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This article indicates that the Chaotian eon has two end points: the solidification of the crust, and the collision with Theia. I think only the latter has anything to do with defining the end of the Choatian. Estimates for when the crust solidified are all over the map, with Cool early Earth putting it long before the impact, the older hypothesis putting it millions of years after the impact. The impact itself is thought to have melted only portions of the earth, since it was a low-velocity impact. Also, we could use a mention of the proto-planet Tellus (Earth before the impact) Zyxwv99 (talk) 22:51, 13 March 2016 (UTC)