Modelling Soil Erosion and Sedimentation in the Oued Haricha Sub-Basin (Tahaddart Watershed, Western Rif, Morocco): Risk Assessment

This study evaluates the annual loss of soil in the sub-basin of Oued Haricha (Tahaddart basin, Western Rif, NW Morocco). The integration of revised (RUSLE) and modified (MUSLE) soil loss empirical equations of Wischmeier and Smith in combination with GIS permits the modelling of soil erosion at the scale of parcels. The characteristics of precipitation and runoff, the soil properties, the culture system and the current working practices of soil in the sub-basin of the Oued Haricha are collected from local data. The digital terrain model is used to generate topographic factors. The combination of different RUSLE factors shows that the annual soil is 62.72 t/ha/year and corresponds to an average level of risk. The total losses calculated by MUSLE method are valued at 221,468 t/year. The rates of loss due to linear erosion are 82,652 t/year. These soil losses represent 20.33% of the total losses, and confirm that the losses on the slopes outweigh the losses due to the river system. Sedimentation module shows that the areas of high erosion (greater than 200 t/ha/year) are concentrated in the reliefs with average and high slope and occupy 38% of the total area. The deposition areas occupy the centre of sub-basin and constitute 9.12% of the total area. These deposits were concentrated on the edges of major rivers and the outlet of the sub-basin and contributed to siltation of the April 9, 1947 dam.

The Late Neoproterozoïc Continental Tholeiitic Basalts of the Toubkal Inlier (Western High-Atlas, Morocco): A Post-Pan-African Rifting Witness in the Northern Margin of the West African Craton

The late Neoproterozo&#239c Toubkal inlier (Ancient Massif of the High-Atlas, Morocco) contains two igneous basaltic series (Tircht and Sidi Chamharouch). Investigated rocks display characteristics of within-plate continental tholeiitic and are similar to rocks originated in orogenic contexts. The geochemical results allow the assumption that subduction active processes are indirectly responsible for the genesis of theses rocks. The orogenic signature is linked probably to a Pan-African magmatic source previously metasomatized in the northern margin of the West African Craton.

Geodiversity Examples of Morocco: From Inventory to Regional Geotourism Development

The soil and subsoil of Morocco are rich in geological phenomena that bear the imprint of a history which goes back in time more than 2000 million years. Very many geologically remarkable sites exposed in accessible outcrops, with good quality remained unknown to the general public and therefore deserved to be vulgarized. It is a memory to acquaint the present generations but also to preserve for future generations. In total, a rich geological heritage in many ways: Varied landscapes, international stratotypes, various geological structures, varied rocks, mineral associations, a huge procession offossiles, remnants of oceanic crust (ophiolites) among oldests ones in the world (800 my), etc. For this geological heritage, an approach of an overall inventory is needed, both regionally and nationally, taking into account all the skills of the earth sciences. This will put the item on the natural (geological) potentialities as a lever for sustainable regional development. For this, it is necessary to implement a strategy of “geoconservation” for the preservation and assessment of the geological heritage. A website “lithothèque du Maroc” is under construction.