Izvorni znanstveni članak

https://doi.org/10.4154/gc.2025.02

Albian biostratigraphy and palaeoecology of the Sharib-1X borehole (northern Egypt): Insights from palynomorphs and palynofacies

Miran Mostafa Khalaf ; Sohag University, Faculty of Science, Geology Department, Sohag, Egypt
Magdy Salah Mahmoud ; Assiut University, Faculty of Science, Geology Department, Assiut, Egypt

Sažetak

Well-preserved terrestrial palynoflora assemblages, dominated by pteridophyte spores (e.g., Deltoidospora, Triplanosporites, and Dictyophyllidites), with angiosperms and elaterate-bearing taxa, were recorded from the Kharita Formation, northern Egypt. Biostratigraphically, the angiosperm pollen Afropollis jardinus is the most significant element, along with elaterates including Elaterosporites klaszii and Elaterocolpites castelainii, in dating the Kharita Formation and confirming its previous (dinoflagellate) Albian dating. We applied current and previous documented redox states in the borehole and discovered evidence of missing of angiosperms and elaterates from some stratigraphic levels. At stratigraphic horizons where opaque phytoclasts are extraordinarily abundant, oxidation is highly expected and, consequently, some palynomorphs of the original palynological assemblages may have been oxidized. At other horizons with mild oxidation, some palynomorphs cannot be preserved due to environmental restrictions. Under these circumstances, if these marker taxa are missing, age assessments can be unreliable. Therefore, care must be taken in order to determine reliable palynostratigraphy. An oxic to dysoxic-suboxic marginal marine environment was inferred, with a few examples of periodic distal settings at the basal and top parts of the Kharita Formation. The Kharita palynofloras, as part of the palynofloristic Albian-Cenomanian African-South American (ASA) province, reflect the influence of the break-up of the continents of Africa and South America. They reflect the resultant global palaeoclimate change near the equator, which brought humid conditions to Egypt during Albian times.

Ključne riječi

palynomorphs; Kharita Formation; Albian; marginal environment; Egypt

Hrčak ID:

328778

URI

https://hrcak.srce.hr/328778

Datum izdavanja:

26.2.2025.

Posjeta: 316 *