Amasia is the working title for a possible future supercontinent that could be formed by the merger of Asia and North America. This prediction relies mostly on the fact that the Pacific Plate is already subducting under Eurasia and North America, a process which if continued will eventually cause the Pacific to close. Meanwhile, because of the Atlantic mid-ocean ridge, North America would be pushed westward. Thus, the Atlantic at some point in the future would be larger than the Pacific. In Siberia, the boundary between the Eurasian and North American Plates has been stationary for millions of years. The combination of these factors would cause North America to be combined with Asia, thus forming a supercontinent. A February 2012 study predicts Amasia will form over the North Pole, in about 50 million to 200 million years.
Paleogeologist Ronald Blakey has described the next 15 to 100 million years of tectonic development as fairly settled and predictable but no supercontinent will form in that time frame. Beyond that, he cautions that the geologic record is full of unexpected shifts in tectonic activity that make further projections "very, very speculative". In addition to Amasia, two other hypothetical supercontinents—Christopher Scotese's "Pangaea Ultima" and Roy Livermore's "Novopangea"—were illustrated in an October 2007 New Scientist article.
- Nield, Ted, Supercontinent: Ten Billion Years in the Life of Our Planet, Harvard University Press, 2009, ISBN 978-0674032453