Laurasia

Laurasia (/lɔːˈreɪʒə/ or /lɔːˈreɪʃiə/) was the northernmost of two supercontinents (the other being Gondwana) that formed part of the Pangaea supercontinent around 300 to 200 million years ago (Mya). It separated from Gondwana 200 to 180 Mya (beginning in the late Triassic period) during the breakup of Pangaea, drifting farther north after the split.

The name combines the names of Laurentia, the name given to the North American craton, and Eurasia. As suggested by the geologic naming, Laurasia included most of the land masses which make up today's continents of the Northern Hemisphere, chiefly Laurentia, Baltica, Siberia, Kazakhstania, and the North China and East China cratons.

Origin

Although Laurasia is known as a Mesozoic phenomenon, today it is believed that the same continents that formed the later Laurasia also existed as a coherent supercontinent after the breakup of Rodinia around 1 billion years ago. To avoid confusion with the Mesozoic continent, this is referred to as Proto-Laurasia. It is believed that Laurasia did not break up again before it recombined with the southern continents to form the late Precambrian supercontinent of Pannotia, which remained until the early Cambrian. Laurasia was assembled, then broken up, due to the actions of plate tectonics, continental drift, and seafloor spreading.