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LU

Emma Hammarlund

Research team manager

LU

The 2.1 Ga old Francevillian biota : Biogenicity, taphonomy and biodiversity

Author

  • Abderrazak El Albani
  • Stefan Bengtson
  • Donald E Canfield
  • Armelle Riboulleau
  • Claire Rollion Bard
  • Roberto Macchiarelli
  • Lauriss Ngombi Pemba
  • Emma Hammarlund
  • Alain Meunier
  • Idalina Moubiya Mouele
  • Karim Benzerara
  • Sylvain Bernard
  • Philippe Boulvais
  • Marc Chaussidon
  • Christian Cesari
  • Claude Fontaine
  • Ernest Chi-Fru
  • Juan Manuel Garcia Ruiz
  • François Gauthier-Lafaye
  • Arnaud Mazurier
  • Anne-Catherine Pierson-Wickmann
  • Olivier Rouxel
  • Alain Trentesaux
  • Marco Vecoli
  • Gerard J M Versteegh
  • Lee White
  • Martin Whitehouse
  • Andrey Bekker
Show all

Summary, in English

The Paleoproterozoic Era witnessed crucial steps in the evolution of Earth's surface environments following the first appreciable rise of free atmospheric oxygen concentrations ∼2.3 to 2.1 Ga ago, and concomitant shallow ocean oxygenation. While most sedimentary successions deposited during this time interval have experienced thermal overprinting from burial diagenesis and metamorphism, the ca. 2.1 Ga black shales of the Francevillian B Formation (FB2) cropping out in southeastern Gabon have not. The Francevillian Formation contains centimeter-sized structures interpreted as organized and spatially discrete populations of colonial organisms living in an oxygenated marine ecosystem. Here, new material from the FB2 black shales is presented and analyzed to further explore its biogenicity and taphonomy. Our extended record comprises variably sized, shaped, and structured pyritized macrofossils of lobate, elongated, and rodshaped morphologies as well as abundant non-pyritized disk-shaped macrofossils and organic-walled acritarchs. Combined microtomography, geochemistry, and sedimentary analysis suggest a biota fossilized during early diagenesis. The emergence of this biota follows a rise in atmospheric oxygen, which is consistent with the idea that surface oxygenation allowed the evolution and ecological expansion of complex megascopic life.

Publishing year

2014-06-25

Language

English

Publication/Series

PLoS ONE

Volume

9

Issue

6

Document type

Journal article

Publisher

Public Library of Science (PLoS)

Status

Published

ISBN/ISSN/Other

  • ISSN: 1932-6203