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Current time:0:00Total duration:5:58

Video transcript

we know that new plate material is being formed and these these these lithospheric plates on the surface of the earth are moving around and that might raise the question in your brain what happens if we kind of reverse things we know we know the direction they're moving in what does that tell us about where they came from so let's just do the thought experiment right now South America and Africa are moving away from each other because of new because of a new plate material being created at the mid-atlantic rift let's rewind it let's bring them back together let's bring them back together we know that India is jamming into the Eurasian Plate right now causing the Himalayas to get higher and higher what if we rewind that let's bring India back down towards Antarctica same thing with Australia we have new we have new plate plate material being formed between Australia and Antarctica that's making the continents move apart let's bring them back together let's rewind let's rewind the clock even North America it's not as obvious from this diagram but if you actually look at the GPS data it becomes pretty obvious that North America right now is kind of moving in a in a counterclockwise rotation so let's rewind it let's rewind it into a let's go back moving it in a clockwise direction let's instead of Eurasia going further away from North America let's bring it back together and so what you can imagine is is a reality where India Australia are jammed down into South America into sorry into Antarctica South America and Africa are jammed together North America is jammed in there and essentially Eurasia is also jammed in so it looks like they're all kind of would clump together if you go back a few hundred million years and based on literally based on just that thought experiment you could imagine at one point the entire all of the continents on the world were kind of merged into one supercontinent and that supercontinent is called Pangaea Pangaea pan for entire whole and Jia for coming from gaya for the world and it turns out that all of the evidence we've seen actually does make us believe that there was a supercontinent call it what we call it Pangaea now obviously there probably weren't things on the planet calling it anything back then well there are things back then but nothing that not things that would actually go and try to label continents that we know of but all of the evidence tells us that Pangaea existed about 200 to 300 million years ago roughly 2 to maybe 250 million give or take years ago and I want to be clear this was not the first this was not the first supercontinent to a large degree is kind of the first the most recent supercontinent that it's easiest for us to construct because it was the most recent one but we believe that there were other super continents before this that if you go if you rewind even more that your kite you would have to kind of break up Pangaea and it would reform but now going back in time or that there were several super continents in the past that broke up reform broke up reformed in the last time that we had a super continent was Pangaea about 250 million years ago and now it's broken up into our current day into our current day geography now I won't go into all of the detail why we believe that there was a Pangaea about 250 million years ago or this diagram tells us about 225 million years ago give or take but I'll go into some of the interesting evidence on a very high level you have a lot of rock commonalities between things that would have had to combine during Pangaea and probably the most interesting thing is the fossil evidence is the fossil evidence there's a whole bunch of fossils and here are examples of it from from species that were round between 200 and 300 million years ago and they're fossils are found in very specific place this animal right here sign OGG mythos I hope I'm pronouncing that right sign Syntagma 'this that this this animals fossils are only found in this area of South America a nice clean band here and this part of Africa so not only does South America look like it fits very nicely kind of into Africa but the fossil evidence also makes it look like there was a nice clean band where this animal lived and where we find the fossil so it make it really makes it seem like these were connected at least when this animal lived maybe on the order of 250 million years ago this species right over here it's fossils are found in this area let me do in a color that has more contrast in this area right over here this plant it's fossils now this starts to connect a lot of dots between a lot of content it's fossils are found in this entire area across South South America Africa Antarctica India and Australia and so not only not only does it look like the continents kind of fit together in a puzzle piece not only do we get it to a configuration like this if we essentially just rewind the movement that we're seeing now but the fossil evidence also kind of confirms that they fit together in this way this this animal right here it'll we find fossils on this nice stripe that goes from Africa through India all the way to Antarctica now this this only gives us evidence of kind of the more the the southern hemisphere of Pangaea but there is other evidence we find we find kind of continuing mountain chains between North America and Europe we find a rock evidence we're you know just the way we see the fossils kind of line up nicely we see common rock that lines up nicely between South America and Africa and other continents that were at once connected so all of the evidence as far as we can tell now does make us think that there at one time was a Pangaea and for all we know all the all the continents are going to keep moving and maybe and it's you know in a few hundred million years we'll we'll have another supercontinent who knows