Palisades Cliffs, New Jersey
Posted on 10/09/2018 2:26:16 PM PDT by ETL
"...roughly 251 million years ago — Earth's continents abutted one another, merging to form the supercontinent Pangea. That land mass, which straddled the equator like an ancient Pac-Man, eventually split into Gondwana in the south and Laurasia in the north.
From there, Gondwana and Laurasia separated into the seven continents that we know today. But the constant movement of Earth's tectonic plates raises a question: Will there ever be another supercontinent like Pangea?
The answer is yes.
Pangea wasn't the first supercontinent to form during Earth's 4.5-billion-year geologic history, and it won't be the last.
"That's the one part of the debate that there isn't much debate over," Ross Mitchell, a geologist at Curtin University in Perth, Australia, told Live Science.
"But what 'the next Pangea' will look like … that's where opinions diverge."
Geologists agree that there is a well-established, fairly regular cycle of supercontinent formation. It's happened three times in the past. The first one was Nuna (also called Columbia), which existed from about 1.8 billion to 1.3 billion years ago. Next came Rodinia, which dominated the planet between 1.2 billion and 750 million years ago. So, there's no reason to think that another supercontinent won't form in the future, Mitchell said.
The convergence and spreading of continents are tied to movements of tectonic plates. The Earth's crust is divided into nine major plates that glide over the mantle, the liquid layer that sits between the core and the semi-solid crust. In a process called convection, hotter material rises from near the Earth's core toward the surface, while colder mantle rock sinks. The rising and falling of mantle material either spreads plates apart, or forces them together by pushing one under another.
(Excerpt) Read more at livescience.com ...
Palisades Cliffs, New Jersey
Positions of the continents is one of the things that affect climate. The other being changes in the Earth’s orbit.
“Reunite Gondwanaland!”. I had that bumper sticker on my truck years ago (geology school). Every so often somebody would say something like “Oh - is that that civil war in Africa?”
Also had the “Earth First!” (we’ll mine the rest of the planets later) sticker.
I like their bread................
The Permian extinction made room for the dinosaurs.
The Cretaceous extinction made room for mammals.
Will they bring back the Continental Football League if that happens?
I really liked Pangea’s early albums. I hope it reunites sooner than 200 million years from now.
Perfect!
It was formed by the accretion of several cratons. Eventually, Gondwana became the largest piece of continental crust of the Paleozoic Era, covering an area of about 100,000,000 km2 (39,000,000 sq mi).[3]
During the Carboniferous, it merged with Euramerica to form a larger supercontinent called Pangaea.
Gondwana (and Pangaea) gradually broke up during the Mesozoic Era [Triassic Period].
The remnants of Gondwana make up about two-thirds of today’s continental area, including South America, Africa, Antarctica, Australia, and the Indian Subcontinent.
The formation of Gondwana began c. 800 to 650 Ma with the East African Orogeny – the collision of India and Madagascar with East Africa – and was completed c. 600 to 530 Ma with the overlapping Brasiliano and Kuunga orogenies – the collision of South America with Africa and the addition of Australia and Antarctica, respectively.[4]
I do miss Pangea.
Well, we all have to move on. Can't dwell on the past.
The ancient supercontinent of Gondwana, once part of the supercontinent Pangaea that constituted all of Earth's landmass, underwent a 60-degree rotation during a period of biological explosion on Earth, called the Cambrian explosion, a new study suggests.
Gondwana made up the southern half of Pangaea, which eventually broke up into smaller supercontinents that further divided into the continents that span Earth's surface today.
The Cambrian explosion was a major diversification of life on Earth that happened relatively quickly, over just a few million years, about 530 million years ago.
A team of Yale University geologists studied the paleomagnetic record of the Amadeus Basin in central Australia, which was part of the Gondwana precursor supercontinent.
Based on the directions of the ancient rock's magnetization, they discovered that the entire Gondwana landmass underwent a rapid 60-degree rotational shift, with some regions attaining a speed of at least 6.3 inches/year (16 centimeters/year), about 525 million years ago. By comparison, the fastest shifts we see today are at speeds of about 1.6 in/year (4 cm/year).
This was the first large-scale rotation that Gondwana underwent after forming, said Ross Mitchell, a Yale graduate student and author of the study detailing the findings in the August issue of the journal Geology.
The shift could either be the result of plate tectonics (the individual motion of continental plates with respect to one another) or "true polar wander," in which the Earth's solid land mass (down to the liquid outer core almost 1,800 miles, or 3,000 kilometers, deep) rotates together with respect to the planet's rotational axis, changing the location of the geographic poles, Mitchell said.
The debate about the role of true polar wander versus plate tectonics in defining the motions of Earth's continents has been going on in the scientific community for decades, as more and more evidence is gathered, Mitchell said.
In this case, Mitchell and his team suggest that the rates of Gondwana's motion exceed those of "normal" plate tectonics as derived from the record of the past few hundred million years.
"If true polar wander caused the shift, that makes sense. If the shift was due to plate tectonics, we'd have to come up with some pretty novel explanations," Mitchell said.
Whatever the cause, the massive shift had some major consequences. As a result of the rotation, the area that is now Brazil would have rapidly moved from close to the southern pole toward the tropics. Such large movements of landmass would have affected environmental factors such as carbon concentrations and ocean levels, Mitchell said.
"There were dramatic environmental changes taking place during the Early Cambrian, right at the same time as Gondwana was undergoing this massive shift," Mitchell said. "Apart from our understanding of plate tectonics and true polar wander, this could have had huge implications for the Cambrian explosion of animal life at that time."
You're right, of course. But sometimes it isn't easy.
Will we ever again have a supercontinent to call our own?
.
The entire physical universe will only be here for another 1000 years or so.
Then bang poof.
It’s all because of Plate Teutonics: my theory that the Germans are moving the continents around.
None of the processes moves very fast at all in terms of the lifetimes of living things. To most living things the processes are crawling slower than a snail and nearly imperceptible even across generations.
The “great shifts” will not even be noticed to most all living things while they are alive. The changes will slowly define what a “new normal” is to each new generation, and not as something radical not even from many previous generations.
By the time California is nearing Hawaii, observers of the day will have always seen them as close.
Only someone with a “time machine” would actually observe any radical change.
And Life? Life writ large will keep adapting, as it always has, in spite of beneficiaries and losers from earth changes.
Way down
Below the ocean
Is where I wanna be
She may be.
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