Laurasia has arguably existed twice in prehistory. It is believed that the continents that made up Laurasia were joined after the breakup of Rodinia around one billion years ago. This supercontinent is generally called Proto-Laurasia, in order to avoid confusion between the Precambrian and Phanerozoic landmasses. Proto-Laurasia began to break up during the Cambrian.
It once again formed when the supercontinent Pangaea started to break up approximately 200 million years ago. This was caused at least in part by the formation of the Atlantic Ocean.
Bits and pieces of Laurasia broke off throughout the Mesozoic, and eventually it separated into the continents of North America and Eurasia (excluding India, which collided with Asia after separating from Gondwana).
- ↑ Houseman, Greg. "Dispersal of Gondwanaland". University of Leeds. Retrieved 21 Oct 2008.