(Table 1) P2O5 contents in diatom oozes from the shelf of the Southwest Africa and their sand-fine gravel size fractions

Available data on composition of sediments from the inner and outer continental shelves of the Southwest Africa, and on currents and variations of sea level in the Upper Quaternary are examined to elucidate the process of phosphate material concentration. Sand and gravel fractions in diatom oozes from the inner shelf have much higher phosphorus contents than adjoining sediments. This is due to presence of diagenetic phosphate nodules. As sea level varies, fine sediments are eroded by waves or currents that leads to formation of coarse-grained phosphate sediments.