>> 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." S02x11 Earth's Deadliest Eruption Original Air Date on February 9, 2010
-- Sync, corrected by elderman -- -- for www.addic7ed.com --
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
300 million years ago. It
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
1,000 miles in all directions.
>> 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.
>> 300 million years ago,
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
1,000 tons of carbon dioxide
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.
7,000 miles away from
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.
>> 300 million years ago,
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
250 million years ago.
>> 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.
>> 250 million years ago,
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
4,000 people. But an accidental
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.
>> 250 million years ago,
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
8 to 10 million years later,
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
25 million years--not just in
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.
-- Sync, corrected by elderman -- -- for www.addic7ed.com --