Clay minerals in soils and sediment as tracers of provenance: The case study of the N'fis watershed, Morocco

Abstract

AbstractReservoir siltation remains a complex and challenging problem worldwide. Understanding the sources of sedimentation will be of great interest to preserving reservoir storage capacity as well as addressing land loss. This study selected the Takerkouste reservoir, at the outlet of the N'fis basin (High Atlas of Morocco). Four sediment cores and 30 soil samples were collected in the basin. Size distribution and mineralogy of soil and sediment samples were compared and used as tracers to identify the provenances of the sediments reaching the reservoirs from different tributaries. Results show that sediments in the Takerkouste reservoir are illite‐rich minerals with high crystallinity mainly originating from the erosion of schist formations situated in the northern part of the watershed. In parallel, mineralogy, illite crystallinity and chemistry indices of sediments in the reservoir indicate a change in sources because of the construction of a new dam upstream.