Calcareous nannofossil biostratigraphy and paleoecology of the Maastrichtian in the western coast of the Gulf of Suez, E
- PDF / 4,923,249 Bytes
- 14 Pages / 595.276 x 790.866 pts Page_size
- 94 Downloads / 191 Views
ORIGINAL PAPER
Calcareous nannofossil biostratigraphy and paleoecology of the Maastrichtian in the western coast of the Gulf of Suez, Egypt Medhat M. M. Mandur & Aly A. E. El Ashwah
Received: 7 December 2013 / Accepted: 5 March 2014 # Saudi Society for Geosciences 2014
Abstract Calcareous nannofossil content of the Maastrichtian succession at the western coast of the Gulf of Suez in Egypt has been studied. This study aims to contribute in the understanding of high-resolution biostratigraphy and paleoecologic interpretations. Five biozones (Reinhardtites levis, Arkhangelskiella cymbiformis, Lithraphidites quadratus, Micula murus, and Micula prinsii) were distinguished. According to the paleoecologic parameters (cool-water, warm-water, productivity, preservation, and the ratio of Micula decussata/Watznaueria barnesae), the studied succession is subdivided into five ecozones. The environment of each ecozone is deduced; M. Prinsii, M. murus, and L. quadratus ecozones are characterized by a cooler climate, but R. levis and A. cymbiformis ecozones are characterized by a warmer climate.
Presently, there is no doubt about the presence of an extraterrestrial body impact in connection with the Maastrichtian, but total agreement does not exist among the authors to determine if there was one or several impacts keller et al. (2004). Today, coccolithophores live in the photic zone and are very sensitive to climatic/oceanographic changes. The calcareous nannofossil assemblages variations found in the geologic record thus reflected the changes of the photic zone. As a result, high-resolution analysis of the variations of calcareous nannofossil assemblages of the Maastrichtian has been provided by many authors (e.g., Perch-Nielsen 1969; Romein 1979; Perch-Nielsen et al. 1982; Monechi 1985; Jiang and Gartner 1986; Ehrendofer and Aubry 1992; Sheldon et al. 2010).
Keywords Maastrichtian . Nannofossil . Biostratigraphy . Paleoecology
Material and methods
Introduction The Maastrichtian is the best studied mass extinction event in the geologic record. The identification of the extinction pattern is essential to the determination of its causes. According to Pospichal (1996), a gradual or step extinction may result from long-term climatic and/or sea level changes, whereas an abrupt mass extinction may result from a catastrophic event such as an impact of a large asteroid Alvarez et al. (1980, 1984) or an intense volcanism Courtillot et al. (1988). M. M. M. Mandur (*) : A. A. E. El Ashwah Egyptian Petroleum Research Institute, Nasser City 11727 Cairo, Egypt e-mail: [email protected] A. A. E. El Ashwah e-mail: [email protected]
The aim of the present study is to document through the lithostratigraphy occurrence, biostratigraphy, and paleoecology of the Maastrichtian calcareous nannofossils of Wadi El Dakhl succession, which is delineated by latitude 28° 42′ N and longitude 32° 25′ E (Fig. 1). This study has been achieved through collecting 75 samples from the upper cretaceous of the studied area. These samples were treated to
Data Loading...
