Ìgbà Dẹfoníà

(Àtúnjúwe láti Devonian)
Ìgbà Dẹfoníà
416–359.2 ẹgbẹgbẹ̀rún ọdun sẹ́yìn
Mean atmospheric O2 content over period duration ca. 15 Vol %[1]
(75 % of modern level)
Mean atmospheric CO2 content over period duration ca. 2200 ppm[2]
(8 times pre-industrial level)
Mean surface temperature over period duration ca. 20 °C[3]
(6 °C above modern level)
Sea level (above present day) Relatively steady around 180m, gradually falling to 120m through period[4]

The Devonian is a geologic period and system of the Paleozoic Era spanning from 416 to 359.2 ẹgbẹgbẹ̀rún ọdún sẹ́yìn (ICS, 2004,[5] chart). It is named after Devon, England, where rocks from this period were first studied.

During the Devonian Period the pectoral and pelvic fins of lobe-finned fish evolved into legs[6] as they started to walk on land as tetrapods around 397 Ma.[7] Various terrestrial arthropods also became well-established.


  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. 
  6. See Tiktaalik.
  7. [1] Fossil tracks record 'oldest land-walkers' - BBC News
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