First carbon isotope chemostratigraphy of the Ouled Abdoun phosphate Basin, Morocco; implications for dating and evolution of earliest African placental mammals

Johan Yans, M'Barek Amaghzaz, Baadi Bouya, Henri Cappetta, Paola Iacumin, László Kocsis, Mustapha Mouflih, Omar Selloum, Sevket Sen, Jean-Yves Storme, Emmanuel Gheerbrant

Research output: Contribution to journalArticle

Abstract

The well-known Maastrichtian-Ypresian vertebrate-bearing phosphate series, in the Ouled Abdoun Basin, Morocco, is classically dated using regional selachian biostratigraphic zonation. These marine sediments yielded Paleocene and Eocene mammals comprising the earliest known placentals from Africa. This study provides the first insight into the organic carbon isotope chemostratigraphy (δ13Corg) of the Moroccan phosphate series and a refined dating of its vertebrate-bearing levels. Four Paleocene-Eocene sections in the NE Ouled Abdoun quarries show consistent δ13Corg long term evolutions, from the base to the top: 1) positive trend in phosphorite Bed IIa, beginning with the lower Bone Bed yielding mammals such as Eritherium, Ocepeia, Abdounodus, Lahimia, of early Thanetian and Selandian age; 2) transitional negative trend in the Intercalary phosphorite Beds II/I that includes the Otodus obliquus and Phosphatherium escuilliei Bone Bed of earliest Ypresian age; 3) negative trend to the lowermost δ13Corg values that are correlative to the early-middle Ypresian interval including ETM 2 and ETM 3 hyperthermal events in the global record; 4) positive trend in chert-enriched facies containing the middle Ypresian EECO global climatic event. Our chemostratigraphic study of the Ouled Abdoun phosphate series provides a new chronostratigraphic framework for calibrating the beginning of the evolution of placental mammals in Africa. The lower Bone Bed level from the Paleocene phosphorite Bed IIa yielding Eritherium is not younger than early Thanetian, and is most likely Selandian. The Phosphatherium Bone Bed in the Intercalary Beds II/I is earliest Ypresian. The phosphorite Bed 0, from which Daouitherium probably came, is early-middle Ypresian, just below the EECO. This suggests that the first large proboscideans evolved after the PETM, during mid-Ypresian warming events. The δ13Corg study does not support the presence of Lutetian in the NE Ouled Abdoun phosphate series and suggests that a noticeable part of the upper Thanetian is absent.

Original languageEnglish
Pages (from-to)257-269
Number of pages13
JournalGondwana Research
Volume25
Issue number1
DOIs
Publication statusPublished - 1 Jan 2014

Fingerprint

Ypresian
chemostratigraphy
carbon isotope
mammal
phosphate
phosphorite
Thanetian
bone
basin
Selandian
Paleocene
vertebrate
Eocene
Lutetian
chert
dating
Maastrichtian
quarry
zonation
marine sediment

Keywords

  • African mammals
  • Carbon isotopes
  • EECO
  • Ouled Abdoun Basin
  • Paleocene-Eocene phosphorites

Cite this

Yans, Johan ; Amaghzaz, M'Barek ; Bouya, Baadi ; Cappetta, Henri ; Iacumin, Paola ; Kocsis, László ; Mouflih, Mustapha ; Selloum, Omar ; Sen, Sevket ; Storme, Jean-Yves ; Gheerbrant, Emmanuel. / First carbon isotope chemostratigraphy of the Ouled Abdoun phosphate Basin, Morocco; implications for dating and evolution of earliest African placental mammals. In: Gondwana Research. 2014 ; Vol. 25, No. 1. pp. 257-269.
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First carbon isotope chemostratigraphy of the Ouled Abdoun phosphate Basin, Morocco; implications for dating and evolution of earliest African placental mammals. / Yans, Johan; Amaghzaz, M'Barek; Bouya, Baadi; Cappetta, Henri; Iacumin, Paola; Kocsis, László; Mouflih, Mustapha; Selloum, Omar; Sen, Sevket; Storme, Jean-Yves; Gheerbrant, Emmanuel.

In: Gondwana Research, Vol. 25, No. 1, 01.01.2014, p. 257-269.

Research output: Contribution to journalArticle

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T1 - First carbon isotope chemostratigraphy of the Ouled Abdoun phosphate Basin, Morocco; implications for dating and evolution of earliest African placental mammals

AU - Yans, Johan

AU - Amaghzaz, M'Barek

AU - Bouya, Baadi

AU - Cappetta, Henri

AU - Iacumin, Paola

AU - Kocsis, László

AU - Mouflih, Mustapha

AU - Selloum, Omar

AU - Sen, Sevket

AU - Storme, Jean-Yves

AU - Gheerbrant, Emmanuel

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