Geochemistry and mineralogy of modern floodplain Nile sediments of Sohag area, Egypt: an environmental perspective

• Published in: Environmental earth sciences Vol. 83; no. 11; p. 350
• Main Authors: Ali, Mohammed H., Aal, Ahmed Abd El, Radwan, Ahmed E., Saber, El Sayed A.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-05-2024; Springer Nature B.V
• Subjects: Biogeosciences; Chemical weathering; Clay minerals; Climate and human activity; Climate change; Climatic conditions; Earth and Environmental Science; Earth Sciences; Encroachment; Environmental Science and Engineering; Floodplains; Garnet; Geochemistry; Geology; Geomorphology; Goethite; Greywacke; Heavy minerals; Hydrology/Water Resources; Igneous rocks; Magnetite; Mica; Mineralogy; Original Article; Salinity; Sand; Sediment; Sedimentary rocks; Sediments; Shale; Silica; Silicon dioxide; Silt; Tectonics; Terrestrial Pollution; Trace elements; Weathering; Zircon; Egypt; Climate change; Nile sediments; Environmental; Modern floodplain; Desertification
• ISSN: 1866-6280; 1866-6299
• DOI: 10.1007/s12665-024-11638-7

Understanding the characteristics of modern floodplain sediment (MFS) is important for geomorphological, paleoclimatic, sedimentation, and environmental investigations. We collected samples from present floodplain Nile sediments in Egypt’s Sohag area and used mineralogical and geochemical (i.e., major and trace elements) proxies to investigate the characteristics and establish their provenances, climatic conditions during deposition, and weathering influence. The study revealed that the Nile floodplain sediments are composed mainly of silt (26–77%), clay fraction (7–44%), and sand content (3–63%), and their texture is classified as clayey silt. These sediments are classified geochemically as greywacke to shale. The mineralogical studies revealed two main assemblages of heavy minerals: the first assemblage represented by magnetite, goethite, zircon, epidote, and garnet and reflects the basement complex in the Eastern Desert and its surrounding rocks; and the second assemblage of goethite, pyroxene, hornblend, and mica of fooldplain deposits derived from the Ethiopian highlands. The geochemical studies indicate that the Nile sediments are immature and formed due to the moderate degree and nonsteady chemical weathering of the parent rocks. The geochemical studies show different mixed sources of sediments, where fine sediments are mostly mafic igneous with a partial contribution from siliscic sedimentary rocks, while the coarser ones are derived mainly from siliscic sedimentary and acidic igneous rocks. The sediments of the presented modern fooldplain reflected two different tectonic setting source areas (collision and continental rift tectonic setting for high silica and low silica samples, respectively) that were shared in supplying the sediments to the present basin. The study revealed that the investigated area may become desertified as a result of climate change and human activities such as salinity, fertiliser use, sand encroachment, and pollution.