Chaotian (geology)

The Chaotian is a proposed time division of the geologic time scale. First proposed in 2010[1] as an eon, it is named after Chaos, the primeval void in Greek mythology. This proposal defines the Chaotian eon as a solar system wide time between the initiation of planetary formation and the hypothesised collision of Theia (planet) with the proto-Earth.

A revised proposal in 2012[2] suggested the Chaotian as the first era of the Hadean representing the time between the formation of the solar system c. 4.567 Ga[3] and the oldest preserved crustal material on Earth, a c. 4.404 Ga[4] detrital zircon from the Jack Hills of the Narryer Terrane in Western Australia.

As of 31 July 2020 neither proposal has been adopted or officially ratified by the International Union of Geological Sciences.


The original proposal in 2010 divided the Chaotian into two eras and four periods. No numerical upper age limits were provided, only the younger age limit of ~4.5 Ga for the boundary between the proposed Chaotian and Hadean boundary.

The revised proposal in 2012 did not subdivide the proposed Chaotian era (of the Hadean eon) into periods.

Proposed Chaotian time intervals (2010) [1]
Eon Era Period Age (Ga)
Chaotian Neochaotian Titanomachaen > ~4.5
Eochaotian Erebrean
Proposed Chaotian time intervals (2012) [2]
Eon Era Age (Ga)
Hadean Jack Hillsian or Zirconian 4.404 to 4.030
Chaotian 4.568 to 4.404

See alsoEdit


  1. ^ a b Goldblatt, C.; Zahnle, K.J.; Sleep, N.H.; Nisbet, E.G. (2 February 2010). "The Eons of Chaos and Hades". Solid Earth. 1 (1): 1–3. Bibcode:2010SolE....1....1G. doi:10.5194/se-1-1-2010.
  2. ^ a b Van Kranendonk, Martin J.; Contributors:; Altermann, Wladyslaw; Beard, Brian L.; Hoffman, Paul F.; Johnson, Clark M.; Kasting, James F.; Melezhik, Victor A.; Nutman, Allen P. (2012), "A Chronostratigraphic Division of the Precambrian", The Geologic Time Scale, Elsevier, pp. 299–392, doi:10.1016/b978-0-444-59425-9.00016-0, ISBN 978-0-444-59425-9, retrieved 2020-07-31CS1 maint: extra punctuation (link)
  3. ^ Connelly, J.N.; Bollard, J.; Bizzarro, M. (2017). "Pb–Pb chronometry and the early Solar System". Geochimica et Cosmochimica Acta. 201: 345–363. doi:10.1016/j.gca.2016.10.044.
  4. ^ Wilde, Simon A.; Valley, John W.; Peck, William H.; Graham, Colin M. (11 January 2001). "Evidence from detrital zircons for the existence of continental crust and oceans on the Earth 4.4 Gyr ago". Nature. 409 (6817): 175–178. Bibcode:2001Natur.409..175W. doi:10.1038/35051550. PMID 11196637.