Let's talk about the theory of continental drift. yeet
Why don't we look at a world map?
Have you ever seen one of these? Well of course you've seen one of these.
Everyone has seen a map of the world in fact you probably first saw a map of the world when you were in
kindergarten and what you may have noticed similar to so many people before you is that if you look carefully at the
Continents the giant land masses covering about 29 percent of the earth if you look at them carefully they almost look like
puzzle pieces like they fit together
Especially if you look at certain parts of the world
Like the eastern coast of South America and the west coast of Africa for example. They look like they belong together now
I hate to break your hearts, but this is not a groundbreaking discovery in fact people have known this for hundreds of years
Most people have just taken it for granted that that's just the way the continents look
But there have been a few brave scientists throughout history who have thought that it must be something more
Let me introduce you to one this is Alfred Wegener Alfred Wegener was a German meteorologist. He studied weather
he lived in the late 1800s and early 1900s and as a weather person a scientist of the
Atmosphere of course Vagner spent a lot of time looking in maps and so he noticed this strange shape
Phenomenon just like you did
The problem is he couldn't get past it. He actually devoted his whole life to it
He came up with a radical theory that suggested that the continents were actually once connected and then somehow
Ripped apart to where they are today
He came out and he said I think the continents are moving of
Course people thought this was kind of a silly thought to have how could a continent possibly move?
But Vagner really thought that this was the case and so he devoted his whole career to studying this and coming up with proof of
this radical idea in
Fact Vagner didn't just think the continents were moving he actually believed that there was a time when they were all connected and they have
Since drifted apart to their current look patience
He even came up with a name for that
supercontinent that existed in the past he called it Pangaea the supercontinent that he believed existed about
250 million years ago
Pangaea or Pangaea is actually an appropriate name
It's a greek term that means entire earth or all earth
So if you think about it when all the continents were together if vector is correct
It would make sense to call that landmass pan, Gaia or Pangaea
Here's what he thought it looked like you can see within this diagram the modern-day continents of North America Africa
South America Antarctica India etc
But they don't look quite the same way. They do today and of course
They're in totally different positions all connected into this one supercontinent
Now people thought Vagner was a little bit nutty and
so he knew that if he was going to make any headway with this idea he had to come up with evidence and
So we're gonna take a look at four pieces of evidence that Victor put together
To prove to the public that the continents had in fact drifted
Let's take a look at his first piece of evidence. We'll go back to this map here now the first piece of evidence
We've actually already discussed
It's simply the observation that the continents appear to fit together as
Simple as that Vegh nur didn't believe that this could be simply a coincidence
He feels like there's no possible way the continents would have this appearance
Just randomly and so this becomes evidence number one
we will call it the
Apparent fit of the continents the fact that they look like they fit together and just to expand on that a little bit
Essentially the coastlines of the continents appear to fit together kind of like the pieces of a puzzle
But that's not enough so vecna went back to the drawing board
He dug through piles of books and libraries and became quite interested in fossils and other evidence of prehistoric
life in
Fact Beckner came particularly interested in that guy who just swam across the screen the Meza soros now
Let me tell you about the meso source. This is an ancient reptile that lived only in shallow freshwater
What's interesting though is that there's only two places in the world where we find fossils of this freshwater creature?
One place is the eastern coast of South America and the other is the western coast of Africa
Now there's a couple possible solutions for this now either
the Meza source was living on one of these continents and somehow learned how to fly across the Atlantic Ocean to
Inhabit the other side of the other continent
But that's not likely
the Meza source certainly could not fly and we know the Meza source couldn't have swam across the distance is just too great and
They can't survive in salt water, so that's out of the question
Maybe the water was frozen and he walked across well
That's a possibility, but there's really no evidence to support that and so what vector said is that while the Meza source roamed the land?
Africa and South America were connected
and they were able to freely walk across the land masses and then after going extinct the land masses were torn apart and
Separated carrying some of the fossils to what would become South America and some to what would become Africa
interestingly
Vagner looked into this and found that there were other organisms that lived in the past that had similar fossil distributions
Sign onethis life stress or sandglass a terrace being amongst the more
Notable ones these fossils all have these very unique
distribution patterns that suggest that the continents were once together and
In fact if you in reassemble the continents and map out the locations of these fossils, they line up perfectly so
That's our evidence number two we call it fossil correlation correlation
Simply means matching up so matching up fossils on either side of the ocean
to summarize identical fossils have been found in the rocks on either side of the ocean and
Therefore the continents were once connected and must have drift drifted apart
but Vagner knew he needed a stronger case and so he went back to the library yet again and became fascinated by rocks and
Geologic structures like mountain ranges of the past and he found a really interesting pattern not unlike what he found with foul
In fact if we go back to our world map here and let's zoom in on the North Atlantic
Here if you look at the mountain ranges in the northeastern United States and the mountain ranges in Northern Europe
They match up perfectly and what I mean is that they are made of the same type of rock and the same age of rock
now of course anything is possible and the same exact rocks could have formed in two different locations at the same time but
geologically that's
unlikely a better explanation is that these mountains were once connected and as the continents move they tore them into two and
That becomes evidence number three
We call it rock or mountain correlation and what we see is that?
identical rocks and mountain structures have been found on either side of the ocean
Suggesting that the continents were once connected
But we need one more, and this is probably the most complex of them all
Again, Vecna returned to the librarian this time he returned to his roots as a meteorologist
And he began to look at past climate data meaning
He looked at evidence of cold and warm weather in different parts of the world and he found something fascinated
See he first looked into glaciers
So glaciers are these giant?
Rivers of ice that move slowly across the Earth's surface and of course glaciers have to be found in cold parts of the earth
Today they're restricted to only the highest mountaintops and of course the North and South Poles of the earth
Something interesting about glaciers is that they move and when they move over the rock beneath?
They leave evidence in the form of scratches that we call glacial striations, which you see here
Now how does this relate to climate to a continental drift?
Well if we look at our map if you look in the present day tropical
rainforests of South America and Africa you will find glacial striations here in
These two regions you find these scratches in the bedrock now if you think about that how could there be glaciers in a tropical rainforest?
Unless it wasn't always a tropical rainforest
This suggests that these continents were not always in there war
Equatorial regions like they are now
They were once down near the South Pole. Where could have been cold enough to have glaciers, and they have since drifted apart
But Vagner wanted more from this climate data, and so he began to explore a little deeper, and that's when he came across this rock
This is a sedimentary rock called bituminous coal we know it because we burn it for energy. It's a fossil fuel
What we know about bituminous coal if you were to look in in earth science reference?
Tables you would see that bituminous coal is made from
compacted plant remains
So picture tropical plants like this dying on this forest floor and getting compressed over millions of years
to form coal
Now let's look at where coal is found on earth
Anywhere you see this little icon. We have found coal deposits now. Let's think about this coal forms from tropical plants yet
It's found in Antarctica in northern Europe in northern Asia
And the southern tip of Africa and Australia and in the northern United States
These are not tropical climates yet
They have coal
Which is evidence of a past tropical climate and so this just like the glaciers?
Suggest that the continents have moved over time and that becomes evidence number four
Paleo climate data or past climate data
the observation that coal has been found in cold areas and that glacial evidence has been found in warm areas and
with these four pieces of evidence vague nner
Published his book the origin of continents and oceans in which he laid out his case for continental drift
suggesting that all the continents were once connected in a supercontinent called Pangea, which existed about
250 million years ago and since the continent has ripped apart into the present-day land masses that we know so well
Later in his life Vagner took an expedition to the North Pole and in this expedition
He want to gather more evidence to support his theory of continental drift
Unfortunately on a very cold dark stormy day
feckner set out on an expedition to gather food for his colleagues and
He never was heard from again
Feckner died of exposure and was frozen in the ice and his body is actually still there today frozen forever
The sad thing about that is that vague nerve was never able to explain. What made the continents drive?
What made them move?
What made the supercontinent rip apart and so he died before his theory would become accepted by the scientific community?
He never got to see his life's work come to fruition
That's the story of continental drift, thanks for listening