Amasia: As next supercontinent forms, Arctic Ocean, Caribbean will vanish first

Feb 08, 2012 By Eric Gershon
Yale scientists theorize that the present-day Arctic Ocean and Caribbean Sea will vanish as North and South America fuse during a mutual northward migration that leads to a collision with Europe and Asia.

(PhysOrg.com) -- Geologists at Yale University have proposed a new theory to describe the formation of supercontinents, the epic process by which Earth’s major continental blocks combine into a single vast landmass. The new model radically challenges the dominant theories of how supercontinents might take shape.

In a paper published Feb. 9 in the , Yale researchers introduce a process called orthoversion, in which each succeeding supercontinent forms 90 degrees from the geographic center of its ancient predecessor. Under the theory, the present-day Arctic Ocean and Caribbean Sea will vanish as North and South America fuse during a mutual northward migration that leads to a collision with Europe and Asia.

“After those water bodies close, we’re on our way to the next supercontinent,” said Ross N. Mitchell, the Yale doctoral student who is the paper’s first author. “You’d have the Americas meeting Eurasia practically at the North Pole.”

This video is not supported by your browser at this time.
From the supplementary information of the paper authored by Ross N. Mitchell, Taylor M. Kilian & David A. D. Evans, "Supercontinent cycles and the calculation of absolute palaeolongitude in deep time," Nature 482: 208--211 (09 February 2012). http://dx.doi.org/10.1038/nature10800

The researchers do not speculate in the paper when the next supercontinent, named Amasia for its union of America with Eurasia, will emerge, but the event is far distant — between 50 million and 200 million years away, Mitchell said.

The new theory contrasts with the standard theories about supercontinent formation, introversion and extroversion, which hold that supercontinents form either 0 or 180 degrees away from the geographic center of the previous supercontinent. Under these earlier theories, the Atlantic Ocean will disappear and the next supercontinent will form with a center more or less in the same spot as the last supercontinent’s center (present-day Africa), or, alternately, the Pacific Ocean will disappear and the next supercontinent will form with a center on the opposite side of the globe.

Mitchell and colleagues arrived at the new theory after an extensive analysis of the magnetism of ancient rocks. After each historical supercontinent assembled, it underwent a series of back-and-forth rotations around a stable axis along the equator. From one supercontinent to the next, the axes were offset from each other by about 90 degrees, the Yale team showed — consistent with orthoversion, but not with either introversion or extroversion.

“This kind of analysis gives us a way to arrange continents in both latitude and longitude, providing a better understanding in patterns of biological dispersal and the dynamics of Earth's deep interior,” said Yale doctoral student Taylor M. Kilian, the study’s second author.

The most recent supercontinent, Pangea, formed about 300 million years ago with Africa at its center. It began breaking apart into the seven continents of today with the birth of the Atlantic Ocean about 100 million years later. Researchers believe Pangea is the third or fourth supercontinent in ’s history. Its immediate predecessors were Rodinia (which formed about 1 billion years ago) and Nuna (which formed about 1.8 billion years ago). The paper’s senior author, Professor David A.D. Evans of Yale, has devoted most of his career to studying the internal arrangements of the Earth’s continental blocks.

Under the orthoversion model, either Asia or North America would become the center of Amasia, in a spot currently occupied by the . A newly formed mountain range will stitch them together.

“Such speculations far into the future cannot be tested by waiting around 100 million years, of course,” Evans said, “but we can use the patterns gleaned from ancient supercontinents to think deeply about humanity’s current existence in time and space within the grand tectonic dance of the Earth.”

Explore further: NASA balloons begin flying in Antarctica for 2014 campaign

More information: Supercontinent cycles and the calculation of absolute palaeolongitude in deep time, Nature 482, 208–211 (09 February 2012) doi:10.1038/nature10800

Abstract
Traditional models of the supercontinent cycle predict that the next supercontinent—‘Amasia’—will form either where Pangaea rifted (the ‘introversion’1 model) or on the opposite side of the world (the ‘extroversion’2, 3, 4 models). Here, by contrast, we develop an ‘orthoversion’5 model whereby a succeeding supercontinent forms 90° away, within the great circle of subduction encircling its relict predecessor. A supercontinent aggregates over a mantle downwelling but then influences global-scale mantle convection to create an upwelling under the landmass6. We calculate the minimum moment of inertia about which oscillatory true polar wander occurs owing to the prolate shape of the non-hydrostatic Earth5, 7. By fitting great circles to each supercontinent’s true polar wander legacy, we determine that the arc distances between successive supercontinent centres (the axes of the respective minimum moments of inertia) are 88° for Nuna to Rodinia and 87° for Rodinia to Pangaea—as predicted by the orthoversion model. Supercontinent centres can be located back into Precambrian time, providing fixed points for the calculation of absolute palaeolongitude over billion-year timescales. Palaeogeographic reconstructions additionally constrained in palaeolongitude will provide increasingly accurate estimates of ancient plate motions and palaeobiogeographic affinities.

Related Stories

Bias in the rock record?

Jan 14, 2009

(PhysOrg.com) -- The fossil record is known to be biased by the unevenness of geographical and stratigraphical sampling, and the lack of exposed rocks containing fossils. In a recent Perspective in Science [2 Jan ...

Paleomagnetists put controversy to rest

Oct 02, 2009

(PhysOrg.com) -- Princeton University scientists have shown that, in ancient times, the Earth's magnetic field was structured like the two-pole model of today, suggesting that the methods geoscientists use ...

And the microbes shall inherit the Earth

Oct 13, 2011

(PhysOrg.com) -- Global warming is not a novel phenomenon, and by studying what happened to the planet during a period of global warming about 250 million years ago, one USC Dornsife scientist hopes to discover ...

Plate tectonics may take a break

Jan 03, 2008

Plate tectonics, the geologic process responsible for creating the Earth’s continents, mountain ranges, and ocean basins, may be an on-again, off-again affair. Scientists have assumed that the shifting of crustal plates ...

Recommended for you

Scientists make strides in tsunami warning since 2004

Dec 19, 2014

The 2004 tsunami led to greater global cooperation and improved techniques for detecting waves that could reach faraway shores, even though scientists still cannot predict when an earthquake will strike.

Trade winds ventilate the tropical oceans

Dec 19, 2014

Long-term observations indicate that the oxygen minimum zones in the tropical oceans have expanded in recent decades. The reason is still unknown. Now scientists at the GEOMAR Helmholtz Centre for Ocean Research ...

User comments : 13

Adjust slider to filter visible comments by rank

Display comments: newest first

Shelgeyr
1.2 / 5 (16) Feb 08, 2012
Won't happen, ever.

The oceans and continents are largely balanced in antipodal relationships. Given that continental roots are FAR deeper than originally understood when the concept of them acting like floating rafts was developed, it is unlikely in the extreme that they'll ever form any sort of supercontinent configuration.

Sure they move, a tiny bit, which is why it is best not to build bridges over faults if you can get away without doing so (or seriously factor them into your engineering).

The direction(s) of Continental motion seem to be influenced (possibly highly) by events dated since the supposed spread. For example, North America seems to be rotating counter-clockwise with Chicxulub at the apparent axis. If verified as true, then cataclysmic events might just have more to say about continental motion than the assumed stately progression from "there" to "here" and beyond.

Of course it is always dangerous to generalize from a single example, but there's more examples.
Ronan
5 / 5 (1) Feb 08, 2012
Goodness, I hope this doesn't happen. Supercontinents over the poles are bad news, climatologically speaking, and Earth's life really doesn't need another Snowball Earth period, not after it's come so far and flourished so beautifully. At least the sun will be warmer by then, so the effect won't be as severe as it would otherwise be.
Megapixel
1.1 / 5 (12) Feb 09, 2012
If the configuration and location of Amasia as described comes to pass then the gigantism of life forms that occurred in the Paleozoic and Mesozoic Eras will happen again. The Gravity Theory of Mass Extinction explains this (see www.dinoextinct.com).

Briefly, when the center of mass of the Earth's continental tectonic plates becomes asymmetrical with respect to the equator, the Earth's core elements (inner, outer cores and densest part of lower mantle) must move away from their Earth-centric position based on the Conservation of Angular Momentum Law. When that happens, the distance from a point on the Earth's surface and the new center of mass of the Earth changes, hence a change in surface gravitation.
Au-Pu
Feb 09, 2012
This comment has been removed by a moderator.
Sherrin
3.8 / 5 (4) Feb 09, 2012
Shelgeyr - your understanding of continetal drift compares with the flat Earth theory!

And how typically American (i.e USA) to presume they should name the next supercontinet Amasia - to be honest, the ego-centricity of this naming orogeny simply doesn't Amazeme.
Shelgeyr
1 / 5 (9) Feb 09, 2012
@Sherrin said:
Shelgeyr - your understanding of continetal(sic) drift compares with the flat Earth theory!


Sherrin, you are quite mistaken. I understand the theory quite well, thank you, and also many of the disputes regarding numerous different competing "flavors" of the theory, including how modern (and ongoing) data collection is causing problems with older assumptions (as well it should, what with the scientific advancement of knowledge and all).

Many of the assumptions that the original continental drift theory was based upon have proven to be untrue. This does NOT mean that at the highest level "continental drift" isn't occuring, - oh no - but it means that the originally assumed enabling mechanisms are not true, and that therefore there are many other factors at play here than originally understood.

The latter part of the whole "started as a group over there, broke up, will become a group over here" progression is looking unlikely. It isn't that simple.
barakn
3.3 / 5 (3) Feb 09, 2012
Megapixel - submit a detailed 3D model of the Earth cut up into volume elements, with each volume element containing data on the material(s) contained (chemical name, crystal structure if it has more than one possible structure), temperature, and density (and also of course the 3D coordinates of the volume element and the size of the volume). Make sure your model exhibits a significantly different gravitational field at the surface than the model Earth. We, since we're so awesome, will then analyze your model and make sure that it is gravitationally stable, i.e. there are no volume elements under such great stress that the element will deform plastically or catastrophically. We'll also determine if the surface of this planet is capable of hosting more than bacteria. Since you've already developed this theory and since such a theory would require a 3D model, you must have already developed this model, and I'm expecting to see it shortly. If it looks good, we'll submit a paper.
rubberman
1.7 / 5 (6) Feb 09, 2012
That's why it's called show and tell....not just tell MP. Weve been at this before and the link you posted didn't work then either. Something about the earths gravity doubling or tripling because of a disruption in the earth's angular momentum....several people pointed out why it simply isn't possible.

Pertaining to the article, the knowledge of continental drift as far as speed and direction are very important to providing a seismic measuring stick and helping with earthquake a tsunami prediction. The location and configuration of the next supercontinent is a nice peice of trivial knowledge at best. By the time it happens, we won't be here.
Megapixel
1 / 5 (6) Feb 09, 2012
@barakn, rubberman,

If you read the pdf within www.dinoextinct.com and have any specific questions, I will be glad to answer them.
barakn
3.3 / 5 (3) Feb 10, 2012
Indeed, there are questions. Why does the word "The" appear twice in succession in the title on your main page? I see you have a rudimentary model outlined on http://www.dinoex...ore.jpg. You suggest the gravity ratio at the surface would go as (r/R)^2 where R-r is the core displacement with suggested value 1000 km and r is the pre-displacement radius. r = 6371, so (R/r)^2 = .75. However, there are already several severe problems with this, including the assumption (which you admit to) that all the mass of the entire planet is concentrated at the core. Even if we consider both the inner and outer core, they comprise only 33% of the Earth's mass, so the ratio increases to .92. Furthermore, your math rests on the presumption that when the core displaced, the space it formerly occupied is now empty vacuum. In actuality some of the mantle would have to flow in and fill this void, and it would have its own gravity.
barakn
3 / 5 (2) Feb 10, 2012
Since the core is roughly 2.5x denser than mantle, we might expect this last factor to increase the ratio to .95. However, we had to pull this mantle from somewhere else and already counted its gravity (weaker, because on average it was further away), so this reduces our ratio somewhat depending on the geometry of the situation. To avoid an ugly calculation, we'll just put the ratio at .93. So you had to displace the core by 1000 km, a completely implausible scenario to begin with, to reduce gravity by 7%, though your estimate was 3x bigger because of some bone-headed assumptions you made to make some trivial math even easier. Intellectual laziness isn't pretty.
Megapixel
1 / 5 (5) Feb 10, 2012
barakn,
I will ask you one final time to address your questions to the PDF specified.
Your statement about the inner and outer cores comprising ~ 33% of the mass of the Earth is correct. If you read the PDF, it states that the inner, outer core and the densest part of the lower mantle are offset. This comprises about 85% of the mass of the Earth, not 33%. If you want to use the term "bone-headed" about my assumptions, I will not respond to your questions.
Torbjorn_Larsson_OM
1 / 5 (1) Feb 23, 2012
That is eminently consistent with the published continuity theory of plate growth, which explains the apparent growth discontinuities as sampling problems during supercontinent formation. [Unfortunately I can't find the ref right now.]

Funny how this is a crackpot subject. From the comments:

"it is unlikely in the extreme that they'll ever form any sort of supercontinent configuration"

Well, there is independent confirmation from sediments and fossils.

"The Gravity Theory of Mass Extinction"

Enough said. It doesn't touch the known causes of a few of the large mass extinctions (say, the K-Pg).
Megapixel
1 / 5 (5) Feb 24, 2012
Torbjorn Larsson,
The GTME is able to explain all mass extinctions. Please reread the PDF summary of the theory.

Specifically, the K-T (also called K-Pg) extinctions occurred because the surface gravity on the continental remnants of Pangea increased rapidly. This was the result of Earth's core elements moving toward Earth-centricity. As explained in the theory this would cause a rapid, major drop in sea level(which did occur)as well as a major volcanic flood basalt eruption (which did occur at the Deccan Traps).

The extinctions were caused primarily by the pulse of increased gravitation. The theory also explains the coincidence of the asteroid impact.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.