Skip to comments.Meet 'Amasia,' the Next Supercontinent
Posted on 02/09/2012 9:45:24 AM PST by LibWhacker
No boats required. In the distant future, most if not all of today's continents (brown fragments, depicted with current-day outlines) will assemble into a single landmass called Amasia (shown approximately 100 million years from now).
Over the next few hundred million years, the Arctic Ocean and the Caribbean Sea will disappear, and Asia will crash into the Americas forming a supercontinent that will stretch across much of the Northern Hemisphere. That's the conclusion of a new analysis of the movements of these giant landmasses.
Unlike in today's world, where a variety of tectonic plates move across Earth's surface carrying the bits of crust that we recognize as continents, ancient Earth was home to supercontinents, which combined most if not all major landmasses into one. Previous studies suggest that supercontinents last about 100 million years or so before they break apart, setting the pieces adrift to start another cycle.
The geological record reveals that in the past 2 billion years or so, there have been three supercontinents, says Ross Mitchell, a geophysicist at Yale University. The oldest known supercontinent, Nuna, came together about 1.8 billion years ago. The next, Rodinia, existed about 1 billion years ago, and the most recent, Pangaea, came together about 300 million years ago. In the lengthy intervals between supercontinents, continent-sized-and-smaller landmasses drifted individually via plate tectonics, as they do today.
Scientists can track the comings and goings of those landmasses by analyzing the iron-bearing magnetic minerals in various types of rock deposits. That's because the iron atoms, and sometimes even tiny magnetized bits of iron-bearing rock, line up with Earth's magnetic field when they're free to rotate, as they are when the material that contains them is molten. Once the rocks have solidifiedand if they aren't heated above the temperature at which their magnetic information is wiped cleancareful analyses can reveal where on Earth those rocks were when they first cooled, even if the rocks are hundreds of millions of years old. In particular, the rocks retain a record of their paleolatitude, or how far they were from Earth's magnetic pole.
Although supercontinents before Nuna may have existed, rocks more than 2 billion years old that still preserve evidence of ancient magnetic fields are scarce, Mitchell says. And although scientists have generally agreed that Nuna, Rodinia, and Pangaea existed, exactly where on Earth each came together has been a matter of strong debate. Some geophysical models have suggested that drifting landmasses have come together in the same spot on Earth's surface each cycle. Other teams have proposed that the wandering pieces reassembled on the opposite side of the planet, 180° away from where the previous supercontinent broke apart.
Now, Mitchell and his colleagues suggest an intermediate answerthat each supercontinent has come together about 90° away from its predecessor. The team's analyses, reported online today in Nature, use techniques that determine the paleolatitude of ancient landmasses but also, for the first time, estimate their paleolongitude by taking into account how the locations of Earth's magnetic poles changed through time. Together, these data suggest that the geographic center of Rodinia was located about 88° away from the center of Nuna, and the center of Pangaeawhich was located near present-day Africasat about 87° from Rodinia's center.
These angles are no accident, the researchers suggest: The drifting pieces of crust eventually come together along the former edge of the fractured supercontinentan area approximately 90° away from the former supercontinent's center. That's where relatively dense ocean crust was being shoved beneath the lighter continental crust, causing a downward flow in the underlying mantle that in turn attracted the drifting bits like water running down a drain.
According to this model, the next supercontinenta sprawling landmass dubbed Amasia, which in its earliest stages will merge Asia with the Americaswill stretch across much of the Northern Hemisphere, the researchers suggest. Over the next few hundred million years, Mitchell says, the motions of tectonic plates will cause the Arctic Ocean and the Caribbean Sea to disappear, the western edge of South America to crowd up against the eastern seaboard, and Australia to slam into southeastern Asia. It's unclear whether Antarctica will join the party or be stranded at the South Pole.
"This is a beautiful piece of work," says Joseph Kirschvink, a geophysicist at California Institute of Technology in Pasadena. Most of the high-quality paleomagnetic data available today has been collected in the past 20 years or so, he notes. "And the more data we have, the more we can recognize the patterns of where chunks of Earth's crust must have been."
The team's ideas about how and where supercontinents form are "reasonable but far from proven," says Bernhard Steinberger, a geodynamicist at the German Research Centre for Geosciences in Potsdam. Although Mitchell and his colleagues have identified statistical trends in their paleomagnetic analyses, he notes, "the data still just look like clouds of points to me."
The team's results "are very impressive," says Brendan Murphy, a geologist at St. Francis Xavier University in Antigonish, Canada. Because the breakup and assembly of supercontinents is arguably one of the most important cycles in Earth's biological and geological evolution, the findings will undoubtedly stimulate further research and analyses, he notes. "And even if the new model is wrong," he adds, "we'll learn a lot by testing it."
It always amazes me how they discovered the names of those things.
We have plenty of time to come up with a new name. “Amasia” sucks.
OMG we need to do something about this right now. Call AlGore and DiCaprio. We need to have a summit so we can convince that Asia’s booming birthrate is causing this continental shift. Call Michael Mann and get a samurai sword graph up as quickly as we can on saveourcontinents.com. There is not one single second to waste! With every newborn cry we hear the continents squeeze just a little bit more. We need to solve this by March of 2012 or we are doomed. Doomed do you hear me?
Old maps, realy old maps.
“You’re gonna need a bigger fence...”
Weren’t those the ships Columbus came over here on?
Asia is going to crash into North America? We’d better start working on that airbag right now.
What about those crabs in the Bering sea? Somebody save the crabs!!!!.....and then bring them over with melted butter.
All that is happening is Laurasia breaking apart at the North Europe/East coast America interface, and Laurentia rolling around the North Pole to reconnect at a Siberia/NorthWest Territories interface.
Looks like the game of “Risk” will have to be completely overhauled.
It’s amazing how the earth recycles itself, reshaping itself slowly over long stretches of time.. and think of all the new places to cruise to when this latest one shakes out..
India just breaks off and becomes an island? Where’s that russian airplane guy from India? You’ll have the world’s biggest aircraft carrier! You can have 300 million people sit on the edge and kick their feet in the water to propel it.
“Damnit! The shark got Chaitan! Maybe we can replace him with an Evinrude.”
How ‘exact’ can this science of determining the location by ‘ancient’ magnetic residuals in rock be when we know that the magnetic poles move, all the time, unpredictably, and may have even ‘flipped’, maybe more than once or twice, or a hundred times during it’s existence in the solar system?
It seems, from text in the article, that scientists believe that all continents are floating islands, free to wander the globe. That all mountain ranges are the product of crashes between ‘continents’ as if they were bumper cars at Disneyland.
Now... if they can explain how the continents or islands, which sit on tectonic plates, can move when the tectonic plates themselves all butt up to one another, and interlock better than the pieces of a puzzle, then I am all ears.
The fact that they get contradictions and wildly different opinions from their own ‘tests’, tells me that they must not have the right ‘methodology’, or that I am very unclear about their ‘concept’.
A concept of a ‘growing’ Earth would make more sense as an explanation of tectonic plate ‘movement’. The existence or non-existence of land masses is mostly due to up and down movement in the crust and the subsequent redistribution of the ‘water’.
To paraphrase Robert DeNiro, from the movie "Meet the Parents," -- "Oh, I'll look forward to that, Greg!"
I'll be too old to care by then!
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