Pangaea Ultima

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Pangaea Ultima is a possible future supercontinent configuration, which, consistent with the supercontinent cycle, may occur within the next 250 million years. This potential configuration, hypothesized by Christopher Scotese, earned its name from its similarity to the previous Pangaea supercontinent.<ref name="scotese">Scotese, Christopher R.. Pangea Ultima will form 250 million years in the Future. Paleomap Project. Retrieved on 2006-03-13.</ref>

Supercontinents describe the merger of all, or nearly all, of the Earth's landmass into a single continuous continent. In the Pangaea Ultima scenario, subduction at the western Atlantic, east of the Americas (signs of it can be seen today, the Puerto Rico Trench), leads to the subduction of the Atlantic mid-ocean ridge followed by subduction destroying the Atlantic oceanic basin, causing the Atlantic Ocean to close, bringing the Americas back together with Africa and Europe. As with most supercontinents, the interior of Pangaea Ultima would probably become a semi-arid desert prone to temperature extremes.<ref>Kargel, Jeffrey S. [2004-08-01]. “New World”, Mars. Springer. ISBN 1-85233-568-8.</ref>

1 Formation
2 The Break Up
3 Appearances in Media
4 External links
5 References

[edit] Formation

The Atlantic and Indian Oceans will continue to widen until new subduction zones bring the continents back together, forming a Future Pangea. It seems that most continents and microcontinents collide to Eurasia, such as India, and in the future, Africa, and Australia, just as they did when most continents collided to Laurentia.

50 million years into future looks slightly strange. North America is rotated slightly counter-clockwise (Alaska is now near the subtropical latitudes) and Eurasia is rotated clockwise bringing Britain closer to the North Pole and Siberia southward towards warm, subtropical latitudes. Africa will collide with Europe and Arabia closing the Mediterranean Sea (completely closing the Tethys Ocean (or Neotethys)) and the Red Sea. A long mountain range will extend from Spain, across Southern Europe (the Mediterranean Mountain Range), through the Mideast and into Asia. Some will even have peaks higher than Mt. Everest. Similarly, Australia will beach itself on the doorstep of Southeast Asia and a new subduction zone encircles Australia and extends westward across the Central Indian Ocean. Meanwhile, Baja California has already collided with Alaska, forming new mountain ranges between them.

One of the most important changes in the geography of the future, is the beginning of subduction along the eastern coasts of North America and South America. The Atlantic Ocean has widened, even though the Puerto Rican Trench and Scotia Arc may propagate northward and southward along the east coast of North and South America. In time, this new westward dipping subduction zone will consume the Atlantic Ocean.

About 100 million years from now, the Atlantic ocean stops widening, and begins to shrink because a bit of the Atlantic Ocean mid-ridge has been subducted. A mid ocean ridge between South America and Africa will probably be subducted first.

150 million years from now, the Atlantic Ocean has narrowed as a result of subduction beneath the Americas. The Indian Ocean is also smaller due to northward subduction of oceanic crust into the Central Indian trench. Antarctica has collided along the southern margin of Australia because the Central Indian Trench and the South Australian Trench pushes Antarctica northward to Australia, which is now collided with Southeast Asia. The Mid-Atlantic Ridge, the last vestige of sea floor spreading in the Atlantic Ocean, has nearly been subducted beneath eastern North America. The rock layers that contain the remains of ancient New York City, Boston and Washington lie atop high mountain ranges.

When the last bit of the Mid-Atlantic spreading ridge is subducted beneath the Americas, the Atlantic Ocean will rapidly close and a new Pangea will form.

250 million years in the future, the Atlantic and Indian oceans have closed. North America has collided with Africa, but in a more southerly position than where it rifted. South America is wrapped around the southern tip of Africa, with Patagonia in contact with Indonesia, enclosing a remnant of the Indian Ocean (called the Indo-Atlantic Ocean). Antarctica is once again at the South Pole and the Pacific has grown wider, encircling half the Earth. Like the other major supercontinents, Pangea-Ultima will probably have a very large desert on its center, and extreme temperatures.

[edit] The Break Up

The break-up of Pangea-Ultima may occur more than 300 million years into the future, and it will probably create a new ocean, just like the Atlantic, but no one knows what the Earth will look like when Pangea-Ultima breaks. But maybe like the previous Pangaea, Pangaea Ultima will probably break up in middle of the continent, with the rifting outflow coming from the Pacific. The site of the rifting will possibly be the North America, South America, and southern Africa continent. The flow from the Pacific will probably go from these three continents to the Indo-Atlantic Ocean - the inland ocean in Pangaea Ultima (the remnant of the Atlantic and Indian Oceans). Then like the previous Pangaea, this flow will separate the continent in half, pushing Eurafrasia-Australia-Antarctica northwards, while the Americas southward (Patagonia will separate from Southeast Asia), creating a new ocean between these continents. But North and South America will be separated. The continuation of the separation of Africa from North America, and Australia/Antarctica separation from Asia, which will also open a new ocean between them. Nobody knows what these continents do when they continue to separate. More rifting will continue, and the fragmented pieces may collide with each other, creating a new supercontinent.

It is by no means certain that this configuration will actually occur. An alternative scenario, in which the Atlantic continues to grow and the Pacific is largely consumed by the collision between the Americas and Asia, is referred to as the Amasia supercontinent.

[edit] Appearances in Media

The National Geographic series Naked Science: Colliding Continents, mentions the formation of Pangaea Ultima.
In the Michael Swanwick novel Bones of the Earth, a version of this supercontinent - called Ultima Pangea - is depicted in the fictitious Telezoic Era roughly 500 million years into the future. It is the home of the Unchanging, a new dominant avian species.