The Coastal Sediment Provenance and Their Distribution in the Mediterranean Beaches of NW Morocco

Abstract

This work deals with the granulometric and geochemical features of sediments collected at the foreshore of Tetouan beaches (NW Morocco) and at the mouth of the local five main watercourses in order to establish the links between the continental and coastal areas. The littoral, which underwent a great increase of human pressure in past decades, records great erosion rates that menace different human settlements and natural features of great environmental importance such as dune ridges, fossil cliffs and coastal lagoon. Specifically, the analysis of sediment samples collected along the Tetouan littoral made possible the characterization of the transport and depositional environments as well as the determination of sediment characteristics that are closely related to the geology and hydrology of adjacent basin areas and the relationship among long shore transport and the influence of human activities and natural coastal features that influence the geochemical composition of coastal sediments. The sedimentological studies support coastal monitoring programs for suitable coastal protection and beach nourishment projects. Analyzed beach sediments are essentially composed by quartz-rich sand and can be clearly distinguished two different sectors: (i) the first one, between Ras Mazari and Cabo Negro headlands, is characterized by medium sand, from well to very well-sorted, main sedimentary supplies to the littoral being provided by Martil River; (ii) the second one, between Cabo Negro and Ceuta headlands, consists of coarse to very coarse sediments, poorly sorted, main sedimentary inputs being related to biogenic sources and to the erosion of metamorphic rocks from Cabo Negro headland.