Upper Cenomanian – Lower Turonian (Cretaceous) calcareous algae from the Eastern Desert of Egypt: taxonomy and significance

• Main Authors: Ioan I. Bucur, Emad Nagm, Markus Wilmsen
• Format: Article
• Language: English
• Published: Cluj University Press 2010-04-01
• Series: Studia Universitatis Babes-Bolyai: Geologia
• Online Access: http://scholarcommons.usf.edu/geologia/vol55/iss1/art4/
• ISSN: 1221-0803; 1937-8602

An assemblage of calcareous algae (dasycladaleans and halimedaceans) is described from the Upper Cenomanian to Lower Turonian of the Galala and Maghra el Hadida formations (Wadi Araba, northern Eastern Desert, Egypt). The following taxa have been identified: Dissocladella sp., Neomeris mokragorensis RADOIČIĆ & SCHLAGINTWEIT 2007, Salpingoporella milovanovici RADOIČIĆ 1978, Trinocladus divnae RADOIČIĆ 2006, Trinocladus cf. radoicicae ELLIOTT 1968, and Halimeda cf. elliotti CONARD & RIOULT, 1977. Most of the species are recorded from the first time from Egypt. Three of the identified algae (T. divnae, S. milovanovici and H. elliotti) also occur in Cenomanian limestones of the Mirdita zone, Serbia, suggesting a trans-Tethyan distribution of these taxa during the early Late Cretaceous. The abundance and preservation of the algae suggest an autochthonous occurrence which can be used for the characterization of the depositional environment. The recorded calcareous as well as the sedimentologic and palaeontologic context of the Galala Formation support an open-lagoonal (non-restricted), warm-water setting. The Maghra el Hadida Formation was mainly deposited in a somewhat deeper, open shelf setting. Calcareous algae (Halimeda cf. elliotti CONARD & RIOULT) are restricted to one level in the uppermost Lower Turonian which indicates a brief return to shallow-water deposition after a significant deepening with maximum flooding during the early Early Turonian.