What is Vaalbara?
'''Vaalbara''' is the name of [[Earth]]'s first [[supercontinent]], in the [[Archaean]] [[era]]. Vaalbara started to form about 3,600 million years ago (mya). It formed by about 3,100 mya and broke up by 2,500 mya. The name ''Vaalbara'' comes from the South African Kaapvaal [[craton]] and the West Australian [[Pilbara]] craton. These cratons were combined in the Vaalbara supercontinent. [[South Africa]]'s Kaapvaal craton and [[Western Australia]]'s Pilbara craton are two of the best-preserved [[Archaean]] cratons on Earth. They have remarkably similar early [[Precambrian]] rocks. Identical [[radioactive dating|radiometric]] ages of 3,470 ±2 mya have been got from rocky material thrown out by [[meteorite]] strikes. Similar structures from these two cratons have been dated between 3,500 to 2,700 mya.<ref name=barberton>{{cite journal|title=An Archean impact layer from the Pilbara and Kaapvaal cratons|author1=Byerly, Gary R|author2=Lowe, Donald R|author3=Wooden, Joseph L|author4=Xie, Xiaogang|journal=Science|volume=297| issue = 5585|doi=10.1126/science.1073934|year=2002|url=http://www.sciencemag.org/cgi/content/abstract/297/5585/1325|accessdate=March 27, 2010|pmid=12193781|pages=1325–7|bibcode = 2002Sci...297.1325B |s2cid=23112906}}</ref> Similar [[greenstone belt]]s are found at the edges of the Superior craton of [[Canada]], and across the cratons of the former [[Gondwana]] and [[Laurasia]] [[continents]].<ref name=blog>{{cite web |url=http://paleogeology.blogspot.com/2008/12/archaean-supercontinents.html |title=Paleogeography: paleogeology, paleoclimate, in relation to evolution of life on Earth|date=December 30, 2008|page=2 |accessdate=February 28, 2010 }}</ref> Palaeo[[magnetic]] data from rocks in the cratons showed that at 3,870 mya the two cratons could have been part of the same supercontinent. Both the Pilbara and Kaapvaal cratons show [[Fault (geology)|extensional fault]]s which were active about the same time during [[volcanism]] at the same time as the impact layers were formed. [[Continental plate