Stratigraphic distribution of the palynomorphs and the particulate organic matter in subsurface Lower/Middle Cretaceous deposits, Western Desert of Egypt: Palynological and geochemical approach

摘要

The stratigraphic distribution of the palynomorphs and particulate organic matter was studied in the subsurface Lower/Middle Cretaceous sections in Ii-26-1 and Ig-30-1 wells, located in north Western Desert of Egypt. Some important palynofacies parameters were employed as indicators of proximal–distal trends. The spatial and stratigraphical variations of six palynofacies categories had been illustrated. Optically, the type and nature of the recovered particulate organic matter together with their quantity were combined to reveal the prevailing paleoenvironmental conditions during deposition of the concerning sections. Thirty-seven samples were selected from the two wells to carry the total organic carbon (TOC) and Rock–Eval Pyrolysis analyses in order to geochemically evaluate the source rock.TOC and Rock–Eval Pyrolysis analyses illustrate extremely low TOC and HI values, demonstrating that the Alam El Bueib, Alamein, Dahab, Kharita and Bahariya formations are comprised principally of type IV kerogen and a few type III kerogen components. Therefore, they are inert to slightly gas prone, signifying a strong deficiency of hydrogen-enriched organic matter. Palynofacies analysis implies that all the studied formations have highly oxidized terrestrial organic matter (brown phytoclasts and black woods).