the probability of observing extreme values (Z-score > 2.5) is high. The information carried by these few samples monopolizes a large part of the information conveyed by the entire database. The study of the spatial structure of the data and the identification of the mechanisms responsible for the water quality are then strongly degraded. Data transformation can be proposed to overcome these problems. This study deals with a database of 8110 groundwater analyses (Occitanie region, France), on which the bacteriological load was measured in Escherichia coli and Enterococci, in addition to electrical conductivity, major ions, Mn, Fe, As and pH. Three modes of data conditioning were tested and compared to the treatment with raw data. The results show that log transformation is the best option, revealing a relationship between E. coli content and all the other parameters. By reducing the impact of extreme values without eliminating them, it allowed a concentration of information on the first factorial axes of the PCA, and consequently a better definition of the associated processes. The spatial structure of the principal components and their cartographic representation is improved. The conditioning of the data with the square root function led to an intermediate improvement between the logarithmic transformation and the absence of conditioning. The application of these results should allow a targeted, more efficient, and therefore, less expensive monitoring of water quality by Regional Health Agencies

Data Conditioning Modes for the Study of Groundwater Resource Quality Using a Large Physico-Chemical and Bacteriological Database, Occitanie Region, France

When studying large multiparametric databases with very heterogeneous parameters (microbiological, chemical, and physicochemical), covering a wide and heterogeneous area, the probability of observing extreme values (Z-score > 2.5) is high. The information carried by these few samples monopolizes a large part of the information conveyed by the entire database. The study of the spatial structure of the data and the identification of the mechanisms responsible for the water quality are then strongly degraded. Data transformation can be proposed to overcome these problems. This study deals with a database of 8110 groundwater analyses (Occitanie region, France), on which the bacteriological load was measured in Escherichia coli and Enterococci, in addition to electrical conductivity, major ions, Mn, Fe, As and pH. Three modes of data conditioning were tested and compared to the treatment with raw data. The results show that log transformation is the best option, revealing a relationship between E. coli content and all the other parameters. By reducing the impact of extreme values without eliminating them, it allowed a concentration of information on the first factorial axes of the PCA, and consequently a better definition of the associated processes. The spatial structure of the principal components and their cartographic representation is improved. The conditioning of the data with the square root function led to an intermediate improvement between the logarithmic transformation and the absence of conditioning. The application of these results should allow a targeted, more efficient, and therefore, less expensive monitoring of water quality by Regional Health Agencies

Un enfoque cuantitativo para la evaluación de geositios del Parque Nacional de Talassemtane (NO de Marruecos)

The Talassemtane National Park (TNP), registered in the tentative list of Morocco for a future nomination as World Heritage by the UNESCO, is characterized by its great biodiversity and integration in the Intercontinental Biosphere Reserve of the Mediterranean (UNESCO). Although authorities are very concerned about valorization and protection of biodiversity (flora and fauna), the interest in geological heritage is still much lower. Therefore, this paper intends to expose and provide value to the best sites of geologic interest (Geosites) recognizable in the area. We propose 34 Geosites as the most suitable to be considered representatives of the geological diversity of the National Park, displaying a great variety of geological typologies such as: structural geoloy, stratigraphy, sedimentology and paleontological sites, geomaterials and petrography, landforms and hydrogeology-hydraulic features. In order to classify and rank the Geosites while avoiding subjectivity, a numerical methodology based on two modules has been applied. The two modules consist of the Scientific Value (SV) and Additional Value (AV) each one being composed, in turn, by an important number of criteria. In addition, the Degradation Risk (DR) of the Geosites has also been valorized on the basis of several criteria. Some actions, following the criteria of the Global Geoparks Network by UNESCO, have been proposed for better conservation of the Geosites, as well as to contribute to education and to promote tourism. These actions would also stimulate economic activity and sustainable development in the area by attracting increasing numbers of visitors.El Parque Nacional de Talassemtane (TNP), recogido en la lista tentativa de Marruecos para su nominación como Patrimonio de la Humanidad por la UNESCO, se caracteriza por su gran biodiversidad y está integrado en la Reserva de la Biosfera Intercontinental del Mediterráneo. Aunque las autoridades están muy interesadas en la puesta en valor y protección de la biodiversidad (flora y fauna), su interés en el patrimonio geológico es mucho menor. Así, este trabajo trata de dar a conocer y poner en valor los excelentes lugares de interés geológico (Geositios) reconocibles en el área. Se proponen 34 Geositios que deberían ser considerados parte del patrimonio geológico y que despliegan una gran variedad de tipologías geológicas como geología estructural, estratigrafía, sedimentología, paleontología, geomateriales, petrología, geomorfología e hidrogeología-hidráulica. Para clasificar y ordenar los Geositios, evitando la subjetividad, se ha empleado una metodología numérica basada en dos módulos. Dichos módulos consisten en el Valor Científico (SV) y el Valor Adicional (AV) estando cada uno compuesto, a su vez, por un importante número de criterios. Además, el Riesgo de Degradación (DR) de los Geositios se ha valorado sobre la base de diversos criterios. Para una mejor conservación de los Geositios, pero también para contribuir a la educación y promoción del turismo, se han propuesto algunas acciones siguiendo los criterios de la Red Global de Geoparques de la UNESCO. Esas acciones podrían estimular también la actividad económica y el desarrollo sostenido de la región atrayendo un número creciente de visitantes.Research Project CGL2016-75679-P (Spanish Ministry of Education and Science), Research Groups of the Alicante University (CTMA-IGA)

The Geological Heritage of the Talassemtane National Park and the Ghomara coast Natural Area (NW of Morocco)

The Talassemtane National Park and the Ghomara Coast (TNP-GC) natural area, registered in the list of the exceptional patrimony of Morocco by the UNESCO, are characterized by their great biodiversity integrated in the Intercontinental Biosphere Reserve of the Mediterranean. Although authorities are very interested in valorization and protection of biodiversity (flora and fauna), the interest in geological heritage is still much lower. So, this paper tries to expose and give value to the very best sites of geologic interest (Geosites and Geodiversity sites) recognizable in the area. Forty-one sites are proposed as suitable to be considered as geological heritage. Twenty-nine of which are organized in three accessible georoutes (Oued Laou Valley and Ghomara Coast, Talambote-Akchour, and Chaouen-Ametrasse, respectively), and 12 others are located on trails and forest tracks inside or near the TNP. The 41 selected sites display a great variety of geological typologies as structural geology, stratigraphy-sedimentology, paleontology, geomaterials, petrology, geomorphology, and hydrogeology-hydraulic. In order to classify and rank (avoiding subjectivity) the sites and georoutes, a numerical methodology based on recent literature is applied. The scientific value (SV), potential educational value (PEV), and potential touristic value (PTV) are quantified (using several criteria in each case), making easy for possible users to select the most suitable route according to their goals. The degradation risk (DR) is also measured giving political and technical managers of the region important keys for an adequate geoconservation action plan. Finally, some actions following the criteria of the Global Geoparks Network by the UNESCO are proposed for the better conservation of the sites but also to contribute to education and promote tourism. These actions would also stimulate economic activity and sustainable development in the area by attracting increasing numbers of visitors.Research supported by: Research Project CGL2016-75679-P, Spanish Ministry of Education and Science; Research Groups and Projects of the Generalitat Valenciana, Alicante University (CTMA-IGA)