Palaeoenvironmental and Palaeontological Study of the Gabal Ekma Section (Egypt) Throughout the Coniacian-Santonian Boundary

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Serval ID
serval:BIB_5B64A9379CDB
Type
A part of a book
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Title
Palaeoenvironmental and Palaeontological Study of the Gabal Ekma Section (Egypt) Throughout the Coniacian-Santonian Boundary
Title of the book
The Phanerozoic Geology and Natural Resources of Egypt
Author(s)
Bomou B., Adatte T., Spangenberg J. E.
Publisher
Springer International Publishing
ISBN
9783030956363
9783030956370
ISSN
2522-8714
2522-8722
Publication state
Published
Issued date
2023
Pages
291-304
Language
english
Abstract
The Gabal Ekma section, located in the Sinai desert (Egypt), is characterised by shallow marine deposits of mixed siliciclastic/carbonate sediments of the Matulla Formation which includes the Coniacian and Santonian stages. The section exhibits significant accumulation of organic-rich intervals and phosphatic layers associated with fossiliferous vertebrate remains. The Coniacian- Santonian (CS) carbon isotopic patterns appear to be recognised in the Egyptian section and are used to characterise the interval of the CS oceanic anoxic event (OAE 3). However, this latest Cretaceous OAE appears not to be truly important on a global scale but was more dependent on local or regional conditions. These are mainly limited to shallow-water environments and epi- continental seas of the equatorial and South Atlantic basins and the Western Interior Seaway. Based on a weathering index and mineralogy, climate gradually evolved from warm and seasonal climate to arid condi- tions during the late Coniacian up to the base of the Santonian (Michel Dean Event). Then a significant change to more humid and tropical conditions is observed above the Michel Dean Event (early Santonian), which persisted up to the Buckle Event (base on the late Santonian), coinciding with the organic-rich shales deposits in deeper environments. Fluctuations in total phosphorus (Total-P) contents are clearly independent from detrital input but seem to be controlled by regional anoxia and phosphogenesis. Total-P contents are indeed depleted in the organic-rich interval, suggesting intense P regeneration due to anoxic conditions. This type of P regeneration may explain the formation of the bone bed located at the C-S boundary characterised by very well-preserved shark teeth and vertebra, associated with phosphatised nodules in a sandy phosphatic matrix.
Keywords
Coniacian-Santonian boundary , OAE3, Bone-bed, Gabal Ekma section
Create date
28/09/2023 7:58
Last modification date
16/03/2024 8:57
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