Skip to comments.Volcanic eruptions wiped out ocean life 93 million years ago (major source of today's petroleum)
Posted on 07/21/2008 4:53:56 PM PDT by 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
Well, I guess we can always hope for more of the same.
I wonder how much of my hard earned tax money funded this study.
Seems to me there is a CO2 'bent' here in the story to be used later for justification to take control of everyone's liberty.
While continental shelves have moved around a bit over the last 93 some odd million years wouldn’t it stand to reason that a vast amount of oil may still remain untapped at the bottom of our oceans somewhere?
Unless you’re Canadian, nothing!
Yes, makes sense to me... Alhtough I think the Rocky Mountains are about that age and are made of uplifted sea floor, it seems to me there should still be plenty of ancient sea floor still under water.
I’ve always wondered if oil wasn’t a deposit like iron or quartz rather than being made from decaying matter. I have zero science to back up my thought though.
Which I understand the Messiah plans to re-christen as the element "Obamium" after his ascendency.
Who cares about CO2? It's good for plants. Make more CO2.
The primary evidence that CO2 and the greenhouse effect have anything to do with raising global temperature is missing entirely. It isn't there.
This is a short and easily understandable article showing the plain truth. The hinge pin that links global temperature to the greenhouse effect is missing. It is easily measurable and hundreds of probes have done so.
Let’s see, we can gassify coal. You suppose a geologic process could do the same?
I guess this idea could explain why there is oil miles beneath the oceans where no dinosaur ever trod.
I call BS on this one. How do you get “beds of shale” from a single geologic event? These beds are laid down over tens and hundreds of thousands of years. Perhaps a major earthquake or landside might form a local bedding layer, but world wide bedding layers? I don’t think so. The total biomass from a single event is not going to produce much oil. Again, you need thousands, if not millions of years of accumulation, preferably in an oxygen free environment.
Now, about the amount of biomass involved ~ counting in the vast storehouse of living biomass in the rocks that make up the ocean floor, there's a whale of a lot of stuff down there. Hot, steaming lava could have "cooked" the critters out of the rocks where they reside and allowed them to simply flow to sandstone and other types of rocks, and then buried them.
I understand the concept of catastrophism, in fact I worked on a study in graduate school that helped that mechanism gain favor. This was the study of sedimentation and erosion caused by one event, a massive flood of the Big Thompson Canyon in Colorado following a thunderstorm. The gradualists just had a hard time holding sway after that.
However, the amounts of oil saturation of the shale beds suggested for this event seem to me to be outside the range of possibility. I would have to see the professional paper and their data to understand what they are trying to say, but I’m not convinced. This publication is not exactly a rock solid source, pun intended. I wouldn’t be surprised to find that the real study says something entirely different.
1) The amount of microscopic plankton in the oceans is staggering.
2)There never was a "dinosaur-to-oil" theory.
Certainly plankton produce large amounts of hydrocarbons, especially when compared with dinosaurs or any other large animal. However, given a single event that kills all life in the water column, how much gets deposited on the sea floor? Remember, these plankton require light to survive and are not, therefore, found at great depths. Most of the ocean is a vast desert with little life to be found. Shallow seas, of course are another matter,and I’m living on one here on the plains of Kansas. Still, hard to believe that three hundred feet or so of water above my farm could produce much oil from a one time event. Give it a few millions of years and its a different story.
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