Source rock potential and depositional environment of Upper Cretaceous sedimentary rocks, Abu Gharadig Basin, Western Desert, Egypt: An integrated palynological, organic and inorganic geochemical study

The Abu Roash “F” source rocks are compared with time-equivalent sediments in the Tarfaya Basin in Morocco, which represent more distal settings. The more proximal group (A) is characterized by S/Fe ratios between 0.57 and 0.67 indicating suboxic conditions. It has TOC and HI values not exceeding 4% and 600 mgHC/gTOC, respectively, at variable CaCO3 contents. The more distal Tarfaya sediments (group B) have higher TOC and HI as well as high organic sulfur contents. Group A is higher in terrigenous element concentrations. The Tmax of immature source rocks ranges from 410 to 415 °C in organic‑sulfur rich samples and from 420 to 430 °C in organic‑sulfur poor samples revealing an important impact of organic facies on maturity parameters. Furthermore, there is an inverse relationship between S/Fe and Al2O3/TOC which might become an important tool in paleoenvironmental reconstructions as well as petroleum source rock studies.