June 19, 2010
40 Million Years Ago North America Volcanic Eruptions
North American volcanic eruptions of 40 million years ago spewed climate-cooling sulfur aerosols on a scale not seen in modern times.
Millions of years ago, volcanic eruptions in North America were more explosive and may have significantly affected the environment and the global climate. So scientists report in this week's issue of the journal Nature.
The researchers found the remains--deposited in layers of rocks--of eruptions of volcanoes located on North America's northern high plains that spewed massive amounts of sulfate aerosols into the atmosphere 40 million years ago. The scientists conducted their research at Scotts Bluff National Monument, Neb., and in surrounding areas.
"Combining measurements of the sulfate in ancient volcanic ash beds with a detailed atmospheric chemistry model, we found that the long-ago chemistry of volcanic sulfate gases is distinct from that of more modern times," says Huiming Bao, a geologist at Louisiana State University and lead author of the paper.
"This is the first example showing that the history of massive volcanic sulfate emissions, and their associated atmospheric conditions in the geologic past, may be retrieved from rock records."
The fact that the high sulfate emissions happened 40 million years ago doesn't demonstrate the final end of a geological era. This can happen again. About every 650,00 years or so the Yellowstone area erupts. The last eruption was 640,000 years ago and was 20 times as large as the 1815 Tambora eruption discussed below. This cycle of eruption might not be over yet.
A similar volcanic event to the long-ago past likely will happen again, Bao says: in the next Yellowstone eruption.
If we are lucky the next eruption large enough to prevent summers won't happen until we have enough technology (e.g. nanobots, fusion reactors) to enable us to easily deal with the consequences.
For almost the last couple of centuries have been sufficiently uneventful in terms of volcanic eruptions. So it might seem that nature isn't likely to send something at us that we can't easily handle. But go back just a little further and a different picture emerges.
The closest analog, Bao believes, is the 1783 Laki, Iceland, eruption and the subsequent "dry fogs" in continental Europe.
That event devastated Iceland's cattle population. People with lung problems suffered the worst, he says.
In North America, the very next year's winter, that of 1784, was the longest and one of the coldest on record. The Mississippi River froze as far south as New Orleans. The French Revolution in 1789 may have been triggered by the poverty and famine caused by the eruption, scientists believe.
Climate cooling from volcanoes on the scale of the1783 Laki, Iceland, eruption is not that rare. 1816 is know as the "Year Without Summer" due to the April 10, 1815 Tambora eruption, which was the biggest volcanic eruption in the last 200 years. It caused cold weather for 2 years and widespread hunger. The 1600 Huaynaputina Peru eruption was smaller than Tambora (volcanic explosivity index (VEI) of 6 versus 7 for Tambora). Yet it spewed as much sulfur as some VEI 7 eruptions and caused famine in Russia.
A VEI eruption like Tambora would cause famine in poorer countries. A VEI 8 eruption would cause famine even in some developed countries. A VEI 8 eruption in a developed country would kill millions near the eruption and, depending on where it happens, even kill tens of millions in that country.
Yes, Yellowstone is my #1 disaster that will come to North America... sooner or later. I don't like the shift in the Yellowstone Lake over the past 90 years or so, nor the signs of uplift. After that its hard to choose between the New Madrid Fault Zone or the Cumbra Vieja event, then after those comes the Cascadia megathrust fault, now hitting its cycle period. So is the NMFZ. Mind you we aren't even set up to handle 'The Big One' in LA or SF (wouldn't both be awful?) and those fill out the top 5.
North America is such a great continent with so much happening to it!
Sucks to be seeing so many cycles hitting their periodicity right around now, but that's life.
La Palma is probably going to do in the East Coast before Yellowstone erupts.
"A massive chunk of La Palma, the most volcanically active island in the Canaries archipelago, is unstable, says Simon Day, of the Benfield Grieg Hazard Research Centre at University College London.
He calculates that its flank could collapse the next time the volcano, Cumbre Vieja, erupts.
If so, that would send a dome-shaped wall of water up to 100 metres high racing across the Atlantic at 800 kilometers (500 miles) per hour, hitting the western coast of Africa and southern coast of England within a few hours.
Some eight hours after the collapse, the US East Coast and Caribbean would bear the brunt.
Cities from Miami to New York would get swamped by waves up to 50 metres (160 feet) high, capable of surging up to 20 kilometers (12 miles) inland, according to Day's research."
I've long held that the most preposterous "scientific" theory is that hunting by paleolithic humans wiped out Pleistocene megafauna like Mammoths. There were too many very large and dangerous animals. Not only could the then-extant human population not have eaten that much, there were simply not enough humans at the time to do the job. No, the extinction of large mammals at the end of the Pleistocene was so great that it could only have been caused by an enormous environmental catastrophe like an asteroid impact or massive volcanism. I keep waiting for the evidence of this, so that the "I hate people"-inspired theory of ice-age human over-hunting can be finally put to rest.
Also, in response to Bruce's comment, I do not believe that the collapse of La Palma could create a large tsunami. I think this is a misguided theory falsely extrapolated from Lituya Bay in Alaska, and hyped by specials on the History Channel. (Never trust anything on the History Channel!)
I've long held that the most preposterous "scientific" theory is that hunting by paleolithic humans wiped out Pleistocene megafauna like Mammoths. There were too many very large and dangerous animals. Not only could the then-extant human population not have eaten that much, there were simply not enough humans at the time to do the job.
Until the last couple of centuries, human societies have mostly existed close to Malthusian equilibrium, where population growth saturates the available resources. If the paleolithic humans were in such a state, then they were numerous enough to cause the extinctions (if not, what was keeping their population from growing?)
You may be improperly back-extrapolating the population data at the time of the european push into the Americas. Those populations may have been out of equilibrium due to introduction of european diseases.
There are 3 Calderas in the Western United States United States. Yellow Stone, Long valley and ...Can you name the third? It is also good to note that the Yellow Stone Caldera's Magma Pool is connected to the Cascades. It is better for everyone to worry about earning a living than about what we have no control over.
One thought (with kudos to Uriel):
Consider the remarkable coincidence in the near-simultaneous occurrence of the following events 12k years ago:
1. Extinction of all megafauna;
2. Extinction of Clovis man/culture;
3. Complete melt-off of northern super ice cap (5000 ft+) that covered northern Europe, Canada, US, Russia;
4. "Flash-freezing" of mammoth herds in Siberia...the temperate foliage in stomachs perfectly preserved;
5. Climate change in (formerly temperate) Siberia to ARCTIC environment that persist to present day.
Any one or two of these events could easily be unrelated.
Academia resists the obvious because too many theses become feces if the end of the
Pleistocene is rewritten.
Article should note that North American volcanism 40-million years ago was a consequence of the Rocky Mountain Orogeny, a massive geophysical upheaval that raised towering peaks from Alaska through Central America to the Andes. As for Yellowstone, blowoffs occur more like every 640,000 years than 650,000... as yet, multiplying "seismic swarms" indicate increased magmatic activity, but do not necessarily portend a super-volcano eruption. When that occurs, as it necessarily will, the entire western portion of these United States will be rendered uninhabitable for centuries, if not millennia.
THE super-volcano of record erupted in Toba, Sumatra, about 72,000 - 75,600 years-before-present (YBP). Toba's crater is eighty miles long, thirty-five miles wide... worldwide atmospheric disruptions reduced Earth's hominid population to 1,200 breeding pairs, concentrated west of Kilimanjaro in East Africa's Great Rift massif. Radically reducing nascent humanity's genomic diversity, this geophysically recent event had consequences for adaptive hominid characteristics that emphatically are with us yet.
OMG, the big one's coming!! We're all gonna die!!
Of course, the "big one" is always coming, and we are all going to die. But the two are not necessarily connected.
TimF, thanks for the reference. I withdraw my comment.
You never know. That is the only thing you know. You Know? You just never know.
The third moderately recent supervolcano in the US is Valles Caldera in New Mexico. It erupted about 1.15 million years ago. The largest historic one I can find in the US is La Garita Caldera in Colorado which erupted around 26-28 million years ago, puking out 1,200 cubic miles of stuff.
Note that large volcanic eruptions are a sliding scale, with no definite dividing line between an eruption that is a supervolcano and one that isn't. About the best you can do is look at calderas. Generally, the larger the caldera, the more violent the eruption. For older volcanoes, identifying that a caldera exists is the hard part. Cheers -
Look at the big picture - Mankind needs energy. These events are energetic.
Solar Power Satellites > Tera-watt laser > Lance that boil > Free Energy
"If we are lucky the next eruption large enough to prevent summers won't happen until we have enough technology (e.g. nanobots, fusion reactors) to enable us to easily deal with the consequences."
Even better: If we are lucky, it won't happen until we have developed the engineering skill to relieve the magma pressure with smaller controlled eruptions and thereby prevent a mega-eruption. Of course, we'll never get the chance to develop this skill unless we abandon the dogma of environmentalism that says we must leave nature untouched.