Rise Of The Continents (2013) s01e02 Episode Script
Eurasia
Istanbul.
For more than 2,000 years, it's stood at the crossroads between East and West The point where Europe ends and Asia begins.
The two continents divided by the Bosporus straits.
This is one of the great journeys.
Stepping off the continent, leaving Europe behind.
But crossing the Bosporus isn't all that it seems.
This notion that Europe and Asia are separate-- it's kind of a nonsense.
From a geological perspective, they're both part of the same vast landmass.
Eurasia stretches from the Atlantic coast of Portugal all the way through to Russia's Pacific coast, making it the biggest continent on the planet.
To reveal how this mighty continent formed, I want to reach back in time.
Because if you know where to look, there are clues to its ancient past written into the world around us its landscapes wildlife Hey! Is that karimeen? and the very rock from which it's built The tiniest detail can reveal the history of a vast continent.
evidence that shows how Eurasia was assembled in a series of monumental collisions.
This just kicked off just as we got here.
Catastrophic impacts that created the conditions for civilizations to rise changed the course of life on Earth and left an indelible mark on the landscape.
Just a wall of rock and ice.
A mountain range spanning the entire continent.
And the story of how that formed is the story of how Eurasia formed-- a continent forged in a series of collisions that continue to this day.
And because the process that built Eurasia is still active Whoa-ho-ho-ho! the largest continent on the planet is merely the start of something far bigger.
The first clue to uncovering Eurasia's past can be found here in Istanbul.
For centuries, the city's strategic location at the heart of the continent has made it a major center for trade.
In a way, this city is here because of this stuff-- silk.
Look at it.
It's just gorgeous.
If you go back to the 6th century, this is one of the most expensive, most sought-after commodities, partly because it comes all the way from China and also because how it was made was this closely guarded secret.
The story goes that a delegation of monks would smuggle back a couple of silk worm inside bamboo cane, brought it back here, and then this place-- Istanbul-- just took off as a kind of hub of silk production.
And the fabric gave its name to the Silk Road-- the network of ancient trade routes that runs across the entire continent, connecting China through Istanbul on to Europe.
And the Silk Road is crucial to the story of Eurasia today, because beneath it lies evidence that reveals the origin of the continent itself evidence that can be found 300 miles southeast of Istanbul, where the Taurus Mountains reach the shores of the Mediterranean in a place that's been both a staging post on the Silk Road and a site of pilgrimage since the days of Ancient Greece.
These are the eternal flames-- in Turkish, they're called yanartas, which is just flaming rock.
Look at them.
I mean, today, they may be half a meter high, but ancient times, they were much higher, so that if you were out at sea, you could see this place as a lighthouse.
But my favorite story, though, is because we're so close to Olympus, this could be the source of the first Olympic Flame.
It's such a surreal scene.
But what fuels these flames is far more ancient.
And analyzing it takes you back tens of millions of years to the time Eurasia formed.
Black residue.
An organic compound.
Fossilized sea creatures-- plankton.
3 or 4 kilometers into the earth.
Do you see this-- this black residue here? It's soot-- essentially carbon.
And that tells us that these flames are bonding an organic compound-- in this case, natural gas, or methane.
And geochemical analysis of these flames indicates that that gas is coming from carbon-rich rocks deep underground.
Much of it from fossilized sea creatures-- plankton.
To transform plankton into gas, you have to take the long-chain hydrocarbons that make up the cells, and you have to break them into smaller and lighter bits.
This process happens spontaneously at around 300 degrees temperatures that can be generated by burying the rock 2 miles down into earth.
The best way to do that is to pile layer upon layer upon layer of sediment on top of it.
And the place where that process happens all the time is the bottom of the deep ocean.
The gas here shows that, millions of years ago, this region of Turkey was underwater.
The continent of Eurasia as we know it today didn't exist 200 million years ago.
Where the south of the continent-- Italy, Arabia, and India-- are today, there was a 35-million-square-mile ocean-- the Tethys.
Western Europe was lost beneath its waves.
And Britain was a collection of tropical islands off its Northwestern shores.
Wrapped around its long, arcing coastline, all the Earth's landmasses were joined together into one vast supercontinent.
Called Pangaea, it was a land dominated by the dinosaurs just as fearsome marine reptiles ruled the Tethys.
Today, all those creatures are now extinct, and the Tethys Ocean itself has long since disappeared.
But what destroyed the Tethys and let to the extinction of many of the creatures that lived in it is the same geological process that led to the formation of Eurasia, because the story of Eurasia is essentially the story of how the Tethys died.
The mystery of how Eurasia formed from the death of the Tethys involves one of the greatest mass extinctions in Earth's history, the rise of its ancient civilizations, and will reveal the continent's ultimate fate.
These are the gentle backwaters of Kerala in South India, a place famed for its spices, especially black pepper, and one of the key staging posts on another of those ancient trading routes that crisscross Eurasia.
For centuries, Kerala's lakes and waterways have supported a traditional way of life, a floating existence that still survives to this day.
But I'm here to find something truly ancient, something that's lived in waters like these for over 100 million years a creature that provides a direct link back to the most important event in the formation of Eurasia And is, for the local fisherman, these waters' most prized catch A fish known here as karimeen.
This is it, the karimeen-- Latin name etroplus suratensis a fish whose anatomy reveals the evolution of entire continents.
The anal fin.
Shape of the skull.
It's a type of fish called a cichlid.
They're marked out by a couple of anatomical quirks that make them distinct, and one of them is right at the back.
It's in his rear end, basically-- the anal fin.
Now, in most cichlids, the anal fin's got three or four spines, but this species has many more.
And the other characteristic's at the front end.
It's the distinctive shape of the skull, which relates to the swim bladder, that sac that controls the buoyancy of the fish.
There's only one other group of fish that share these distinctive characteristics the closely related paretroplus cichlids.
And they live 2,500 miles away in Madagascar.
Now, etroplus can tolerate slightly salty conditions, but they're essentially a freshwater fish.
So one thing's for sure is they didn't swim here.
Instead, the answer is that it's not the fish that moved.
It was India.
This is a reconstruction of how the Earth's landmasses looked like 120 million years ago, just before the emergence of the first cichlid fishes.
You can see, up here, China and Siberia fused together.
And you can see the area up here that's gonna become Britain.
And this in here in blue is the Tethys Ocean.
Then down here, past the Equator into the Southern Hemisphere, tucked snugly in beside Madagascar, is India.
Now, if I press play here, I can simulate how the landmasses then move.
And what you find is that 90 million years, India and Madagascar split.
Then, suddenly, 25 million years after they separated, India more than doubled its speed.
I mean, that's dramatic stuff.
That's a mini-continent, something like 3,000 kilometers across just speeding across the globe, crashing into Eurasia.
Fantastic.
I never tire of watching that.
It's great.
India's journey north was a key moment in the formation of Eurasia, because as it moved, it closed the ocean in front of it, spelling the beginning of the end for the Tethys.
But the big question is what caused it to speed up? Because that led to one of the most catastrophic events in Earth's history.
The Deccan.
It's one of those words for a geologist that conjures up these images, this iconic landscape, stepped plateaus and things.
And yet, this kind of gentle landscape holds in it one of the cataclysmic geological events in the planet's past.
But there's telltale signs in that cliff face there.
You see it looks like a set of bands.
They're layers of lava, molten rock that came out, solidified, and then built up layer upon layer upon layer over tens, hundreds of thousands of years to form these hills.
68 million years ago, this landscape was very different.
Eruption after eruption poured 300,000 cubic miles of lava across Southern India enough to cover the UK in a layer of rock 3 miles thick.
All over these hills, there's gems like these just carved into the lava.
But there is no volcanic activity in India today.
So the question is-- where is the source of these eruptions? And how did it speed India up? This whole cave is carved out of a type of lava called basalt.
Aluminate and magnetite.
Latitude.
It's got really fine crystals.
About 10% a mineral that's called iron oxide-- rust.
It gives it this red-y, brown-y tint.
Minerals like aluminate and magnetite.
And that's the clue, because these iron oxides are magnetic.
Just after the lava solidifies, its temperature drops below 1,000 degrees Fahrenheit.
And the magnetic fields of the iron-oxide crystals align themselves with the planet's own field.
Now, the thing about the Earth's magnetic field is that it changes depending on your position on the planet, where you are between the South Pole and the North Pole-- in other words, your latitude.
It's a property known as its inclination, and it means that the basalt contains a record of its position at the precise moment it solidified, which allows you to pinpoint exactly where it formed.
Today, this temple's at a latitude of 18.
7 degrees North.
But the thing is, the magnetic inclination of the rock itself tells us that it formed at a latitude of about 20 degrees South.
In other words, this lava formed in the Southern Hemisphere.
So the thing is that the source of this volcano isn't to be found deep beneath my feet here.
Instead, it's several thousand kilometers in that direction.
If you trace India's journey back to the point it crossed 20 degrees South, you arrive directly over a mantle plume a huge column of superheated rock that rises up from near the Earth's core.
As India moved over the plume, it triggered the Deccan Eruptions.
But deep underground, it had another impact.
Something that can explain India's dramatic acceleration.
Continents float on the mantle like vast ships.
And just as a hull of a ship lies below the waterline, so the bulk of a continent-- maybe 80% of it-- extends deep into the earth.
Today, the Indian continent's half the thickness of the other great landmasses.
It's thought that that's because as the Indian plate moved across that mantle plume, it melted away the base of the continental plate.
According to that idea, that huge loss of mass, combined with the lubricating effect of that molten rock and also maybe an extra push from the mantle plume caused India to double its speed, propelling it towards Eurasia.
It was a geological cataclysm.
But the implications for life were even more dramatic, because the Deccan Eruptions contributed to one of the greatest turning points in the history of life on Earth.
As the plume burnt its way up through the continent, it pumped billions of tons of ash and toxic gas directly into the atmosphere.
Over hundreds of thousands of years, this slowly choked the planet and poisoned the oceans, wiping out 50% of all life.
And for the dinosaurs, it led to a drawn-out decline until, it's thought, an asteroid finally finished them off.
But the end of the dinosaurs turned out to be our gain, because as one group of animals died out, so another rose to take their place.
The mammals.
Now, the extinction was curiously selective.
I mean, you and I would never have survived.
In fact, no land vertebrate larger than 25 kilograms made it through.
But back then, our distant ancestors had just the right mix of characteristics to survive.
And there's one modern mammal that's thought to have similar adaptations today.
Because what's walked in the past also walks in the mean streets of Mumbai.
The city has such a large rat problem, it employs a small army of rat catchers, like Rakesh Darji Missel.
So, we think of humans as being the most successful mammal, but I reckon we're looking at the ultimate one here-- rats.
I mean, they've certainly got all the essential traits for survival.
They're small enough they can get into nooks and crannies and just keep themselves tucked away from harm.
And then food-- they're voracious eaters.
Eat anything.
And that not having to rely on a single source of food is really useful.
It's-- pbht! And I guess the main thing is sex.
I mean, these things breed like rats, really, which is why the rat catchers of Mumbai are struggling to keep up.
You know, if it's a question of who's gonna survive the next apocalypse, my money's on them.
It's curious to think that it might have been characteristics possessed by the humble rat that enabled our distant ancestors to survive where the dinosaurs had perished and that it was the movement of India that ultimately paved the way for us to inherit the Earth.
As it continued north, India left the mantle plume behind.
But now traveling twice as fast, it crashed into the rest of Eurasia changing the face of the continent and sealing the fate of the Tethys Ocean.
But the demise of the Tethys would have another major impact on human history, shaping the rise of Eurasia's civilizations.
- Morning, Max.
- Hello, sir.
- Hey! - Welcome aboard.
Oh, yeah.
It's small, isn't it? To see how that lost ocean influenced our past and still affects us today, you need to take a closer look at the most obvious result of the collision.
Where's the music coming from? Where's your tape deck or CDs? Ah! I love the music.
I just can't get over the music.
Jojo Marudo.
Lovely.
Whoo! Quite a place you have here.
Ah.
It's a long way down.
It is a very, very long way down.
These are the Himalayas, the greatest mountain range on Earth.
Oh, now we're seeing the mountains.
Here they are.
You might think these contorted rocks are pieces of the land scrunched upwards as the two continents plowed into each other.
But the reality is far more surprising.
This is one of the great rivers of Eurasia, the Kali Gandaki.
Starts up there in the north in Tibet and flows down through the wilds of Mustang Province of Northern Nepal, down through here to India in the south.
For millions of years, it's been carving its way down through the Himalayas to produce what down there is one of the deepest gorges in the world.
And it's in rivers like these that you can find clues to the origin of the rock from which these mountains are formed.
Curious stones called salagrams by the locals who worship them as manifestations of the Hindu God Vishnu.
Now, this-- this is a salagram.
Look at that.
Absolutely beautiful.
Geologists know it better as an ammonite.
And it's the fossilized remains of an extinct member of the squid family.
The modern-day version would be the nautilus.
The body would be in here, and the head and tentacles would start out here.
And the thing is, just like the modern-day nautilus, these creatures didn't live in the mountains.
They lived in the ocean.
That's the thing about geology.
It's not really the rocks themselves that are important.
I mean, this is a rather boring black mud, but it's the stories they tell.
I mean, these ammonites were swimming around in Jurassic seas when dinosaurs roamed the land, when Eurasia was really coming together.
That's what the story of the rocks tell.
The walls of this valley, nearly 9,000 feet above sea level, are brimming with the remains of ancient sea creatures.
Marine fossils have been found right across the Himalaya, including right to the top of Mount Everest.
It's astonishing to think that rocks that started out at the bottom of the Tethys Ocean are now at the roof of the world.
When India collided with Eurasia, the ocean floor at the margins of the Tethys was thrust upwards Forming an immense barrier across the continent.
And it's by creating that barrier that the Tethys has had a profound effect on the course of human history and still does to this day because mountains this high can't help but interfere with the climate.
That is one angry sky up there, isn't it? That's the thing about mountains.
They create their own weather.
And the bigger they are, the bigger the weather they create.
And somewhere behind that cloud and mess, there's the Himalayas-- the biggest on the planet.
So it's no real surprise, then, that it produces one of the most important weather systems on the planet-- the monsoon.
The winds that bring the moist air rise up along these slopes and just dump rain and snow on those hills, and you get these brutal downpours, like these, kind of running up to the wet season, that dump water in the gorges and rivers up there.
Creates mudslides and landslides that just chuck it down-- chuck material.
If you could just see, there's a river down there that's flooded, that's just full of mud and dirt that's been taken out of that mountain range.
This is one of the most dynamic, active environments in the world and also one of the wettest.
These sediment-laden waters flow down from the mountains and out onto the plains of India, Pakistan, and China.
And combined with the monsoon rains, water and nutrient-rich soils from the Himalayas support 3 billion people nearly half the world's population.
But the formation of Eurasia has had a much wider impact on civilization because India's collision was only the beginning of the end for the Tethys.
Arabia also moved north, creating the Zagros and Taurus Mountains that run through Iran and Turkey.
Italy and Greece collided with Northern Europe, building the Alps and completing a mountain chain that spans the entire length of Eurasia and marks the final resting place of the once-great Tethys Ocean.
This is Strombolicchio.
It's actually the solidified throat of an ancient volcano.
200,000 years ago, that rock was molten, rising up to spew and explode out of a volcano that would have risen above our heads.
And then, around that time, that volcanic activity switched to the south, and this thing just crumbled and collapsed back down into the seas, so that all that's left is a solid volcanic neck-- the innards, the guts of an ancient volcano.
Today, the tiny island of Strombolicchio lies just over a mile north of Stromboli Italy's most continually active volcano Grazie.
and a place you can see Eurasia's destiny taking shape.
The thing about volcanoes is that they're windows into the Inner Earth.
And this particular one is a window into the most important process driving the movement of the continents.
The only trouble is that to understand it, I have to get right up there.
The summit towers nearly 3,000 feet above sea level casting a long shadow over the island and the villages that cling to its shores.
Look at it steaming away.
Oh, that's perfect.
This just kicked off, just as we got here.
They call it "puffing" here-- a big puff, and you can see all the boulders just rolling down the hill in the smoke there.
God.
We've arrived.
Whoa! Hey, hey! Look at that.
That's Stromboli for you.
Isn't that magnificent? This volcano has been doing this-- exploding like this-- every 10, 20 minutes, really, for the last 2,000 years.
Whoa! That's a good one.
That's a cracker.
It's so hard to get an idea of the intensity of that, but those-- those orange balls that are getting kicked out of there are actually meter-size boulders.
And the temperature of that must be 500, 600 degrees.
Extraordinary.
You really don't want to be much closer than this.
Well, I do, but What makes Stromboli special is it doesn't really produce that much lava.
I mean, unlike volcanoes like Hawaii and Etna that spew out these huge lava flows, this volcano's eruptions are almost exclusively explosive.
And at night, when the sun goes down and the fireworks really start, you really understand why it's called the Lighthouse of the Mediterranean.
Stromboli's regular explosive eruptions create one of the planet's most astonishing spectacles.
But more than that, they're a clue to understanding the process shaping the fate of the continent.
Ho-ho-ho-ho! Viscous and sticky.
Trapped gases.
So explosive.
The Tethys destroying itself.
This crater rim is just littered with blocks that have been thrown out of that vent down there.
Stuff like that.
I mean, this material is actually made of a rock called andesite.
Andesite is quite a light-gray rock, and that's 'cause it's got a lot of silica in it, and because it's got a fair amount of silica in it, tends to make the magma quite sticky and viscous, and that means it traps gases.
There's just lots and lots of bubbles in this rock and it turns out that it's those bubbles that's the reason why those eruptions are so explosive.
As the magma rises to the surface, the gas trapped inside expands until the bubbles burst and the rock explodes but the gas responsible isn't one you'd immediately associate with a volcano.
It's water vapor, or steam.
This rock actually explains where the water comes from, too, to drive those steam eruptions.
Now, you might think that the steam comes from seawater sinking into the volcano, but, actually, the water's already in the rock.
Look at this.
This is an andesite without all those bubbles, so that you can see all the beautiful crystals, called pyroxene.
Pyroxene crystals form at depths of 3 to 6 miles and as they grow, they encase tiny quantities of magma, locking it away and carrying it up to the surface.
Now, if you could look into those tiny specks of the original magma that formed this rock, you'd find that there was water in them.
In other words, the water was actually in the magma, deep down in the mantle.
The only way water could be found so deep in the Inner Earth was if something carried it there.
Subduction generally happens when ocean crust meets continental crust.
Now, the ocean-crust rocks are denser, so they sit lower in the mantle, and when they collide, the ocean crust gets pushed underneath the lighter continental crust, descending down into the mantle.
So, that eruption up there actually started off about 100 kilometers beneath our feet.
Down there, water gets forced out of those ocean rocks and causes the rocks around them to melt, which rise up and eventually, bursts out as volcanoes.
Subduction is the ultimate fate of all ocean crust but it isn't a consequence of the continents moving.
Subduction is the engine that drives the movement in the first place.
As the ocean crust descends beneath the continental crust, it doesn't break off.
It's still attached to all that ocean floor, and it's that vast slab of rock heading down into the mantle that pulls the ocean crust and, in turn, hauls the land masses behind it, dragging the continents across the face of the Earth.
Maybe it's because we live on the land that it's tempting to think that it's the land masses moving around that closed the oceans, that it was the northward movement of India that destroyed the Tethys, but, actually, it's the exact opposite.
It was the Tethys that pulled the continents together, destroying itself in the process.
It was subduction that built Eurasia and it's subduction that's shaping its ultimate destiny.
For 300 million years, subduction has been gradually, inexorably closing the Tethys, creating Eurasia, and as time goes on, it will close the Med, too.
Africa will continue northwards.
This whole area will emerge as land, and these islands will be the peaks of the Mediterranean Mountains-- a great mountain chain at the heart of a new supercontinent.
As Africa plows northwards, France and Germany become ever more mountainous and those peaks would look out over a vast desert covering the whole of Central Europe and Asia.
It's thought that, 250 million years in the future, all of our continents will once again be joined together as one, with Eurasia right in the heart of it.
Australia joins up with Southern China the Americas crash into the shores of Africa and Britain is swept up towards the North Pole and with the formation of this vast, new land, the planet's grand cycle, that epic break up and movement of the continents across the face of the Earth will begin once again.
For more than 2,000 years, it's stood at the crossroads between East and West The point where Europe ends and Asia begins.
The two continents divided by the Bosporus straits.
This is one of the great journeys.
Stepping off the continent, leaving Europe behind.
But crossing the Bosporus isn't all that it seems.
This notion that Europe and Asia are separate-- it's kind of a nonsense.
From a geological perspective, they're both part of the same vast landmass.
Eurasia stretches from the Atlantic coast of Portugal all the way through to Russia's Pacific coast, making it the biggest continent on the planet.
To reveal how this mighty continent formed, I want to reach back in time.
Because if you know where to look, there are clues to its ancient past written into the world around us its landscapes wildlife Hey! Is that karimeen? and the very rock from which it's built The tiniest detail can reveal the history of a vast continent.
evidence that shows how Eurasia was assembled in a series of monumental collisions.
This just kicked off just as we got here.
Catastrophic impacts that created the conditions for civilizations to rise changed the course of life on Earth and left an indelible mark on the landscape.
Just a wall of rock and ice.
A mountain range spanning the entire continent.
And the story of how that formed is the story of how Eurasia formed-- a continent forged in a series of collisions that continue to this day.
And because the process that built Eurasia is still active Whoa-ho-ho-ho! the largest continent on the planet is merely the start of something far bigger.
The first clue to uncovering Eurasia's past can be found here in Istanbul.
For centuries, the city's strategic location at the heart of the continent has made it a major center for trade.
In a way, this city is here because of this stuff-- silk.
Look at it.
It's just gorgeous.
If you go back to the 6th century, this is one of the most expensive, most sought-after commodities, partly because it comes all the way from China and also because how it was made was this closely guarded secret.
The story goes that a delegation of monks would smuggle back a couple of silk worm inside bamboo cane, brought it back here, and then this place-- Istanbul-- just took off as a kind of hub of silk production.
And the fabric gave its name to the Silk Road-- the network of ancient trade routes that runs across the entire continent, connecting China through Istanbul on to Europe.
And the Silk Road is crucial to the story of Eurasia today, because beneath it lies evidence that reveals the origin of the continent itself evidence that can be found 300 miles southeast of Istanbul, where the Taurus Mountains reach the shores of the Mediterranean in a place that's been both a staging post on the Silk Road and a site of pilgrimage since the days of Ancient Greece.
These are the eternal flames-- in Turkish, they're called yanartas, which is just flaming rock.
Look at them.
I mean, today, they may be half a meter high, but ancient times, they were much higher, so that if you were out at sea, you could see this place as a lighthouse.
But my favorite story, though, is because we're so close to Olympus, this could be the source of the first Olympic Flame.
It's such a surreal scene.
But what fuels these flames is far more ancient.
And analyzing it takes you back tens of millions of years to the time Eurasia formed.
Black residue.
An organic compound.
Fossilized sea creatures-- plankton.
3 or 4 kilometers into the earth.
Do you see this-- this black residue here? It's soot-- essentially carbon.
And that tells us that these flames are bonding an organic compound-- in this case, natural gas, or methane.
And geochemical analysis of these flames indicates that that gas is coming from carbon-rich rocks deep underground.
Much of it from fossilized sea creatures-- plankton.
To transform plankton into gas, you have to take the long-chain hydrocarbons that make up the cells, and you have to break them into smaller and lighter bits.
This process happens spontaneously at around 300 degrees temperatures that can be generated by burying the rock 2 miles down into earth.
The best way to do that is to pile layer upon layer upon layer of sediment on top of it.
And the place where that process happens all the time is the bottom of the deep ocean.
The gas here shows that, millions of years ago, this region of Turkey was underwater.
The continent of Eurasia as we know it today didn't exist 200 million years ago.
Where the south of the continent-- Italy, Arabia, and India-- are today, there was a 35-million-square-mile ocean-- the Tethys.
Western Europe was lost beneath its waves.
And Britain was a collection of tropical islands off its Northwestern shores.
Wrapped around its long, arcing coastline, all the Earth's landmasses were joined together into one vast supercontinent.
Called Pangaea, it was a land dominated by the dinosaurs just as fearsome marine reptiles ruled the Tethys.
Today, all those creatures are now extinct, and the Tethys Ocean itself has long since disappeared.
But what destroyed the Tethys and let to the extinction of many of the creatures that lived in it is the same geological process that led to the formation of Eurasia, because the story of Eurasia is essentially the story of how the Tethys died.
The mystery of how Eurasia formed from the death of the Tethys involves one of the greatest mass extinctions in Earth's history, the rise of its ancient civilizations, and will reveal the continent's ultimate fate.
These are the gentle backwaters of Kerala in South India, a place famed for its spices, especially black pepper, and one of the key staging posts on another of those ancient trading routes that crisscross Eurasia.
For centuries, Kerala's lakes and waterways have supported a traditional way of life, a floating existence that still survives to this day.
But I'm here to find something truly ancient, something that's lived in waters like these for over 100 million years a creature that provides a direct link back to the most important event in the formation of Eurasia And is, for the local fisherman, these waters' most prized catch A fish known here as karimeen.
This is it, the karimeen-- Latin name etroplus suratensis a fish whose anatomy reveals the evolution of entire continents.
The anal fin.
Shape of the skull.
It's a type of fish called a cichlid.
They're marked out by a couple of anatomical quirks that make them distinct, and one of them is right at the back.
It's in his rear end, basically-- the anal fin.
Now, in most cichlids, the anal fin's got three or four spines, but this species has many more.
And the other characteristic's at the front end.
It's the distinctive shape of the skull, which relates to the swim bladder, that sac that controls the buoyancy of the fish.
There's only one other group of fish that share these distinctive characteristics the closely related paretroplus cichlids.
And they live 2,500 miles away in Madagascar.
Now, etroplus can tolerate slightly salty conditions, but they're essentially a freshwater fish.
So one thing's for sure is they didn't swim here.
Instead, the answer is that it's not the fish that moved.
It was India.
This is a reconstruction of how the Earth's landmasses looked like 120 million years ago, just before the emergence of the first cichlid fishes.
You can see, up here, China and Siberia fused together.
And you can see the area up here that's gonna become Britain.
And this in here in blue is the Tethys Ocean.
Then down here, past the Equator into the Southern Hemisphere, tucked snugly in beside Madagascar, is India.
Now, if I press play here, I can simulate how the landmasses then move.
And what you find is that 90 million years, India and Madagascar split.
Then, suddenly, 25 million years after they separated, India more than doubled its speed.
I mean, that's dramatic stuff.
That's a mini-continent, something like 3,000 kilometers across just speeding across the globe, crashing into Eurasia.
Fantastic.
I never tire of watching that.
It's great.
India's journey north was a key moment in the formation of Eurasia, because as it moved, it closed the ocean in front of it, spelling the beginning of the end for the Tethys.
But the big question is what caused it to speed up? Because that led to one of the most catastrophic events in Earth's history.
The Deccan.
It's one of those words for a geologist that conjures up these images, this iconic landscape, stepped plateaus and things.
And yet, this kind of gentle landscape holds in it one of the cataclysmic geological events in the planet's past.
But there's telltale signs in that cliff face there.
You see it looks like a set of bands.
They're layers of lava, molten rock that came out, solidified, and then built up layer upon layer upon layer over tens, hundreds of thousands of years to form these hills.
68 million years ago, this landscape was very different.
Eruption after eruption poured 300,000 cubic miles of lava across Southern India enough to cover the UK in a layer of rock 3 miles thick.
All over these hills, there's gems like these just carved into the lava.
But there is no volcanic activity in India today.
So the question is-- where is the source of these eruptions? And how did it speed India up? This whole cave is carved out of a type of lava called basalt.
Aluminate and magnetite.
Latitude.
It's got really fine crystals.
About 10% a mineral that's called iron oxide-- rust.
It gives it this red-y, brown-y tint.
Minerals like aluminate and magnetite.
And that's the clue, because these iron oxides are magnetic.
Just after the lava solidifies, its temperature drops below 1,000 degrees Fahrenheit.
And the magnetic fields of the iron-oxide crystals align themselves with the planet's own field.
Now, the thing about the Earth's magnetic field is that it changes depending on your position on the planet, where you are between the South Pole and the North Pole-- in other words, your latitude.
It's a property known as its inclination, and it means that the basalt contains a record of its position at the precise moment it solidified, which allows you to pinpoint exactly where it formed.
Today, this temple's at a latitude of 18.
7 degrees North.
But the thing is, the magnetic inclination of the rock itself tells us that it formed at a latitude of about 20 degrees South.
In other words, this lava formed in the Southern Hemisphere.
So the thing is that the source of this volcano isn't to be found deep beneath my feet here.
Instead, it's several thousand kilometers in that direction.
If you trace India's journey back to the point it crossed 20 degrees South, you arrive directly over a mantle plume a huge column of superheated rock that rises up from near the Earth's core.
As India moved over the plume, it triggered the Deccan Eruptions.
But deep underground, it had another impact.
Something that can explain India's dramatic acceleration.
Continents float on the mantle like vast ships.
And just as a hull of a ship lies below the waterline, so the bulk of a continent-- maybe 80% of it-- extends deep into the earth.
Today, the Indian continent's half the thickness of the other great landmasses.
It's thought that that's because as the Indian plate moved across that mantle plume, it melted away the base of the continental plate.
According to that idea, that huge loss of mass, combined with the lubricating effect of that molten rock and also maybe an extra push from the mantle plume caused India to double its speed, propelling it towards Eurasia.
It was a geological cataclysm.
But the implications for life were even more dramatic, because the Deccan Eruptions contributed to one of the greatest turning points in the history of life on Earth.
As the plume burnt its way up through the continent, it pumped billions of tons of ash and toxic gas directly into the atmosphere.
Over hundreds of thousands of years, this slowly choked the planet and poisoned the oceans, wiping out 50% of all life.
And for the dinosaurs, it led to a drawn-out decline until, it's thought, an asteroid finally finished them off.
But the end of the dinosaurs turned out to be our gain, because as one group of animals died out, so another rose to take their place.
The mammals.
Now, the extinction was curiously selective.
I mean, you and I would never have survived.
In fact, no land vertebrate larger than 25 kilograms made it through.
But back then, our distant ancestors had just the right mix of characteristics to survive.
And there's one modern mammal that's thought to have similar adaptations today.
Because what's walked in the past also walks in the mean streets of Mumbai.
The city has such a large rat problem, it employs a small army of rat catchers, like Rakesh Darji Missel.
So, we think of humans as being the most successful mammal, but I reckon we're looking at the ultimate one here-- rats.
I mean, they've certainly got all the essential traits for survival.
They're small enough they can get into nooks and crannies and just keep themselves tucked away from harm.
And then food-- they're voracious eaters.
Eat anything.
And that not having to rely on a single source of food is really useful.
It's-- pbht! And I guess the main thing is sex.
I mean, these things breed like rats, really, which is why the rat catchers of Mumbai are struggling to keep up.
You know, if it's a question of who's gonna survive the next apocalypse, my money's on them.
It's curious to think that it might have been characteristics possessed by the humble rat that enabled our distant ancestors to survive where the dinosaurs had perished and that it was the movement of India that ultimately paved the way for us to inherit the Earth.
As it continued north, India left the mantle plume behind.
But now traveling twice as fast, it crashed into the rest of Eurasia changing the face of the continent and sealing the fate of the Tethys Ocean.
But the demise of the Tethys would have another major impact on human history, shaping the rise of Eurasia's civilizations.
- Morning, Max.
- Hello, sir.
- Hey! - Welcome aboard.
Oh, yeah.
It's small, isn't it? To see how that lost ocean influenced our past and still affects us today, you need to take a closer look at the most obvious result of the collision.
Where's the music coming from? Where's your tape deck or CDs? Ah! I love the music.
I just can't get over the music.
Jojo Marudo.
Lovely.
Whoo! Quite a place you have here.
Ah.
It's a long way down.
It is a very, very long way down.
These are the Himalayas, the greatest mountain range on Earth.
Oh, now we're seeing the mountains.
Here they are.
You might think these contorted rocks are pieces of the land scrunched upwards as the two continents plowed into each other.
But the reality is far more surprising.
This is one of the great rivers of Eurasia, the Kali Gandaki.
Starts up there in the north in Tibet and flows down through the wilds of Mustang Province of Northern Nepal, down through here to India in the south.
For millions of years, it's been carving its way down through the Himalayas to produce what down there is one of the deepest gorges in the world.
And it's in rivers like these that you can find clues to the origin of the rock from which these mountains are formed.
Curious stones called salagrams by the locals who worship them as manifestations of the Hindu God Vishnu.
Now, this-- this is a salagram.
Look at that.
Absolutely beautiful.
Geologists know it better as an ammonite.
And it's the fossilized remains of an extinct member of the squid family.
The modern-day version would be the nautilus.
The body would be in here, and the head and tentacles would start out here.
And the thing is, just like the modern-day nautilus, these creatures didn't live in the mountains.
They lived in the ocean.
That's the thing about geology.
It's not really the rocks themselves that are important.
I mean, this is a rather boring black mud, but it's the stories they tell.
I mean, these ammonites were swimming around in Jurassic seas when dinosaurs roamed the land, when Eurasia was really coming together.
That's what the story of the rocks tell.
The walls of this valley, nearly 9,000 feet above sea level, are brimming with the remains of ancient sea creatures.
Marine fossils have been found right across the Himalaya, including right to the top of Mount Everest.
It's astonishing to think that rocks that started out at the bottom of the Tethys Ocean are now at the roof of the world.
When India collided with Eurasia, the ocean floor at the margins of the Tethys was thrust upwards Forming an immense barrier across the continent.
And it's by creating that barrier that the Tethys has had a profound effect on the course of human history and still does to this day because mountains this high can't help but interfere with the climate.
That is one angry sky up there, isn't it? That's the thing about mountains.
They create their own weather.
And the bigger they are, the bigger the weather they create.
And somewhere behind that cloud and mess, there's the Himalayas-- the biggest on the planet.
So it's no real surprise, then, that it produces one of the most important weather systems on the planet-- the monsoon.
The winds that bring the moist air rise up along these slopes and just dump rain and snow on those hills, and you get these brutal downpours, like these, kind of running up to the wet season, that dump water in the gorges and rivers up there.
Creates mudslides and landslides that just chuck it down-- chuck material.
If you could just see, there's a river down there that's flooded, that's just full of mud and dirt that's been taken out of that mountain range.
This is one of the most dynamic, active environments in the world and also one of the wettest.
These sediment-laden waters flow down from the mountains and out onto the plains of India, Pakistan, and China.
And combined with the monsoon rains, water and nutrient-rich soils from the Himalayas support 3 billion people nearly half the world's population.
But the formation of Eurasia has had a much wider impact on civilization because India's collision was only the beginning of the end for the Tethys.
Arabia also moved north, creating the Zagros and Taurus Mountains that run through Iran and Turkey.
Italy and Greece collided with Northern Europe, building the Alps and completing a mountain chain that spans the entire length of Eurasia and marks the final resting place of the once-great Tethys Ocean.
This is Strombolicchio.
It's actually the solidified throat of an ancient volcano.
200,000 years ago, that rock was molten, rising up to spew and explode out of a volcano that would have risen above our heads.
And then, around that time, that volcanic activity switched to the south, and this thing just crumbled and collapsed back down into the seas, so that all that's left is a solid volcanic neck-- the innards, the guts of an ancient volcano.
Today, the tiny island of Strombolicchio lies just over a mile north of Stromboli Italy's most continually active volcano Grazie.
and a place you can see Eurasia's destiny taking shape.
The thing about volcanoes is that they're windows into the Inner Earth.
And this particular one is a window into the most important process driving the movement of the continents.
The only trouble is that to understand it, I have to get right up there.
The summit towers nearly 3,000 feet above sea level casting a long shadow over the island and the villages that cling to its shores.
Look at it steaming away.
Oh, that's perfect.
This just kicked off, just as we got here.
They call it "puffing" here-- a big puff, and you can see all the boulders just rolling down the hill in the smoke there.
God.
We've arrived.
Whoa! Hey, hey! Look at that.
That's Stromboli for you.
Isn't that magnificent? This volcano has been doing this-- exploding like this-- every 10, 20 minutes, really, for the last 2,000 years.
Whoa! That's a good one.
That's a cracker.
It's so hard to get an idea of the intensity of that, but those-- those orange balls that are getting kicked out of there are actually meter-size boulders.
And the temperature of that must be 500, 600 degrees.
Extraordinary.
You really don't want to be much closer than this.
Well, I do, but What makes Stromboli special is it doesn't really produce that much lava.
I mean, unlike volcanoes like Hawaii and Etna that spew out these huge lava flows, this volcano's eruptions are almost exclusively explosive.
And at night, when the sun goes down and the fireworks really start, you really understand why it's called the Lighthouse of the Mediterranean.
Stromboli's regular explosive eruptions create one of the planet's most astonishing spectacles.
But more than that, they're a clue to understanding the process shaping the fate of the continent.
Ho-ho-ho-ho! Viscous and sticky.
Trapped gases.
So explosive.
The Tethys destroying itself.
This crater rim is just littered with blocks that have been thrown out of that vent down there.
Stuff like that.
I mean, this material is actually made of a rock called andesite.
Andesite is quite a light-gray rock, and that's 'cause it's got a lot of silica in it, and because it's got a fair amount of silica in it, tends to make the magma quite sticky and viscous, and that means it traps gases.
There's just lots and lots of bubbles in this rock and it turns out that it's those bubbles that's the reason why those eruptions are so explosive.
As the magma rises to the surface, the gas trapped inside expands until the bubbles burst and the rock explodes but the gas responsible isn't one you'd immediately associate with a volcano.
It's water vapor, or steam.
This rock actually explains where the water comes from, too, to drive those steam eruptions.
Now, you might think that the steam comes from seawater sinking into the volcano, but, actually, the water's already in the rock.
Look at this.
This is an andesite without all those bubbles, so that you can see all the beautiful crystals, called pyroxene.
Pyroxene crystals form at depths of 3 to 6 miles and as they grow, they encase tiny quantities of magma, locking it away and carrying it up to the surface.
Now, if you could look into those tiny specks of the original magma that formed this rock, you'd find that there was water in them.
In other words, the water was actually in the magma, deep down in the mantle.
The only way water could be found so deep in the Inner Earth was if something carried it there.
Subduction generally happens when ocean crust meets continental crust.
Now, the ocean-crust rocks are denser, so they sit lower in the mantle, and when they collide, the ocean crust gets pushed underneath the lighter continental crust, descending down into the mantle.
So, that eruption up there actually started off about 100 kilometers beneath our feet.
Down there, water gets forced out of those ocean rocks and causes the rocks around them to melt, which rise up and eventually, bursts out as volcanoes.
Subduction is the ultimate fate of all ocean crust but it isn't a consequence of the continents moving.
Subduction is the engine that drives the movement in the first place.
As the ocean crust descends beneath the continental crust, it doesn't break off.
It's still attached to all that ocean floor, and it's that vast slab of rock heading down into the mantle that pulls the ocean crust and, in turn, hauls the land masses behind it, dragging the continents across the face of the Earth.
Maybe it's because we live on the land that it's tempting to think that it's the land masses moving around that closed the oceans, that it was the northward movement of India that destroyed the Tethys, but, actually, it's the exact opposite.
It was the Tethys that pulled the continents together, destroying itself in the process.
It was subduction that built Eurasia and it's subduction that's shaping its ultimate destiny.
For 300 million years, subduction has been gradually, inexorably closing the Tethys, creating Eurasia, and as time goes on, it will close the Med, too.
Africa will continue northwards.
This whole area will emerge as land, and these islands will be the peaks of the Mediterranean Mountains-- a great mountain chain at the heart of a new supercontinent.
As Africa plows northwards, France and Germany become ever more mountainous and those peaks would look out over a vast desert covering the whole of Central Europe and Asia.
It's thought that, 250 million years in the future, all of our continents will once again be joined together as one, with Eurasia right in the heart of it.
Australia joins up with Southern China the Americas crash into the shores of Africa and Britain is swept up towards the North Pole and with the formation of this vast, new land, the planet's grand cycle, that epic break up and movement of the continents across the face of the Earth will begin once again.