All language subtitles for Rise of the Continents 1of4 Africa 720p HDTV_Subtitles01.ENG

This is what we go on, is it?

This is one of those boats the
locals used...long time back.

Oh, dear.

GRUNTS

On 17th November 1855,

on the banks of the Zambezi
here in southern Africa,

the Victorian missionary
explorer David Livingstone

stepped into a traditional dugout
canoe, like this,

and set off downstream.

Right, let's go.

What Livingstone stumbled upon that
day

would not only help put Africa
on the map, it would also explain

how this huge continent was created
in the first place.

In this series,

I'm going to do something I've never
really done before -

search out the clues

that take us back to the key moments
in the story of each continent...

LAUGHS

..because the continents
are constantly on the move...

..and the traces of their secret past
are hidden all around us...

HISSES

..in the Earth's rocks,
but also in its landscapes...

That is very spectacular.

..and even its wildlife.

It's moving.

The tiniest detail can reveal
the history of a vast continent.

I'm beginning in Africa,
the most ancient continent...

LAUGHTER

ROARS

..and discovering the main turning
points that forged this land...

They're just all around us,
aren't they?

..creating its wealth, fuelling
its wars,

shaping its ancient civilisations...

..and seeing how events deep in
Africa's past

have influenced the whole planet.

But Africa now stands on the
threshold of a spectacular change,

as the immense forces
that shaped this continent

now threaten to bring about
its destruction.

The discovery of Africa's
deepest origins

started with Livingstone's fateful
expedition 150 years ago.

As he made his way down
the Zambezi river,

Livingstone found his progress
suddenly interrupted

by a strange sight...

..a huge curtain of mist rising up
from the river ahead...

..accompanied by
a steadily increasing roar.

Right.

Leaving his team behind, for fear of
putting them in danger,

the explorer continued
his journey on foot...

..only to find his way blocked by the
most impenetrable of all obstacles...

..known to the locals
as Mosi oa Tunya -

"the smoke that thunders".

We, of course, know it
as the Victoria Falls.

And the ultimate way to experience
the Falls

involves getting your feet wet.

Ah!

Oh, dear!

LAUGHS

This is the way to see the
Victoria Falls.

Oh, my God!

Aah!

While the water around me

cascades down more than 100 metres to
the river below...

..this pool forms a hidden sanctuary.

Livingstone thought the Falls
so lovely,

they must have been gazed
upon by angels in their flight.

Staring down at this
precarious drop,

it's not hard to see how Livingstone
was completely bowled over

by the scale, the grandeur
and beauty of the Falls.

But what he had no way of
knowing

was how this feature has got
huge geological significance.

But to appreciate that significance,

we need to go back some 200 million
years.

The Earth looked very different.

All the continents were clumped
together into one enormous landmass,

a supercontinent called Pangaea.

It was a land of extremes...

..an enormous mountain range higher
and longer than the Himalayas...

..and an interior covered in a vast
desert

five times the size of the Sahara.

Victoria Falls can tell us

how Africa was carved out from the
heart of that great supercontinent.

You can see exactly what happened
here 180 million years ago

by looking in the vast gorge
beneath the Falls.

Because hidden in the rocks
is some intriguing evidence

of a cataclysmic geological event

that would create Africa as we know
it today.

What a place! It's like a...
an amphitheatre of rock.

The thing is, all these cliffs
are carved from the same rock,

a rock called basalt,

and it comes to us from
deep underground,

rising up as molten magma.

To appreciate basalt, to understand
what it's trying to tell us,

you have to get inside it, though.

In here are the secrets of its
formation.

These crystals...

cooled really rapidly.

You see there's a...there's a slight
speckled appearance,

which, if you look with a hand
lens,

you can see is lots and lots
of tiny, tiny crystals.

These crystals were formed
as the hot rock cooled,

and their size tells you
how quickly it happened.

So, what this is telling us, really,

is that this rock must have cooled
really rapidly.

Sudden cooling of searing-hot magma

means crystals don't have
time to grow,

which is why they're so small.

And one way to rapidly cool a
rock like basalt

is to erupt it from the surface,

expose it to the air,

and it just solidifies very quickly
before the crystals can grow.

So, all of these rocks here,

all these basalts were erupted
out as lava flows.

Lava flows that reveal their
size in the soaring cliffs.

What takes your breath away here

is just the sheer scale of the
eruptions.

I mean, that cliff there
is 120 metres high,

and it's just layer upon layer
upon layer of lava flows.

And the thing is, that continues down
underneath for hundreds of metres.

I mean, across this region, it's
thought that over a kilometre of lava

was erupted out in a million years or
so.

It must have been the most staggering
volcanic event.

These eruptions were the start of an
immensely destructive event

that happens only rarely
in the Earth's history.

They would have stretched
for thousands of kilometres,

burying huge swathes
of what was to become Africa

under millions of cubic
kilometres of molten lava.

The cause of this mayhem was one of
the Earth's most powerful forces...

..huge upwellings of superheated rock
called a mantle plume.

The sheer force of those mantle
plumes,

making their way towards the
surface,

pushed the land up,
causing it to thin and crack,

cracks which eventually got so big

that the land slowly began to
fragment,

so beginning the break-up

of the single largest landmass the
Earth had ever seen.

Pangaea.

As the supercontinent
began to split apart,

one by one, the Earth's continents
were torn from its outer edges.

The eruptions at Victoria Falls

led to the formation of India and
Antarctica.

Another mantle plume cleaved off
North America, then South America,

leaving behind Africa as we
know it today.

The break-up of Pangaea meant that
for the first time in its history,

Africa stood alone,

a continent in its own right.

And for the next
hundred million years or so

that newfound isolation would
transform Africa beyond recognition,

its landscape, its climate,
but also its wildlife.

It forced animals to adapt

to a myriad of different complex
environments.

And to my mind, the most remarkable
of all those adaptations

didn't happen here on land,
but just out to sea.

The coast of Africa, carved out
180 million years ago,

is today home to a wealth of life.

Perhaps most spectacular of
all are whales.

WHALESONG

Today these ocean giants are
undoubtedly the kings of the sea.

(WHALESONG)

But look far enough back in time

and we find the evolution of
these giant animals

is a direct consequence
of the cataclysmic events

that gave birth to the African
continent.

The first piece of evidence

can be found at another of
Africa's most famous sites.

Welcome to morning rush
hour in Cairo, Egypt,

the biggest city in the African
continent.

This is a place that's been
undergoing

really dramatic political
change in recent times.

Now, geologically, it's long
been stable,

but 100 million years ago,

it underwent the most colossal
geological transformation.

A change driven by the same event
which gave us the Victoria Falls.

And some tiny remnants of this
transformation

can still be seen today

amongst the ruins of Egypt's most
famous landmark.

The pyramids of Giza.

You get little hints there.

Nothing really good.

There must be something
better than...

The trouble with this face is it's
been dressed by the stonemasons.

You've got all these chisel marks.
You just can't see anything.

How frustrating!

Ah, now, this...this is more like it.
That's what I'm looking for.

VOICE ECHOES:
Creamy-coloured discs...

Every whale in the ocean...

These features have intrigued and
confused people for centuries.

The Greek historian Herodotus
reckoned that they were...

they were
the petrified remains of lentils

that the pharaoh gave the slaves
that built this monument.

But the truth's actually far more
bizarre, far more interesting.

If Herodotus had one of these,
a hand lens,

he might have made
a different interpretation,

because the surface of these,

they've got these exquisite whirls
and swirls.

They're clearly something
that's living.

These are actually nummulites.

They're the shells, really,

of the very largest single-celled
marine organism that's ever lived.

These nummulites can tell us

what the seas in which they
lived would have been like...

..because from chemical
analysis of their shells

we know that these nummulites shared
their homes

with millions of photosynthesising
microbes...

..creatures requiring an abundant
source of sunlight.

And that means that the seas in which
these nummulites once lived...

..must have been extremely shallow.

So, why is that important?

Well, it's because every
single block in this entire site

has been quarried from just a short
distance from here.

In other words, those shallow
seas, that the nummulites lived in,

were right here.

100 million years ago,
something happened,

something connected with the birth of
the African continent,

to transform much of northern Africa

into a shallow sea, teeming with
life.

As the great supercontinent
of Pangaea broke up...

..so the rising molten magma
beneath its surface

threw up a chain of underwater
volcanic mountains.

These displaced enormous
volumes of water,

contributing to a staggering
300-metre rise in sea levels

that not only swamped much of the
North African coast,

it even split the newly formed
continent in two.

And it was this transformation of the
landscape

that was to lead to the evolution of
that most spectacular of mammals...

..the whale.

To discover how, I've come to Egypt's
Western Desert...

..home to a remote valley

of sandstone cliffs and wind-carved
rocks called Wadi al-Hitan...

Echo!

ECHOING

..that once used to be full
of marine life.

ECHOING VOICE
This sculpture underneath rocks...

'Palaeontologist Charlie Underwood
has spent the past four years

'studying this long-lost seascape.'

Here's just quite a nice place
to show

what the sea floor
was really like at the time.

Right. Really...

Oh, wow. Yeah.

Yeah, you see, if you get up
here... Yeah.

These are incredible. These
tubes are burrows, are they?

Yeah, so we've got... This is
essentially an ancient sea floor,

and these are the burrows of
the various animals

that were burrowing into this.
Shrimps. Small lobsters. Crabs.

'The closer you look, the more this
aquatic landscape comes to life.'

I can see a snail. There's a little
gastropod shell.

Just in here. Yeah.

There's the small tooth of a
lemon shark.

You've trumped me.

That's lovely.

So sharp.

There's a small nummulite.
Ah, yes. Saw these in Giza.

Fairly small ones here, but they
really show this is shallow water.

Yeah.

Beautiful way they get
sculpted by sandblasting.

'But it's the discovery of some
other, much larger marine fossils

'that has made this valley
such a focal point

'for scientists trying to piece
together the story of whales.'

Look at this.

Yeah. Amazing, isn't it?
What a size!

Yeah, it's impressive, isn't it?

What is this, then?
This is a thing called basilosaurus.

Basilosaurus.
What a fantastic name!

'Since 1983,

'scientists have uncovered the
remains of around 300 skeletons

'belonging to a very early type
of whale, basilosaurus.'

So, how long were they, then?

A big one of these could well be
something like 15 metres.

The tail is sort of going off
in that direction,

but the head is sort of going
off into the cliff.

Do you think the head'll still
be here? It may well be.

You can just see...

'And what's so special about
basilosaurus are the various features

'that reveal what these very
early whales evolved from.'

There we are, look. What's this?

There's a tooth starting to
come out.

Oh, that's great.

That's fantastic.

They're very sharp.
This is a tooth for cutting.

This isn't a tooth just for gripping
small fish,

like those little
conical teeth of a dolphin.

Yeah. These are for grabbing a big
animal,

killing it, cutting it up,
swallowing the bits.

Basil was a bit of a fearsome thing.

In what other ways
is this creature different?

Just in...in many ways.
This weird mix of features.

Small back legs. Back legs? Yeah.

These early whales had
back legs? Yeah.

No use for walking. They're much too
small for that.

But all the bones are there.

WHALESONG

Little pores around the jaw that
suggest maybe it had whiskers.

Whiskers? Yeah.

Its nostrils aren't quite in the
position of those of a whale,

with a blowhole.

A list of features
that places basilosaurus

at almost the midway point,
in evolutionary terms,

between a modern whale and a
four-legged land mammal.

What kind of animal are we talking
about for what they came from?

If this is a transition,
what did they come from?

Well, the closest living
relative of whales

are actually some of the
hoofed animals.

Right. Things like pigs, hippos,
even antelope.

But, unlike modern hoofed
animals,

the ancestors of
these were carnivorous.

The shallow seas that formed here
would have offered rich pickings

to tempt the carnivorous animals
living along its shores

into the water...

..over time losing their connection
with the land completely,

to evolve into whales.

The fossils here at Wadi al-Hitan are
just spectacular.

And they prove that around 50 million
years ago,

a small group of four-legged mammals
made this extraordinary leap,

going from living on the land to a
completely sea-based existence.

It was an incredible evolutionary
U-turn

that led to every whale in the
ocean,

and it was the direct result
of the break-up of Pangaea

and the birth of the African
continent.

By 30 million years ago, sea levels
dropped, the seas dried out,

and the familiar outline

of the Africa we know today
finally emerged.

The break-up of Pangaea

explains how Africa emerged from the
wreckage of the supercontinent.

The next critical moment in
Africa's story

doesn't take us
further forward in time,

it takes us back into an even more
distant past...

..back to an extraordinary sequence
of events

early in the Earth's history.

These deep origins
help explain the formation

of some of Africa's
most iconic landscapes,

and they also explain one of the
great puzzles about the Earth -

why the continents move at all.

The clue that solves these mysteries
is found in Sierra Leone.

I've come to the large market
town of Kenema...

Hello! Hello! Hello!

..a busy commercial hub

of over 100,000 people.

Everywhere you look,
people are selling stuff.

Like, this is obviously vegetables.

Hi! What are these called?

What are these...?
Oh, these are okra.

There's some, er, beauty
products here.

This market is kicking. It's really
got a lot of energy to it.

You know, it's strange,
you say Sierra Leone

and you immediately think
of that civil war ten years ago

and all those horrific pictures

that you were getting nightly
on the television.

And yet, when you come here,
it's just completely different. Hi!

It's such a great place,

but there's one commodity that really
fuels the economy round here,

but you won't find it in this market.

A commodity that can tell us

what this part of Africa was
like billions of year ago,

long before Pangaea.

'About 30 kilometres outside
Kenema...'

This is one of the pits.

'..lies a cluster
of steep-sided sandy pits...

'..called Jah Kingdom.'

Look at that.

Three-quarters of working-age men in
the area work in pits like these...

..digging their way through the deep
sand of an ancient river bed,

to uncover a layer of gravel
scattered with precious raw diamonds.

What you don't appreciate
till you're actually here

is the amount of material
they have to remove

just to get at the diamond-bearing
gravels which are underneath here.

How much time to dig down?
A month. More than a month.

Just to get through all of the
sediments that don't have diamonds

to get down to the ones underneath
here that do. Yes, sir. It's amazing.

During Sierra Leone's civil war,

these diamond fields were bitterly
fought over.

Now the war's over,

but the work of finding diamonds
amongst the gravel

still relies on the same simple
technique today as it always has.

What's happening here is the diamonds
are really dense, quite heavy,

so they...they kind of sink down,

and you find it glinting in amongst
all those dark stones there.

Nothing. Nothing.

What happens when someone finds a
diamond? Does everyone go shout?

And...is there lots of noise?

You keep cool. Keep cool? Yes.

Say, "I have a diamond, I
have a diamond"? No, no, no.

Just keep quiet. Cool.
Be discretional. A precious stone.

For the lucky few,
their hard work will pay off,

as very occasionally a diamond is
discovered lying amongst the gravel.

This is what it's all about,
a raw, natural diamond.

This is what everyone's looking for.

For the guys around here,
this is about a month's salary.

And for the jeweller that buys it

and fashions it into something
like an engagement ring,

it's probably several hundred
dollars' worth here.

But for a geologist... I don't know,

I think it's even more valuable, even
more beautiful,

because it's a window back in time.

It takes us back right to the birth
of the very first continents.

This diamond contains within it

the secret of the earliest
origins of this part of Africa.

IAIN'S VOICE ECHOES:
Carbon atoms...

compression and temperature...

If you could see deep into this
diamond,

what you'd find are carbon atoms that
are really tightly bonded together

and arranged into a kind of pyramid
shape, and that arrangement

is because of the intense pressures
that form the diamond,

something like 50,000 atmospheres.

The only place we know of where you
can find that kind of pressure

is 150 kilometres below
the Earth's surface,

within an exceptionally hot layer of
rock known as the mantle.

But to form diamonds' distinctive
arrangement of carbon atoms

also requires very specific
temperatures, about 1,100 degrees.

And that's really odd, that,
because the Earth's mantle

has got temperatures that are much
higher than that.

Temperatures over 1,600 degrees.

So, to explain diamond formation,

you need to find a place that's over
150 kilometres deep

to give the right pressure, but
not a part of the normal mantle...

..because this mantle is too hot.

The only place on the planet

that's got the right pressure,
right temperature,

is at the base of huge slabs
of continental rock

that extend way down into the mantle.

Those slabs are called cratons.

Cratons are incredibly thick
pieces of solid rock

that extend deep beneath
the Earth's crust.

But because of Earth's solidity,

a craton is much cooler than the
surrounding mantle...

..which means the bottom of a craton

has the perfect conditions
in which to form diamonds.

The diamonds here found
their way to the surface

in ancient volcanic eruptions,

and they tell us something remarkable
about Africa's past.

Radio isotope dating of diamonds show
that they're billions of years old.

I mean, this one's probably
nearly three billion years old,

but some of them go back
to three and a half.

What this means,

what the very existence of this
diamond here reveals,

is that I'm standing on top
of an ancient craton,

a piece of land that formed
nearly three billion years ago.

It's called the West African Craton.

It's one of the very oldest
pieces of land on Earth.

But it's not the only craton in
Africa.

There are five of these ancient
building blocks,

each forming a distinctive
landscape.

In the south lies the Kalahari
Craton,

that lies beneath
most of southern Africa.

To the east lies the Congo Craton,

which today forms one of the greatest
river basins on Earth.

Further north beneath the Sahara lies
another of these ancient landmasses.

The cratons were formed at a time
when the Earth was in its infancy.

Three billion years ago, the Earth
looked very different to today.

The only landmasses were
the cratons,

and unlike the continents today,
they didn't move.

They were static islands
in one giant ocean.

Because they're so ancient, the
cratons have preserved evidence

that solves one of the great
mysteries about the continents -

when and why they first
began to move.

Without this momentous event,

there would have been no Pangaea and
no Africa.

The evidence for why the
Earth's crust began to move

lies hidden inside Africa's diamonds.

This is the Government
Gold And Diamond Office,

where a team of highly
trained valuers

are examining diamonds from the mines
all over Sierra Leone.

It's a process
few outsiders ever get to see.

So, how do you do the process?

Say, if you get a pile of diamonds,
where do you start?

Here we look for the shape, the
size, the clarity and the colour.

So, what is...? I see a big one here!
What is the size of that one?

Like, this stone here...
is a 20-carat stone.

So, what would that be worth?

Well, it depends on the quality.

Now, I have looked at this stone,
and there's no inclusion inside,

meaning blemishes
inside or outside. Right.

Or inclusions that would be inside
the stone.

The shape is not so good.
But the colour is excellent.

So, this kind of stone would
normally be about $15,000 a carat.

So, multiplied by 20? Yes.

$300,000. $300,000 stone, yes.

In the rough. That's quite nice.

So you're looking for ones that are
perfect, without any flaws, ideally.

Without...ideally, no flaws at all.
No flaws. Right.

But it's the diamonds
with the flaws, or inclusions,

that I've come here to see.

IAIN'S VOICE ECHOES:
Pyroxene and olivine...

Diamonds like these,
that contain inclusions,

provide the perfect portal for
geologists,

because hidden in each of
these is a clue

to probably the biggest geological
change in the planet's history.

One that explains
how three billion years ago

the isolated cratons came together
to form the first continents.

Inside every one of these

is a fragment of the rock that was
around the diamond when it formed.

A fragment from the base of the
craton

150 kilometres beneath
the Earth's surface.

And the key is a change in the sort
of rock that's found down there.

You see, diamonds that are
older than 3.2 billion years

contain minerals
like pyroxene and olivine.

Olivine is typical of the rock
normally found underneath cratons.

But from three billion years onwards,

there's a strange change in the
composition of these inclusions

to include fragments of a garnet-rich
rock called eclogite.

Eclogite isn't normally found
where diamonds are made,

deep in the base of the cratons.

It comes from much higher up,

from the rock that forms the ocean
floor, the oceanic crust.

What's intriguing is,

why did bits of oceanic crust end up
beneath Earth's cratons

from three billion years onwards?

The answer turns out to be
pretty simple, and that's because

these tiny differences in the
inclusions in the diamonds

allow scientists to precisely
date when rafts of oceanic crust

first began to be forced
underneath continental crust.

It was a crucial turning point
in the mechanics of the Earth.

RUMBLING

Three billion years ago,
the dense rock of the ocean floor

began to sink down beneath the
cratons...

..a process called subduction.

This sinking conveyor belt of rock

had a dramatic effect on the land
above,

dragging the cratons together.

It was this process

that would eventually create the
African continent we see today.

Driven by subduction,
the Earth's cratons,

which up until this point in time had
been relatively static,

began to move.

So starting an epic geological cycle,

with cratons coming together and
separating,

to create and destroy a series of
long-lost continents...

..until finally,
550 million years ago,

subduction brought the five cratons
that make up Africa together,

part of an even bigger
continent called Gondwana.

In the half a billion years since,

the planet has seen extraordinary
change,

the creation of Pangaea

and, 100 million years later,
its violent destruction.

But Africa's cratons
have stayed together...

..ancient, stable and solid...

..until now.

Because, after half a billion years
of stability,

the long history of this African
land is coming to an end.

Beneath the surface,
there's a destructive force

that now threatens to break
up the entire continent.

A clue to what's happening

can be seen in how it's shaped life
here in the Serengeti.

For the final chapter
in our story of Africa,

we've come here to the plains
of northern Tanzania,

to see an animal that's synonymous
with this part of the continent.

An animal with one of the most
spectacular migrations on the planet.

This is the largest concentration of
grazing animals

to be found anywhere on Earth.

A massed gathering of herbivores...

They're just all around us, aren't
they?

..that owe their very existence

to a geological struggle
going on beneath their feet.

This is what we've come to
see. Wildebeest.

Some of them will start heading to
the north...

Mm-hm.

..to an area which is
up on our left side here.

This annual migration of between one
and two million wildebeest

is one of the great animal
movements on this planet,

and here we are right in the
middle of it.

But look closely, though,

and something rather odd about these
animals jumps out at you.

It's interesting, all the calves are
exactly the same size.

So, how old are they, then?

They have...
They were born in February

so up till now they have
three and a half to four months.

So, in February,

that's the time they deliver their
babies at once, all of them.

That must be an incredible period,

because just in those few short
weeks... Sure, sure, sure.

..you're getting hundreds of
thousands of calves being born. Yeah.

Hundreds of thousands of calves,

born not only at the same time
but also in exactly the same place.

And the reason why they all descend
on this same area,

to have their babies at the same
time,

is the grass that grows on the
ground.

At the start of every rainy season,

one particular small patch
of the Serengeti

becomes covered with some of the most
nutrient-rich grass on Earth...

THUNDERCLAP

..containing four times the calcium

and nine times the amount of
phosphorous

than grasses just a few
kilometres away.

Nutrients that are crucial
to healthy calf development.

It means this one comparatively tiny
patch of fortified grass

can support millions
of nursing wildebeest.

The reason why this grass is so
unusual

can be found looming over the herds.

Towering almost 3,000 metres above
the Serengeti plains

is one of Africa's strangest
and most explosive volcanoes.

Ol Doinyo Lengai,
or "Mountain of God".

Back in 2007, an eruption lasting
almost 12 months threw a giant column

of steam and ash nearly
five kilometres into the air...

..destroying countless crops...

..and forcing thousands
to flee their homes.

This ash is unlike any other
volcanic ash on the planet...

..with a chemical make-up so odd,
so rich in minerals,

that the grass around it
has become supercharged.

It's this volcano, and the ash that
comes from deep within it,

that enables the wildebeest to breed
in such huge numbers here.

Without Ol Doinyo Lengai, this
wildlife spectacle wouldn't exist,

and the reason why Ol Doinyo Lengai
is so unusual,

why it's so nutrient-rich,

is because of what's going
on deep beneath it,

something that threatens not just
the future of Tanzania,

but the entire African continent.

And we're off.

It's a journey into the unknown.

It looks like any normal volcano,
really. You get the conical shape.

You get a few parasitic little cones
there that's erupted out.

There's some evidence of lava flow.

But actually, that's just one of the
strangest volcanoes on the planet.

We're just coming round to
the top now.

You can start to see
the fresher stuff from 2007,

and that's all the previous
eruptions,

so this just ahead of us here
is the crater rim.

We're coming right up over it.

Oh, my God. I don't think I've ever
approached a volcano

in quite this way before.

Look at this!

Look at that. There's a crater!
Staring into the abyss.

That is just magnificent.

Very simple.

It's like your characteristic
volcano, and yet it's not.

It's hiding this great secret.

The secret of Ol Doinyo Lengai may
lie kilometres down,

but it can be uncovered by looking at
some of its very odd lava.

To get my hands on some of it,

local Masai guides Rafael and Serengi
lead me to a recent flow.

So, how many times
have you been up to the top?

Times? 20. 20 times?

The same for you? Yeah, yeah.

So, do you worry it will erupt
again? Yeah, we worry.

Eventually, we reach a patch of
recent lava.

What a white wonderland!
This is from the last eruption?

Within this flow lies the secret to
Africa's future.

I want to get a sample. Really?
Yeah, I got a hammer.

OK. Ta-da. Yeah!

I'm going to see if I can...

OK.

This lava contains evidence of two
huge geological forces at work.

IAIN'S VOICE ECHOES:
Carbon dioxide...

Releasing its clues involves
some basic chemistry.

So, I want to...I want to show you
how special these lavas are.

I'm just going to...
crush them down a little bit.

Cos I'm going to do something that
really only this lava can do.

For that I need some acid. This is
weak...some dilute acid.

And what I'm going to do is I'm just
going to pour it onto the rocks.

If I poured this on a normal lava,
say a basalt,

then you'd just get no reaction.

But watch what happens
when I put it on this lava.

Look at that. Isn't that amazing?

It's just foaming away,
effervescing away.

And...

What's coming off here is
carbon dioxide.

It's that carbon dioxide
that's really important because,

as well as these lavas being rich in
sodium and calcium and phosphorous,

all of the elements that make the
Serengeti grasses so nutrient-rich,

it's also incredibly rich in carbon.

And it's an indication that there's
something really mysterious

going on deep beneath this volcano.

So-called carbonatite lava like this

only forms when rocks rich in carbon

are melted at incredibly high
pressure.

And there's only one place
in the planet

where you find carbon-rich
rock at high pressure.

And that's the same place
that diamonds are formed...

..the base of cratons.

The magma that's feeding that volcano
must be punching its way up

through one of the five deep-seated
continental building blocks

that's formed the African landmass,

in this case, the incredibly thick
and ancient Tanzanian Craton.

This part of Africa may have been
stable for three billion years,

but now something
is melting the rock beneath it.

The mere fact that magma's rising up

through the deepest and
oldest landmass on the planet

means that beneath Ol Doinyo Lengai

there's an even more powerful
force at work.

Deep below this part of Africa lies
a giant rising mass of magma...

..a super-plume,

and for the last 45 million years,

this super-plume has been steadily
forcing its way upwards.

It's not only melting the base of the
ancient Tanzanian Craton,

it extends north over 1,000
kilometres across the continent...

..with spectacular results.

This super-plume beneath Africa and
its surface volcanoes

have created the very DNA
of this landscape.

Everything you see relates to that.

But in a way, the real impact of that
super-plume has yet to be felt,

because beneath my feet there's a
violent geological struggle going on.

It's one that began
25 million years ago...

..when the bulging
super-plume beneath Africa

started to rip and tear
the land above...

..creating a 6,000-kilometre scar

running half the length of eastern
Africa.

There it is.

The Great African Rift.

The Great Rift Valley

is one of the most complex ecosystems
on the planet...

..home to a staggering array
of plant and animal life...

..as well as being the birthplace, of
course, of our own species.

The Great African Rift Valley
is not just

one of the most spectacular wildlife
parks in the world,

it's also one of the most exciting
geological places on the planet,

a huge crack in the Earth that runs
the line of these cliffs

and is literally a tear in the
fabric of this ancient land,

all of it caused by this super-plume

of molten rock puncturing its
way up through the continent.

Now, here in Tanzania, we're at the
southern tip of that tear,

but at the northern end of that tear,

the continent is already being ripped
apart.

At the far end of the Rift,

Ethiopia's Danakil Depression is in
the throes of violent change.

Great tears are growing
in the fabric of the Earth...

..as the super-plume beneath

stretches and cracks the surface
above...

..breaking through
at volcanoes like Erte Ale.

The land here is so torn,
it's sinking below sea level...

..leading scientists to predict

that the neighbouring Red Sea will
one day flood this entire plain,

splitting the region in two.

So, the big question is, what's going
to happen at the other end?

What we do know is that the split
will start here in Ethiopia

and propagate through Kenya to the
edge of the Tanzanian Craton.

It's here that it gets tricky.
Some people argue

that it will cut right through the
craton, splitting it in two,

but others argue that it will exploit
weaknesses

to go around the edge of it,
either this way or round here.

From there, it's possible that the
split will follow

just the line of the rift, down to
the ocean through Mozambique.

But some people argue that it'll
actually swing to the west,

down in this way, cutting a swathe
through southern Africa.

Whatever course it takes,
one thing is virtually certain,

and that is that Africa,
that most ancient of lands,

will one day break up.

For over three and half billion
years, the African continent

has borne witness to the upheavals
of our restless planet,

an epic journey that has shaped every
aspect of life here today.

The creation of the very first land
on Earth, the ancient cratons...

..that have left their legacy in the
diamond mines of Sierra Leone.

These cratons, the stable heartlands
of Africa...

..have seen the world around them rip
and tear asunder

through the creation and destruction
of the supercontinent Pangaea,

a series of violent upheavals

that have left their mark in the
spectacular cliff of Victoria Falls.

They created the ancient seas that
shaped our civilisations...

..and the creatures around us.

But now Africa's changing
in other ways too,

because, economically,
this is a continent on the rise,

on the cusp of dramatic
cultural and social change.

The transformation that's
taking place in African society

is echoed by an even bigger
transformation

to the very fabric
of the continent itself.

The immense geological forces that
are at work beneath my feet

are preparing to redraw the
African map, tearing it in two.

So, for all Africa's long, long
history, this is, in every sense,

a continent that's in the process of
being remoulded and reborn.