Encyclopedia of Astrobiology

2011 Edition
| Editors: Muriel Gargaud, Ricardo Amils, José Cernicharo Quintanilla, Henderson James (Jim) CleavesII, William M. Irvine, Daniele L. Pinti, Michel Viso

Apex Chert, Microfossils

Reference work entry
DOI: https://doi.org/10.1007/978-3-642-11274-4_1866

Keywords

 Apex chert,  apex basalt, biomarkers, cyanobacteria,  microfossils

Definition

The Apex Chert is a bedded, microcrystalline silica (SiO2) deposit interlayered with pillow lavas and massive flows of the Apex Basalt Formation,  Pilbara Craton, Western Australia. The basalts were dated at 3,465–3,458 Ma. The origin of the chert is disputed and interpretations of primary silica deposition on the ocean floor or alternatively secondary, hydrothermal silicification (chertification) of clastic or carbonate sedimentary and volcano-sedimentary rocks rival one another. The putative microfossils of Apex Chert are carbonaceous filaments found in ca. 3,465 Ma old chert lenses at the so-called “Schopf locality,” Chinaman Creek near Marble Bar.

Overview

The name of the locality derives from that of the American paleontologist and paleobiologist, J. William (Bill) Schopf, who, at this site, reported 11 morphological taxa of prokaryotic, filamentous, and coccoidal microfossils embedded in chert...
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References and Further Reading

  1. Allwood AC, Walter MR, Kamber BS, Marshall CP, Burch IW (2006) Stromatolite reef from the Early Archaean era of Australia. Nature, 441, doi:10.1038CrossRefGoogle Scholar
  2. Altermann W (2005) The 3.5 Ga Apex fossil assemblage – consequences of an enduring discussion. 14th Internat. Conference on the Origin of Life, ISSOL’05, Beijing, China, 136–137Google Scholar
  3. Altermann W (2007) The early Earth’s record of enigmatic cyanobacteria and supposed extremophilic bacteria at 3.8 to 2.5 Ga. In: Seckbach J (Ed) Algae and cyanobacteria in extreme environments. cellular origin, life in extreme habitats and astrobiology (COLE) 11, pp 759–778, Springer, BerlinCrossRefGoogle Scholar
  4. Altermann W, Kazmierczak J (2003) Archean microfossils: a reappraisal of early life on Earth. Res Microbiol 154:611–617CrossRefGoogle Scholar
  5. Awramik SM, Schopf JW, Walter MR (1983) Filamentous fossil bacteria from the Archean of Western Australia. Precambrian Res 20:357–374CrossRefGoogle Scholar
  6. Brasier MD, Green OR, Jephcoat AP, Kleppe AK, Van Kranendonk MJ, Lindsay JF, Steele A, Grassineau NV (2002) Questioning the evidence for Earth’s oldest fossils. Nature 416:76–81ADSCrossRefGoogle Scholar
  7. Brasier M, Green O, Lindsay J, Steele A (2004) Earth’s oldest (similar to 3.5 Ga) fossils and the “Early Eden hypothesis”: questioning the evidence. Orig Life Evol Biosph 34:257–269ADSCrossRefGoogle Scholar
  8. Brasier M, Green O, Lindsay J, Mcloughlin N, Steele A, Stoakes C (2005) Critical testing of Earth’s oldest putative fossil assemblage from the ∼3.5Ga Apex chert, Chinaman Creek, Western Australia. Precambrian Res 140:55–102CrossRefGoogle Scholar
  9. Brasier M, Mcloughlin N, Green O, Wacey D (2006) A fresh look at the fossil evidence for early Archaean cellular life. Phil T Roy Soc B 361:887–902CrossRefGoogle Scholar
  10. Buick R (1984) Carbonaceous filaments from North Pole Western Australia: are they fossil bacteria in Archaean stromatiolites? Precambrian Res 24:157–172ADSCrossRefGoogle Scholar
  11. Buick R (1990) Microfossil recognition in archean rocks: an appraisal of spheroids and filaments from a 3500 M.Y. Old Chert-Barite Unit at North Pole, Western Australia. Palaios 5:441–459CrossRefGoogle Scholar
  12. De Gregorio BT, Sharp TG (2006) The structure and distribution of carbon in 3.5 Ga Apex chert: implications for the biogenicity of Earth’s oldest putative microfossils. Am Mineral 91:784–789CrossRefGoogle Scholar
  13. Derenne S, Robert F, Skrzypczak-Bonduelle A, Gourier D, Binet L, Rouzaud J-N (2008) Molecular evidence for life in the 3.5 billion year old Warrawoona chert. Earth Planet Sci Lett 272:476–480ADSCrossRefGoogle Scholar
  14. Kazmierczak J, Kremer B (2002) Thermal alteration of the Earth’s oldest fossils. Nature 420:447–478ADSCrossRefGoogle Scholar
  15. McCollom T, Seewald J (2006) Carbon isotope composition of organic compounds produced by abiotic synthesis under hydrothermal conditions, Earth Planet. Sci Lett 243:74–84Google Scholar
  16. Oehler DZ, Robert F, Walter MR, Sugitani K, Allwood A, Meibom A, Mostefaoui S, Selo M, Thomen A, Gibson EK (2009) NanoSIMS: insights to biogenicity and syngeneity of Archaean carbonaceous structures. Precambrian Res 173:70–78CrossRefGoogle Scholar
  17. Pinti DL, Mineau R, Clement V (2009) Hydrothermal alteration and microfossil artefacts of the 3, 465-million-year-old Apex chert. Nat Geosci 2:640–643ADSCrossRefGoogle Scholar
  18. Schopf JW (1992) Paleobiology of the Archean. In: Schopf JW, Klein C (eds) The Proterozoic biosphere. Cambridge University Press, New York, pp 25–39CrossRefGoogle Scholar
  19. Schopf JW (1993) Microfossils of the early Archean apex chert: new evidence of the antiquity of life. Science 260:640–646ADSCrossRefGoogle Scholar
  20. Schopf JW (1999) The cradle of life. Princeton University Press, New YorkGoogle Scholar
  21. Schopf WJ (2006) Fossil evidence of Archaean life. Phil T Roy Soc B 361:869–885CrossRefGoogle Scholar
  22. Schopf JW, Kudryavtsev AB (2005) Three-dimensional Raman imagery of Precambrian microscopic organisms. Geobiology 3:1–12CrossRefGoogle Scholar
  23. Schopf JW, Packer BM (1987) Early Archean (3.3- billion to 3.5-billion-year-old) microfossils from Warrawoona Group, Australia. Science 237:70–73ADSCrossRefGoogle Scholar
  24. Schopf JW, Kudryavtsev AB, Agresti DG, Wdowiak TJ, Czaja AD (2002) Laser-Raman imagery of Earth’s earliest fossils. Nature 416:73–76ADSCrossRefGoogle Scholar
  25. Schopf JW, Kudryavtsev AB, Agresti DG, Czaja AD, Wdowiak TJ (2005) Raman imagery: a new approach to assess the geochemical maturity and biogenicity of permineralized Precambrian fossils. Astrobiology 5:333–371ADSCrossRefGoogle Scholar
  26. Schopf JW, Kudryavtsev AB, Czaja AD, Tripathi AB (2007) Evidence of Archean life: stromatolites and microfossils. Precambrian Res 158:141–155CrossRefGoogle Scholar
  27. Ueno Y, Maruyama S, Isozaki Y, Yurimoto H (2001) Early Archean (ca. 3.5 Ga) microfossils and 13C-depleted carbonaceous matter in the North Pole area, Western Australia. In: Nakashima S, Maruyama S, Brack A, Windley BF (eds) Field occurrence and geochemistry, in geochemistry and the origin of life. Universal Academic Press, Tokyo, pp 203–236Google Scholar
  28. Van Kranendonk MJ, Pirajno F (2004) Geochemistry of metabasalts and hydrothermal alteration zones associated with c. 3.45 Ga chert and barite deposits. Implications for the geological setting of the Warrawoona Group, Pilbara Craton, Australia. Geochem Explor Environ Anal 4:253–278CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2011

Authors and Affiliations

  1. 1.GEOTOP & Department of Earth and Atmospheric sciencesUniversité du Québec à MontréalMontréalCanada
  2. 2.Department of GeologyUniversity of PretoriaPretoriaSouth Africa