How the Earth Was Made (2009) s02e11 Episode Script
211 - Earth's Deadliest Eruption
Earth, a unique planet, restless and dynamic.
Continents shift and clash.
Volcanoes erupt.
Glaciers grow and recede.
Titanic forces that are constantly at work, leaving a trail of geological mysteries behind.
This investigation ventures deep into remote Russia in search of a vast sea of stone called the Siberian Traps.
Experts will dig deep into Earth's ancient past to discover how this rocky wilderness formed, and unearth evidence in surprising places to prove how deadly volcanic eruptions in Siberia wiped out nearly every living thing on Earth.
The most dramatic episode yet in the story of "How the Earth Was Made.
" Earth's Deadliest Eruption The investigation into the cataclysmic event that radically changed planet Earth begins in the deep frozen land of Siberia.
50% bigger than the entire United States, this land is locked in ice for most of the year.
Temperatures plummet to minus 90 degrees fahrenheit and below.
But in summer, the ice melts and reveals one of the largest and most mysterious geological formations on Earth.
The Siberian Traps.
Nearly 5% of Earth's land mass is covered by this ancient sea of rock.
Deep canyons expose layers hundreds of feet thick.
These giant stepped formations are called traps, from the Swedish Word for "stairs.
" They were discovered under unusual circumstances.
Polish geologist Aleksander Czekanowski was exiled to Siberia in 1863 for "political crimes" against Russia.
While banished, he surveyed the landscape and stumbled upon this unique, unexplained expanse of layered rock.
Today, the journey to fully understand how this strange stone formation was made begins in a swamp.
I'm not sitting in this swamp just for fun.
This swamp's actually very characteristic of what Siberia was probably like before the Siberian Traps formed.
This vegetation, this shallow, stagnant water is very different to the environment we see in Siberia today.
The clue that enabled scientists to figure out that Siberia was once a swamp came from a particular kind of rock found beneath the traps.
Coal trillions of tons of it.
This rock here is coal.
It's very important in Siberia.
It forms when plant matter, trees, the thick vegetation dies and falls into a swamp, and over millions of years of geological time, they're compressed into a hard rock substance like the one I'm holding in my hand today.
The age of the coal was determined by dating the plant fossils trapped inside the rock.
The process revealed that the coal was formed more than continued to collect and be compressed over the next 50 million years.
So, the environment was very stable--swamps, thick vegetation.
Then suddenly, 250 million years ago, it all stops, and you have the Siberian Traps lying on top of the coal.
So, something fairly dramatic must have happened at that time, so we really need to study this phenomenon to investigate the geology and see what we can find out.
But investigating the geology of the Siberian Traps is no easy task, because they're located in one of the most remote and least explored areas of the planet.
It's an arduous journey for Howard and his team, a 1,000-mile trek through Siberia over land and water, camping out in mosquito-infested forests.
It's taken us nearly 7 days to get to this remote corner of Siberia, but this afternoon, we've finally found the rocks that we were hoping to study.
These towering pinnacles of rock mark the edge of the Siberian Traps.
Even from a distance, without leaving their boat, the geologists can identify this distinctive formation.
The rocks you can see behind me are basalts forming wonderful towers.
We've stopped and studied these in several locations.
And what we've seen is only a tiny part of the basalt which covers such a large part of Siberia.
This evidence unlocks the mystery of how the traps were made.
Basalt is what geologists call "igneous rock.
" and that only comes from one source--a volcanic eruption.
The Siberian Traps must once have been a vast, red-hot lava field.
I think the Siberian Traps would have been 1,000 times more intense than anything I've seen doing my own fieldwork.
And if I could go in a time machine and watch it all happen, it would be really just fantastic to see the scale of it.
The length of the lava flows, and the height of the fire fountains would have been really something to see.
There are several types of lava rock.
This basaltic lava is a free-flowing liquid when it first erupts from the ground.
Just looking at how fluid this rock appears gives us some of the clues what it might have been like in Siberia if we could have gone there.
There would have been really gooey, goopy, runny lava flowing across the land surface for This semi-liquid lava gives these rocky plains their name--flood basalts.
They still erupt today in Kilauea in Hawaii, currently the world's most active volcano.
After 25 years of constant eruption, the basalt lava field has engulfed more than 4 square miles of Hawaii's Big Island.
But the Siberian traps are bigger--500,000 times bigger.
Each distinct step is laid down by an individual lava flow.
Layer pours out upon layer until the traps are more than a mile deep in black hardtop, over an area nearly the size of the continental U.
S.
So, imagine the entire United States covered in a lumpy, uneven parking lot, like asphalt, everywhere as far as the eye can see, and that is what the Siberian Traps looked like when it first formed.
Geologists have discovered how the traps were made.
The next step is calculating how long this vast Siberian super eruption lasted.
Fortunately, volcanic rocks contain little minerals that formed when the rock crystallized--when the rock cooled and solidified.
And some of these minerals are radioactive, and they decay over time.
And so they're like little time clocks.
They start when the rock cools, and then when we measure them, the clock stops.
And we know how much time has passed since that rock formed.
Dating the oldest lava here reveals that the Siberian traps first ripped the landscape apart 250 million years ago.
And by also dating the youngest lava, scientists can figure out exactly how long the eruptions lasted.
The results are surprising.
They show that lava carried on pouring out and building up into ever-deeper layers for an almost unimaginable one million years, forging the largest lava flow on land.
The next step in the journey is to figure out why this vast eruption happened here in Siberia.
Most volcanoes exist at plate boundaries, thin spots on Earth's crust where the floating plates that support the continents jostle together as they drift across the face of the Earth.
Yet, the Siberian Traps are right in the heart of a huge continent.
So experts have to come up with an explanation.
This is a mantle plume.
It may not look like it.
And you have to imagine that this is going on over about 1,500 miles, rather than a bottle.
But it's quite a good simulation of how mantle plumes work.
They're heated from below.
This candle is the Earth's core supplying heat.
And this is the bottom of the mantle.
And the heat is heating up some of the mantle.
And it rises up as these blobs up towards the Siberian Traps which are up at the top here.
Mantle plumes are one of geology's great mysteries.
No one knows why they switch on or off.
But their shape is a crucial clue as to why plume eruptions are so fierce and so massive.
That mushroom head in reality can be 1,500 miles across.
And so, the volcanic eruptions can cover huge areas--hundreds of thousands of square miles.
And also, the actual head is a very short-lived phenomenon that probably erupts in hundreds of thousands of years, at most, a million years.
Evidence has been uncovered to reveal how and when the Siberian Traps formed.
250 million years ago, a vast magma bubble burst, cracking and slashing open Earth's crust.
And for life on Earth, a new devastating era began.
Two types of rock are proof of very different landscapes in ancient Siberia.
Coal reveals that before the traps existed, this area was a swamp.
Basalt lava is evidence this era ended with a bang--a super volcanic eruption.
But now, geologists have evidence that the Siberian super volcano was about to become Earth's greatest-ever killer.
The deadliest million years in Earth's history were about to begin.
Siberia was a swamp.
But deep underground, a plume of hot mantle rock was rising.
250 million years ago, the bulging crust burst open, and boiling lava erupted onto the surface.
The most cataclysmic and destructive million years in Earth's existence was about to begin.
With every eruption, basalt lava surged across Siberia in rivers and waves.
Terrifying forest fires raged.
Animals were burnt alive.
A new deadly Earth story was underway, one which would have catastrophic consequences for all life on Earth.
To figure out what chaos this mega-eruption caused for the Planet, geologists are taking a closer look at Siberia's ancient lava rocks.
This rock is very typical of what you see in flood basalt provinces.
And we have many what we call vesicles.
They're small holes in the rock, and those suggest that gases left this rock.
They escaped from this rock when this rock started cooling at the surface of the Earth.
The search for what kind of gas Siberia was producing begins nearly 8,000 miles away at Mammoth Mountain in California.
This is an ancient dormant volcano.
For years, it was thought to be harmless.
But then in 1989, a ranger had a terrifying experience.
It was wintertime, and a ranger was just checking on the area.
And he wanted to take a break from the wind, so he crawled in through a hatch that's in the roof of this cabin.
And he became very dizzy inside and didn't feel well.
And he had the commonsense to think that maybe there was some bad air in the cabin, and he crawled back up the ladder and got out safely.
But it always kind of remained a mystery initially.
Then just a few months later, the trees here began to die.
Clearly, something strange was happening.
So it required an explanation of what could combine with making a person feel dizzy and disoriented, and what would also kill trees at the same time.
Farrar's research revealed that a poisonous gas was to blame, one that was seeping upwards out of the ground.
Analysis proved that the gas was carbon dioxide, a byproduct of volcanic activity.
It's released when magma rises from deep underground.
So, just like this bottle of soda water, the magma beneath us contains dissolved carbon dioxide.
And when it reaches the surface of the Earth, the pressure is released.
Just like this, when you open the water, the pressure is released and carbon dioxide is coming out of this bottle of soda water, and that's the same gas that's coming out here at Mammoth.
Today, lava deep beneath Mammoth Mountain pumps out every day.
This suggests to scientists that trillions of tons of gas could have been released into the atmosphere by one of the Earth's largest eruptions in Siberia 250 million years ago.
And evidence comes from an unlikely source.
Well, this is a ginkgo tree.
And ginkgo trees are very special, because the ginkgo family has been around for a very long time--270 million years.
And it's remained fairly unchanged over the course of Earth's history.
Because the ginkgo changes so little over time, it is the ideal specimen for comparing the present with the past.
The leaf's surface is peppered with microscopic pores called stomata.
Plants use these stomata like tiny mouths to breathe in carbon dioxide.
The number of stomata on the leaves of a ginkgo indicate how much carbon dioxide is available to them in the atmosphere.
When there's a lot of carbon dioxide in the atmosphere, they only need to have a few.
When we look at fossils of ginkgo leaves that formed 250 million years ago, we notice that they have very, very few stomata to take up carbon dioxide.
And this means that there was a lot of carbon dioxide available in the atmosphere.
Investigators have studied ancient leaves from locations all over the world and calculated that there was 3 times more carbon dioxide in Earth's atmosphere 250 million years ago than there is today.
This was a deadly and global gas disaster.
And the only culprit capable of producing such substantial quantities of carbon dioxide is volcanic activity, on a truly massive scale.
When you have an eruption the size of something like the Siberian Traps, you imagine something almost apocalyptic in nature--ash blocking out the sun.
But then you have a kind of double whammy where you also have the release of volcanic gases from the eruptions.
And these gases trap in the heat, so it gets hotter and hotter.
Lava from the traps turns Siberia into a lifeless disaster zone.
But carbon dioxide can mingle and mix in the atmosphere, trapping heat inside like a parked car on a hot day.
Siberia is South Africa's Karoo Basin.
Here, evidence in rocks gives geologists a tip-off that carbon dioxide from the eruption provoked a climate disaster that wasn't confined to Siberia.
An old river channel slices through the landscape, exposing the layers.
These rocks have been dated to just before and just after the Siberian Traps began to erupt.
These are mudstones.
They form on lakebeds from squashed mud, so they're evidence that, just as in Siberia, the land was once swamp-like and covered in water.
But they're also evidence of change.
These rocks beneath my feet, which are green in color, are the older rocks here.
And then these rocks, which have got a more red color, are the younger rocks.
And the red color indicates that there's an environmental change.
That the climate was possibly drying out and becoming warmer.
The mud is rich in iron.
When it is shaded by plants or covered by water, it stays green.
When it's exposed to the sun, it turns rusty red.
So the red stones are evidence that plants and water, which shaded the mud, had disappeared.
250 million years ago, as Siberia spewed volcanic gases into the air, South Africa was drying out, warming up, and turning to desert.
The Karoo Basin is also where the first evidence was discovered that it was not just the plants that were dying.
Well, this animal was found in 1934.
My aunt, who was then a little girl at school--she came home from school one day and she said to her father, "daddy, what is a fossil?" and my grandfather's response was, "let's go off into the hills for a picnic and see if we can find one.
" so they went off to the hills.
And amongst other bones, they found this.
In their own backyard, the Rubidge family had unearthed yhe remains of an animal completely unknown to science.
This creature is a gorgonopsid.
It was a carnivorous lizard 10 feet long which roamed South Africa during an era called the Permian, hundreds of millions of years before even dinosaurs evolved.
But dating these fossils reveals that as Siberia began to erupt, these animals were dying.
Gorgonopsids are the dominant predators of the Permian period, and we find them in all these different layers in the Permian rocks.
Gorgons lived in this area about 260 to about 251 million years ago.
And then suddenly, when you get higher up at this sort of level in the Permian sequence, they disappear.
And the gorgonopsids were not alone.
There are virtually no animal fossils here younger than 250 million years.
7,000 miles from the Siberian super volcano, something caused the land to dry up, plants to die, and nearly every land animal to go extinct.
And one critical cause of this global disaster is carbon dioxide from the lava rocks.
Yet, this deadly, million-year-long chain reaction, triggered by Siberian eruptions, is only just starting.
The investigation has uncovered how volcanic activity in Siberia created a global catastrophe.
Fossil leaves of the gingko tree reveal evidence that the atmosphere was full of volcanic carbon dioxide.
Gorgonopsid skulls show animals were dying out at the same time.
But worse was to come.
The catastrophic Siberian eruptions were about to unleash a new murderous nightmare.
Siberia was a waterlogged, swampy bog.
50 million years later, Earth's biggest-ever volcanic eruption on land was smothering Siberia in layer after layer of solid, silvery basalt lava hundreds of feet thick.
An atmosphere saturated with volcanic carbon dioxide had raised global temperatures by around 10 degrees fahrenheit.
Life on land was dying.
Now the hunt is on to uncover evidence of how Siberia's super volcano precipitated a marine catastrophe in all of Earth's oceans.
But scientists aren't looking for answers in the sea.
They're climbing 10,000 feet above sea level up into the Dolomites Mountains.
Here in the mountains of northern Italy, these rocks give evidence of one of the greatest crises in the history of the planet.
Crack open the layered rocks and fascinating secrets are revealed.
Mysterious and long- extinct sea creatures called trilobites are preserved in their millions.
Their existence here proves these peaks were once a seabed.
The trilobites were trapped in sediment settling on the ocean floor.
over millions of years, geological upheavals have thrust them two miles up in the air.
The rock layers here are a oerfect record of life in the ancient oceans.
What we can see is, just below the level of my hand, there's lots of nice fossils, a big diversity of things we can find in here.
And then these younger rocks just above, just a little bit higher--basically, there's very few fossils in here, and a much lower diversity.
In between the two different layers of life, Wignall hacks into a black band.
In here, there are not just fewer fossils.
Here, there are none at all.
This is what geologists call the extinction zone.
It has been dated as 250 million uears old.
Worrying evidence that, having killed off most of the life on land, the Siberian super volcanic disaster was spreading to the seas.
This black clay contains microscopic, glittering clues--crystals of a mineral called iron pyrites.
Its shiny appearance has earned this rock the nickname "fools' Gold.
" it's worth just a few cents, but it holds priceless information about ocean waters where the rock formed This mineral, this iron pyrites will only form in the absence of oxygen.
And so therefore, it's a nice, very direct line of evidence for what's going on at this time.
The presence of fools' gold is evidence that the water in which it formed had no oxygen at all.
And scientists believe the warming effect of volcanic carbon dioxide from the Siberian eruptions was directly to blame for this lack of oxygen.
The ocean circulation is driven by the fact that we have a good temperature gradient.
It's cold at the poles and it's warm at the equator.
And so, the water circulates between the poles and the equator, like a conveyor belt.
But if you make everywhere warm, the conveyor belt turns off, and the water just sits there and stagnates and no longer has the ability to sort of resupply oxygen.
The ocean had become as still and warm as bath water.
And warm water absorbs less oxygen.
It's possible to recreate these nasty conditions in a fish tank, in fact.
All you need do with a fish tank is to put it in the window on a bright, sunny day.
The sun will warm the water up, and the water will start to lose its oxygen, and it'll--basically, it'll stagnate.
If you leave it for too long, your fish will die, and you'll have a sort of mini-recreation of one of the greatest extinction events of all time.
As volcanic eruptions tore Siberia apart, life was fighting for survival in the oxygen-depleted seas.
But the Siberian eruptions were about to flood an even more deadly poison into the oceans.
To find out what happened next, researchers hunted for a modern-day location that could recreate life in the Siberian-damaged Permian Ocean.
Unexpectedly, they found it in central New York state--Green Lakes State Park.
This unusual, little lake is extremely salty, and nearly 200 feet deep, making it a model in miniature of the ancient seas.
We get asked, "why do you go to a lake to study the Permian Ocean?" It turns out this lake is a lot like the ocean, actually.
It's fairly salty.
and its circulation system--the process that brings oxygen down deep into this lake--is shut down, just like we think happened to the Permian Ocean.
The top layer of the lake is healthy and thriving.
But deep down, the bottom layer is stagnant and still.
By lowering a water sampler 150 feet down, Kump's diving deep into the past to a time when the Siberian Traps were erupting.
Well, we have a couple clues from this water that's telling us about what's going on down there at the bottom of the lake, one of which is its color.
And this water is pink because it's loaded with tens of millions of purple bacteria cells in each ounce of water.
And the other is the smell.
So if I open up the lid here and take a whiff, it's a very potent smell of rotten eggs.
And that's a very characteristic smell of hydrogen sulfide.
Oxygen is toxic to purple bacteria, so stagnant water is a perfect breeding ground.
These single-celled survivalists flourish where other sea life suffocates.
But they have a nasty side.
They produce a noxious and pungent poison gas called hydrogen sulfide.
The tiniest amounts can be fatal.
The same bacteria live in sewers, so workers there must carry gas detectors.
Hydrogen sulfide deprives your body of oxygen.
It's also a strong neurotoxin, so it has that detrimental effect, as well.
And the really insidious thing about hydrogen sulfide is that it paralyzes our olfactory nerve.
In other words, we can't smell it anymore.
And that's what's so terrible, because right after you stop being able to smell it, if the level keeps building up, it can become instantly poisonous.
Kump's trying to figure out if the same lethal microbes plagued the seas stripped of oxygen by the Siberian eruptions.
He's searching for proof in rocks from 250 million years ago.
But bacteria don't leave fossils.
So instead, he's pursuing the chemical traces they leave behind.
So, the clues we're looking for are compounds called biomarkers.
These are chemical fossils.
They're fragments of the organism that have been preserved over long periods of geologic time in these rocks.
And from these fragments--from these chemical fossils, we can try to identify what organisms might have been involved in this mass extinction.
Like a fragment of bone or shell, a chemical fossil is a fingerprint identifying the micro-organism which made it.
And Kump's struck lucky.
This is it.
This is the clue we've been looking for.
This is the chemical fossil, the biomarker that tells us that these organisms were existing at the time of the greatest mass extinction of all time.
As Siberia erupted, the purple bacteria were in paradise, vigorously poisoning the water with hydrogen sulfide.
The sea became a suffocating, toxic cesspool.
The trilobites and virtually every other species of sea life died out and never returned.
The evidence is building up as to how massive volcanic eruptions in Siberia wiped out nearly all marine life on Earth.
Fools' gold shows the sea lost its oxygen.
Biomarkers show it was also poisoned with lethal hydrogen sulfide.
The Earth was choking.
Life could no longer depend on its two most vital resources--air and water.
But a new threat loomed, as Siberia's underground coal reserves added fuel to the flames.
a sudden violent volcanic eruption began in Siberia.
The traps erupted over the next million years, forging basalt lava layers thousands of feet thick.
Buried underneath the basalts were 5 trillion tons of coal.
As Siberia erupted, a powerful fuel was about to catch fire.
For geologists, coal is a crucial clue in figuring out how a huge volcano wiped out nearly all life on Earth.
Coal is the remains of dead plant material.
And when coal burns, the volatile materials are released, and these include gases such as methane.
And lava from the volcanic eruption was the ultimate source of ignition.
It was like pouring gasoline on a barbecue.
Now Saltzman is hunting for evidence of how this colossal coal fire damaged the planet.
His search begins in a barren blacktop wasteland.
But this is not Siberia.
This is a town in Pennsylvania.
I'm standing here in what looks like a war zone.
It's hard to believe this was the main road into a thriving community of several thousand people.
These cracks and these gases all around me are a clue not only to what extinguished this town, but also provide one of the key clues into the mystery of the greatest mass extinction of all time.
In 1962, the mining town of Centralia was a community of fire ignited a coal seam and caused an uncontrollable underground blaze.
Dangerous methane gas began to seep from the ground.
Today, the residents have abandoned the town.
The fire still rages underneath Centralia and methane is still released into the air.
The situation raises the question of whether the burning of Siberia's far greater coal reserves, set alight by lava 250 million years ago, also released catastrophic levels of methane gas into the air.
The volcanoes in Siberia would have erupted through the coals to get to the surface.
On their way, they would have cooked these coals.
And this burning of coal would have released methane, amongst other gases, and this methane would have had an extreme effect on the global climate.
As Siberia continued to erupt, temperatures all over the planet rose by a further 10 degrees.
It's a climatic change too dramatic to be caused by carbon dioxide alone.
There must be an additional culprit.
Methane is top of the list, because it's over 20 times more effective in trapping heat in the atmosphere than carbon dioxide.
Today, scientists are analyzing rocks for proof that methane from the Siberian coal fire was the culprit.
They've discovered a telltale chemical clue: light carbon.
It's a fingerprint of methane gas, and it has been recorded in every extinction zone all over the globe, from Antarctica to Italy--proof of the eruption's global reach.
The levels of light carbon geologists have discovered are so incredibly high, it equates to the sudden release of a trillion tons of gas.
Temperatures surge as the methane from Siberia spread across the globe, leaving every part of the planet devastated by climate chaos and mass extinction.
This would have been a very nasty place to live.
There would have been less oxygen in the oceans.
There would have been much warmer and drier conditions on land.
There would have been problems with the depletion of the ozone layer as a result of this methane-rich atmosphere.
And so it just would have been a very, very inhospitable place to be.
But burning coal isn't the pnly possible source of the methane gas that warmed the world a quarter of a billion years ago.
At the Brookhaven Energy lab, scientists are making ice.
But this is ice that burns--methane ice.
In nature, it's buried beneath seabeds and locked into permafrost.
Its discovery got geologists very excited, because there's more energy locked inside methane ice than all Earth's other fossil fuels put together.
It could be the fuel of the future, but it could also be the key to the past.
After hundreds of thousands of years of eruption, burning coal and melting ice together released enough methane to raise temperatures by some 20 degrees fahrenheit.
Life on Earth was heading for total wipeout.
Finally, a million years after the Earth's deadliest eruption began, the most catastrophic event in the planet's history is at an end.
But life on Earth paid a high price.
Over 95% of species have been driven to extinction.
The investigation reveals the reach of the volcanic eruption and how Planet Earth continued to change.
Light carbon found in rocks is evidence of a methane- rich atmosphere.
Burning coal in Siberia is thought to be the source of this gas.
The Earth is a different place from just a million years ago, from the air to the land to the sea.
The few species that have survived are pioneers in a brave, new world.
They are about to change the course of history.
a volcano erupted into life, paving Siberia with basalt lava layers a mile and a half thick.
At the end of the worst million years in Earth's existence, as life teetered on the brink of total wipeout, the eruptions finally stopped.
Now geologists want to find out whether the volcano died, or whether it simply changed location.
The place where a mantle plume hits the surface is called a "hotspot.
" The plume's shape is a clue to the hotspot's activity over time.
The head is a huge lava bubble which feeds short-lived, but massive, eruptions.
When the lava plume head is all used up, the mega eruptions stop.
But the narrow tail can live on, like a chimney spouting small eruptions for hundreds of millions of years, while Earth's tectonic plates are shifting above it.
Here is a mantle plume.
It could be Siberia, it could be Hawaii.
And here is the plate.
And the hotspot, obviously, is stationary, but we're going to see that the plate is actually moving above it.
So the plate is continuously moving.
The hotspot's staying put.
And you've goto imagine lots and lots of lavas are erupting out at the same time.
So I think what we've achieved is actually a rather good representation of a hotspot track.
At this end, the old end, that's where the plume had first hit the top of the mantle.
Over time, it's left a track that would in reality have been lots of other volcanoes just like the one that we find in the Hawaiian Islands today.
The Hawaiian chain was forged by a plume as the Pacific Plate passed above it--at a speed of 30 miles every million years.
But scientists searching for a plume track in Siberia are left scratching their heads, because there's no evidence of a trail.
The investigation has discovered Siberia's hotspot caused a million years of worldwide chaos and destruction.
But after that, the hotspot trail goes cold.
The Siberian Traps would have left a line of volcanic landforms that relate it to that movement.
But over such a long period of time, the geological processes have hidden the evidence, buried it, and parts of it may have been subducted back into the Earth's mantle.
What happened to the hotspot after it forged the Siberian Traps is a mystery that may never be solved.
The dynamic Earth has wiped away all trace of the evidence.
One thing is certain.
Siberia didn't succeed in destroying all life on Earth.
But it was a very close call.
This is the worst extinction of all time.
And a part of the measure of that is just how long it took to the planet to recover from this.
We estimate there was still only the very beginnings of recovery, the increasing diversity of life on Earth.
Coal, which opened the investigation into the Siberian Traps, testifies to the volcano's devastating effects.
No new coal formed for another Siberia, but around the entire world.
It's conclusive proof that, although tree life survived the mass extinction, it could not and did not thrive for tens of millions of years.
And the same is true for South Africa's land animals.
On his family's land, Rubidge has discovered yet another fossil crucial to the investigation.
If burrow holes fill up with sand or mud, they can themselves become fossils.
Anything trapped inside is fossilized, too.
This is the plug of an ancient burrow.
But the exciting part about this particular specimen is that it's got a little animal actually curled up, preserved in the burrow.
This animal died here in this burrow about 250 million years ago, and that is what he looks like.
There you can see is the head, and you can see there's his little tail over there.
Amazingly, this tiny creature plays an enormous role in the last 250 million years of life on this planet.
This fossil represents the future of life on Earth.
This burrow has huge significance for our presence here today.
Because this little animal is one of the distant ancestors of mammals.
This is our ancestor.
And the reason why he's preserved in a burrow after the extinction event is because this burrow maybe protected him from what was causing other animals to go extinct.
And so maybe it's thanks to a hole like that that you and I are here today.
The eruption of the Siberian Traps triggered a brutal race for survival.
Over 95% of the competition was eliminated.
Only the well-adapted and the lucky made the finish line.
It was Earth's worst million years.
But from the perspective of life on Earth today, it was the best thing that ever happened.
This was the greatest crisis that life has ever suffered.
But if it wasn't for this, then evolution would have taken a different course, and humans wouldn't be here today.
The million-year eruption of the Siberian Traps drastically altered the entire Earth.
From the atmosphere to the ocean depths, the planet changed at a rate so rapid, evolution could not keep pace.
In this new geologic world, life was hopelessly outdated.
The few animals that survived shaped the future, passing adaptations on to their descendants.
Dinosaurs, birds, mammals, and humans.
The tree of life had undergone some drastic pruning, but it allowed our branch to flourish, and humans to evolve.
Yet, today, 250 million years after Siberia erupted, life is still fragile, still at the mercy of the ever-changing, volatile, and unpredictable Earth.
Continents shift and clash.
Volcanoes erupt.
Glaciers grow and recede.
Titanic forces that are constantly at work, leaving a trail of geological mysteries behind.
This investigation ventures deep into remote Russia in search of a vast sea of stone called the Siberian Traps.
Experts will dig deep into Earth's ancient past to discover how this rocky wilderness formed, and unearth evidence in surprising places to prove how deadly volcanic eruptions in Siberia wiped out nearly every living thing on Earth.
The most dramatic episode yet in the story of "How the Earth Was Made.
" Earth's Deadliest Eruption The investigation into the cataclysmic event that radically changed planet Earth begins in the deep frozen land of Siberia.
50% bigger than the entire United States, this land is locked in ice for most of the year.
Temperatures plummet to minus 90 degrees fahrenheit and below.
But in summer, the ice melts and reveals one of the largest and most mysterious geological formations on Earth.
The Siberian Traps.
Nearly 5% of Earth's land mass is covered by this ancient sea of rock.
Deep canyons expose layers hundreds of feet thick.
These giant stepped formations are called traps, from the Swedish Word for "stairs.
" They were discovered under unusual circumstances.
Polish geologist Aleksander Czekanowski was exiled to Siberia in 1863 for "political crimes" against Russia.
While banished, he surveyed the landscape and stumbled upon this unique, unexplained expanse of layered rock.
Today, the journey to fully understand how this strange stone formation was made begins in a swamp.
I'm not sitting in this swamp just for fun.
This swamp's actually very characteristic of what Siberia was probably like before the Siberian Traps formed.
This vegetation, this shallow, stagnant water is very different to the environment we see in Siberia today.
The clue that enabled scientists to figure out that Siberia was once a swamp came from a particular kind of rock found beneath the traps.
Coal trillions of tons of it.
This rock here is coal.
It's very important in Siberia.
It forms when plant matter, trees, the thick vegetation dies and falls into a swamp, and over millions of years of geological time, they're compressed into a hard rock substance like the one I'm holding in my hand today.
The age of the coal was determined by dating the plant fossils trapped inside the rock.
The process revealed that the coal was formed more than continued to collect and be compressed over the next 50 million years.
So, the environment was very stable--swamps, thick vegetation.
Then suddenly, 250 million years ago, it all stops, and you have the Siberian Traps lying on top of the coal.
So, something fairly dramatic must have happened at that time, so we really need to study this phenomenon to investigate the geology and see what we can find out.
But investigating the geology of the Siberian Traps is no easy task, because they're located in one of the most remote and least explored areas of the planet.
It's an arduous journey for Howard and his team, a 1,000-mile trek through Siberia over land and water, camping out in mosquito-infested forests.
It's taken us nearly 7 days to get to this remote corner of Siberia, but this afternoon, we've finally found the rocks that we were hoping to study.
These towering pinnacles of rock mark the edge of the Siberian Traps.
Even from a distance, without leaving their boat, the geologists can identify this distinctive formation.
The rocks you can see behind me are basalts forming wonderful towers.
We've stopped and studied these in several locations.
And what we've seen is only a tiny part of the basalt which covers such a large part of Siberia.
This evidence unlocks the mystery of how the traps were made.
Basalt is what geologists call "igneous rock.
" and that only comes from one source--a volcanic eruption.
The Siberian Traps must once have been a vast, red-hot lava field.
I think the Siberian Traps would have been 1,000 times more intense than anything I've seen doing my own fieldwork.
And if I could go in a time machine and watch it all happen, it would be really just fantastic to see the scale of it.
The length of the lava flows, and the height of the fire fountains would have been really something to see.
There are several types of lava rock.
This basaltic lava is a free-flowing liquid when it first erupts from the ground.
Just looking at how fluid this rock appears gives us some of the clues what it might have been like in Siberia if we could have gone there.
There would have been really gooey, goopy, runny lava flowing across the land surface for This semi-liquid lava gives these rocky plains their name--flood basalts.
They still erupt today in Kilauea in Hawaii, currently the world's most active volcano.
After 25 years of constant eruption, the basalt lava field has engulfed more than 4 square miles of Hawaii's Big Island.
But the Siberian traps are bigger--500,000 times bigger.
Each distinct step is laid down by an individual lava flow.
Layer pours out upon layer until the traps are more than a mile deep in black hardtop, over an area nearly the size of the continental U.
S.
So, imagine the entire United States covered in a lumpy, uneven parking lot, like asphalt, everywhere as far as the eye can see, and that is what the Siberian Traps looked like when it first formed.
Geologists have discovered how the traps were made.
The next step is calculating how long this vast Siberian super eruption lasted.
Fortunately, volcanic rocks contain little minerals that formed when the rock crystallized--when the rock cooled and solidified.
And some of these minerals are radioactive, and they decay over time.
And so they're like little time clocks.
They start when the rock cools, and then when we measure them, the clock stops.
And we know how much time has passed since that rock formed.
Dating the oldest lava here reveals that the Siberian traps first ripped the landscape apart 250 million years ago.
And by also dating the youngest lava, scientists can figure out exactly how long the eruptions lasted.
The results are surprising.
They show that lava carried on pouring out and building up into ever-deeper layers for an almost unimaginable one million years, forging the largest lava flow on land.
The next step in the journey is to figure out why this vast eruption happened here in Siberia.
Most volcanoes exist at plate boundaries, thin spots on Earth's crust where the floating plates that support the continents jostle together as they drift across the face of the Earth.
Yet, the Siberian Traps are right in the heart of a huge continent.
So experts have to come up with an explanation.
This is a mantle plume.
It may not look like it.
And you have to imagine that this is going on over about 1,500 miles, rather than a bottle.
But it's quite a good simulation of how mantle plumes work.
They're heated from below.
This candle is the Earth's core supplying heat.
And this is the bottom of the mantle.
And the heat is heating up some of the mantle.
And it rises up as these blobs up towards the Siberian Traps which are up at the top here.
Mantle plumes are one of geology's great mysteries.
No one knows why they switch on or off.
But their shape is a crucial clue as to why plume eruptions are so fierce and so massive.
That mushroom head in reality can be 1,500 miles across.
And so, the volcanic eruptions can cover huge areas--hundreds of thousands of square miles.
And also, the actual head is a very short-lived phenomenon that probably erupts in hundreds of thousands of years, at most, a million years.
Evidence has been uncovered to reveal how and when the Siberian Traps formed.
250 million years ago, a vast magma bubble burst, cracking and slashing open Earth's crust.
And for life on Earth, a new devastating era began.
Two types of rock are proof of very different landscapes in ancient Siberia.
Coal reveals that before the traps existed, this area was a swamp.
Basalt lava is evidence this era ended with a bang--a super volcanic eruption.
But now, geologists have evidence that the Siberian super volcano was about to become Earth's greatest-ever killer.
The deadliest million years in Earth's history were about to begin.
Siberia was a swamp.
But deep underground, a plume of hot mantle rock was rising.
250 million years ago, the bulging crust burst open, and boiling lava erupted onto the surface.
The most cataclysmic and destructive million years in Earth's existence was about to begin.
With every eruption, basalt lava surged across Siberia in rivers and waves.
Terrifying forest fires raged.
Animals were burnt alive.
A new deadly Earth story was underway, one which would have catastrophic consequences for all life on Earth.
To figure out what chaos this mega-eruption caused for the Planet, geologists are taking a closer look at Siberia's ancient lava rocks.
This rock is very typical of what you see in flood basalt provinces.
And we have many what we call vesicles.
They're small holes in the rock, and those suggest that gases left this rock.
They escaped from this rock when this rock started cooling at the surface of the Earth.
The search for what kind of gas Siberia was producing begins nearly 8,000 miles away at Mammoth Mountain in California.
This is an ancient dormant volcano.
For years, it was thought to be harmless.
But then in 1989, a ranger had a terrifying experience.
It was wintertime, and a ranger was just checking on the area.
And he wanted to take a break from the wind, so he crawled in through a hatch that's in the roof of this cabin.
And he became very dizzy inside and didn't feel well.
And he had the commonsense to think that maybe there was some bad air in the cabin, and he crawled back up the ladder and got out safely.
But it always kind of remained a mystery initially.
Then just a few months later, the trees here began to die.
Clearly, something strange was happening.
So it required an explanation of what could combine with making a person feel dizzy and disoriented, and what would also kill trees at the same time.
Farrar's research revealed that a poisonous gas was to blame, one that was seeping upwards out of the ground.
Analysis proved that the gas was carbon dioxide, a byproduct of volcanic activity.
It's released when magma rises from deep underground.
So, just like this bottle of soda water, the magma beneath us contains dissolved carbon dioxide.
And when it reaches the surface of the Earth, the pressure is released.
Just like this, when you open the water, the pressure is released and carbon dioxide is coming out of this bottle of soda water, and that's the same gas that's coming out here at Mammoth.
Today, lava deep beneath Mammoth Mountain pumps out every day.
This suggests to scientists that trillions of tons of gas could have been released into the atmosphere by one of the Earth's largest eruptions in Siberia 250 million years ago.
And evidence comes from an unlikely source.
Well, this is a ginkgo tree.
And ginkgo trees are very special, because the ginkgo family has been around for a very long time--270 million years.
And it's remained fairly unchanged over the course of Earth's history.
Because the ginkgo changes so little over time, it is the ideal specimen for comparing the present with the past.
The leaf's surface is peppered with microscopic pores called stomata.
Plants use these stomata like tiny mouths to breathe in carbon dioxide.
The number of stomata on the leaves of a ginkgo indicate how much carbon dioxide is available to them in the atmosphere.
When there's a lot of carbon dioxide in the atmosphere, they only need to have a few.
When we look at fossils of ginkgo leaves that formed 250 million years ago, we notice that they have very, very few stomata to take up carbon dioxide.
And this means that there was a lot of carbon dioxide available in the atmosphere.
Investigators have studied ancient leaves from locations all over the world and calculated that there was 3 times more carbon dioxide in Earth's atmosphere 250 million years ago than there is today.
This was a deadly and global gas disaster.
And the only culprit capable of producing such substantial quantities of carbon dioxide is volcanic activity, on a truly massive scale.
When you have an eruption the size of something like the Siberian Traps, you imagine something almost apocalyptic in nature--ash blocking out the sun.
But then you have a kind of double whammy where you also have the release of volcanic gases from the eruptions.
And these gases trap in the heat, so it gets hotter and hotter.
Lava from the traps turns Siberia into a lifeless disaster zone.
But carbon dioxide can mingle and mix in the atmosphere, trapping heat inside like a parked car on a hot day.
Siberia is South Africa's Karoo Basin.
Here, evidence in rocks gives geologists a tip-off that carbon dioxide from the eruption provoked a climate disaster that wasn't confined to Siberia.
An old river channel slices through the landscape, exposing the layers.
These rocks have been dated to just before and just after the Siberian Traps began to erupt.
These are mudstones.
They form on lakebeds from squashed mud, so they're evidence that, just as in Siberia, the land was once swamp-like and covered in water.
But they're also evidence of change.
These rocks beneath my feet, which are green in color, are the older rocks here.
And then these rocks, which have got a more red color, are the younger rocks.
And the red color indicates that there's an environmental change.
That the climate was possibly drying out and becoming warmer.
The mud is rich in iron.
When it is shaded by plants or covered by water, it stays green.
When it's exposed to the sun, it turns rusty red.
So the red stones are evidence that plants and water, which shaded the mud, had disappeared.
250 million years ago, as Siberia spewed volcanic gases into the air, South Africa was drying out, warming up, and turning to desert.
The Karoo Basin is also where the first evidence was discovered that it was not just the plants that were dying.
Well, this animal was found in 1934.
My aunt, who was then a little girl at school--she came home from school one day and she said to her father, "daddy, what is a fossil?" and my grandfather's response was, "let's go off into the hills for a picnic and see if we can find one.
" so they went off to the hills.
And amongst other bones, they found this.
In their own backyard, the Rubidge family had unearthed yhe remains of an animal completely unknown to science.
This creature is a gorgonopsid.
It was a carnivorous lizard 10 feet long which roamed South Africa during an era called the Permian, hundreds of millions of years before even dinosaurs evolved.
But dating these fossils reveals that as Siberia began to erupt, these animals were dying.
Gorgonopsids are the dominant predators of the Permian period, and we find them in all these different layers in the Permian rocks.
Gorgons lived in this area about 260 to about 251 million years ago.
And then suddenly, when you get higher up at this sort of level in the Permian sequence, they disappear.
And the gorgonopsids were not alone.
There are virtually no animal fossils here younger than 250 million years.
7,000 miles from the Siberian super volcano, something caused the land to dry up, plants to die, and nearly every land animal to go extinct.
And one critical cause of this global disaster is carbon dioxide from the lava rocks.
Yet, this deadly, million-year-long chain reaction, triggered by Siberian eruptions, is only just starting.
The investigation has uncovered how volcanic activity in Siberia created a global catastrophe.
Fossil leaves of the gingko tree reveal evidence that the atmosphere was full of volcanic carbon dioxide.
Gorgonopsid skulls show animals were dying out at the same time.
But worse was to come.
The catastrophic Siberian eruptions were about to unleash a new murderous nightmare.
Siberia was a waterlogged, swampy bog.
50 million years later, Earth's biggest-ever volcanic eruption on land was smothering Siberia in layer after layer of solid, silvery basalt lava hundreds of feet thick.
An atmosphere saturated with volcanic carbon dioxide had raised global temperatures by around 10 degrees fahrenheit.
Life on land was dying.
Now the hunt is on to uncover evidence of how Siberia's super volcano precipitated a marine catastrophe in all of Earth's oceans.
But scientists aren't looking for answers in the sea.
They're climbing 10,000 feet above sea level up into the Dolomites Mountains.
Here in the mountains of northern Italy, these rocks give evidence of one of the greatest crises in the history of the planet.
Crack open the layered rocks and fascinating secrets are revealed.
Mysterious and long- extinct sea creatures called trilobites are preserved in their millions.
Their existence here proves these peaks were once a seabed.
The trilobites were trapped in sediment settling on the ocean floor.
over millions of years, geological upheavals have thrust them two miles up in the air.
The rock layers here are a oerfect record of life in the ancient oceans.
What we can see is, just below the level of my hand, there's lots of nice fossils, a big diversity of things we can find in here.
And then these younger rocks just above, just a little bit higher--basically, there's very few fossils in here, and a much lower diversity.
In between the two different layers of life, Wignall hacks into a black band.
In here, there are not just fewer fossils.
Here, there are none at all.
This is what geologists call the extinction zone.
It has been dated as 250 million uears old.
Worrying evidence that, having killed off most of the life on land, the Siberian super volcanic disaster was spreading to the seas.
This black clay contains microscopic, glittering clues--crystals of a mineral called iron pyrites.
Its shiny appearance has earned this rock the nickname "fools' Gold.
" it's worth just a few cents, but it holds priceless information about ocean waters where the rock formed This mineral, this iron pyrites will only form in the absence of oxygen.
And so therefore, it's a nice, very direct line of evidence for what's going on at this time.
The presence of fools' gold is evidence that the water in which it formed had no oxygen at all.
And scientists believe the warming effect of volcanic carbon dioxide from the Siberian eruptions was directly to blame for this lack of oxygen.
The ocean circulation is driven by the fact that we have a good temperature gradient.
It's cold at the poles and it's warm at the equator.
And so, the water circulates between the poles and the equator, like a conveyor belt.
But if you make everywhere warm, the conveyor belt turns off, and the water just sits there and stagnates and no longer has the ability to sort of resupply oxygen.
The ocean had become as still and warm as bath water.
And warm water absorbs less oxygen.
It's possible to recreate these nasty conditions in a fish tank, in fact.
All you need do with a fish tank is to put it in the window on a bright, sunny day.
The sun will warm the water up, and the water will start to lose its oxygen, and it'll--basically, it'll stagnate.
If you leave it for too long, your fish will die, and you'll have a sort of mini-recreation of one of the greatest extinction events of all time.
As volcanic eruptions tore Siberia apart, life was fighting for survival in the oxygen-depleted seas.
But the Siberian eruptions were about to flood an even more deadly poison into the oceans.
To find out what happened next, researchers hunted for a modern-day location that could recreate life in the Siberian-damaged Permian Ocean.
Unexpectedly, they found it in central New York state--Green Lakes State Park.
This unusual, little lake is extremely salty, and nearly 200 feet deep, making it a model in miniature of the ancient seas.
We get asked, "why do you go to a lake to study the Permian Ocean?" It turns out this lake is a lot like the ocean, actually.
It's fairly salty.
and its circulation system--the process that brings oxygen down deep into this lake--is shut down, just like we think happened to the Permian Ocean.
The top layer of the lake is healthy and thriving.
But deep down, the bottom layer is stagnant and still.
By lowering a water sampler 150 feet down, Kump's diving deep into the past to a time when the Siberian Traps were erupting.
Well, we have a couple clues from this water that's telling us about what's going on down there at the bottom of the lake, one of which is its color.
And this water is pink because it's loaded with tens of millions of purple bacteria cells in each ounce of water.
And the other is the smell.
So if I open up the lid here and take a whiff, it's a very potent smell of rotten eggs.
And that's a very characteristic smell of hydrogen sulfide.
Oxygen is toxic to purple bacteria, so stagnant water is a perfect breeding ground.
These single-celled survivalists flourish where other sea life suffocates.
But they have a nasty side.
They produce a noxious and pungent poison gas called hydrogen sulfide.
The tiniest amounts can be fatal.
The same bacteria live in sewers, so workers there must carry gas detectors.
Hydrogen sulfide deprives your body of oxygen.
It's also a strong neurotoxin, so it has that detrimental effect, as well.
And the really insidious thing about hydrogen sulfide is that it paralyzes our olfactory nerve.
In other words, we can't smell it anymore.
And that's what's so terrible, because right after you stop being able to smell it, if the level keeps building up, it can become instantly poisonous.
Kump's trying to figure out if the same lethal microbes plagued the seas stripped of oxygen by the Siberian eruptions.
He's searching for proof in rocks from 250 million years ago.
But bacteria don't leave fossils.
So instead, he's pursuing the chemical traces they leave behind.
So, the clues we're looking for are compounds called biomarkers.
These are chemical fossils.
They're fragments of the organism that have been preserved over long periods of geologic time in these rocks.
And from these fragments--from these chemical fossils, we can try to identify what organisms might have been involved in this mass extinction.
Like a fragment of bone or shell, a chemical fossil is a fingerprint identifying the micro-organism which made it.
And Kump's struck lucky.
This is it.
This is the clue we've been looking for.
This is the chemical fossil, the biomarker that tells us that these organisms were existing at the time of the greatest mass extinction of all time.
As Siberia erupted, the purple bacteria were in paradise, vigorously poisoning the water with hydrogen sulfide.
The sea became a suffocating, toxic cesspool.
The trilobites and virtually every other species of sea life died out and never returned.
The evidence is building up as to how massive volcanic eruptions in Siberia wiped out nearly all marine life on Earth.
Fools' gold shows the sea lost its oxygen.
Biomarkers show it was also poisoned with lethal hydrogen sulfide.
The Earth was choking.
Life could no longer depend on its two most vital resources--air and water.
But a new threat loomed, as Siberia's underground coal reserves added fuel to the flames.
a sudden violent volcanic eruption began in Siberia.
The traps erupted over the next million years, forging basalt lava layers thousands of feet thick.
Buried underneath the basalts were 5 trillion tons of coal.
As Siberia erupted, a powerful fuel was about to catch fire.
For geologists, coal is a crucial clue in figuring out how a huge volcano wiped out nearly all life on Earth.
Coal is the remains of dead plant material.
And when coal burns, the volatile materials are released, and these include gases such as methane.
And lava from the volcanic eruption was the ultimate source of ignition.
It was like pouring gasoline on a barbecue.
Now Saltzman is hunting for evidence of how this colossal coal fire damaged the planet.
His search begins in a barren blacktop wasteland.
But this is not Siberia.
This is a town in Pennsylvania.
I'm standing here in what looks like a war zone.
It's hard to believe this was the main road into a thriving community of several thousand people.
These cracks and these gases all around me are a clue not only to what extinguished this town, but also provide one of the key clues into the mystery of the greatest mass extinction of all time.
In 1962, the mining town of Centralia was a community of fire ignited a coal seam and caused an uncontrollable underground blaze.
Dangerous methane gas began to seep from the ground.
Today, the residents have abandoned the town.
The fire still rages underneath Centralia and methane is still released into the air.
The situation raises the question of whether the burning of Siberia's far greater coal reserves, set alight by lava 250 million years ago, also released catastrophic levels of methane gas into the air.
The volcanoes in Siberia would have erupted through the coals to get to the surface.
On their way, they would have cooked these coals.
And this burning of coal would have released methane, amongst other gases, and this methane would have had an extreme effect on the global climate.
As Siberia continued to erupt, temperatures all over the planet rose by a further 10 degrees.
It's a climatic change too dramatic to be caused by carbon dioxide alone.
There must be an additional culprit.
Methane is top of the list, because it's over 20 times more effective in trapping heat in the atmosphere than carbon dioxide.
Today, scientists are analyzing rocks for proof that methane from the Siberian coal fire was the culprit.
They've discovered a telltale chemical clue: light carbon.
It's a fingerprint of methane gas, and it has been recorded in every extinction zone all over the globe, from Antarctica to Italy--proof of the eruption's global reach.
The levels of light carbon geologists have discovered are so incredibly high, it equates to the sudden release of a trillion tons of gas.
Temperatures surge as the methane from Siberia spread across the globe, leaving every part of the planet devastated by climate chaos and mass extinction.
This would have been a very nasty place to live.
There would have been less oxygen in the oceans.
There would have been much warmer and drier conditions on land.
There would have been problems with the depletion of the ozone layer as a result of this methane-rich atmosphere.
And so it just would have been a very, very inhospitable place to be.
But burning coal isn't the pnly possible source of the methane gas that warmed the world a quarter of a billion years ago.
At the Brookhaven Energy lab, scientists are making ice.
But this is ice that burns--methane ice.
In nature, it's buried beneath seabeds and locked into permafrost.
Its discovery got geologists very excited, because there's more energy locked inside methane ice than all Earth's other fossil fuels put together.
It could be the fuel of the future, but it could also be the key to the past.
After hundreds of thousands of years of eruption, burning coal and melting ice together released enough methane to raise temperatures by some 20 degrees fahrenheit.
Life on Earth was heading for total wipeout.
Finally, a million years after the Earth's deadliest eruption began, the most catastrophic event in the planet's history is at an end.
But life on Earth paid a high price.
Over 95% of species have been driven to extinction.
The investigation reveals the reach of the volcanic eruption and how Planet Earth continued to change.
Light carbon found in rocks is evidence of a methane- rich atmosphere.
Burning coal in Siberia is thought to be the source of this gas.
The Earth is a different place from just a million years ago, from the air to the land to the sea.
The few species that have survived are pioneers in a brave, new world.
They are about to change the course of history.
a volcano erupted into life, paving Siberia with basalt lava layers a mile and a half thick.
At the end of the worst million years in Earth's existence, as life teetered on the brink of total wipeout, the eruptions finally stopped.
Now geologists want to find out whether the volcano died, or whether it simply changed location.
The place where a mantle plume hits the surface is called a "hotspot.
" The plume's shape is a clue to the hotspot's activity over time.
The head is a huge lava bubble which feeds short-lived, but massive, eruptions.
When the lava plume head is all used up, the mega eruptions stop.
But the narrow tail can live on, like a chimney spouting small eruptions for hundreds of millions of years, while Earth's tectonic plates are shifting above it.
Here is a mantle plume.
It could be Siberia, it could be Hawaii.
And here is the plate.
And the hotspot, obviously, is stationary, but we're going to see that the plate is actually moving above it.
So the plate is continuously moving.
The hotspot's staying put.
And you've goto imagine lots and lots of lavas are erupting out at the same time.
So I think what we've achieved is actually a rather good representation of a hotspot track.
At this end, the old end, that's where the plume had first hit the top of the mantle.
Over time, it's left a track that would in reality have been lots of other volcanoes just like the one that we find in the Hawaiian Islands today.
The Hawaiian chain was forged by a plume as the Pacific Plate passed above it--at a speed of 30 miles every million years.
But scientists searching for a plume track in Siberia are left scratching their heads, because there's no evidence of a trail.
The investigation has discovered Siberia's hotspot caused a million years of worldwide chaos and destruction.
But after that, the hotspot trail goes cold.
The Siberian Traps would have left a line of volcanic landforms that relate it to that movement.
But over such a long period of time, the geological processes have hidden the evidence, buried it, and parts of it may have been subducted back into the Earth's mantle.
What happened to the hotspot after it forged the Siberian Traps is a mystery that may never be solved.
The dynamic Earth has wiped away all trace of the evidence.
One thing is certain.
Siberia didn't succeed in destroying all life on Earth.
But it was a very close call.
This is the worst extinction of all time.
And a part of the measure of that is just how long it took to the planet to recover from this.
We estimate there was still only the very beginnings of recovery, the increasing diversity of life on Earth.
Coal, which opened the investigation into the Siberian Traps, testifies to the volcano's devastating effects.
No new coal formed for another Siberia, but around the entire world.
It's conclusive proof that, although tree life survived the mass extinction, it could not and did not thrive for tens of millions of years.
And the same is true for South Africa's land animals.
On his family's land, Rubidge has discovered yet another fossil crucial to the investigation.
If burrow holes fill up with sand or mud, they can themselves become fossils.
Anything trapped inside is fossilized, too.
This is the plug of an ancient burrow.
But the exciting part about this particular specimen is that it's got a little animal actually curled up, preserved in the burrow.
This animal died here in this burrow about 250 million years ago, and that is what he looks like.
There you can see is the head, and you can see there's his little tail over there.
Amazingly, this tiny creature plays an enormous role in the last 250 million years of life on this planet.
This fossil represents the future of life on Earth.
This burrow has huge significance for our presence here today.
Because this little animal is one of the distant ancestors of mammals.
This is our ancestor.
And the reason why he's preserved in a burrow after the extinction event is because this burrow maybe protected him from what was causing other animals to go extinct.
And so maybe it's thanks to a hole like that that you and I are here today.
The eruption of the Siberian Traps triggered a brutal race for survival.
Over 95% of the competition was eliminated.
Only the well-adapted and the lucky made the finish line.
It was Earth's worst million years.
But from the perspective of life on Earth today, it was the best thing that ever happened.
This was the greatest crisis that life has ever suffered.
But if it wasn't for this, then evolution would have taken a different course, and humans wouldn't be here today.
The million-year eruption of the Siberian Traps drastically altered the entire Earth.
From the atmosphere to the ocean depths, the planet changed at a rate so rapid, evolution could not keep pace.
In this new geologic world, life was hopelessly outdated.
The few animals that survived shaped the future, passing adaptations on to their descendants.
Dinosaurs, birds, mammals, and humans.
The tree of life had undergone some drastic pruning, but it allowed our branch to flourish, and humans to evolve.
Yet, today, 250 million years after Siberia erupted, life is still fragile, still at the mercy of the ever-changing, volatile, and unpredictable Earth.