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Representative samples from the Al-Hisa Phosphorite Formation (AHP) in the SE desert of Jordan, are selected from three sections: Batn El-Ghoul, Nagb Etayyeg, and Zgaimat Al-Hasah. The samples are investigated geochemically and petrographically. Geochemistry is discussed through the analysis of the major, trace and rare earth elements (REEs), loss on ignition (LOI), sulphur, and organic matter. The studied sections differ from the AHP in central Jordan by having highly reduced thicknesses, omission of underlying formations, abundant detrital quartz sand and age. The phosphate particles are of authigenic and biogenic origin. Early reworking from phosphate mud is evident from the shape and sorting of the phosphate particles. Major and trace elements are distributed into five factors: upwelling , provenance, redox potential , sea level changes , and resistates. The studied sediments were formed under oxic marine conditions because their REEs patterns preserve the REEs seawater linear pattern: depletion of LREEs, a negative Ce anomaly, and an enrichment of HREEs. This signature seems to have persisted through reworking and late diagenetic cementation , dolomitization and silicification . The SE desert phosphorite - siliciclastic sequence is better correlated with the Paleocene Jalamid Formation of northwestern Saudi Arabia because of similarities in age and lithology due to being both deposited on the western flanks of the Sirhan Paleohigh and the Rutba Paleohigh, respectively. The siliciclastics were delivered from a mixed mafic-felsic-older cycle siliciclastic provenance, and subjected to intensive chemical weathering under tectonic quiescence giving rise to mature quartzarenites. |
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