L’étude sédimentologique du Jurassique dans la région d’Ait Ourir (cuvette d’Ouanina) a permis d’individualiser deux ensembles : un ensemble silto–carbonato–évaporitique caractérisant le Lias et un ensemble gréso–silteux et microconglomératique caractérisant le Dogger. Les deux ensembles sont organisés en deux mégaséquences successives régressives et margino-littoral. Le premier ensemble est constitué de deux unités : silto–argileuse à évaporitique (U1) et carbonato–évaporitique (U2), il est formé dans un milieu peu profond, intertidal supérieur à supratidal lagunaire avec des phases de forte énergie et sous un climat chaud et aride. Le deuxième ensemble est constitué aussi de deux unités : argilo–silto– gréseuse (U3) et gréso–microconglomératique et silteuse (U4), il est formé dans une plaine d’inondation avec des chenaux gréseux qui évolue vers un milieu margino–littoral.
The detailed sedimentological study of the Senonian in the Wanina basin of Aït Ourir basins attached to the northern slope of the High Atlas Marrakech, gave the deposit silty carbonato-evaporite, which are carried out in an environment of type sebkha where alternate phases of detrital inputs, under a hot and arid climate and in conditions of bridging favoring the installation of evaporite deposition, and the phases of carbonate deposits more marine installed under the action of a slight increase in sea level degenerating quickly, in an upper intertidal temporarily emerged. In general these carbonate benches mark to their surfaces a rupture of the sedimentation that is materialized by ferruginous hardened surfaces.
A study was conducted in Northern part of Atlantic Sahara coast (SW of Morocco) with the aim of assessing change of suspended sediment concentration (SSC) with time in sea surface from Landsat data with 30 m spatial resolution in order to understand the sand encroachment in the continental area. We must be report that is the first study of SSC monitoring in Southwest of Morocco using earth observation satellite (EOS). The methodology adopted in this research is simple and based on using band ratio (Green/Blue) for two images Landsat Thematic Mapper (TM) from the years 1987 and 2005. A step of classification was necessary, so unsupervised classification using K-means algorithm was applied on both band results from band ratio. After that, the statistical data result from classification was compared to determine the SSC and sand change with time. The results show that the sand increase in continental surface was in relationship with SSC decrease in coastal area. The SSC variation in surface sea indicates that sand input be decreased in next year's.
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