Ìgbà Ọ̀rdòfísíà

Ìgbà Ọ̀rdòfísíà
488.3–443.7 ẹgbẹgbẹ̀rún ọdun sẹ́yìn
Mean atmospheric O2 content over period duration ca. 13.5 Vol %[1]
(68 % of modern level)
Mean atmospheric CO2 content over period duration ca. 4200 ppm[2]
(15 times pre-industrial level)
Mean surface temperature over period duration ca. 16 °C[3]
(2 °C above modern level)
Sea level (above present day) 180m; rising to 220m in Caradoc and falling sharply to 140m in end-Ordovician glaciations[4]

The Ordovician (pronounced /ɔrdəˈvɪʃən/) is a geologic period and system, the second of six of the Paleozoic Era, and covers the time between 488.3±1.7 to 443.7±1.5 million years ago (ICS, 2004,[5] chart). It follows the Cambrian Period and is followed by the Silurian Period. The Ordovician, named after the Celtic tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same rock beds in northern Wales into the Cambrian and Silurian periods respectively. Lapworth, recognizing that the fossil fauna in the disputed strata were different from those of either the Cambrian or the Silurian periods, realized that they should be placed in a period of their own.

  1. Image:Sauerstoffgehalt-1000mj.svg
  2. Image:Phanerozoic Carbon Dioxide.png
  3. Image:All palaeotemps.png
  4. Haq, B. U.; Schutter, SR (2008). "A Chronology of Paleozoic Sea-Level Changes". Science 322 (5898): 64–68. doi:10.1126/science.1161648. PMID 18832639. 
  5. Gradstein, Felix M.; Ogg, J. G.; Smith, A. G. (2004). A Geologic Time Scale 2004. Cambridge: Cambridge University Press. ISBN 0521786738. 
Preceded by Proterozoic Eon 542 Ma - Phanerozoic Eon - Present
542 Ma - Paleozoic Era - 251 Ma 251 Ma - Mesozoic Era - 65 Ma 65 Ma - Cenozoic Era - Present
Kámbríà Ọ̀rdòfísíà Sílúríà Dẹfoníà Eléèédú Pẹ́rmíà Tríásíkì Jùrásíkì Ẹlẹ́fun Ìbíniàtijọ́ Ìbíniọ̀tun Quaternary