When Will a Contenent Grow Again
Roughly i,000 kilometers east of Madagascar lies the minor tropical island of Mauritius. Seemingly adrift in the Indian Bounding main, it's home to the extinct Dodo, rolling fields of sugarcane and — according to new research — three tiny crystals that date back 2.5 to 3 billion years. Oddly, that's billions of years older than the isle itself, which scientists call back formed ix million years ago from lava spewed by undersea volcanoes.
What explains such a discovery? Lewis Ashwal at the Academy of the Witwatersrand in Johannesburg, Due south Africa, and his colleagues think the crystals once belonged to a drowned landmass and were dragged up to the surface during the formation of Mauritius. In other words: They came from an aboriginal continent hidden deep beneath the Indian Ocean.
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The continent, dubbed Mauritia, is probable as large as Japan and dates dorsum to the time of the dinosaurs. The world looked much different then: The continents were joined together in a single enormous landmass chosen Pangea. Over fourth dimension, the dinosaurs went extinct and that mighty supercontinent fractured, causing Mauritia to drown beneath the waves.
Merely the newly discovered continent is more than just collateral damage. It's a reminder that Earth's continents are always on the motion, continuously drifting together before breaking apart in a never-catastrophe cycle.
"This is actually the pulse of the Earth, if you will — the central rhythm," says Ross Mitchell of Curtin University in Perth, Australia, who was not involved in the study.
That rhythm will continue to bring the adjacent supercontinent into view hundreds of millions of years from now in a world that volition look almost alien to our own.
Pangea'due south Dramatic Pause Up
The world'south latest enormous landmass was first hypothesized when scientists noticed eerie similarities across vast stretches of the globe. Consider fossils of the lizard-like brute Lystrosaurus, which accept been found in South Africa, Republic of india, and Antarctica. Or the extinct seed fern Glossopteris, which once thrived in the polar circumvolve and the tropics. Or the Appalachian Mountains of the eastern United States and Scotland's Caledonian Mountains, which were so similar they seemed geologically related.
Such oddities made sense only if the continents were once nuzzled up next to each other as parts of Pangea. Look at an atlas and information technology might be tempting to slide the Americas eastward, hooking them into Africa like three puzzle pieces.
Scientists now know the c-shaped supercontinent consisted of two smaller continents that collided at the equator: Laurasia in the Northern Hemisphere, which encompassed North America, Greenland, Europe and much of Asia, and Gondwanaland in the Southern Hemisphere, which was equanimous of South America, Africa, Bharat, Australia and Antarctica.
Pangea conspicuously didn't final. During the Triassic period some 250 one thousand thousand years agone, earthquakes began to rock the spot where New Bailiwick of jersey nestled confronting Morocco. Volcanic eruptions spewed huge amounts of lava and gas. Equally a effect, the region literally began to pull itself apart.
"Equally it rifted, it stretched and thinned that piece of [continental] crust just like if you accept a scrap of toffee and pull the two sides of it," says Alan Collins at the University of Adelaide in South Australia, who was not involved in the report.
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Just as the toffee might droop, the continental crust formed valleys then deep that ocean water rushed in. The region connected to spread and the Atlantic Ocean was formed.
That ocean continues to grow today. Take a submarine from New Jersey toward Morocco now and halfway into your trip you'll hit this mid-ocean ridge — a jagged volcanic seam where magma oozes upward creating new seafloor. It's the same seam that originally rifted the two sites apart millions of years ago.
That rift was but ane of the many that broke Pangea apart. But these processes were anything only smooth. "When you rift continents apart, y'all air current up leaving pieces backside of various sizes," Ashwal says. The long-lost continent of Mauritia is one of those pieces. It was part of the nexus of Madagascar and Republic of india before the landmasses separated roughly 84 meg years ago.
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"It'southward not every mean solar day that someone discovers a new piece of continent," Ashwal says.
Geologists are thrilled at the detect equally information technology better helps them map Pangea.
"We're going to have a lot of fun testing the idea," says Mitchell, who admits he'due south already thinking near buying a plane ticket to Iceland — the merely place in the world where a mid-bounding main ridge bubbling up to the surface. If these ancient crystals really are from an sometime continent lost in Pangea's breakdown, information technology's likely that other ancient crystals can exist found at similar sites.
Building the World's Adjacent Supercontinent
Today, geologists know Pangea was but the most recent in a series of mighty supercontinents. Wind the clock dorsum farther and Rodina was the ruling supercontinent betwixt 750 million and 1.3 billion years ago. Go back further withal and all the continents had coalesced to form Nuna — the oldest known supercontinent. Although scientists are painting a picture of these long-lost worlds, the adjacent supercontinent is perhaps the near tantalizing.
At the moment, Australia is traveling north, suggesting that it volition one day sideswipe Asia and collide with Japan, Korea and eastern Prc. Meanwhile, Africa is rotating counterclockwise into Europe where it volition drive a Himalayan-scale mountain range skyward. Scientists remain unsure what will happen to the Americas, leaving two contentious theories for Pangea 2.0: Either the Atlantic will terminate growing and one twenty-four hours close again, or the Atlantic volition continue to aggrandize. Both create very different futures.
"Everyone admits that you can't just accept the nowadays-day plate motions and printing fast forward," Mitchell says. Plates have a tendency to alter grade unexpectedly. That can be seen in a kink in the Hawaiian-Emperor seamount chain — the by and large undersea mountain range that composes the Hawaiian Islands and shows the movement of the Pacific plate over the past several million years. The kink, which took identify some 47 million years ago, shows a shift in the plate that caused the islands to inexplicably veer Northwest.
All the same, it's fun to speculate. Collins thinks the Atlantic volition soon stop expanding and in accordion-like style start closing, its seafloor sucked downwards beneath the continents. This will transform the eastern Americas and Western Europe and Africa into worlds struck by earthquakes and eruptions from newly formed volcanoes. The eastern United States will no longer be known for the peaceful greenish slopes of Appalachians, just for snow-covered giants that occasionally spew lava and ash, more than akin to the Cascades.
"Information technology'southward not every day that someone discovers a new piece of continent."
Such a shift will crusade the aboriginal continents to reform. The get-go two crash sites will take identify when Newfoundland collides with Spain, and Brazil bumps into South Africa.
Another model, notwithstanding, suggests the Atlantic volition continue to aggrandize, causing the Americas to swing around as the Pacific closes and ultimately crash into Asia, forming a continent called Amasia. This model splits each supercontinent open and lets each fragment wing abroad from each other until they meet again on the other side of the globe.
In both of these theories, the side by side supercontinent forms at the equator. But Mitchell has a slightly different idea: Although he agrees that the Pacific will close, he thinks that Amasia will actually form at the top of the World before eventually slumping toward the equator. In such a scenario, S America swings up while rotating, Ecuador hits Florida, and the ii are nuzzled side past side as they slowly move northwestward toward Asia.
Ashwal remains skeptical. "You can't predict how the Earth is going to acquit in the futurity," he says. "If we could do that with cracking certainty, we would exist able to predict when an earthquake or volcanic eruption is going to occur."
That doesn't mean geologists can't join in on the fun.
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Source: https://www.nbcnews.com/storyline/the-big-questions/what-lies-ahead-earth-s-shifting-continents-just-might-surprise-n717276
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