Rare earth elements in Egyptian phosphorites

Egyptian phosphorites from Abu Tartur (Western Desert), El Mahamide mine (Nile Valley) and Rabah mine (Eastern Desert) show variable degrees of relative REE enrichment. Black plateau phosphorites of Abu Tartur are substantially enriched in REE as compared to the Red Sea and Nile Valley phosphorites. P-rich organic matter from the Abu Tartur and Rabah mines recorded negative Ce and positive Eu anomalies. Positive Eu anomaly reveals an anoxic event prior to the phase of Late Cretaceous phosphate formation. Ce is a redox indicator. Mixing of sea water and upwelling during the Late Cretaceous was responsible for the recording of positive Eu and negative Ce anomalies in the Egyptian phosphorites.