Editing Supercontinent (section)

== Cycles ==
A [[supercontinent cycle]] is the break-up of one supercontinent and the development of another, which takes place on a global scale.<ref name="bradley" /> Supercontinent cycles are not the same as the [[Wilson cycle]], which is the opening and closing of an individual [[oceanic basin]]. The Wilson cycle rarely synchronizes with the timing of a supercontinent cycle.<ref name="rogers" /> However, supercontinent cycles and Wilson cycles were both involved in the creation of Pangaea and Rodinia.<ref name="flutaeu" />

[[Secular variation|Secular]] trends such as [[carbonatite]]s, [[granulite]]s, [[eclogite]]s, and [[greenstone belt]] deformation events are all possible indicators of Precambrian supercontinent cyclicity, although the Protopangea–Paleopangea solution implies that Phanerozoic style of supercontinent cycles did not operate during these times. Also, there are instances where these secular trends have a weak, uneven, or absent imprint on the supercontinent cycle; secular methods for supercontinent reconstruction will produce results that have only one explanation, and each explanation for a trend must fit in with the rest.<ref name="bradley" />

The following table names reconstructed ancient supercontinents, using Bradley's 2011 looser definition,<ref name="Bradley" /> with an approximate timescale of millions of years ago (Ma).

{| class="wikitable"
! Supercontinent name !! Age (Ma) || Period/Era Range || Comment
|-
|[[Vaalbara]]
|3,636–2,803 || Eoarchean-Mesoarchean ||Also described as a supercraton or just a continent<ref name="de_Kock__etal_2009">{{Cite journal |last1=de Kock |first1=M.O. |last2=Evans |first2=D.A.D. |last3=Beukes |first3=N.J. |date=2009 |title=Validating the existence of Vaalbara in the Neoarchean |url=https://people.earth.yale.edu/sites/default/files/files/Evans/35_09g-deKock+Vaalbara.pdf |journal=Precambrian Research |volume=174 |issue=1–2 |pages=145–154 |doi=10.1016/j.precamres.2009.07.002|bibcode=2009PreR..174..145D }}</ref>
|-
| [[Ur (continent)|Ur]] || 2,803–2,408 || Mesoarchean-Siderian ||Described as both a continent<ref name="Rogers_&_Santosh_2002"/> and a supercontinent<ref name="Mahapatro_etal_2011">{{Cite journal |last1=Mahapatro |first1=S.N. |last2=Pant |first2=N.C. |last3=Bhowmik |first3=S.K. |last4=Tripathy |first4=A.K. |last5=Nanda |first5=J.K. |date=2011 |title=Archaean granulite facies metamorphism at the Singhbhum Craton–Eastern Ghats Mobile Belt interface: implication for the Ur supercontinent assembly |url=https://www.academia.edu/26707795|journal=Geological Journal |volume=47 |issue=2–3 |pages=312–333 |doi=10.1002/gj.1311|s2cid=127300220 |doi-access=free }}</ref>
|-
| [[Kenorland]] || 2,720–2,114 || Neoarchean-Rhyacian ||Alternatively the continents may have formed into two groupings [[Superior craton|Superia]] and [[Sclavia craton|Sclavia]]<ref name="Nance_etal_2014">{{Cite journal |last1=Nance |first1=R.D. |last2=Murphy |first2=J.B. |last3=Santosh |first3=M. |date=2014 |title=The supercontinent cycle: A retrospective essay |journal=Gondwana Research |volume=25 |issue=1 |pages=4–29 |doi=10.1016/j.gr.2012.12.026|bibcode=2014GondR..25....4N }}</ref><ref name="bradley" />
|-
| [[Arctica]] || 2,114–1,995 || Rhyacian-Orosirian ||Not generally regarded as a supercontinent, depending on definition<ref name="Rogers_&_Santosh_2002"/>
|-
|[[Atlantica]]
|1,991–1,124 || Orosirian-Stenian ||Not generally regarded as a supercontinent, depending on definition<ref name="Rogers_&_Santosh_2002"/>
|-
| [[Columbia (supercontinent)|Columbia (Nuna)]] || 1,820–1,350 || Orosirian-Ectasian ||<ref name="Nance_etal_2014"/>
|-
| [[Rodinia]] || 1,130–750 || Stenian-Tonian ||<ref name="Nance_etal_2014"/>
|-
| [[Pannotia]] || 633–573 || Ediacaran ||<ref name="Nance_etal_2014"/>
|- 
|[[Gondwana]] || 550–175 || Ediacaran-Jurassic ||From the Carboniferous, formed part of Pangaea,<ref name="bradley" /> not always regarded as a supercontinent<ref name="Evans_2013">{{Cite journal |last=Evans |first=D.A.D. |date=2013 |title=Reconstructing pre-Pangean supercontinents
|url=https://people.earth.yale.edu/sites/default/files/files/Evans/58-GSAB125.pdf |journal=GSA Bulletin |volume=125 |issue=11–12 |pages=1736 |doi=10.1130/B30950.1|bibcode=2013GSAB..125.1735E }}</ref>
|-
| [[Pangaea]] || 336–175 || Carboniferous-Jurassic ||
|}