Laurasia was an ancient supercontinent of the Northern Hemisphere formed, with Gondwanaland to the south, after the splitting of Pangea (see continental drift) along a rift, the Tethyan trench. It appears to have comprised present-day Europe, North America, and northern Asia. The name is a combination of Laurentian, a geological period in North America, and Eurasia. Continental drift and plate tectonics caused Laurasia to split up into the separate continents that exist today.