Facts About Pangaea The breakup of the Pangaea supercontinent. Credit: U.S. Geological Survey About 300 million years ago, Earth didn't have seven continents, but instead one massive supercontinent called Pangaea, which was surrounded by a single ocean called Panthalassa. The explanation for Pangaea's formation ushered in the modern theory of plate tectonics , which posits that the Earth's outer shell is broken up into several plates that slide over Earth's rocky shell, the mantle. Over the course of the planet's 3.5 billion-year history, several super continents have formed and broken up, a result of churning and circulation in the Earth's mantle , which makes up most of planet's volume. This breakup and formation of supercontinents has dramatically altered the planet's history. "This is what's driven the entire evolution of the planet through time. This is the major backbeat of the planet," said Brendan Murphy, a geology professor at the St. Francis Xavier University, in Antigonish, Nova Scotia.

History More than a century ago, the scientist Alfred Wegener proposed the notion of an ancient supercontinent, which he named Pangaea (sometimes spelled Pangea), after putting together several lines of evidence. The first and most obvious was that the "continents fit together like a tongue and groove," something that was quite noticeable on any accurate map, Murphy said. Another telltale hint that Earth's continents were all one land mass comes from the geologic record. Coal deposits found in Pennsylvania have a similar composition to those spanning across Poland, Great Britain and Germany from the same time period. That indicates that North America and Europe must have once been a single landmass. And the orientation of magnetic minerals in geologic sediments reveals how Earth's magnetic poles migrated over geologic time, Murphy said. In the fossil record, identical plants, such as the extinct seed fern Glossopteris, are found on now widely disparate continents. And mountain chains that now lie on different continents, such as the Appalachians in the United States and the Atlas Mountains in Morocco, were all part of the Central Pangaea Mountains, formed through the collision of the supercontinents Gondwana and Laurussia.

Pangaea formed through a gradual process spanning a few hundred million years. Beginning about 480 million years ago, a continent called Laurentia, which includes parts of North America, merged with several other micro-continents to form Euramerica. Euramerica eventually collided with Gondwana, another supercontinent that included Africa, Australia, South America and the Indian subcontinent. About 200 million years ago, the supercontinent began to break up. Gondwana (what is now Africa, South America, Antarctica, India and Australia) first split from Laurasia (Eurasia and North America). Then about 150 million years ago, Gondwana broke up. India peeled off from Antarctica, and Africa and South America rifted, according to a 1970 article in the Journal of Geophysical Research . Around 60 million years ago, North America split off from Eurasia. Life and climate Having one massive landmass would have made for very different climactic cycles. For instance, the interior of the continent may have utterly dry, as it was locked behind massive mountain chains that blocked all moisture or rainfall, Murphy said.

But the coal deposits found in the United States and Europe reveal that parts of the ancient supercontinent near the equator must have been a lush, tropical rainforest, similar to the Amazonian jungle, Murphy said. (Coal forms when dead plants and animals sink into swampy water, where pressure and water transform the material into peat, then coal.) "The coal deposits are essentially telling us that there was plentiful life on land," Murphy told Live Science. Pangaea existed for 100 million years, and during that time period several animals flourished, including the Traversodontidae , a family of plant-eating animals that includes the ancestors of mammals. During the Permian period , insects such as beetles and dragonflies flourished. But the existence of Pangaea overlapped with the worst mass extinction in history, the Permian-Triassic (P-TR) extinction event. Also called the Great Dying, it occurred around 252 million years ago and caused most species on Earth to go extinct. The early Triassic period saw the rise of archosaurs, a group of animals that eventually gave rise to crocodiles and birds, and a plethora of reptiles.

And about 230 million years ago some of the earliest dinosaurs emerged on Pangaea, including theropods, largely carnivorous dinosaurs that mostly had air-filled bones and feathers similar to birds. Cycle in history The current configuration of continents is unlikely to be the last. Supercontinents have formed several times in Earth's history, only to be split off into new continents. Right now for instance, Australia is inching toward Asia, and the eastern portion of Africa is slowly peeling off from the rest of the continent. Geologists have noticed that there is a quasi-regular cycle in which supercontinents form and break up every 300 to 400 million years, but exactly why is a mystery, Murphy said. But most scientists believe that the supercontinent cycle is largely driven by circulation dynamics in the mantle, according to a 2010 article in the Journal of Geodynamics . Beyond that, the details get fuzzy. While the heat formed in the mantle likely comes from the radioactive decay of unstable elements, such as uranium, scientists don't agree on whether there are mini-pockets of heat flow within the mantle, or if the entire shell is one big heat conveyor belt, Murphy said.

Follow Tia Ghose on Twitter and Google+ . Follow LiveScience @livescience , Facebook & Google+ . Additional resources Continents in Collision: Pangea Ultima | Science Mission Directorate Science Mission Directorate Oct 5, 2000 Continents in Collision: Pangea Ultima Creeping more slowly than a human fingernail grows, Earth's massive continents are nonetheless on the move. (requires RealPlayer ) October 6, 2000 -- The Earth is going to be a very different place 250 million years from now. Africa is going to smash into Europe as Australia migrates north to merge with Asia. Meanwhile the Atlantic Ocean will probably widen for a spell before it reverses course and later disappears. Two hundred and fifty million years ago the landmasses of Earth were clustered into one supercontinent dubbed Pangea. As Yogi Berra might say, it looks like "deja vu all over again" as the present-day continents slowly converge during the next 250 million years to form another mega-continent: Pangea Ultima. Above: A map of the world as it might appear 250 million years from now.

Notice the clumping of most of the world's landmass into one super-continent, "Pangea Ultima," with an inland sea -- all that's left of the once-mighty Atlantic Ocean. Image courtesy of Dr. Christopher Scotese. The surface of the Earth is broken into large pieces that are slowly shifting -- a gradual process called " plate tectonics ." Using geological clues to puzzle out past migrations of the continents, Dr. Christopher Scotese, a geologist at the University of Texas at Arlington, has made an educated " guesstimate " of how the continents are going to move hundreds of millions of years into the future. "We don't really know the future, obviously," Scotese said. "All we can do is make predictions of how plate motions will continue, what new things might happen, and where it will all end up." Among those predictions: Africa is likely to continue its northern migration, pinching the Mediterranean closed and driving up a Himalayan-scale mountain range in southern Europe. What's it like to see two continents collide? Just look at the Mediterranean region today. Africa has been slowly colliding with Europe for millions of years, Scotese said.

"Italy, Greece and almost everything in the Mediterranean is part of (the African plate), and it has been colliding with Europe for the last 40 million years." That collision has pushed up the Alps and the Pyrenees mountains, and is responsible for earthquakes that occasionally strike Greece and Turkey, Scotese noted. Above: The possible appearance of the Earth 50 million years from now. Africa has collided with Europe, closing off the Mediterranean Sea. The Atlantic has widened, and Australia has migrated north. Image courtesy of Dr. Christopher Scotese. "The Mediterranean is the remnant of a much larger ocean that has closed over the last 100 million years, and it will continue to close," he said. "More and more of the plate is going to get crumpled and get pushed higher and higher up, like the Himalayas." Australia is also likely to merge with the Eurasian continent. "Australia is moving north, and is already colliding with the southern islands of Southeast Asia," he continued.

"If we project that motion, the left shoulder of Australia gets caught, and then Australia rotates and collides against Borneo and south China -- sort of like India collided 50 million years ago -- and gets added to Asia." Meanwhile, the Americas will be moving further away from Africa and Europe as the Atlantic Ocean steadily grows. The Atlantic sea floor is split from north to south by an underwater mountain ridge where new rock material flows up from Earth's interior. The two halves of the sea floor slowly spread apart as the ridge is filled with the new material, causing the Atlantic to widen. "It's about as fast as your fingernails grow. Maybe a little bit slower," Scotese said. Still, over millions of years that minute movement will drive the continents apart. Left: NASA's LAGEOS II satellite measures tiny shifts in continental positions from Earth orbit. [ more information ] That part of the prediction is fairly certain, because it is just the continuation of existing motions. Beyond about 50 million years into the future, prediction becomes more difficult. "The difficult part is the uncertainty in (new behaviors)," Scotese said.

"It's like if you're traveling on the highway, you can predict where you're going to be in an hour, but if there's an accident or you have to exit, you're going to change direction. And we have to try to understand what causes those changes. That's where we have to make some guesses about the far future -- 150 to 250 million years from now." In the case of the widening Atlantic, geologists think that a "subduction zone" will eventually form on either the east or west edges of the ocean. At a subduction zone, the ocean floor dives under the edge of a continent and down into the interior of the Earth. "The subduction zone turns out to be the most important part of the system if you want to understand what causes the plates to move," Scotese said. Like cold air drifting down from an open attic in winter, the cold, dense seabed at the ocean's edges sometimes starts sinking into the playdough-like layer beneath the crust, called the "mantle." Above: A diagram showing the major processes of plate tectonics. "As it sinks, it pulls the rest of the plate with it," like a tablecloth sliding off a table.

This accounts for most of the force that moves the plates around, Scotese said. This "slab pull" theory for the mechanism driving the motion of the plates stands in opposition to the older "river raft" theory. "For a long time, geologists had this model that there were 'conveyer belts' of mantle convection, and the continents were riding passively on these conveyer belts, sort of like a raft on a river," Scotese said. "But that theory's all wrong." Sign up for EXPRESS SCIENCE NEWS delivery If a subduction zone starts on one side of the Atlantic -- Scotese thinks it will be the west side -- it will start to slowly drag the sea floor into the mantle. If this happens, the ridge where the Atlantic sea floor spreads would eventually be pulled into the Earth. The widening would stop, and the Atlantic would begin to shrink. Tens of millions of years later, the Americas would come smashing into the merged Euro-African continent, pushing up a new ridge of Himalayan-like mountains along the boundary. At that point, most of the world's landmass would be joined into a super-continent called "Pangea Ultima." The collision might also trap an inland ocean, Scotese said.

"It's all pretty much fantasy to start with. But it's a fun exercise to think about what might happen," he said. "And you can only do it if you have a really clear idea of why things happen in the first place." For now it appears that in 250 million years, the Earth's continents will be merged again into one giant landmass...just as they were 250 million years before now. From Pangea, to present, to Pangea Ultima! Web Links PALEOMAP -- Web site for the project that produced the predictions of the future positions of Earth's continents. The site also has reconstructions of the past positions of the continents, as well as estimates of past climate. BBC - Earth - In 250 million years Earth might only have one continent Geology In 250 million years Earth might only have one continent Earth's continents are constantly in motion, and by running the tape forwards and backwards we can figure out where they were in the past – and where they might go in the future By Chris Baraniuk 1 August 2016 Science calls it "Pangaea Proxima". You might prefer to call it the Next Big Thing.

A supercontinent is on its way that incorporates all of Earth's major landmasses, meaning you could walk from Australia to Alaska, or Patagonia to Scandinavia. But it will be about 250 million years in the making. For Christopher Scotese at Northwestern University in Evanston, Illinois, the fact that our continents are not stationary is tantalising. How were they arranged in the past – and how will they be positioned in the future? "Fifty million years from now, Australia will be in collision with southeast Asia to a much larger degree," he says. Africa will also be pushing right up against southern Europe, while the Atlantic will be a far wider ocean than it is today. View image of This video is no longer available However, he admits that projections for the period beyond 50 million years in the future – which include his Pangaea Proxima prediction – are "very speculative". Earth's continents rest on a system of plates and these move at differing speeds. Some travel about 1.2in (30mm) per year while others might move at five times that rate. These are roughly the speeds at which human fingernails and hair grow, respectively.

These days, plate motion is tracked with satellite positioning instruments embedded into the ground . But we knew that plates moved long before such technology was invented. How? How did we ever realise that we were standing on huge, shifting plates, given that they move so slowly and are so massive? The idea that the continents moved around dates back centuries, but the first time anyone produced any serious evidence in favour of the idea was 100 years ago. That someone was German geophysicist Alfred Wegener. For many geologists, continental drift was a crackpot idea with little hard evidence He noticed remarkable similarities between the fossilised plants and animals found on continents that were separated by vast oceans. This suggested to him that those continents were connected when those now fossilised species were alive. What's more, when Wegener looked at his maps, he could clearly see that South America and Africa were like two giant puzzle pieces – they fit together. Could that really just be coincidence, or were they connected millions of years ago, only to drift apart? That was the essence of Wegener's theory: continental drift . But few people liked it. In fact, for many geologists, continental drift was a crackpot idea with little hard evidence. How exactly could massive continents move?

Wegener could not provide a satisfactory explanation. He died in 1930. But his idea lived on, and 20 years later, his vindication would begin. South America and Africa were like two giant puzzle pieces – they fit together The crucial secrets that would unlock the truth of his theory were not to be found on those moving continents. They were all hidden under the sea. Marie Tharp was one of the first people to realise that mountain ranges and huge valleys were not just features found on land, but under the oceans as well. In the early 1950s Tharp helped to map a gigantic submarine mountain range , thousands of kilometres long but only a few kilometres wide, zigzagging right down the middle of the Atlantic Ocean. Similar ranges lie beneath the waves of other oceans. They have since been named "mid-ocean ridges" – and their discovery helped turn the tide of thought on how the Earth's surface had formed. Harry Hess, an American geologist and submarine commander in World War Two, recognised the potential significance of the mid-ocean ridges. This sideways movement of rock...

could ultimately explain why the continents themselves moved During the war, Hess had used sonar to map some areas of the ocean floor in detail . He had found it to be far from the flat, featureless landscape most geologists had assumed it to be. The discovery of mid-ocean ridges fit with an idea he was developing – namely that the ocean floor is constantly, but very slowly, renewing itself. He suggested that hot magma welled up along the mid-ocean ridges and cooled into rock. Then, as more hot magma welled up at the ridge, the cool rock was pushed down the ridge flanks to make room. This sideways movement of rock, perpendicular to the mid-ocean ridges, could ultimately explain why the continents themselves moved. They were being pushed around by the upwelling of magma along the mid-ocean ridges. His theory became known as "seafloor spreading". But still, other geologists were sceptical. Other features under the sea were providing more clues, though, and gradually turning the tide of opinion in Hess's favour. It was, simply, the best evidence yet of a driving force that could shift continents Many rocks on Earth contain magnetic minerals.

Before these rocks solidified from magma, those minerals could spin around like tiny compass needles and align themselves with the Earth's magnetic field. Upon cooling, the "compass needles" became frozen in place. Canadian geologist Lawrence Morley and British geologists Frederick Vine and Drummond Matthews realised that this alignment process provided more evidence for seafloor spreading. Every so often the Earth's magnetic field flips: our compass needles would point towards Antarctica rather than the Arctic. That flipping process showed up in the rocks that make up the very fabric of the seabed. It was "striped", laid out in bars of normal and reverse polarity that lay parallel to the mid-ocean ridge. The best way to explain this was through seafloor spreading. The plates are like little bits of crust on top of the soup The magnetic minerals in hot lava at a mid-ocean ridge are aligned to the Earth's magnetic field, and then frozen when the lava cools. As rock is formed and then moves down the flanks and away from the ridge, it preserves a record of the changes in Earth's magnetic field over tens of thousands of years. The study of these records is called "palaeomagnetism".

The idea also explained why the stripes on each side of the ridge were generally exact mirror images of each other. Rock usually trundles away from both sides of the mid-ocean ridge at the same rate. It was, simply, the best evidence yet of a driving force that could shift continents. Geologists now accept that Hess – and Wegener before him – were right to envisage Earth's geography as constantly in motion. View image of The boundary between two continental plates (Credit: Photo Researchers Inc/Alamy) "It's like a big soup cauldron," says Susan Hough , a seismologist at the US Geological Survey in California. "The plates are like little bits of crust on top of the soup." The plates are in a kind of eternal war, fighting for position on the face of the Earth There are two layers in the Earth's crust and upper mantle that are described by this metaphor. The lithosphere – the hard, cooler part of the crust, including the plates themselves – and the asthenosphere, where molten rock moves up towards the lithosphere and sometimes breaks through at the mid-ocean ridges. The ground under your feet is not as rock-solid as you might have thought .

All of this convection and mechanical activity drives the motion of plates. They can bump into each other, slide past or shift away from each other. Some plates can even become buried, or "subducted", under neighbouring plates, "recycling" their rock back to the Earth's interior. The plates are in a kind of eternal war, fighting for position on the face of the Earth. We know that the plates have moved, but how can we actually plot their positions back through time? Scotese has produced animations showing what we believe to be the movements of the continents over the last 750 million years . "It's sort of like a CSI investigation," he says. "You have to use all the evidence you can to tell the story because there's no eyewitnesses, there's no video cameras taking pictures." Fossils of Mesosaurus are found, not just in South America, but Africa as well Despite the challenge, Scotese says we can get 70 million years into the past with a good degree of confidence. That's because we can track the progress made by seafloor spreading quite accurately to work out where the continents used to be. But there are also different types of geological records that let us see even further back.

Scotese gives the example of ancient fossil coral reefs. Between 300 and 400 million years ago, what is now North Africa was crossing from polar to tropical latitudes. "If you look carefully, you can see exactly when it crossed that boundary from being in the cold half of the hemisphere to the warm half," explains Scotese. "So coral reefs appear for the first time [in this region] and begin to grow on these carbonate platforms." Indeed, the fossil record is a hugely significant area of evidence. This, of course, was what initially gave Wegener confidence in his ideas. When Mesosaurus was alive, it was possible to walk between almost any two points on any two continents Take the example of Mesosaurus , a creature not dissimilar from today's crocodiles. It was a freshwater reptile with a long, powerful jaw, which lived between 270 and 300 million years. Here is the weird part. Fossils of Mesosaurus are found, not just in South America, but Africa as well. It was a freshwater animal and could never have swum across the Atlantic Ocean to develop colonies on both continents.

How did its fossils end up on either side of that vast ocean, then? The answer is simple: 300 million years ago, there was no Atlantic. Those two continents were joined, and Mesosaurus never had to swim that distance. In fact, when Mesosaurus was alive it was possible to walk between almost any two points on any two continents. All the landmasses were united in the supercontinent Pangaea – which is something Scotese expects to happen again about 250 million years from now when his "Pangaea Proxima" supercontinent forms. The existence of the ancient Pangaea is recorded in the distribution of other fossils. Lystrosaurus, for example, was a giant herbivore. Its fossil remains are now found in Africa, India and even Antarctica . Beyond 300 million years ago, the ancient magnetic record becomes much more patchy Even the plant Glossopteris, a woody shrub that grew to 98ft (30m) in height, helps to confirm the idea that at one stage all of today's continents were jammed together as Pangaea.

Fossil evidence of Glossopteris has been discovered in South America, Africa, India, Antarctica and Australia. Importantly, the seeds of the plant were massive and could not have floated or been blown on the wind to other land masses . A supercontinent, on which the seeds could be dispersed via land, is thought to be the only credible explanation. However, all these forms of evidence have their limitations. Beyond 300 million years ago, the ancient magnetic record becomes much more patchy, so it is difficult to find hard evidence of continental movements. And at 500 million years, says Scotese, the fossil record also becomes less detailed. As for predicting what will happen in the future, Scotese does this first of all by looking at how the plates are moving today and then extrapolating that movement over time. This is the simplest way to develop a prediction. But, he adds, after many millions of years, there is no telling what geological events might cause unforeseen changes to that movement.

Plate tectonics give us valleys and huge mountain ranges, earthquakes and continental boundaries "In the plate tectonic world, plates do evolve slow and steady until we have one of these plate tectonic catastrophes like continental collisions," he says. "This fundamentally changes plate tectonic regimes." Various statistical models help to provide a range of options for how the continents will be arranged more than 100 million years from now. But that is so far in the future, it is not clear to anyone how accurate these are. Still, it is fun to speculate, and it helps reinforce the reality that the Earth is an active, dynamic planet – the very face of which keeps changing. Plate tectonics give us valleys and huge mountain ranges, earthquakes and continental boundaries. And there are still mysteries about how they work. Plus, our knowledge of plate tectonics on other planets is incredibly limited. Indeed, we have only recently found some evidence that suggests tectonics on Mars and Jupiter's moon, Europa . The continents really did move – and they have not stopped yet "You get into some interesting questions," says Hough.

"Like, is it a coincidence that we live on a tectonically-active planet, or was that somehow important for the emergence of life?" For now we can only wonder. But plate tectonics have undoubtedly been significant for the development and dispersal of life on Earth. The secrets of the shifting ground beneath our feet have largely been revealed – and mostly within the last 50 years. For a long time we thought there was little more stationary and stable than the Earth beneath us. But now we know that Wegener, in principle, was right. The continents really did move – and they have not stopped yet. Join over five million BBC Earth fans by liking us on Facebook , or follow us on Twitter and Instagram . If you liked this story, sign up for the weekly bbc.com features newsletter called "If You Only Read 6 Things This Week". A handpicked selection of stories from BBC Future, Earth, Culture, Capital, Travel and Autos, delivered to your inbox every Friday.

Paleozoic Era: Facts & Information Paleozoic Era: Facts & Information By Stephanie Pappas, Live Science Contributor | June 19, 2013 09:34pm ET MORE Credit: Alena Hovorkova The Paleozoic Era, which ran from about 542 million years ago to 251 million years ago, was a time of great change on Earth. The era began with the breakup of one supercontinent and the formation of another. Plants became widespread. And the first vertebrate animals colonized land. Life in the Paleozoic The Paleozoic began with the Cambrian Period , 53 million years best known for ushering in an explosion of life on Earth. This "Cambrian explosion" included the evolution of arthropods (ancestors of today's insects and crustaceans) and chordates (animals with rudimentary spinal cords). In the Paleozoic Era, life flourished in the seas. After the Cambrian Period came the 45-million-year Ordovician Period, which is marked in the fossil record by an abundance of marine invertebrates.

Perhaps the most famous of these invertebrates was the trilobite , an armored arthropod that scuttled around the seafloor for about 270 million years before going extinct. After the Ordovician Period came the Silurian Period (443 million years ago to 416 million years ago), which saw the spread of jawless fish throughout the seas. Mollusks and corals also thrived in the oceans, but the big news was what was happening on land: the first undisputed evidence of terrestrial life. This was the time when plants evolved, though they most likely did not yet have leaves or the vascular tissue that allows modern plants to siphon up water and nutrients. Those developments would appear in the Devonian Period, the next geological period of the Paleozoic. Ferns appeared, as did the first trees. At the same time, the first vertebrates were colonizing the land.

These vertebrates were called tetrapods , and they were widely diverse: Their appearance ranged from lizardlike to snakelike, and their size ranged from 4 inches (10 cm) long to 16 feet (5 meters) long, according to a study released in 2009 in the Journal of Anatomy. As the tetrapods took over, they had company: The Devonian Period saw the rise of the first land-living arthropods, including the earliest ancestors of spiders . The skeleton of Eryops, one of the earliest land-walking tetrapods. Credit: © Christine M. Janis Paleozoic evolution Life continued its march in the late Paleozoic. The Carboniferous Period, which lasted from about 359 million years ago to 299 million years ago, answered the question, "Which came first — the chicken or the egg?" definitively. Long before birds evolved, tetrapods began laying eggs on land for the first time during this period, allowing them to break away from an amphibious lifestyle. Trilobites were fading as fish became more diverse. The ancestors of conifers appeared, and dragonflies ruled the skies.

Tetrapods were becoming more specialized, and two new groups of animals evolved. The first were marine reptiles, including lizards and snakes. The second were the archosaurs, which would give rise to crocodiles, dinosaurs and birds. Most creepily, this era is sometimes referred to as the "Age of the Cockroaches," because roaches' ancient ancestor ( Archimylacris eggintoni ) was found all across the globe during the Carboniferous. The last period of the Paleozoic was the Permian Period, which began 299 million years ago and wrapped up 251 million years ago. This period would end with the largest mass extinction ever: the Permian extinction. Before the Permian mass extinction, though, the warm seas teemed with life. Coral reefs flourished, providing shelter for fish and shelled creatures, such as nautiloids and ammonoids. Modern conifers and ginkgo trees evolved on land. Terrestrial vertebrates evolved to become herbivores, taking advantage of the new plant life that had colonized the land. Paleozoic geology and climate All this evolution took place against the backdrop of shifting continents and a changing climate.

During the Cambrian Period of the Paleozoic, the continents underwent a change. They had been joined as one supercontinent, Rodinia, but during the Cambrian Period, Rodinia fragmented into Gondwana (consisting of what would eventually become the modern continents of the Southern Hemisphere) and smaller continents made up of bits and pieces of the land that would eventually make up today's northern continents. The Cambrian was warm worldwide, but would be followed by an ice age in the Ordovician, which caused glaciers to form, sending sea levels downward. Gondwana moved further south during the Ordovician, while the smaller continents started to move closer together. In the Silurian Period, the land masses that would become North America, central and northern Europe, and western Europe moved even closer together. Sea levels rose again, creating shallow inland seas. In the Devonian, the northern land masses continued merging, and they finally joined together into the supercontinent Euramerica. Gondwana still existed, but the rest of the planet was ocean. By the last period of the Paleozoic, the Permian, Euramerica and Gondwana became one, forming perhaps the most famous supercontinent of them all: Pangaea .

The giant ocean surrounding Pangaea was called Panthalassa. Pangaea's interior was likely very dry, because its massive size prevented water-bearing rain clouds from penetrating far beyond the coasts. Author Bio Stephanie Pappas, Live Science Contributor Stephanie Pappas is a contributing writer for Live Science. She covers the world of human and animal behavior, as well as paleontology and other science topics. Stephanie has a Bachelor of Arts in psychology from the University of South Carolina and a graduate certificate in science communication from the University of California, Santa Cruz. She has ducked under a glacier in Switzerland and poked hot lava with a stick in Hawaii. Stephanie hails from East Tennessee, the global center for salamander diversity. Follow Stephanie on Google+ . Stephanie Pappas, Live Science Contributor on Latest on Paleozoic Era: Facts & Information PlateTectonicsStudent.ppt - Supercontinent! PlateTectonicsStudent.ppt View Full Document Supercontinent! ■ ~250 million years ago all the continents were joined together to form one “supercontinent” called Pangea.

■ roughly “C” shaped landmass that spread across the equator ■ body of water that was believed to have been enclosed within the resulting crescent has been named the Tethys Sea ■ the inland regions appear to have been very dry, due to the lack of rain or snowfall ■ potentially have allowed terrestrial animals to migrate freely all the way from the South Pole to the North Pole! This preview has intentionally blurred sections. Sign up to view the full version. Make your own Pangea…. . ■ The modern day continents have been cut out for you in the ziplock bag. ■ India has been separated from continental Asia ■ Try matching up the coastlines and fitting the continents together to form the supercontinent Pangea How did your reconstruction compare? Did you have trouble fitting all of the continents together? Why? This preview has intentionally blurred sections. Sign up to view the full version. View Full Document Please put all continent pieces back in bag ☺ Other evidence besides continents fitting together… ■ same and similar fossil species are found on continents that were once joined together ■ evidence for the same rock sequences found on both South America and Africa This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Matching mountain ranges Figure 2.6 Paleoclimatic evidence Figure 2.7 glacier deposits found at the modern day equator landmasses and coral reef deposits found in Antarctica This preview has intentionally blurred sections. Sign up to view the full version. BBC Earth - Supercontinents join nearly all the Earth's dry land Over 200 million years ago, the continents were joined together. Dr Iain Stewart explains how the Earth's moving tectonic plates resulted in a supercontinent called Pangaea. Supercontinents In geology, a supercontinent is the assembly of most or all of Earth's continental blocks or cratons to form a single large landmass. However, the definition of a supercontinent can be ambiguous. Many earth scientists, such as P.F. Hoffman (1999), use the term "supercontinent" to mean "a clustering of nearly all continents". This definition leaves room for interpretation when labeling a continental body and is easier to apply to Precambrian times.

Using the first definition provided here, Gondwana (aka Gondwanaland) is not considered a supercontinent, because the landmasses of Baltica, Laurentia and Siberia also existed at the same time but physically separate from each other. The landmass of Pangaea is the collective name describing all of these continental masses when they were in proximity to one another. This would classify Pangaea as a supercontinent. According to the definition by Rogers and Santosh (2004), a supercontinent does not exist today. Supercontinents have assembled and dispersed multiple times in the geologic past (see table). The positions of continents have been accurately determined back to the early Jurassic. However, beyond 200 Ma, continental positions are much less certain. Apocalypse Then | Science Mission Directorate Science Mission Directorate Feb 22, 2001 Apocalypse Then They say lightning never strikes twice. Well, how about asteroids? A violent collision with a space rock, like the one that doomed the dinosaurs, may have also caused our planet's greatest mass extinction 250 million years ago.

(requires RealPlayer ) February 23, 2001 -- New findings provide evidence that Earth's most severe mass extinction -- an event 250 million years ago that wiped out 90 percent of the life on Earth -- was triggered by a collision with a comet or asteroid. Over 90 percent of all marine species and 70 percent of land vertebrates perished as a result, according to the NASA-funded research team, led by Dr. Luann Becker of the University of Washington (UW), Seattle. The team's findings will be published in today's issue of the journal Science. The collision wasn't directly responsible for the extinction, but rather triggered a series of events, such as massive volcanism and changes in ocean oxygen, sea level and climate. That in turn led to extinctions on a wholesale level, according to the team. Sign up for EXPRESS SCIENCE NEWS delivery Above: This artist's rendition shows how an asteroid collision might appear at the moment of impact, although the space rock in this image is considerably larger than the one Becker's team believes hit 250 million years ago. "If the species cannot adjust, they perish. It's a survival-of-the-fittest sort of thing," said Becker.

"To knock out 90 percent of organisms, you've got to attack them on more than one front." Scientists don't know the site of the impact 250 million years ago, when all Earth's land formed a supercontinent called Pangea. However, the space body left a calling card -- complex carbon molecules called buckminsterfullerenes, or Buckyballs, with the noble gases helium and argon trapped inside the caged structure. Fullerenes, which contain at least 60 carbon atoms and have a structure resembling a soccer ball or a geodesic dome, are named for Buckminster Fuller, inventor of the geodesic dome. The researchers know these particular Buckyballs are extraterrestrial because the noble gases trapped inside have an unusual ratio of isotopes, atoms whose nuclei have the same number of protons but different numbers of neutrons. Terrestrial helium is mostly helium-4 (two neutrons and two protons), while extraterrestrial helium is enriched with helium-3 (one neutron and two protons). "These things form in carbon stars. That's what's exciting about finding fullerenes as a tracer," Becker said.

The extreme temperatures and gas pressures in carbon stars are perhaps the only way extraterrestrial noble gases could be forced inside a fullerene, she explained. Above: The most common Buckyball (C60) has a shape consisting of hexagons and pentagons arranged in the same pattern found on most soccer balls. Researchers found unusual isotopes of helium trapped in this "cage" that indicate they came from outer space. These gas-laden fullerenes were formed outside the Solar System, and their concentration in the sedimentary layer at the boundary of the Permian and Triassic periods means they were delivered by comets or asteroids. The researchers estimate the comet or asteroid was roughly 6 to 12 kilometers across, or about the same size as the asteroid believed responsible for wiping out the dinosaurs 65 million years ago. The telltale fullerenes containing helium and argon were extracted from sites where the Permian-Triassic boundary layer had been exposed in Japan, China and Hungary. The evidence was not as strong from the Hungary site, but the China and Japan samples bear strong evidence, Becker said. The team's work was made more difficult because there are few 250 million-year-old rocks left on Earth.

Most rocks that old have been recycled through the planet's tectonic processes. "It took us two years to do this research, to try to narrow it down enough so that we could see this fullerene signature," Becker said. Above: This new evidence incriminates cosmic collisions in a second major mass extinction. Scientists believe another collision wiped out the dinosaurs 65 million years ago -- the crater from this collision can still be seen from space near the Yucatan Peninsula in Mexico. Scientists have long known of the mass extinction 250 million years ago, since many fossils below the boundary -- such as trilobites, which once numbered more than 15,000 species -- diminish sharply close to the boundary and are not found above it. There also is strong evidence suggesting the extinction happened very rapidly, on the order of 8,000 to 100,000 years, which the latest research supports. Previously, scientists thought that any asteroid or comet collision would leave strong evidence of the element iridium, the signal found in the sedimentary layer from the time of the dinosaur extinction.

Iridium was found at the Permian-Triassic boundary, but not nearly in the concentration as from the dinosaur extinction. Becker believes that difference is because the two space bodies that slammed into Earth had different compositions. Members of the research team are Becker; Robert Poreda and Andrew Hunt from the University of Rochester, NY; Ted Bunch of the NASA's Ames Research Center, Moffett Field, CA; and Michael Rampino of New York University and NASA's Goddard Institute of Space Sciences, New York. Funding for the research was provided by NASA's Astrobiology and Cosmochemistry programs and the National Science Foundation. Web Links Near-Earth Asteroid Tracking -- Web site for the NASA Jet Propulsion Laboratory project that keeps an eye on asteroids that pass close to the Earth Potentially Hazardous Asteroids -- information on the 289 asteroids considered to pose a threat to Earth A Close Encounter with a Space Rock -- Science@NASA article: Today a half-km asteroid is passing by the Earth 12 times farther from our planet than the Moon. Scientists say it's an unusually good opportunity to study a near-Earth object. Trick or Treat: It's Toutatis!

-- Science@NASA article: NASA scientists are monitoring a large near-Earth asteroid that tumbled past our planet on Halloween 2000. Join our growing list of subscribers - sign up for our express news delivery and you will receive a mail message every time we post a new story!!! Next supercontinent will be called Amasia, and will be centered around the North Pole Next supercontinent will be called Amasia, and will be centered around the North Pole 0 Mihai Andrei Based on how the tectonic plates are moving now, no later than one hundred million years, Asia and the Americas will merge into one huge supercontinent, named Amasia. Geophysicists have long theoretized this, but a team of researchers from Yale University offered a new view on how Amasia will be formed. Continental drift Continental drift was proposed by Alfred Wegener in 1912, and it was proven right soon afterwards. Basically, it states that the Earth’s continents are in a state of relative motion, a theory which was improved in the 60s with the tectonic plates theory. Basically, the whole crust on our planet can be split into ten major tectonic plates which moves as the seafloor spreads.

As almost always with geology, in order to understand something taking place now, we have to take a look into our planet’s past. The Earth’s first supercontinent, Rodinia, was formed 1.1 billion years ago and lasted until 750 million years ago, and was surrounded by a huge planetary ocean called Mirovia. However, tectonic plates didn’t stop moving, so the continent split and reformed again and 250 million years ago, Pangaea, the next supercontinent was formed, surrounded by an ocean called Panthalassa. However, this didn’t last forever either, and continents started to rescramble into pretty much what we see today. Next stop: Amasia Advertisement A great part of the information we have about these supercontinents comes from geopaleomagnetic measurements (‘geo‘ means ‘earth’, ‘paleo‘ means ‘old’). When certain minerals are formed, they ‘lock’ in a record of the intensity and direction of the magnetic field when they formed. This record can be analyzed hundreds of millions later and still hold highly accurate indications about the tectonic plates they were formed in.

Yale University geology and geophysics professor David Evans, along with graduate students Taylor Kilian and Ross N. Mitchell, studied the magnetism in some ancient rocks to figure out when they were positioned when they formed and how they moved as the years passed. “The Americas will remain in the Pacific ‘ring of fire’ girdle of post-Pangaean subduction, closing the Arctic Ocean and Caribbean Sea,” the Yale geophysicists wrote in a Nature journal article published today. In other words, they think Amasia will form over the Arctic, 90 degrees away from the original Pangea. To geologists, this geophysical idea sounds perfect, as previous supercontinents appear to have formed successively at 90 degrees to each other. After all, Asia and the Americas are already tied together by economic and social issues – and 100 million years from now, they will be literally tied. Like us on Facebook Feb 14, 2012 at 11:37 am 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.

A new theory explains this (see and click on ‘The Gravity Theory of Mass Extinction’). 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. Leave a Reply Earth's future supercontinent Earth's future supercontinent Based on the way continents are currently drifting, this map shows what Earth will look like in 250 million years. One giant supercontinent. Advertisement Two hundred and fifty million years ago, nearly all land mass above sea level was squashed together into one giant supercontinent, called Pangea. During this time, invertebrate life gave way to small vertebrates on the land and sea, to amphibians, to reptiles, and eventually large land and sea animals.

Then the mega-continent began breaking apart, isolating that life to the point where one continent could successfully grow koala bears and thus justify the entire painful and tedious process of evolution. But continents can't stay apart for long. It seems that supercontinents have been forming and re-forming throughout the four billion year history of the earth. Right now, the continents are scattered and isolated, but they're on a collision course, and will smush together to form another supercontinent, Pangea Ultima within the next 250 million years. Advertisement India has already smashed into Asia, creating the Himalayas, and Africa is jetting up towards Europe. North and South America will unite and then head over towards Afreurasia. Lastly, the most remote of continents, Antarctica, will slide off the south pole and press up against Australia. The result will be the Americas, Eurasia, and Africa forming a ring around a large, landlocked sea, with Antarctica and Australia separated from them by just a small strip of water. What will that set the stage for?

Question: 250 million years ago, the Earth had one supercontinent. What was it called?
Answer: Pangaea