Apport De La Stratigraphie Sequentielle Dans L’evolution Jurassique Du Moyen Atlas Central (Maroc)

The Jurassic evolution of the central Middle Atlas is governed by various factors (climate and eustatism). The use of the concepts of sequential stratigraphy in the regions of Tagnamas and Boulemane allowed to interpret the geometry and the vertical sequence of sedimentary sets. Twelve sequences are identified and delimited by sedimentary discontinuities. The lithostratigraphic division adopted in this study is synchronous with the coastal aggradation charter of Haq & al. (1987 & 1988) and Rioult & al. (1991). The correlations on a regional scale, between different Jurassic lithostratigraphic units is possible, whose the major factors controlling the evolution of intraplate basins are climate and eustatism

Etude Sédimentologique Et Stratigraphique Des Dépôts Des Abris GAUDRY Et LARTET Du Gisement De Montgaudier, Charente, France

The sedimentological and stratigraphic study of the two shelters: Gaudry and Lartet of the Montgaudier deposit made it possible to characterize the large sedimentary assemblages and to describe within each of the discontinuities revealed by the granulometric characteristics that have subdivided them into distinct layers. Moreover, the detailed sedimentological analyzes of these two shelters have led to the conclusion that the sediments are deposited under the cold climatic conditions alternated by the temperate episodes. On the other hand, the stratigraphic lithostratigraphic arguments allowed us to establish a stratigraphic relationship between the two shelters. From a chronological point of view, the deposits of the shelter Lartet appear to a Mousterian Charentian type contemporary to the old würm. As for the Gaudry shelter, layers 1 and 2 are contemporary with Magdalenian and layer 5 is attributed to the aurignacian. This is confirmed by an absolute date

Cartographie De L’erosion Qualitative Des Sols Du Bassin Versant De L’aoudour (Rif-Maroc)

The Aoudour watershed located in the northwest of Morocco and spreads over an area of approximately 1000 km2, and occupying the northeastern part of the Ouergha basin contently experiencing the effects of severe water erosion caused by the interaction of several natural factors such as the amount and aggressiveness of rainfall, plenty of steep slopes, low vegetation density and also the dominance of friable land. The Aoudour watershed also undergoes a human action that makes it very vulnerable to environment erosion, the degradation of the vegetation cover in recent decades and also by poor farming techniques. PAP / RAC is a method of qualitative study of water erosion that can prioritize the surface of a watershed in separate units according to its vulnerability to erosion. The method consists of a descriptive and predictive mapping in relation to the identification; evaluation and integration of basic physical factors such as slope, lithology and / or soils and vegetation cover, with the aim of establish initial assumptions about the risk of erosion. The use of remote sensing and GIS tools enabled us creating and overlying of thematic maps, executing speedily the cartographic works and, processing of databases

Comparative Study of the Physico-Chemical and Metallic Quality of Waters and Sediments in the Larbaa Basin (Morocco) in the Dry and Wet Period

The catchment area of Oued Larbaâ is located in the eastern prerif at the very eastern end of the large Innaouene basin, a stream of Oued Sebou [Lahrach. A et al., 1994]. The objective of the study was to establish a quality comparison of the watershed during the dry and wet seasons. Eight water and sediment samples were taken during the two seasons, all along the main channel of the Larbaa river, taking into account anthropogenic activities and the areas of confluence with its tributaries: Tarmasst, Taza, Larouireg, Defali and Jaouna. The physicochemical parameters (pH, EC, TDS, nitrates, sulfates, chlorides), as well as metal contamination (Al, Zn, Ni, Pb, Ag, Fe, Cd, Cr, Cu, Mg, Mn) were studied in summer. The results revealed the alkaline pH higher than 7, a significant electrical conductivity in several stations, but still conforming to the Moroccan standards. Laboratory analyses reflect that the waters of the basin have generally good quality, except for a few peaks that indicate metallic contamination in Fe and Al. In order to better assess whether there is an anthropogenic effect influencing these results, and to remove the relationships between the different parameters studied, a statistical analysis was carried out with the PCA tool. This analysis made it possible to indicate Cr, Ni and Al as indices of pollution in certain areas. Although the results obtained have been tolerant until now, it is necessary to put in place an action plan to control the areas at risk of contamination during the years