The hypothetical supercontinent that existed before the formation of Pangaea. Named after the Russian word for motherland, scientists speculate that it formed about 1100 million years ago and broke up 750 million years ago. One of the resulting continents, Laurentia, is identified as the origin of North America. Part of the separation process left a "crack" in Laurentia called the Reelfoot Rift, which includes the modern-day Mississippi valley.
Some even posit even more ancient landmasses called Ur, Arctica, Baltica and Atlantica that were the building blocks of Rodinia, and that these were the first and masses to rise from the global sea. The cores of these landmasses, called cratons, are thought to be over 3 billion years old.
Part of the magic of Plate Tectonics.