Rise Of The Continents (2013) s01e04 Episode Script
Australia
This is the way to see rocks.
I want to reach back in time, using the clues that are hidden all around us.
You don't get much clearer evidence than that.
in living creatures Oh, there's one.
Can you see that just over there? in landscapes and written into the rocks.
The tiniest detail can reveal the history of a vast continent.
I'm going to piece together these clues to uncover key moments in Australia's history and find out how Australia's journey has created the conditions that allowed people to settle this harsh land and shaped the lives of those who followed, but also how that journey continues to affect the destiny of people far beyond the shores of this island continent.
I've come to the Yarra valley in the state of Victoria to search for the creature that takes us back to the beginning of Australia's geological story.
It is a legendary creature.
I mean, it's described as venomous, egg-laying, duckbilled, beaver-tailed, otter-footed, mole-furred.
Plus, it's odd.
It lactates but it's got no nipples.
I mean, the lactating business means it is a mammal, but the egg-laying That's much more like a reptile.
It's a it's an odd fusion of animal.
I'm here with Josh griffiths, a biologist who does regular surveys So, have you caught them here before? Yeah, I've caught some just upstream here before.
to check on the welfare of these unusual animals.
We just need to stretch this out and tie it up to a bank so it's nice and secure.
This creature which links back to Australia's past lives today only in the wetter, forested parts of the continent, but it's hard to track down because it leaves almost no detectable trace, so we could be in for a very long night.
Do you think they can see us? Do you think they're laughing? Finally, after seven hours, I get my first glimpse of an animal that few people have ever seen in the wild a platypus.
Oh, my gosh.
That's incredible.
This is what we've been waiting for.
It's a male, too? Yeah, it's a male.
It's an adult one.
Can I see his face? Can I see that classic, classic face? 3:00 in the morning, it is.
You kept us up till 3:00 in the bloomin' morning.
But isn't that worth the wait? I know.
Absolutely.
Can I stroke it? He's perfectly happy, is he? Lovely.
I mean, the fur is very mammalian.
Fur is definitely mammal and the way that they regulate their temperature.
Their eyes are quite reptilian, and the way their legs are splayed out to the side, it's like a lizard.
This strange mix exists in the platypus because it's a link back to a world 160 million years ago, a time when our mammal ancestors were just beginning to evolve from early reptiles.
Millions of years ago, we all would've shared a common ancestor, and it would've been very reptilian, and it would've looked a lot more like a platypus than it would've looked like you or me.
I have to say it's hard to imagine that we've got a common ancestor.
It just looks so different from us.
It certainly does now, but millions of years ago, we all would've looked much the same.
While the platypus survives in the backwaters of Australia, the common ancestor is long gone.
All that's left are tiny fossil fragments that reveal creatures from that long-lost world.
The animal that gave rise to the platypus and to all of the mammals we see today might well have looked something like this.
Crucially, their remains have been found across the globe.
These creatures were living all over the place, and that suggests something highly intriguing.
Just as all life has a common ancestor, so, too, does the land that we're standing on.
So, imagine that you got to try to undo the shape and position of each continent.
It's been imprinted in your brain by every atlas and world map you've ever seen.
If you turn back the clock through geological time you see Australia was once part of a huge landmass in which most of today's continents were joined and over which the platypus ancestors roamed.
It's hard to imagine what this ancient world looked like and how our modern continents were arranged within it.
But there are clues if you know where to look, and the first one comes from the substance that has helped to make modern Australia one of the wealthiest nations on the planet.
This black layer that I've been following here is coal.
This is a natural layer that's been exposed by the waves.
Just a few Miles away, though, there's vast diggers pulling this stuff out of the ground.
Around one million tons of coal are exhumed from this land each and every day.
But it has another value that goes beyond the financial.
What I'm looking for is a fossil that's in here.
There's a nice one.
See that just here? There's a little fragment.
That's a nice one, too.
These fossils contain evidence of Australia's past and that of the whole Southern hemisphere.
From these fossils I can find the type of vegetation that once covered Australia.
Glossopteris.
Lush forest.
Fossils found in Antarctica.
Just packed full of plant debris.
These are leaves of a tree called glossopteris Which formed 255 million years ago.
And that means that 255 million years ago, this part of Australia was lush forest.
It was these glossopteris forests that transformed over time into Australia's enormous coal reserves, and that's why the fossils are found inside them.
But more importantly, because the exact same fossil is found in Antarctica, it means that Antarctica was also lush forest.
But that's not all.
Glossopteris fossils from elsewhere also reveal the extent of the landmass.
In fact, glossopteris is found right across the Southern hemisphere.
It's found in Southern Africa.
It's found in South America.
The thing is the spores of these glossopteris just couldn't be transported across vast oceans.
In other words, all those landmasses must have been together.
Glossopteris has helped reveal the arrangement of all the continents in the Southern hemisphere at the time.
Not only was Australia linked to Antarctica but also to Africa, India, and South America.
This vast landmass was called gondwana A supercontinent which was the Southern half of the even larger landmass of pangaea.
The primeval land of gondwana was on an almost mythic scale.
It was carpeted with glossopteris trees, a forest more than four times the size of the Amazon basin, stretching further than any eye could see.
A tiny fraction of gondwana's forest still remains today in a cool pocket of new South wales in eastern Australia.
Australia was green and lush for over 300 million years enduring through the reign of the dinosaurs as well as the rise of the mammals.
Gondwana was so huge that it was destined to break up, and it was that breakup that created the character of Australia.
The mighty supercontinent of gondwana and its fairy-tale forests would soon be lost forever.
A great change was about to come across this land, an event that would transform Australia into the continent we know today.
To piece together what happened, you need to travel deep into this continent's red heart.
This is the unusual country town of coober pedy unusual because the 3,000 people who live here mostly live underground.
Houses, restaurants, hotels, churches There's even a subterranean book shop.
The people here have dug out these caves to escape the desert heat.
You know, at first, the idea of people living underground Modern-day troglodytes Just seems bizarre, and there's definitely odd things here.
But, actually, it maybe makes sense.
It's not claustrophobic.
It's cool, and it's airy.
And for a geologist like me to be surrounded by rocks It's just ideal.
The reason the townsfolk go to such lengths is because this rock contains a treasure, one of the most precious jewels on the planet.
For them, it provides a livelihood.
For me, it's a crucial clue to how this land changed when gondwana broke up A precious gemstone that, at best quality, has more value than diamond.
Opals are extraordinary.
The highly specific conditions in which they form have occurred only rarely in the history of our planet, and then mainly here in the Australian outback.
Opals only occur because of what happened during the demise of gondwana.
Ah, now, there's a bit.
And I can figure out those ancient events by examining these gemstones.
Silica.
Sulfuric acid.
Bacteria.
An inland sea.
What I love about opal is it forms through this peculiar set of conditions.
You need two raw ingredients for it.
One of them is silica and the other is acid.
Now, the silica is pretty simple.
It comes from minerals in the rock around here.
But for the acid, you need a really strong acid, like sulfuric acid, and the sulfur for that comes from bacteria that eat sulfur when oxygen is not around Bacteria that live in the mud at the bottom of a stagnant sea.
To turn that sulfur into sulfuric acid, you essentially need to put oxygen into it, so you need to take the sea away, exposing it to the air.
So, now you've got sulfuric acid, and what that does is, it just leaches its way through the rock, picking up the silica and concentrating it into these little, narrow bars.
What all that complicated chemistry tells us is that there used to be an inland sea here.
But, actually, down here in the few places, the opals preserve far more obvious evidence of that sea.
Now, look at that seashells.
You don't get much clearer evidence than that.
It's hard to imagine now, but here in the dry, dusty interior of Australia, there existed for just a while an inland sea.
This sea was created by an event of epic proportions The breakup of gondwana.
Around 180 million years ago, huge upwellings of hot rock began to rise from the mantle deep below the earth's crust.
These plumes wore away at weak spots in that crust Until finally, 150 million years ago, they gave way.
This was the beginning of the breakup of gondwana.
As the continents separated, new seafloor was created between them.
This new material was hot, which made it expand and displace the seas above it.
This was what caused global sea levels to rise so that water rushed into the flat center of what would become Australia, creating the inland sea.
And it lasted for over 35 million years.
When it retreated, the sea left in its wake the specific conditions for the formation of opals.
But the breakup of gondwana also created something else extraordinary, something which would help people survive here millions of years later.
The interior of Australia is harsh, forbidding.
When the Europeans first came here over two centuries ago, they realized the key to settling this land was to find water.
From the time the Europeans arrived in Australia, they had an obsession, and that was to get into the country's interior.
They were absolutely convinced that somewhere in this vast landscape had to be an inland sea.
After all, all the other continents that they explored had one The Great Lakes in the U.
S.
, caspian in Asia.
Why should this place be any different? They were, of course, 100 million years too late to find Australia's inland sea.
But they didn't know that, and such was the importance of finding water that they kept on trying.
But, of course, there was a people who had lived here for many thousands of years, and they knew a source of water that the Europeans didn't.
Dean ah chee is an elder of the lower Southern arrernte people and was schooled from earliest youth in the aboriginal ways of finding water in this dry land.
And so do all the songlines relate to water? So, how far can you navigate on songlines? So, how do you find it? Tell me the secrets.
Really? So, it's that important, it's that crucial, that's it's almost kept, like, a secret.
A secret.
Yeah.
Yeah? The aboriginal people, for thousands of years, have used these songlines to lead them to a reliable source of water in the desert Water that emerges from underground into what's called mound Springs.
Ah! What the aboriginal people couldn't know was how their songlines linking up one mound spring to another echoed the geology below.
Because deep in the ground, all these mound Springs were linked in a vast reservoir of water.
What's really intriguing about these Springs is just how many there are.
In this area, there's a handful, but across the region, there's something like 700.
What's even more remarkable is that I'm swimming above this enormous reserve of water that's deep down there and extends beneath almost 1/4 of Australia's land surface.
This reserve is called the great artesian basin, and incredibly, it holds enough water to fill 26 billion olympic-size swimming pools.
It's a giant aquifer, porous rock under the ground which holds water, and a key part of it exists here thanks to the ancient inland sea.
Even before gondwana began to break up, the first element of the great artesian basin was in place.
Deep underground, there were layers of porous sandstone rock, but any water which got into that rock would quickly escape again because there was nothing to contain it.
The inland sea brought and left behind the crucial ingredient needed to trap the water inside mud.
The mud hardened into a lead of impermeable rock which lay across the top of the sandstone.
So when rainwater fell, it could trickle around the edges of the lead and get into the sandstone.
But crucially, that same lead prevented the water from evaporating away.
At a few places where the lead's broken, the water escapes.
These are the mound Springs that have sustained the aboriginal people for thousands of years.
And because these Springs provide the only reliable source of water for much of inland Australia, they're a vital lifeline for wildlife here, as well as the great sheep and cattle stations of the Australian outback.
It's an extraordinary thought that the muddy remains of a long-lost sea still provide water that sustains life here today.
By around 100 million years ago, gondwana had broken apart, but Australia still didn't exist as a separate continent.
There was one big split yet to come one that would transform Australia and lead to the evolution of one of the most spectacular animals on the planet.
This is the great Australian bight, over 600 Miles of coastline on the Southern edge of Australia.
It's just vast.
The cliffs themselves are 250 feet high, falling away to the sea.
If I'd been walking along here 90 million years ago, then there would've been no cliff.
There would've been no ocean.
Instead, I would've been able to take a single step from here directly onto Antarctica.
This is how the coastline of Antarctica and Australia joined up.
Despite the inevitable erosion, it's still a neat fit to this day.
Although these two continents are now almost opposites, back then the story was very different.
They were effectively identical twins, both temperate, forested lands which lay together near the South pole.
And like all twins, they weren't easy to separate.
Although gondwana was gone, Australia and Antarctica stayed close together for many millions of years.
But the process that transformed them into radically different lands also had another consequence The evolution of the largest group of animals that ever lived on the planet.
These whales spend most of the year in Antarctica, feeding.
But at this time of year, August, they journey up to 1,500 Miles here to breed.
These are Southern rights Third largest whale species on the planet.
You're only seeing about 10% of the animal.
The bulk of it, 90%, is underneath.
These whales can grow up to 50 feet in length, and they can reach such a size because of what they eat, scooping up two to three tons of food each day Millions and millions of miniscule krill.
How these great animals came to survive on these tiny creatures is a direct consequence of Australia's geological history and its separation from Antarctica.
90 million years ago, something happened to finally separate Australia from Antarctica.
Volcanic activity from deep within the earth's mantle forced up a new ocean crust between them, creating a mid-ocean Ridge which broke them apart.
Australia was, at last, a separate island continent.
And that left Antarctica sitting all alone over the South pole, still temperate and forested.
That was until the isolation of Antarctica created an unusual effect in the waters around it.
Normally, the wind drives surface currents, pushing the water onto shores like these, where the energy dissipates.
But thousands of kilometers over there is Antarctica.
There, the situation is slightly different.
The water goes 'round and 'round that huge mass, building up flow.
And without land to get in the way to disrupt it, the current just gets stronger and deeper.
The oceans were free to flow all around Antarctica, driven by the winds, and this was the beginning of the circum-antarctic current.
Its effect on Antarctica was profound, cutting off the continent from the warm waters to the north.
In just one million years, Antarctica was transformed from a temperate, forested land to one entombed in ice.
From now on, Antarctica would be a land of desolation inhabited by nothing bigger than a penguin.
But in the ocean, this new current had a more positive effect, playing a significant role in the evolution of all filter-feeding whales, the Southern right whale among them.
The motion of this current forced up water from the depths of the ocean to the surface, carrying with it nutrients which support tiny creatures such as phytoplankton and krill.
This was a rich source of food just waiting to be scooped up.
And sure enough, around the time the current appeared, sea-dwelling mammals began to develop a new way of eating Filter-feeding those vast volumes of krill.
Giant whales, to this day, feed in the same way.
I could watch them all day, just doing their stuff out there.
It's lovely to think that it's the circum-antarctic current that played such an important role in allowing these giants to develop and also keeps them fed today.
In a way, these whales are the last remaining link between two continents that started as twins and have grown so far apart.
Australia's fate was to be very different to that of Antarctica.
It, too, would change dramatically, but in almost the opposite way.
While Antarctica turned to ice, Australia was turned to dust.
It continued moving northwards, and around 20 million years ago, Australia pushed into warmer latitudes and this would have significant consequences for this land and anything trying to live on it.
The forest died away, save for a few tiny pockets.
It was replaced with bare, red land and the one tree that thrived in these new, arid conditions The eucalyptus A tree that now accounts for almost 80% of the forest in Australia.
For the animals, it was a brutal case of adapt or die.
Only a few were able to evolve quickly enough to survive.
And a classic case of that rapid evolution is this fellow.
He's big.
He's really big.
I'm assuming you want a big koala.
Yeah, yeah.
Big koalas are good.
I don't have necessarily a preference.
Okay.
Just don't move so it can climb across.
Over this way, sweetheart.
There you are.
Good boy.
He's not sure Under his bum.
Yeah, I got him.
Gosh oh.
It is heavy.
What's that? You say 11 kilos? About 111/2, I think he is, yeah.
It's just Good boy.
The koala's Teddy-bear features and the anatomy that underpins them are the result of having only the eucalyptus tree to munch on.
A very chewy tree at that As paleontologist Mike archer showed me.
- This is a modern koala.
- So this ah.
Most of this head has to do with smelling, eating Here's all the teeth And the muscles that drive the powerful jaws, because these trees are hard to eat.
So, basically, their head is a chewing machine.
Exactly.
Now, if you look at some of the fossils Now, these fossils are 20 million years old.
You've got an animal here that's about half the size of the modern koala.
So, this thing has become gigantic.
It's a bigger and bigger face.
The eucalyptus trees didn't change only the koala's machinery for eating, but also for communicating.
This bubble of bone here is an echolocating chamber that's very good at picking up low-frequency vibrations.
A low-frequency sound? Yes, that weird sound they make transmits long distances, and they have to, because where they live here, the trees are far apart.
So, koalas have made this kind of alliance with this tree, really.
And then eventually that little niche is the one that then spreads.
So they're the lucky ones.
They lucked out.
They were the furry parasite that lucked out.
The koala's face reflects the dramatic climate shift that Australia has undergone turning from verdant forest to mostly red, dry desert.
The drying out of Australia is just one more phase in the changing history of this continent that was born in the arms of the giant gondwana was flooded by sea when that supercontinent broke up And spent much of its life attached to an unlikely twin before finally becoming an island.
Throughout all that, Australia has been relentlessly moving northwards, and it's still going, which means Australia's transformation isn't over yet.
An unexpected fate awaits.
The Indonesian waters of the banda sea.
Hi.
Hi.
Can I come in? This is mein, a member of the bajau, so-called sea gypsies and masters of these waters.
He's taking me on a fishing trip into the seas which are his home.
He's completely gone.
Mein makes it look effortless.
And the bajau can almost reach out and take all they need from the sea.
Because with over 2,000 species of fish and over 600 species of coral, these waters, known as the coral triangle, are the most biodiverse and productive in the world.
To find out why the waters here are so rich and what this can reveal about the future of Australia, I'm going ashore to the nearby island of wangi-wangi.
The bajau villages are strung out all the way along the coast on this island.
But I've come inland, up here into the hills, to look for something rather peculiar.
Because strangely, the key to understanding the richness of the waters down there is the rock on this hill up here.
This is what I've been looking for here.
It's coral.
You can see a whole kind of colony of polyps.
There's another one here, and there's another one.
I mean, essentially, all of the gray rock you can see is coral, which is hardly something you expect to see at the top of a hill, and that's because this is an ancient coral reef that's been uplifted above the sea.
It's absolutely spectacular.
And by looking at this fossilized coral, I could find crucial clues to the future of Australia.
Strontium.
Strontium.
Three million years.
A layer cake.
The clams and corals in this reef are absolutely exquisitely preserved, beautiful.
But what's really interesting is the age of them.
Scientists have dated these corals with a form of element called strontium, which builds up over time, and the age that they get is less than three million years, which makes this reef a geological infant.
This means that this whole island came up above the waves no more than three million years ago.
But the biggest surprise is what lies beneath this reef A layer cake of ancient strata.
Beds of sand and mud that have built up gradually over time in conditions of tranquility and stability.
Those conditions just aren't found, really, in the crumple zone of southeast Asia.
Instead, they're absolutely typical of one place Australia.
The implication's intriguing.
These wakatobi islands are in Indonesia, so you just assume that they're part of Asia.
In fact, they're a fragment of the Australian continent.
It all points to one thing That Australia has moved so far north that it's colliding with Asia.
Continent is now grinding directly against continent.
The reason why the collision of these two continents creates such a bounty of fish for the bajau here is all due to the effect it has on the seabed.
The thing is, the seafloor around here is constantly shifting, constantly going up and down, and so you're always revealing new pockets.
And it's that separation, mixing, separation, mixing that drives evolution here so fast.
And that's what, in turn, creates these phenomenally rich seas and a way of life for these people.
Being in this place Here, now It's kind of a rare moment in time, a time when two continents are starting to directly collide into each other.
But the effects of Australia's move north are much, much bigger than the fabulous haul of fish around these islands.
They're visible all along the boundary where these two continents meet as a startling variety of dramatic natural phenomena.
It's forced up many of the volcanoes of Indonesia, even whole islands, such as Timor.
And on the pacific side, in Papua New Guinea, it's thrust up entire new Mountain ranges as high as Europe's alps.
And the action isn't over, not by any means, because this is Australia's future To effectively become a part of Asia.
It's impossible to tell exactly how that collision will pan out, but a likely version of events is that Australia crushes the islands of Indonesia into Vietnam, pushes on into China, and sideswipes Japan.
One thing's for sure Australia's brief existence as an island continent is coming to an end.
Australia's destiny is to become much more like this place Indonesia, no longer isolated and with a lush climate once again.
What's happening now is the biggest change in the history of Australia, and it's happening right before our eyes.
Of course, eventually all of this will be utterly transformed.
For a geologist, it makes it just so exciting because this is one of the most dynamic places on the planet.
And it's all down to the slow and steady movement of the one continent that's always been considered quiet and stable.
For so long, Australia was thought of as dry, unchanging, isolated, but its story is so very different from that.
In the past, it was twinned with Antarctica, and its future is in the making as it merges with Asia to become this tropical land of forest and mountains.
That's why, for me, Australia is the most surprising continent of all.
I want to reach back in time, using the clues that are hidden all around us.
You don't get much clearer evidence than that.
in living creatures Oh, there's one.
Can you see that just over there? in landscapes and written into the rocks.
The tiniest detail can reveal the history of a vast continent.
I'm going to piece together these clues to uncover key moments in Australia's history and find out how Australia's journey has created the conditions that allowed people to settle this harsh land and shaped the lives of those who followed, but also how that journey continues to affect the destiny of people far beyond the shores of this island continent.
I've come to the Yarra valley in the state of Victoria to search for the creature that takes us back to the beginning of Australia's geological story.
It is a legendary creature.
I mean, it's described as venomous, egg-laying, duckbilled, beaver-tailed, otter-footed, mole-furred.
Plus, it's odd.
It lactates but it's got no nipples.
I mean, the lactating business means it is a mammal, but the egg-laying That's much more like a reptile.
It's a it's an odd fusion of animal.
I'm here with Josh griffiths, a biologist who does regular surveys So, have you caught them here before? Yeah, I've caught some just upstream here before.
to check on the welfare of these unusual animals.
We just need to stretch this out and tie it up to a bank so it's nice and secure.
This creature which links back to Australia's past lives today only in the wetter, forested parts of the continent, but it's hard to track down because it leaves almost no detectable trace, so we could be in for a very long night.
Do you think they can see us? Do you think they're laughing? Finally, after seven hours, I get my first glimpse of an animal that few people have ever seen in the wild a platypus.
Oh, my gosh.
That's incredible.
This is what we've been waiting for.
It's a male, too? Yeah, it's a male.
It's an adult one.
Can I see his face? Can I see that classic, classic face? 3:00 in the morning, it is.
You kept us up till 3:00 in the bloomin' morning.
But isn't that worth the wait? I know.
Absolutely.
Can I stroke it? He's perfectly happy, is he? Lovely.
I mean, the fur is very mammalian.
Fur is definitely mammal and the way that they regulate their temperature.
Their eyes are quite reptilian, and the way their legs are splayed out to the side, it's like a lizard.
This strange mix exists in the platypus because it's a link back to a world 160 million years ago, a time when our mammal ancestors were just beginning to evolve from early reptiles.
Millions of years ago, we all would've shared a common ancestor, and it would've been very reptilian, and it would've looked a lot more like a platypus than it would've looked like you or me.
I have to say it's hard to imagine that we've got a common ancestor.
It just looks so different from us.
It certainly does now, but millions of years ago, we all would've looked much the same.
While the platypus survives in the backwaters of Australia, the common ancestor is long gone.
All that's left are tiny fossil fragments that reveal creatures from that long-lost world.
The animal that gave rise to the platypus and to all of the mammals we see today might well have looked something like this.
Crucially, their remains have been found across the globe.
These creatures were living all over the place, and that suggests something highly intriguing.
Just as all life has a common ancestor, so, too, does the land that we're standing on.
So, imagine that you got to try to undo the shape and position of each continent.
It's been imprinted in your brain by every atlas and world map you've ever seen.
If you turn back the clock through geological time you see Australia was once part of a huge landmass in which most of today's continents were joined and over which the platypus ancestors roamed.
It's hard to imagine what this ancient world looked like and how our modern continents were arranged within it.
But there are clues if you know where to look, and the first one comes from the substance that has helped to make modern Australia one of the wealthiest nations on the planet.
This black layer that I've been following here is coal.
This is a natural layer that's been exposed by the waves.
Just a few Miles away, though, there's vast diggers pulling this stuff out of the ground.
Around one million tons of coal are exhumed from this land each and every day.
But it has another value that goes beyond the financial.
What I'm looking for is a fossil that's in here.
There's a nice one.
See that just here? There's a little fragment.
That's a nice one, too.
These fossils contain evidence of Australia's past and that of the whole Southern hemisphere.
From these fossils I can find the type of vegetation that once covered Australia.
Glossopteris.
Lush forest.
Fossils found in Antarctica.
Just packed full of plant debris.
These are leaves of a tree called glossopteris Which formed 255 million years ago.
And that means that 255 million years ago, this part of Australia was lush forest.
It was these glossopteris forests that transformed over time into Australia's enormous coal reserves, and that's why the fossils are found inside them.
But more importantly, because the exact same fossil is found in Antarctica, it means that Antarctica was also lush forest.
But that's not all.
Glossopteris fossils from elsewhere also reveal the extent of the landmass.
In fact, glossopteris is found right across the Southern hemisphere.
It's found in Southern Africa.
It's found in South America.
The thing is the spores of these glossopteris just couldn't be transported across vast oceans.
In other words, all those landmasses must have been together.
Glossopteris has helped reveal the arrangement of all the continents in the Southern hemisphere at the time.
Not only was Australia linked to Antarctica but also to Africa, India, and South America.
This vast landmass was called gondwana A supercontinent which was the Southern half of the even larger landmass of pangaea.
The primeval land of gondwana was on an almost mythic scale.
It was carpeted with glossopteris trees, a forest more than four times the size of the Amazon basin, stretching further than any eye could see.
A tiny fraction of gondwana's forest still remains today in a cool pocket of new South wales in eastern Australia.
Australia was green and lush for over 300 million years enduring through the reign of the dinosaurs as well as the rise of the mammals.
Gondwana was so huge that it was destined to break up, and it was that breakup that created the character of Australia.
The mighty supercontinent of gondwana and its fairy-tale forests would soon be lost forever.
A great change was about to come across this land, an event that would transform Australia into the continent we know today.
To piece together what happened, you need to travel deep into this continent's red heart.
This is the unusual country town of coober pedy unusual because the 3,000 people who live here mostly live underground.
Houses, restaurants, hotels, churches There's even a subterranean book shop.
The people here have dug out these caves to escape the desert heat.
You know, at first, the idea of people living underground Modern-day troglodytes Just seems bizarre, and there's definitely odd things here.
But, actually, it maybe makes sense.
It's not claustrophobic.
It's cool, and it's airy.
And for a geologist like me to be surrounded by rocks It's just ideal.
The reason the townsfolk go to such lengths is because this rock contains a treasure, one of the most precious jewels on the planet.
For them, it provides a livelihood.
For me, it's a crucial clue to how this land changed when gondwana broke up A precious gemstone that, at best quality, has more value than diamond.
Opals are extraordinary.
The highly specific conditions in which they form have occurred only rarely in the history of our planet, and then mainly here in the Australian outback.
Opals only occur because of what happened during the demise of gondwana.
Ah, now, there's a bit.
And I can figure out those ancient events by examining these gemstones.
Silica.
Sulfuric acid.
Bacteria.
An inland sea.
What I love about opal is it forms through this peculiar set of conditions.
You need two raw ingredients for it.
One of them is silica and the other is acid.
Now, the silica is pretty simple.
It comes from minerals in the rock around here.
But for the acid, you need a really strong acid, like sulfuric acid, and the sulfur for that comes from bacteria that eat sulfur when oxygen is not around Bacteria that live in the mud at the bottom of a stagnant sea.
To turn that sulfur into sulfuric acid, you essentially need to put oxygen into it, so you need to take the sea away, exposing it to the air.
So, now you've got sulfuric acid, and what that does is, it just leaches its way through the rock, picking up the silica and concentrating it into these little, narrow bars.
What all that complicated chemistry tells us is that there used to be an inland sea here.
But, actually, down here in the few places, the opals preserve far more obvious evidence of that sea.
Now, look at that seashells.
You don't get much clearer evidence than that.
It's hard to imagine now, but here in the dry, dusty interior of Australia, there existed for just a while an inland sea.
This sea was created by an event of epic proportions The breakup of gondwana.
Around 180 million years ago, huge upwellings of hot rock began to rise from the mantle deep below the earth's crust.
These plumes wore away at weak spots in that crust Until finally, 150 million years ago, they gave way.
This was the beginning of the breakup of gondwana.
As the continents separated, new seafloor was created between them.
This new material was hot, which made it expand and displace the seas above it.
This was what caused global sea levels to rise so that water rushed into the flat center of what would become Australia, creating the inland sea.
And it lasted for over 35 million years.
When it retreated, the sea left in its wake the specific conditions for the formation of opals.
But the breakup of gondwana also created something else extraordinary, something which would help people survive here millions of years later.
The interior of Australia is harsh, forbidding.
When the Europeans first came here over two centuries ago, they realized the key to settling this land was to find water.
From the time the Europeans arrived in Australia, they had an obsession, and that was to get into the country's interior.
They were absolutely convinced that somewhere in this vast landscape had to be an inland sea.
After all, all the other continents that they explored had one The Great Lakes in the U.
S.
, caspian in Asia.
Why should this place be any different? They were, of course, 100 million years too late to find Australia's inland sea.
But they didn't know that, and such was the importance of finding water that they kept on trying.
But, of course, there was a people who had lived here for many thousands of years, and they knew a source of water that the Europeans didn't.
Dean ah chee is an elder of the lower Southern arrernte people and was schooled from earliest youth in the aboriginal ways of finding water in this dry land.
And so do all the songlines relate to water? So, how far can you navigate on songlines? So, how do you find it? Tell me the secrets.
Really? So, it's that important, it's that crucial, that's it's almost kept, like, a secret.
A secret.
Yeah.
Yeah? The aboriginal people, for thousands of years, have used these songlines to lead them to a reliable source of water in the desert Water that emerges from underground into what's called mound Springs.
Ah! What the aboriginal people couldn't know was how their songlines linking up one mound spring to another echoed the geology below.
Because deep in the ground, all these mound Springs were linked in a vast reservoir of water.
What's really intriguing about these Springs is just how many there are.
In this area, there's a handful, but across the region, there's something like 700.
What's even more remarkable is that I'm swimming above this enormous reserve of water that's deep down there and extends beneath almost 1/4 of Australia's land surface.
This reserve is called the great artesian basin, and incredibly, it holds enough water to fill 26 billion olympic-size swimming pools.
It's a giant aquifer, porous rock under the ground which holds water, and a key part of it exists here thanks to the ancient inland sea.
Even before gondwana began to break up, the first element of the great artesian basin was in place.
Deep underground, there were layers of porous sandstone rock, but any water which got into that rock would quickly escape again because there was nothing to contain it.
The inland sea brought and left behind the crucial ingredient needed to trap the water inside mud.
The mud hardened into a lead of impermeable rock which lay across the top of the sandstone.
So when rainwater fell, it could trickle around the edges of the lead and get into the sandstone.
But crucially, that same lead prevented the water from evaporating away.
At a few places where the lead's broken, the water escapes.
These are the mound Springs that have sustained the aboriginal people for thousands of years.
And because these Springs provide the only reliable source of water for much of inland Australia, they're a vital lifeline for wildlife here, as well as the great sheep and cattle stations of the Australian outback.
It's an extraordinary thought that the muddy remains of a long-lost sea still provide water that sustains life here today.
By around 100 million years ago, gondwana had broken apart, but Australia still didn't exist as a separate continent.
There was one big split yet to come one that would transform Australia and lead to the evolution of one of the most spectacular animals on the planet.
This is the great Australian bight, over 600 Miles of coastline on the Southern edge of Australia.
It's just vast.
The cliffs themselves are 250 feet high, falling away to the sea.
If I'd been walking along here 90 million years ago, then there would've been no cliff.
There would've been no ocean.
Instead, I would've been able to take a single step from here directly onto Antarctica.
This is how the coastline of Antarctica and Australia joined up.
Despite the inevitable erosion, it's still a neat fit to this day.
Although these two continents are now almost opposites, back then the story was very different.
They were effectively identical twins, both temperate, forested lands which lay together near the South pole.
And like all twins, they weren't easy to separate.
Although gondwana was gone, Australia and Antarctica stayed close together for many millions of years.
But the process that transformed them into radically different lands also had another consequence The evolution of the largest group of animals that ever lived on the planet.
These whales spend most of the year in Antarctica, feeding.
But at this time of year, August, they journey up to 1,500 Miles here to breed.
These are Southern rights Third largest whale species on the planet.
You're only seeing about 10% of the animal.
The bulk of it, 90%, is underneath.
These whales can grow up to 50 feet in length, and they can reach such a size because of what they eat, scooping up two to three tons of food each day Millions and millions of miniscule krill.
How these great animals came to survive on these tiny creatures is a direct consequence of Australia's geological history and its separation from Antarctica.
90 million years ago, something happened to finally separate Australia from Antarctica.
Volcanic activity from deep within the earth's mantle forced up a new ocean crust between them, creating a mid-ocean Ridge which broke them apart.
Australia was, at last, a separate island continent.
And that left Antarctica sitting all alone over the South pole, still temperate and forested.
That was until the isolation of Antarctica created an unusual effect in the waters around it.
Normally, the wind drives surface currents, pushing the water onto shores like these, where the energy dissipates.
But thousands of kilometers over there is Antarctica.
There, the situation is slightly different.
The water goes 'round and 'round that huge mass, building up flow.
And without land to get in the way to disrupt it, the current just gets stronger and deeper.
The oceans were free to flow all around Antarctica, driven by the winds, and this was the beginning of the circum-antarctic current.
Its effect on Antarctica was profound, cutting off the continent from the warm waters to the north.
In just one million years, Antarctica was transformed from a temperate, forested land to one entombed in ice.
From now on, Antarctica would be a land of desolation inhabited by nothing bigger than a penguin.
But in the ocean, this new current had a more positive effect, playing a significant role in the evolution of all filter-feeding whales, the Southern right whale among them.
The motion of this current forced up water from the depths of the ocean to the surface, carrying with it nutrients which support tiny creatures such as phytoplankton and krill.
This was a rich source of food just waiting to be scooped up.
And sure enough, around the time the current appeared, sea-dwelling mammals began to develop a new way of eating Filter-feeding those vast volumes of krill.
Giant whales, to this day, feed in the same way.
I could watch them all day, just doing their stuff out there.
It's lovely to think that it's the circum-antarctic current that played such an important role in allowing these giants to develop and also keeps them fed today.
In a way, these whales are the last remaining link between two continents that started as twins and have grown so far apart.
Australia's fate was to be very different to that of Antarctica.
It, too, would change dramatically, but in almost the opposite way.
While Antarctica turned to ice, Australia was turned to dust.
It continued moving northwards, and around 20 million years ago, Australia pushed into warmer latitudes and this would have significant consequences for this land and anything trying to live on it.
The forest died away, save for a few tiny pockets.
It was replaced with bare, red land and the one tree that thrived in these new, arid conditions The eucalyptus A tree that now accounts for almost 80% of the forest in Australia.
For the animals, it was a brutal case of adapt or die.
Only a few were able to evolve quickly enough to survive.
And a classic case of that rapid evolution is this fellow.
He's big.
He's really big.
I'm assuming you want a big koala.
Yeah, yeah.
Big koalas are good.
I don't have necessarily a preference.
Okay.
Just don't move so it can climb across.
Over this way, sweetheart.
There you are.
Good boy.
He's not sure Under his bum.
Yeah, I got him.
Gosh oh.
It is heavy.
What's that? You say 11 kilos? About 111/2, I think he is, yeah.
It's just Good boy.
The koala's Teddy-bear features and the anatomy that underpins them are the result of having only the eucalyptus tree to munch on.
A very chewy tree at that As paleontologist Mike archer showed me.
- This is a modern koala.
- So this ah.
Most of this head has to do with smelling, eating Here's all the teeth And the muscles that drive the powerful jaws, because these trees are hard to eat.
So, basically, their head is a chewing machine.
Exactly.
Now, if you look at some of the fossils Now, these fossils are 20 million years old.
You've got an animal here that's about half the size of the modern koala.
So, this thing has become gigantic.
It's a bigger and bigger face.
The eucalyptus trees didn't change only the koala's machinery for eating, but also for communicating.
This bubble of bone here is an echolocating chamber that's very good at picking up low-frequency vibrations.
A low-frequency sound? Yes, that weird sound they make transmits long distances, and they have to, because where they live here, the trees are far apart.
So, koalas have made this kind of alliance with this tree, really.
And then eventually that little niche is the one that then spreads.
So they're the lucky ones.
They lucked out.
They were the furry parasite that lucked out.
The koala's face reflects the dramatic climate shift that Australia has undergone turning from verdant forest to mostly red, dry desert.
The drying out of Australia is just one more phase in the changing history of this continent that was born in the arms of the giant gondwana was flooded by sea when that supercontinent broke up And spent much of its life attached to an unlikely twin before finally becoming an island.
Throughout all that, Australia has been relentlessly moving northwards, and it's still going, which means Australia's transformation isn't over yet.
An unexpected fate awaits.
The Indonesian waters of the banda sea.
Hi.
Hi.
Can I come in? This is mein, a member of the bajau, so-called sea gypsies and masters of these waters.
He's taking me on a fishing trip into the seas which are his home.
He's completely gone.
Mein makes it look effortless.
And the bajau can almost reach out and take all they need from the sea.
Because with over 2,000 species of fish and over 600 species of coral, these waters, known as the coral triangle, are the most biodiverse and productive in the world.
To find out why the waters here are so rich and what this can reveal about the future of Australia, I'm going ashore to the nearby island of wangi-wangi.
The bajau villages are strung out all the way along the coast on this island.
But I've come inland, up here into the hills, to look for something rather peculiar.
Because strangely, the key to understanding the richness of the waters down there is the rock on this hill up here.
This is what I've been looking for here.
It's coral.
You can see a whole kind of colony of polyps.
There's another one here, and there's another one.
I mean, essentially, all of the gray rock you can see is coral, which is hardly something you expect to see at the top of a hill, and that's because this is an ancient coral reef that's been uplifted above the sea.
It's absolutely spectacular.
And by looking at this fossilized coral, I could find crucial clues to the future of Australia.
Strontium.
Strontium.
Three million years.
A layer cake.
The clams and corals in this reef are absolutely exquisitely preserved, beautiful.
But what's really interesting is the age of them.
Scientists have dated these corals with a form of element called strontium, which builds up over time, and the age that they get is less than three million years, which makes this reef a geological infant.
This means that this whole island came up above the waves no more than three million years ago.
But the biggest surprise is what lies beneath this reef A layer cake of ancient strata.
Beds of sand and mud that have built up gradually over time in conditions of tranquility and stability.
Those conditions just aren't found, really, in the crumple zone of southeast Asia.
Instead, they're absolutely typical of one place Australia.
The implication's intriguing.
These wakatobi islands are in Indonesia, so you just assume that they're part of Asia.
In fact, they're a fragment of the Australian continent.
It all points to one thing That Australia has moved so far north that it's colliding with Asia.
Continent is now grinding directly against continent.
The reason why the collision of these two continents creates such a bounty of fish for the bajau here is all due to the effect it has on the seabed.
The thing is, the seafloor around here is constantly shifting, constantly going up and down, and so you're always revealing new pockets.
And it's that separation, mixing, separation, mixing that drives evolution here so fast.
And that's what, in turn, creates these phenomenally rich seas and a way of life for these people.
Being in this place Here, now It's kind of a rare moment in time, a time when two continents are starting to directly collide into each other.
But the effects of Australia's move north are much, much bigger than the fabulous haul of fish around these islands.
They're visible all along the boundary where these two continents meet as a startling variety of dramatic natural phenomena.
It's forced up many of the volcanoes of Indonesia, even whole islands, such as Timor.
And on the pacific side, in Papua New Guinea, it's thrust up entire new Mountain ranges as high as Europe's alps.
And the action isn't over, not by any means, because this is Australia's future To effectively become a part of Asia.
It's impossible to tell exactly how that collision will pan out, but a likely version of events is that Australia crushes the islands of Indonesia into Vietnam, pushes on into China, and sideswipes Japan.
One thing's for sure Australia's brief existence as an island continent is coming to an end.
Australia's destiny is to become much more like this place Indonesia, no longer isolated and with a lush climate once again.
What's happening now is the biggest change in the history of Australia, and it's happening right before our eyes.
Of course, eventually all of this will be utterly transformed.
For a geologist, it makes it just so exciting because this is one of the most dynamic places on the planet.
And it's all down to the slow and steady movement of the one continent that's always been considered quiet and stable.
For so long, Australia was thought of as dry, unchanging, isolated, but its story is so very different from that.
In the past, it was twinned with Antarctica, and its future is in the making as it merges with Asia to become this tropical land of forest and mountains.
That's why, for me, Australia is the most surprising continent of all.