Mineralogical, petrographical, geochemical, diageneses and provenance of the Cretaceous Black Shales, Duwi Formation at Quseir-Safaga, Red Sea, Egypt

The average values of Cu, Ni, Zn, Cr, V, As and Se and, with the ratios Rb/Sr and Cr/Ni, are enriched with respect to those of the PAAS values. This could be attributed to the abundance of mafic components. The felsic source rocks were considered as an added source similar to Cretaceous and Cambrian black shales in India and China; respectively. The ratios V/Cr, V/(V + Ni) and Mo/Al and the high concentrations of the redox sensitive elements revealed that the studied black shales were deposited under relatively euxinic to anoxic reducing marine environments coupled with hydrothermal solutions. They were found comparable to the Cretaceous Gulf of California, Posidonia, Cretaceous/Tertiary black shales, and those in the Black Sea. The studied black shales can be classified as good to excellent source of oil and trace elements. The chemical composition of the studied black shales of the Duwi Formation (Cretaceous) was correlated to published data at different localities and ages.