3) Topographical feature with mineral occurrences
Topographical data was downloaded from the SRTM archives in NASA. The present available version of SRTM DEM data covering Mauritania with the spatial resolution of 30 m is an intermediate edit version (not final edited version) and there can be seen inappropriate features especially in desert area (eastern Mauritania). However, you might be able to obtain characteristics of general topographic feature from this map.