Sedimentological study of a Quaternary fluvial-estuarine deposit at the mouth of the Tensift River, Souiria Laqdima, Morocco.

Abstract

The study was carried out on a Quaternary fluvial-estuarine deposit situated in the Souiria region, at the mouth of Tensift. This region is part of the coastal meseta and is located 30 kilometers south of the Moroccan city of Safi on the Atlantic coast of Morocco. An investigation was conducted on samples obtained from a stratigraphic log to analyze them physicochemical and mineralogical properties. This involved using techniques such as X-ray diffraction, calcimetry, and petrographic examination of thin sections. The objective was to assess the changes in mineral, clay, and carbonate content along the log. The log consists of successive layers arranged in a vertical sequence: summit marl, marly sandstone, alternating layers of sandstone and conglomerate, laminated sandstone, and finally massive sandstone. The proportion of calcium carbonate progressively rises from the lowermost section to the interface between sandstone and conglomerate, when it experiences a marginal decline. The presence of clayey, non-clayey, and carbonated minerals, including smectite, kaolinite, vermiculite, illite, diopside, anorthite, aragonite, dolomite, and calcite, was confirmed using X-ray diffraction analysis. Certain minerals present provide indications of a calm, non-agitated coastal setting and a hot and dry ancient climate. The examination of thin sections of the samples ‘’Alternating sandstone and conglomerate’’, ’Laminated Sandstone’’, and ‘’Massive sandstone’’ through petrographic analysis indicated the occurrence of quartz, biotite, modified volcanic fragments, iron oxide, and bioclasts, namely algae, suggesting a shallow setting, along with gastropods and ostracods.