GSSP for the Thanetian Ypresian Boundary


Definition:

The Global boundary Stratotype Section and Point (GSSP) for the base of the Ypresian Stage of the Eocene Series is defined in the DBH subsection of the Dababiya Section, near Luxor, Egypt, at the base of a lithostratigraphic unit where the base of the so-called Carbon Isotope Excursion (CIE) is recorded.


Location:

The Ypresian boundary is located at the Dababiya section, a composite of a series of adjacent overlapping sections (DBA, DBE, DBH, AND DBD), on the east bank of the Nile River, 25km south of Luxor. The GSSP is located in the DBH subsection 1.57m above the base of the subsection. The GSSP location is approximately at a latitude of 25°30'N and a longitude of 32°31'52"E.
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Sedimentology:

The Dababiya Quarry Beds are 3.68m thick in the DBH subsection. The GSSP lies at the base of Bed 1.

Bed 5: 1.00m thick, marly calcarenitic limestone.
Bed 4: 0.71m thick, grey shale.
Bed 3: 0.84m thick, cream colored. laminated phosphatic shale with sparse coprolites.
Bed 2: 0.5m thick, phosphatic brown shale with numerous coprolites.
Bed 1: 0.63cm thick, dark laminated non-calcareous clay with a few phosphatic coprolites at the base.

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Primary Markers:

The GSSP is located at the base of a lithostratigraphic unit where the base of the so-called Carbon Isotope Excursion (CIE) is recorded

Secondary Markers:

Foraminifera:
Acarinina sibaiyaensis and Acarinina africana appear for the first time 2.5m above the base of the outcrop.
Nannoplankton:
Discoaster anartios appears for the first time 2.3m above the base of the outcrop.

References:

Dupuis, C., Aubry, M., Steurbaut, E., Berggren, W.A., Ouda, K., Magioncalda, R., Cramer, B. S., Kent, D. V., Speijer, R. P., and Heilmann-Clausen, C., 2003. TheDababiya Quarry Section: Lithostratigraphy, clay mineralogy, geochemistry and paleontology. Micropaleontology 49/1, p.41 59.