A supercontinent is a mass of land comprising more than one continent. Since the definition of continent is arbitrary, the definition of supercontinent is also arbitrary (as is the definition of a subcontinent), but the term refers to a landmass containing more than one of the modern continents.

Present day supercontinents are Eurasia, Africa-Eurasia, and The Americas.

Most commonly, the term supercontinent is used to refer to a landmass consisting of all the modern continents. Such a landmass is formed or destroyed, through continental drift, about every 250 million years. Supercontinents block the flow of heat from the Earth's interior, and thus cause the asthenosphere to overheat. Eventually, the lithosphere will begin to dome upward and crack, magma will then rise, and the fragments will be pushed apart.

The supercontinent Rodinia broke up roughly 600 million years ago. One of the fragments included large parts of the modern southern hemisphere continents. Continental drift then brought the fragments together in a different configuration, resulting in another supercontinent, Pangaea, forming in the late Paleozoic. Pangaea broke up into the northern and southern supercontinents, Laurasia and Gondwana.

Recently Drs Rogers and Santosh have proposed the existence of a yet older supercontinent, Columbia, that was formed and broken up during a period of 1.8 to 1.5 billon years ago.

• Africa-Eurasia
• Eurasia
• The Americas

• Euramerica
• Gondwana
• Laurasia

• Columbia (~1.8-~1.5 billion years ago)
• Rodinia (~1.1-~.75 billion years ago)
• Pannotia (~650-~540 million years ago)
• Pangea (~280-~135 million years ago)
• Pangæa Ultima (~250-~400 million years from now)

The Paleomap Project -- Christopher R. Scotese