Atef M. Kasem, S. Wise, M. Faris, S. Farouk, E. Zahran
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引用次数: 9
Abstract
Calcareous nannofossil, carbonate content, and δ18O and δ13C data were utilized to reveal the nature of the Paleocene-Eocene (P-E) boundary at the Gunnah section, Western Desert, Egypt. The uppermost Tarawan Formation (Fm.), Esna Fm., and the lowermost, Farafra Fm., were included in this study. Lithostratigraphically, the Esna Fm. was subdivided into the Hanadi, Dababiya Quarry, and Mahmiya Members. Three calcareous nannofossil zones (NP7/8, NP9, and NP10) and four subzones (NP9a, NP9b, NP10a, and NP10b) were recognized. The biostratigraphic significances of calcareoust nannofossil bioevents associated with the P-E boundary at the study section were discussed. The base of the Eocene was placed at the base of the Dababiya Quarry Member in coincidence with the base of subzone NP9b, which is coincident with the LOs of Rhomboaster cuspis, R. calcitrapa, R. bitrifidia, Pontosphaera pulchra, and Zygrhablithus bijugatus. However, Discoaster araneus first occurred about 3 m below the base of subzone NP9b. The global decreases of the δ13C and δ18O values and carbonate contents across the P-E boundary were documented in the Gunnah section, which represents one of the most expanded and complete P-E sequences in Egypt.
期刊介绍:
One of the oldest journals in geology, The Journal of Geology has since 1893 promoted the systematic philosophical and fundamental study of geology.
The Journal publishes original research across a broad range of subfields in geology, including geophysics, geochemistry, sedimentology, geomorphology, petrology, plate tectonics, volcanology, structural geology, mineralogy, and planetary sciences. Many of its articles have wide appeal for geologists, present research of topical relevance, and offer new geological insights through the application of innovative approaches and methods.