Abstract
Calcareous nannofossil, δ13C, δ18O, and carbonate content data were used to define and reveal the variations across the latest Paleocene-earliest Eocene interval at the Misheiti Section, Central Sinai, Egypt. The upper part of Tarawan Formation, the Esna Formation, and the lowermost Thebes Formation were included in this study. In this study, the Esna Formation is informally divided into Hanadi/Mahmiya and Abu Had members. Four calcareous nannofossil zones (NP9, NP10, NP11, and NP12) and four subzones (NP9a, NP9b, NP10a, and NP10b) were recognized. The biostratigraphic importance of significant calcareous nannofossil bioevents associated with the P/E boundary was discussed. The LOs of Rhomboaster spp., Discoaster araneus, and/or D. anartios were used to delineate the base of earliest Eocene Subzone NP9b within the lower part of the Esna Formation. The global decreases of δ13C, δ18O, and carbonate contents at the P/E boundary were documented in the study section.
Highlights
Significant micropaleontological, sedimentological, and isotopic changes mark the Paleocene/Eocene (P/E) boundary (Dupuis et al, 2003)
The best characteristic for delineating the base of the Eocene at the GSSP section is the onset of the global Carbon Isotope Excursion that is coincident with the major Benthonic Foraminifera Extinction Event (BFE; Thomas et al, 2000; Dupuis et al, 2003)
The P/E boundary is placed at the base of Subzone NP9b that is delineated by the LOs of Rhomboaster spp., Discoaster anartios, and/or D. araneus (Table)
Summary
Significant micropaleontological, sedimentological, and isotopic changes mark the Paleocene/Eocene (P/E) boundary (Dupuis et al, 2003). The lower 8.2 m of dark gray calcareous shale in the Esna Formation are informally assigned to the Hanadi/Mahmiya Member (Figure 2). Discoaster multiradiatus Zone (NP9) (Bramlette and Sullivan, 1961; emended by Martini, 1971) This zone covers the sequence from the LO of Discoaster multiradiatus to the LO of Tribrachiatus bramlettei It is assigned a Thanetian-Ypresian age and is about 3 m in the Esna Formation (Figure 2). Aubry et al (1999) subdivided Zone NP into two subzones depending on the LOs of Rhomboaster spp., and/or D. araneus This subdivision suggestion was followed by many authors Distribution chart of calcareous nannofossil taxa across the P/E transition at the Misheiti Section, Central Sinai, Egypt (continued)
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