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What caused Pangaea to break apart?

There’s another way to look at this question. People tend to think in terms of supercontinents forming and then breaking up again due to convection currents in the mantle, hot material rising and causing rifts in weaker spots, possibly in old sutures where the continents were shoved together — but what is really happening is that ocean basins are opening and closing, and the ocean has an active role in subduction.

The opening and closing of an ocean basin is called a Wilson Cycle. It begins when hot material rising from the mantle stretches the overlying crust. As molten material rises, a rift is formed. The rift is widened as material continues to squeeze into it. If that rifting goes on long enough, through a broad enough swath of a continent, ocean water will eventually flow into it, and an ocean basin begins to form. The upwelling of hot material will continue to rise through that thinner area of crust, pushing the plates apart. The Atlantic Ocean is an example of a basin that is well along in the Wilson Cycle; eventually subduction is going to begin at its margins, and the whole shebang will pivot.

This will happen because at the edge of continents, sediments accumulate. The weight of those sediments, combined with the weight of the water, drives the heavier, denser edge of the oceanic plate under the continental crust, which is fatter and lighter. Eventually subduction begins, and the basin begins to close again. The Pacific Ocean is an example of a basin that’s closing.

If you look at a map of the oceanic rift zones, you’ll notice that the one in the Atlantic is pretty much in the middle of that ocean, but the Pacific rift zone has been pulled all the way over to North America above Central America. Subduction is actively occurring on all margins of that plate.

The simple picture is that the continents are moving toward each other across the Pacific Ocean while the Atlantic Basin continues to widen. The truth is more complicated. When plates subduct, the water in the crust lowers the melting point of those rocks, so partial melting occurs. The partially melted material begins to rise through the overlying rocks, because it’s less dense, and decompression melting occurs. Eventually, the upwelling of hot material forms plutons and volcanoes above the subduction zones. Fore-arc and Back-arc basins can form. As the oceanic crust is pulled under the continental plate, island chains and other chunky bits get sutured to the edge of the continent along with sediments, making it larger. Our world is ~4.6 billion years old, so our continents are really large, now. They’re unlikely to rift through the ancient cratons that formed their hearts.

What will happen if subduction begins on the Eastern side of North America before the Pacific Basin closes? The margin next to California is a transform fault; it’s not subducting. Will it eventually push itself under that part of North America again, or will the transform zone get bigger? The hot spot that was driving the ancient Farallon Plate under North America was eventually overridden by the southwestern states (Arizona, New Mexico, etc.) forming a rift zone. Will it continue to rift or poop out?

There are computer models predicting what supercontinent may form next. They will continue to change as our understanding of tectonic processes gets more accurate.


This information was taken from Quora. Click here to view the original post.

Have you ever heard about Pangaea before? Do you agree with the theory stated?

#Geography #Science #History #Nature #Quora

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What are your thoughts on this subject?
29 Comments
Linda Stegall
Interesting article but I thought it was supposed to be about Pangaea.
0
Sep 3, 2021 4:13PM
Darlene Davidson
I was expecting to read about Pangaea.
1
Jun 7, 2021 8:40PM
Dave Street
Didn’t mention anything about Pangaea or how it split into Gondwanaland and Laurasia.
2
Jul 8, 2020 3:12AM
Allison Aspden
Thankyou for this information.
0
May 4, 2020 10:04PM
mmariano
Highly informative and interesting material.I enjoyed reading it, immensely. Thank you so much.
0
Mar 29, 2020 7:33PM
Sean Philips
Captain Bob III, I stayed in Beverley Hills last year and then toured California - it was beautiful !
0
Feb 26, 2020 1:32AM
Linda Spreng
Kathryn Cavanagh, Try using the 'Report' button. There is where you can describe the problems you are encountering.
0
Dec 16, 2019 2:24AM
Olivia Jasso
Enjoyed article!
0
Dec 7, 2019 4:22PM
potzbuff
Definitely makes you think about earthquakes
0
Oct 28, 2019 4:52PM
June Henwood
Thank you for this post.
0
Oct 13, 2019 6:22AM
Kathryn Cavanagh
Why is it that I can never see any of the pictures on this line of stories..??? All I ever get, if I'm lucky, is the words..!!
0
Sep 30, 2019 5:47PM
Don Racette
Criona Walsh Nothing will ever split us dogs apart!
1
Aug 1, 2019 4:59PM
tracewallace
Marvy Peterson Payne, Gotta love the baby!!🤣🤣 Cute show
0
Jul 7, 2019 5:30AM
Ilias Tsiabardas
One think I know it took billions of years to do all that process ,I won't be here to see what is going to happen anyway, but it's good to know. Thank you
1
Jul 5, 2019 5:19PM
ninakamwene
Informative and interesting read. Thank you.
1
Jun 15, 2019 12:20AM

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