Editing Plate tectonics (section)

== Plate reconstruction ==
{{Main|Plate reconstruction}}
Reconstruction is used to establish past (and future) plate configurations, helping determine the shape and make-up of ancient supercontinents and providing a basis for paleogeography.

=== Defining plate boundaries ===
Active plate boundaries are defined by their seismicity.{{sfn|Condie|1997}} Past plate boundaries within existing plates are identified from a variety of evidence, such as the presence of [[ophiolites]] that are indicative of vanished oceans.{{sfn|Lliboutry|2000}}

=== Emergence of plate tectonics and past plate motions ===
The timing of the emergence of plate tectonics on Earth has been the subject of considerable controversy, with the estimated time varying wildly between researchers, spanning 85% of Earth's history.<ref name=":0">{{Cite journal |last=Marshall |first=Michael |date=2024-08-14 |title=Geology's biggest mystery: when did plate tectonics start to reshape Earth? |journal=Nature |language=en |volume=632 |issue=8025 |pages=490–492 |doi=10.1038/d41586-024-02602-3|pmid=39143339 |bibcode=2024Natur.632..490M |doi-access=free }}</ref> Some authors have suggested that during at least part of the [[Archean]] period (~4-2.5 billion years ago) the mantle was between 100 and 250&nbsp;°C warmer than at present, which is thought to be incompatible with modern-style plate tectonics, and that Earth may have had a [[stagnant lid]] or other kinds of regimes. The increasingly [[felsic]] nature of preserved rocks between 3 and 2.5 billion years ago implies that subduction zones had emerged by this time, with preserved zircons suggesting that subduction may have begun as early as 3.8 billion years ago. Early subduction zones appear to have been temporary and localized, though to what degree is controversial. Modern plate tectonics are suggested to have emerged by at least 2.2 billion years ago with the formation of the first recognised supercontinent Columbia, though some authors have suggested that modern-style plate tectonics did not appear until 800 million years ago based on the late appearance of rock types like [[blueschist]] which require cold subducted material.<ref name=":0" /> Other authors have suggested that plate tectonics were already functional in the [[Hadean]], over 4 billion years ago.<ref>{{Cite journal |last=Korenaga |first=Jun |date=July 2021 |title=Hadean geodynamics and the nature of early continental crust |url=https://linkinghub.elsevier.com/retrieve/pii/S0301926821001066 |journal=Precambrian Research |language=en |volume=359 |pages=106178 |doi=10.1016/j.precamres.2021.106178|bibcode=2021PreR..35906178K }}</ref>
[[File:Tectonic plate model 1Ga.webm|thumb|upright=1.6|right|Animation of a full-plate tectonic model extended one billion years into the past <br />
{{legend-line|#ac1f25 solid 3px|{{0}}Convergent boundary}}
{{legend-line|#a08eda solid 3px|{{0}}Divergent boundary}}
{{legend-line|#000000 solid 3px|{{0}}Transform boundary}}
{{Legend striped|#ac1f25|#ffffff00|border=none|{{0}}{{0}}Arrows point to the upthrown side}}
{{legend|#b5b71f|{{0}} [[Continental crust]] (older crust)}}
{{legend|#6f8ebf|{{0}} Continental crust (younger crust)}}
{{legend|#ffffff|{{0}} [[Oceanic crust]]}} ]]

Various types of quantitative and semi-quantitative information are available to constrain past plate motions. The geometric fit between continents, such as between west Africa and South America is still an important part of plate reconstruction. Magnetic stripe patterns provide a reliable guide to relative plate motions going back into the [[Jurassic]] period.<ref>{{Cite web |last=Torsvik |first=Trond Helge |title=Reconstruction Methods |url=http://www.geodynamics.no/GMAP/Methods/Introduction_to_Methods.htm |url-status=live |archive-url=https://web.archive.org/web/20110723121811/http://www.geodynamics.no/GMAP/Methods/Introduction_to_Methods.htm |archive-date=23 July 2011 |access-date=18 June 2010}}</ref> The tracks of hotspots give absolute reconstructions, but these are only available back to the [[Cretaceous]].{{sfn|Torsvik|Steinberger|2008}} Older reconstructions rely mainly on [[paleomagnetic pole]] data, although these only constrain the latitude and rotation, but not the longitude. Combining poles of different ages in a particular plate to produce apparent polar wander paths provides a method for comparing the motions of different plates through time.{{sfn|Butler|1992}} Additional evidence comes from the distribution of certain [[sedimentary rock]] types,<ref>{{Cite web |last=Scotese |first=C.R. |date=2002-04-20 |title=Climate History |url=http://www.scotese.com/climate.htm |url-status=live |archive-url=https://web.archive.org/web/20100615150530/http://www.scotese.com/climate.htm |archive-date=15 June 2010 |access-date=18 June 2010 |website=Paleomap Project}}</ref> faunal provinces shown by particular fossil groups, and the position of [[orogeny|orogenic belts]].{{sfn|Torsvik|Steinberger|2008}}

==== Formation and break-up of continents ====
The movement of plates has caused the formation and break-up of continents over time, including occasional formation of a [[supercontinent]] that contains most or all of the continents. The supercontinent [[Columbia (supercontinent)|Columbia]] or Nuna formed during a period of {{Ma|2000|1800}} and broke up about {{Ma|1500|1300}}.{{sfn|Zhao|Cawood|Wilde|Sun|2002}}{{sfn|Zhao|Sun|Wilde|Li|2004}} The supercontinent [[Rodinia]] is thought to have formed about 1{{nbsp}}billion years ago and to have embodied most or all of Earth's continents, and broken up into eight continents around {{Ma|600}}. The eight continents later re-assembled into another supercontinent called [[Pangaea]]; Pangaea broke up into [[Laurasia]] (which became North America and Eurasia) and [[Gondwana]] (which became the remaining continents).

The [[Himalayas]], the world's tallest mountain range, are assumed to have been formed by the collision of two major plates. Before uplift, the area where they stand was covered by the [[Tethys Ocean]].