Volcanic eruptions wiped out ocean life 93 million years ago (major source of today's petroleum)

PhysOrg ^ | 7/16/08

[LibWhacker]

University of Alberta scientists contend they have the answer to mass extinction of animals and plants 93 million years ago. The answer, research has uncovered, has been found at the bottom of the sea floor where lava fountains erupted, altering the chemistry of the sea and possibly of the atmosphere.

Undersea volcanic activity triggered a mass extinction of marine life and buried a thick mat of organic matter on the sea floor about 93 million years ago, which became a major source of oil, according to a new study.

"It certainly caused an extinction of several species in the marine environment," said University of Alberta Earth and Atmospheric Science researcher Steven Turgeon. "It wasn't as big as what killed off the dinosaurs, but it was what we call an extreme event in the Earth's history, something that doesn't happen very often."

U of A scientists Turgeon and Robert Creaser say the lava fountains that erupted altered the chemistry of the sea and possibly of the atmosphere.

"Of the big five mass extinctions in the Earth's history, most of them were some kind of impact with the planet's surface," said Turgeon. "This one is completely Earth-bound, it's strictly a natural phenomenon."

Turgeon and Creaser found specific isotope levels of the element osmium, an indicator of volcanism in seawater, in black shale-rocks containing high amounts of organic matter-drilled off the coast of South America and in the mountains of central Italy.

"Because the climate was so warm back than, the oceanic current was very sluggish and it initially buffered this magmatic pulse, but eventually it all went haywire," said Turgeon. "The oxygen was driven from the ocean and all the organic matter accumulated on the bottom of the sea bed, and now we have these nice, big, black shale deposits worldwide, source rocks for the petroleum we have today."

According to their research, the eruptions preceded the mass extinction by a geological blink of the eye. The event occurred within 23 thousand years of the extinction and the underwater volcanic eruption had two consequences: first, nutrients were released, which allowed mass feeding and growth of plants and animals. When these organisms died, their decomposition and fall towards the sea floor caused further oxygen depletion, thereby compounding the effects of the volcanic eruption and release of clouds of carbon dioxide in to the oceans and atmosphere. The result was a global oceanic anoxic event, where the ocean is completely depleted of oxygen. Anoxic events-while extremely rare-occur in periods of very warm climate and a raise in carbon dioxide levels, which means that this research could not only help prove a mass-extinction theory, but also help scientists studying the effects of global warming.

An odd side-effect of the mass extinction, the result of the anoxic event caused as an indirect result of the underwater volcanic eruptions, was that temperatures and carbon dioxide levels on the Earth's surface actually dropped.

"Organic matter that's decaying returns components like carbon and CO2 to the atmosphere," said Turgeon. "But this event locked them up at the bottom of the ocean, turning them into oil, drawing down the CO2 levels of the ocean and the atmosphere."

After 10,000-50,000 years, the carbon dioxide levels rose again. "Business as usual," said Turgeon, adding that this might hold a warning for organic life on the planet today, he said.

"There's a bit of an analogy for what's going on today," he said. "What happens if we pump more CO2 into the atmosphere? This tells me that the oceans maybe have limited buffering capacity for CO2 ."

The research appears on Thursday in the weekly science journal Nature.

Source: University of Alberta

[SunkenCiv]

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[ukie55]

My understanding of anaerobic conditions in large bodies of water is that once it goes anaerobic, it doesn’t clean itself up.

That was a concern with the Great Lakes in the 60’s when laundry detergent contained phosphorous. There’s always an anaerobic area at the bottom of the lake but since the phosphorus feeds the algae, the danger was that the anaerobic area would grow to a certain size at which it basically couldn’t be stopped. The whole of Lake Erie would go anaerobic with no chance of going back to aerobic conditions. It would have become a permanently polluted lake, like a stagnant pond. That’s why the legislation was passed banning phosphates from laundry detergent.

HISTORICAL PERSPECITVE OF THE PHOSPHATE DETERGENT CONFLICT

http://www.colorado.edu/conflict/full_text_search/AllCRCDocs/94-54.htm

So if that’s the case for the lakes, how would the ocean have been able to go back to aerobic if it had been anaerobic?

[Fred Nerks]

http://www.space.com/scienceastronomy/planetearth/asteroid_oil_991213.html

“Tar-coated comets and oily asteroids

The idea that complex hydrocarbons (the main components of petroleum oil) are a natural part of the Earth’s crust should come as no surprise to scientists who study comets and asteroids. Some of the meteorites that fall to Earth are rich in tar-like hydrocarbons. Comets such as Halley and Hale-Bopp are thought to have a skin of tar-like material covering a “dirty snowball” — like an ice cream dipped in chocolate.

The early Earth was made of the same stuff as comets and asteroids, so the presence of hydrocarbons deep within the Earth is to be expected. It used to be thought that the fierce heat deep underground was sufficient to break up any hydrocarbon molecules. However, Russian scientists have demonstrated that the enormous pressures prevent this.

Even if the Earth did not manage to retain its original supply of hydrocarbons it is likely that the rain of comets, space dust and asteroids over billions of years would have kept the crust of the Earth topped off with the raw ingredients for oil.

Could there be too much oil?

Oil is best found near impact structures. Oil forms deep underground from non-biological processes. If these ideas prove correct then Donofrio’s estimates for the United States should apply to other parts of the world. For areas of similar size there are possibly 20 buried impact craters with perhaps half having commercial oil reserves. The search for these elusive craters could be very rewarding.

It may turn out that there is too much oil for our own good. A massive increase in known oil reserves could lower oil prices and drastically devalue existing reserves...”

[Fred Nerks]

http://query.nytimes.com/gst/fullpage.html?res=9B0DE3DD123EF935A25757C0A961948260

Oil From Comets? Shades of Velikovsky!
April 16, 1987

To the Editor:

It appears that Prof. Thomas Gold of Cornell University has discovered natural gas and oil beneath a meteorite crater in Sweden (news article, March 22). If this finding is confirmed, then vast amounts of hydrocarbons lie deeply hidden in the earth’s crust. This finding would have far-reaching implications for energy-related industries.

According to Professor Gold’s hypothesis, once the planets were forming, they generated enough gravity to alter the orbits of comets and asteroids. Many of these objects rich in hydrocarbons and other organic compounds struck the earth. Therefore, natural gas and petroleum were derived from substances that fell from the sky.

The conventional view of most scientists is that natural gas and petroleum originated from fossil remains of living organisms. However, the extraterrestrial source of hydrocarbons was suggested much earlier by Immanuel Velikovsky in 1950 in his book ‘’Worlds in Collision.’’ Velikovsky argued that the earth’s petroleum deposits came from comets. The idea that petroleum came from space was ridiculed at the time. Now it is put forward by others in perfect seriousness.

A related article, ‘’A New Light in the Sky’’ (New York Times Magazine, March 29), described ‘’a tarlike chemical, mainly molecules of carbon and hydrogen, that was discovered in Comet Halley last year.’’ The article continued: ‘’There are strong suspicions that the dark substance contributes to the blast crust that was found to cover Halley’s. Such dark surfaces are also seen on some of the satellites of Jupiter and Saturn, leading scientists to wonder if there are connections between the planetary satellites and comets.’’

Perhaps Velikovsky was right! Clearly, his ideas are intriguing and have attracted many supporters. Recent discoveries in space and in the earth’s crust have demonstrated, at the least, that his cataclysmic concept of the world’s history must be taken seriously. ROBERT R. GALLO Auburn, N.Y., April 1, 1987