View source for Earth:Chaotian (geology)

{{Short description|Proposed era of the Hadean eon}}
{{Infobox geologic timespan
| name                         = Chaotian
| top_bar                      = all time
| time_start                   = 4568
| time_end                     = 4404
| earliest                     =
| latest                       =
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<!--Chronology-->
| timeline                     = 
| subdivisions                 = [[Earth:Chaotian (geology)#Subdivisions|See text]]
| proposed_subdivision1        =
| proposed_subdivision1_coined =
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<!--Etymology-->
| chrono_name                  =
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<!--Usage Information-->
| celestial_body               = Earth
| usage                        = Proposed subdivision of the [[Earth:Hadean|Hadean]] eon
| timescales_used              =
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| formerly_used_by             =
| not_used_by                  =
<!--Definition-->
| chrono_unit                  = Era
| strat_unit                   = Erathem
| proposed_by                  = C., Zahnle, K. J., Sleep, N. H., and Nisbet, E. G., 2010
| type_section                 =
| lower_boundary_def           = Formation of the Earth
| lower_stratotype_location    =
| upper_boundary_def           = Collision between Proto-Earth and the Protoplanet [[Astronomy:Theia (planet)|Theia]]
| upper_stratotype_location    =
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}}

The '''Chaotian''' is a proposed time division of the [[Earth:Geologic time scale|geologic time scale]]. First proposed in 2010<ref name="solidearth1">{{cite journal|last1=Goldblatt|first1=C.|last2=Zahnle|first2=K.J.|last3=Sleep|first3=N.H.|last4=Nisbet|first4=E.G.|date=2 February 2010|title=The Eons of Chaos and Hades|url=https://www.solid-earth.net/1/1/2010/se-1-1-2010.html|journal=Solid Earth|volume=1|issue=1|pages=1–3|bibcode=2010SolE....1....1G|doi=10.5194/se-1-1-2010|doi-access=free}}</ref> as an [[Earth:Eon (geology)|eon]], it is named after [[Religion:Chaos (mythology)|Chaos]], the primeval void in [[Religion:Greek mythology|Greek mythology]]. This proposal defines the Chaotian eon as a [[Astronomy:Solar System|Solar System]]-wide time between the initiation of planetary formation and the [[Astronomy:Giant-impact hypothesis|hypothesised collision]] of the [[Astronomy:Earth trojan|trojan]] [[Astronomy:Dwarf planet|dwarf planet]] [[Astronomy:Theia (planet)|Theia]] with the [[Earth:History of Earth|proto-Earth]]. 

A revised proposal in 2012<ref name=":0">{{Citation|last=Van Kranendonk|first=Martin J.|title=A Chronostratigraphic Division of the Precambrian|date=2012|url=https://linkinghub.elsevier.com/retrieve/pii/B9780444594259000160|work=The Geologic Time Scale|pages=299–392|publisher=Elsevier|language=en|doi=10.1016/b978-0-444-59425-9.00016-0|isbn=978-0-444-59425-9|access-date=2020-07-31|others=Altermann, Wladyslaw; Beard, Brian L.; Hoffman, Paul F.; Johnson, Clark M.; Kasting, James F.; Melezhik, Victor A.; Nutman, Allen; Papineau, Dominic; Pirajno, Franco}}</ref> suggested the Chaotian as the first [[Earth:Era (geology)|era]] of the [[Earth:Hadean|Hadean]] representing the time between the formation of the Solar System c.&nbsp;4.567&nbsp;[[Year#SI prefix multipliers|Ga]]<ref>{{Cite journal|last1=Connelly|first1=J.N.|last2=Bollard|first2=J.|last3=Bizzarro|first3=M.|date=2017|title=Pb–Pb chronometry and the early Solar System|journal=Geochimica et Cosmochimica Acta|language=en|volume=201|pages=345–363|doi=10.1016/j.gca.2016.10.044|doi-access=free}}</ref> and the oldest preserved [[Earth:Earth's crust|crust]]al material on Earth, a detrital zircon c.&nbsp;4.404&nbsp;Ga<ref>{{cite journal|last1=Wilde|first1=Simon A.|last2=Valley|first2=John W.|last3=Peck|first3=William H.|last4=Graham|first4=Colin M.|date=11 January 2001|title=Evidence from detrital zircons for the existence of continental crust and oceans on the Earth 4.4 Gyr ago|journal=Nature|volume=409|issue=6817|pages=175–178|bibcode=2001Natur.409..175W|doi=10.1038/35051550|pmid=11196637|s2cid=4319774}}</ref> from the Jack Hills of the [[Earth:Narryer Gneiss Terrane|Narryer Terrane]] in Western Australia.

{{As of|2023|09}}, neither proposal had been adopted or officially ratified by the [[Organization:International Union of Geological Sciences|International Union of Geological Sciences]].<ref>https://stratigraphy.org/chart</ref>

== Subdivisions ==
The original proposal in 2010 divided the Chaotian into two eras and four [[Earth:Geological period|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. 
{| class="wikitable"
|+Proposed Chaotian time intervals (2010) <ref name="solidearth1" />
!Eon
!Era
!Period
!Age (Ga)
|-
| rowspan="4" |Chaotian
| rowspan="2" |Neochaotian
|Titanomachaen
|> ~4.5
|-
|Hyperitian
|
|-
| rowspan="2" |Eochaotian
|Erebrean
|
|-
|Nephelean
|
|}
{| class="wikitable"
|+Proposed Chaotian time intervals (2012) <ref name=":0" />
!Eon
!Era
!Age (Ga)
|-
| rowspan="2" |Hadean
|[[Earth:Geologic time scale#Proposed Precambrian timeline|Jack Hillsian or Zirconian]]
|4.404 to 4.030
|-
|Chaotian
|4.568 to 4.404
|}

== See also ==

* [[Earth:Age of the Earth|Age of the Earth]]
* [[Astronomy:Formation and evolution of the Solar System|Formation and evolution of the Solar System]]
* [[Earth:Geologic time scale|Geologic time scale]]

== References ==
{{reflist}}

{{Geological history|c}}

[[Category:Geological eons]]
[[Category:Geological eras]]
[[Category:Hadean]]

{{Sourceattribution|Chaotian (geology)}}