TITLE:
Late Maastrichtian Calcareous Nannofossil Biostratigraphy and Paleoecology of the Tamera Well, Siwa Area, Western Desert, Egypt
AUTHORS:
Esam Zahran
KEYWORDS:
Formation; Nannofossils; Micula Prins; Late Maastrichtian
JOURNAL NAME:
International Journal of Geosciences,
Vol.4 No.6,
August
14,
2013
ABSTRACT:
The upper Cretaceous interval of the Khoman Formation in
the Tamera well, Siwa area, Western Desert of Egypt was studied for the first
time on the basis of calcareous nannofossils. Twenty-one nannofossil
species were identified from this interval. The study interval includes the Micula murus Zone, which is
precisely dated as Late Maastrichtian age. The Micula murus Zone
includes besides the marker species: Micula decussata, Watznaueria barnesae, Arkhangelsktella cymbiformis and relatively
rare occurrences of Eiffellithus turrisieffellii, Cribrosphaerella ehrenbergii, Thoracosphaera operculata and Braarudosphaera bigelowii. The latest Maastrichtian Micula prinsi Zone is missing, and
an unconformity surface is detected in this well. The high abundance of Micula decussata is indicative of
very low surface productivity and high-stress environmental conditions. Several
nannofossil species are recognized as cool water indicators such as Micula decussata, and Arkhangelsktella cymbiformis.