Pangaea Ultima

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Pangaea Ultima (also Neopangaea) 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.^[1]

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.^[2]

Contents 1 Formation 2 The Breakup and the Future 3 Appearances in culture 4 See also 5 References 6 External links

[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 will collide to Eurasia, such as India, and in the future, Africa, and Australia, just as they did when most continents collided to Laurentia.

Fifty million years into future looks slightly strange. North America will rotate slightly counterclockwise (Alaska would then be near the subtropical latitudes) and Eurasia would rotate 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 will encircle Australia and extend westward across the Central Indian Ocean. Meanwhile, Baja California will have 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 will have widened, even though the Puerto Rican Trench and Scotia Arc (on the eastern edges of Caribbean plate and Scotia plate, respectively) 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 will stop widening and begin to shrink because a bit of the Atlantic Ocean mid-ridge will have been subducted. A mid-ocean ridge between South America and Africa will probably be subducted first.

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

At 250 million years in the future, the Atlantic and Indian oceans will have closed. North America will have already collided with Africa, but be in a more southerly position than where it rifted. South America will be 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 will be once again at the South Pole and the Pacific will have grown wider, encircling half the Earth.

[edit] The Breakup and the Future

The breakup 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. The Pangea Ultima will probably break into two or more continents like its predecessors. More rifting will continue, and the fragmented pieces may collide with each other, creating a new supercontinent. The supercontinent cycle will continue well into the future until the Sun expands into a red giant phase, which will possibly consume the Earth and the other inner planets, thereby ending the cycle once and for all, more than 5 billion years from now. Even if the Earth escapes the red giant phase, billions of years from now, its core and the mantle will probably cool, stopping the cycle and turning the Earth into a cold world orbiting what's left of the dead Sun, a shining, white dwarf.

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 culture

• 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.
• In the TV series The Future Is Wild, it shows that the Earth's continents will all reunite into a supercontinent in 200 million years.
• Chris Roberson's novel Paragaea is set on a world whose one continent is a version of Pangea Ultima.

[edit] See also

• Pangaea
• Amasia

[edit] References

[edit] External links

• A map of Pangaea Ultima according to Professor Scotese