What was the most devastating volcanic eruption
in history? Maybe volcanoes likes Mount St. Helens, Krakatau, or Mount Vesuvius come to
mind. After all, there is a reason these names are remembered till today, decades, centuries
and even millennia after their most famous eruptions. The eruption of Mt. St. Helens
of instance killed over 50 people and caused over 1b$ dollars in damages. Mt Vesuvius famously
killed at least 1000 people from Pompeii and three other roman cities. And the catastrophic
eruption of Krakatau killed at least 36000 people
But there are of course volcanic eruptions that are still considerably worse
Supervolcanoes like the one beneath Yellowstone national park for instance which last erupted
630.000 years ago. This eruption was in terms of material ejected around 50 times larger
than Krakatau. But even that is miniscule compared to what
our planet is capable of at its worst. This is a Flood Basalt Eruption. Even though
their name might not suggest it, they are the largest and most devastating lava eruptions
in history. Eruptions so massive they have again and again changed life on this planet
in a way and on a scale like no other natural phenomenon.
To understand how enormous these eruptions were and what impact they had on Earth and
its inhabitants, we have to go on a journey into the deep past.
Intro Let me take you back in time 252 million years,
to the Late Permian Period - Roughly 10 million years before the appearance of the first dinosaurs.
At that time all the continental plates were fused into one gigantic supercontinent called
Pangea. The conditions during this time weren’t unlike todays. The earth recently had come
out of an ice age and the South Pole was still covered in ice sheets. Over the last couple
million years the climate had slowly but steadily warmed and giant desert areas had begun to
form in the center of the continent. Nevertheless, much of the temperate regions were still covered
in huge conifer and fern forests that presented a wide variety of lush environments for life
to exist. Even more than that, life flourished and diversified resulting in a wide range
of new plant and animal species. The rulers of this era were the Therapsids – mammal
like reptiles – that had over the course of the Permian developed into the dominant
life forms on the planet. Among them were giant predators such as Gorgonopsians, a family
of carnivorous Therapsids that were characterized by their long saber-tooth-like canines and
could reach a size comparable to that of lions or tigers as well as a wide variety of large
medium and small herbivores. This was also the time when the first Cynodonts appeared,
the group of Therapsids that would eventually give rise to the first true mammals some 50
million years later. Amphibians and other Reptiles were present too in these forests
but they were slowly getting relegated to the sidelines. But that would soon change,
because among them you could already find the ancestors of the first dinosaurs, the
group of animals that would dominate the planet for the next almost 200 million years.
In the oceans life was able to develop similarly unhindered. Even though the formation of the
supercontinent had resulted in the drop of sea levels and the loss of continental shelf
regions, what remained of shallow coastal waters presented an ideal habitat for small
and large life forms alike. This is the scene of the biggest natural disasters
in history - a key event that would alter the planet on such a scale it would forever
change the course of evolution. And it began here – In the North of the
supercontinent - in the area that would later become todays Siberia. Around 252 million
years ago an unimaginable amount of molten rock, risen from inside the earth, had accumulated
directly beneath the earth’s crust and was now at various points beginning to make its
way to the surface. The widespread release of gas from the ground, major and continuous
earthquakes as well as the uprising of the crust by several hundred meters were signs
of the impending catastrophe. It probably started in the north-west of Siberia
in the Tunguska Basin, near today’s city of Norilsk. Over an area of more than 100.000
km² (40.000 mi2) a vast network of volcanic vents began to open producing huge pyroclastic
and phreatomagmatic eruptions with fire fountains 30km or 20mi high and spreading enormous quantities
of gas, molten rock and ash across the lands, which quickly turned a region the size of
France into hell on earth. But these weren’t your typical volcanic eruptions – These
eruptions were fed by a gigantic bubble of magma beneath the crust with a diameter of
maybe 1000km or 600mi. And through the countless rifts and vents that had opened up this magma
now began to spread across earth’s surface. Quickly the emerging lava masses flooded vast
areas of today’s Siberia with layers of molten basaltic rock up to 50m or 160 ft high.
A seemingly endless reservoir of magma meant that each individual lava flow continued for
more than a hundred years, burying the land under up to 2000 km³ or 500 mi³ of molten
rock. Additionally, over the centuries and millennia, ever new rifts and vents meant
that magma continued to leak onto the surface for close to 350.000 years. And so layer by
layer the masses of lava were not only spread over a huge area but also built up to enormous
heights As if the giant lava floods weren’t enough,
gases like sulphur dioxide, chlorine and fluorine, released in vast quantities by the enormous
eruptions caused devastation even hundreds of kilometres away. Basaltic lavas are especially
rich in sulphur dioxide. When released into the atmosphere it reacts with water vapour
in the air to form sun blocking aerosols. These aerosols can for months – sometimes
years – result in a significant temperature decrease – a volcanic winter. Acid rain,
the result of the condensation of hydrogen chloride and hydrogen fluoride, can cause
burns and poising in plants and animals that come into contact with it. Additionally, Fluorine
and Chlorine can cause damage to the ozone layer, potentially exposing vast areas to
dangerous UV-radiation that can cause tumours and gene-defects. Although all these gases
are typically removed from the atmosphere rather quickly, the prolonged nature of the
volcanic eruptions in Siberia meant the destructive potential of them was constantly renewed.
When the lava flows eventually stopped, the floods had buried an area of more than 4.000.000
km² or 1.500.000 mi² - so an area half the size of the United States– under a layer
of lava more than 2 km or 1 mi thick. But despite the incredible destruction this
catastrophe had caused in the North of the supercontinent over the past 300.000 years,
the rest of the Pangea as well as in the oceans were relatively unaffected by it. But that
would soon change. Because what on the face of it looked like
the end of the large scale volcanism in Siberia was only the beginning of a second much more
catastrophic phase, which was looming hidden beneath the now solidified masses of lava.
The trillions and trillions of tons of volcanic rock that were now bearing down on the earth’s
crust acted as a giant lid that prevented more of the still abundant magma inside the
ground to rise up to the surface. With no way up the magma instead began to force its
way laterally into the rock, creating a huge underground network of sheet like horizontal
intrusion so called sills. This network began to heat up an enormous area of continental
crust like a giant underfloor heating system. As the hot magma came into contact with the
volatile-rich sediment of Permian Siberia vast quantities of organic and inorganic CO2
were freed from the rocks. Additionally, the destruction of pre-existing oil and coal-bearing
deposits by the sill intrusions released even more gases. When the sills eventually reached
the boundaries of the lava province and found their way to the surface, these gases were
released all at once in one catastrophic pulse – maybe up to 100.000 GTs of CO2 got released
into the atmosphere. This had far reaching consequences for the
climate, which this time weren’t limited to the northern hemisphere – the entire
planet was affected. Almost instantly the global average temperature rose by 5°C or
9°F – the result of catastrophic global warming. Compared to the daily weekly and
seasonal temperature variations we experience constantly 5° might not sound that much but
yearly global averages are much bigger deal. During the last ice age when much of North
America and Europa were buried under more than a kilometre of ice the global average
temperature was only about 5°C lower than it is now. So you can imagine what consequences
a jump of 5°C in the other direction must have had.
And this was only the beginning, as the warming of the oceans soon would set off of a chain
reaction that would raise temperatures by another 5-10°C or 18°F – Through the release
of oceanic methane. At the bottom of the oceans along the continental slopes there exist immense
reserves of frozen methane, so called methane hydrate. This methane was produced by tiny
microbes as a metabolic by-product over millions of years and was then at depths of over 200m
or 650 ft frozen into ice crystals through high pressure and low temperatures. That way,
it is stored stably and safely for long times. It is however very responsive to changes in
the environment particularly to changes in temperature and so 252 my as the result of
the warming of the oceans vast quantities of methane got released into the atmosphere
as big portions of the methane hydrate deposits melted. Like CO2 methane is a greenhouse gas
– its effect in the atmosphere are however 30-86 times stronger and so the planet subsequently
warmed another 5-10° - to a total of 15°C or 27°F
This cataclysmic temperature increase transformed the planet from a lush paradise into a barren
hellscape. Imagine the Northern United States or the UK at temperatures like the Sahara
or tropical ocean temperatures of over 40° or 104°F
Because of this intense heat most of the plant life perished, the large temperate forests
all but disappeared and the desert areas that before had only existed in the center of Pangea
began to spread across the entire continent, killing everything that wasn’t adapted for
life in such harsh conditions. Most of the few land animals that survived
were small generalists that could survive on little water and weren’t too picky about
their food. Many of them were only able to survive these extreme temperatures because
they lived in underground in burrows. Our ancestors, the Cynodonts, were one of these
few survivors. The oceans were affected even worse. The enormous
amounts of CO2 in the atmosphere resulted in a similar increase in oceanic CO2. As a
consequence, the PH level of the water dropped and the ocean acidified. This made building
exoskeletons, shells or other calcium carbonate structures increasingly difficult, making
animals that need these structures to survive like corals, zooplankton and shellfish the
first major victims of the crisis. At the same the ocean began to lose its oxygen.
Warmer water can hold fewer gases than colder water so large scale ocean anoxia was the
result. Like a goldfish in a glass left out in the sun, entire species and of animals
suffocated because of this. These conditions also promoted the development of anaerobic
bacteria, which only thrive in oxygen-depleted environments. Instead of oxygen, these bacteria
produced hydrogen sulphite, a highly toxic gas that poisoned the water
Initially these effects were limited to shallow coastal waters but as due the warming of the
Polar Regions the ocean currents were disrupted the entire ocean was affected. What remained
of the largest ocean in history was a stale toxic oxygen depleted graveyard.
In the end the volcanism in Siberia had transformed the planet from an oasis of life into the
largest mass grave in history. Within only 60.000 years, the global animal
population had decreased by more than 99.9%. 95% of all species in the ocean and 75% of
all species on land died out. The end Permian extinction was the biggest extinction in earth’s
history and only one that almost wiped out all land plants and also severely affected
insects It would take Life on earth almost 10 million
years to fully recover from this catastrophe. But while the formation of this so called
“large igneous province” had brought complex life to the brink of extinction it was also
a new beginning for the few animals that survived. Like an evolutionary reset-button it had reshuffled
the deck and gave those species that had managed to fight through the inferno the unique opportunity
to conquer the earth. What group of animals made best use of this chance is probably needless
to say With an area of maybe more than 4.000.000
km² and a volume of around 3-4 million km³ - That’s enough lava to cover all of today’s
land area with a layer of rock 10m 32ft thick – the province in Siberia, also called the
Siberian Traps, is definitely one of the largest of these provinces, but it’s certainly not
the only one. Large igneous provinces are defined as magmatic
plateaus that span over 100.000 km² or more and have a volume of at least 100.000km³.
By that definition we know at least 40 of these provinces from the last 540 million
years alone, of which about a dozen probably exceeded the definition by at least 10-fold.
Of course erosion and tectonic processes have in most cases weathered away or destroyed
a lot of it making estimations of their original extent challenging, but the fact that you
can still see the astonishing remnants of these eruptions today - in some cases hundreds
of millions of years after their formation – speaks to scale of these eruptions.
We can divide large igneous provinces into continental and oceanic provinces; our record
of oceanic ones is however limited because as opposed to continental plates the oceanic
crust is constantly getting recycled by tectonic processes and is therefore with rare exceptions
nowhere older than 180 million years. The most notable of the oceanic provinces
is probably the great ontong java plateau in the south west pacific. It consists of
a series of provinces that during their formation 120 million years ago probably made up one
enormous plateau. Here, over an area the size of Australia, the largest lava eruption in
the last couple hundred million years took place. Over the course of 7 million years
a total of 80.000.000 km³ of basaltic lavas were expelled. That is enough lava to bury
the entire United States under 10km or 6mi of molten rock..
On land we have – aside from the Siberian traps – for instance the Central Atlantic
magmatic province that formed 201 million years ago in the center of Pangea, before
the subsequent breakup of the supercontinent scattered it across three of todays continents.
Its original extent is estimated to have covered between 7-11 million km² making it in terms
of area the largest of the continental provinces. In Asia we can also find the remnants of the
Deccan Traps, an up to up to 2km thick province that once covered half of modern India. It
formed 66 million years ago at the end of the cretaceous period.
The North Atlantic igneous province in Europe is between 55 and 60 my old and was later
broken up by the opening of the North Atlantic Ocean. With an original volume 2-3 larger
than that of the Siberian traps it is perhaps the most voluminous continental province.
At last we have Columbia River Basalt Group, a comparably small large igneous province
in the western United States. Only between 17-6 million years old is one of the youngest
and best studied provinces on earth. Today it remnants stretch across 4 states, cover
an area of 160.000 km² or 60.000mi² and reach a thickness of roughly 1.8 km or 1.1m
Of course, these are only a few of the dozens of provinces that we know of.
Considering the devastation the Siberian Traps caused, it’s perhaps interesting to examine
what impact the formation of some of the other mentioned provinces had on the planet.
What causes these catastrophic lava eruptions also remains to be answered.
All of this will be part of the second video on Flood Basalts.
Absolutely fascinating and well-done video, thanks for sharing!
It's crazy how our home could also just be a giant ticking time bomb about to make our species extinct. Or our sun sends out a massive flair and kills us all. Or a Gamma ray burst we never see coming wipes us out. We gotta get our eggs out of this one basket.
Climate deniers need to learn how wicked the climate on this planet has gotten.
That methane causing an additional 10 degree warning? Bacterial poop.
This is exactly why what we're doing with co2 emissions is so dangerous.
It's just insane knowing the danger of living up to that kind of world is determined by whether or not will the average global temperature rise 5 degrees higher. Very well done video!
Terrifying
Fascinating.
Yes.. quite, quite. 🧐
Thanks I hate it.
Very interesting. Thx for tha !!👍