A Cretaceous sporomorph palynozonation and the palaeobiogeography of northern Egypt

The multiple biozonal nomenclatures given for the same time segment at different locations in northern Egypt are problematic, as such multiplicity is highly confusing and considerably limits the correlative value of these nomenclatures within the Egyptian territory, in the Elaterates phytogeoprovince and in the Tethyan Realm. Thirty-one wells are selected and used in this work to establish a standard and unified, semi-formal, generalised Egyptian sporomorph palynozonation scheme for northern Egypt. Marker taxa are carefully picked and tracked from the different previously established palynostratigraphies, and they are methodically re-used in the present unified framework on a regular basis, where their first down-hole appearance [last appearance datum (LAD)] palynoevents are utilised to erect a regional palynostratigraphical scheme. Ten sporomorph interval zones (IZ) and two subzones are reconstructed, established and palynologically specified from all of the studied wells. The authors surveyed the palynofloral assemblages characterising different areas of the world in order to derive meaningful palaeobiogeographical implications. Connecting these databases furnishes a comprehensive palynostratigraphical framework for inter-continental correlations with the Egyptian assemblages. In addition, such correlations confirm the dating acquired from the recovered palynological markers and assemblages presented in the current review. Comparisons of coeval assemblages confirm that the extensions and boundary limits of the palaeoprovinces of the recorded sporomorphs exhibited a gradual change and that their areal extent evolved with time. Due to the wide geographical occurrences of the recorded marker taxa during the pre-Albian stages of North and West Africa, western Atlantic and east South America, the proposed sporomorph zones can be confidently applied in these areas. During the Albian-Cenomanian such correlations can be applied only between North and West Africa and east South America.