Scientists find ancient asphalt domes off California coast

Apr 25, 2010
High-resolution bathymetry shows extinct asphalt volcanoes on the sea-floor off California. Credit: Dana Yoerger, WHOI

They paved paradise and, it turns out, actually did put up a parking lot. A big one. Some 700 feet deep in the waters off California's jewel of a coastal resort, Santa Barbara, sits a group of football-field-sized asphalt domes unlike any other underwater features known to exist.

About 35,000 years ago, a series of apparent undersea volcanoes deposited massive flows of petroleum 10 miles offshore. The deposits hardened into domes that were discovered recently by scientists from the Woods Hole Oceanographic Institution (WHOI) and UC Santa Barbara (UCSB).

Their report—co-authored with researchers from UC Davis, the University of Sydney and the University of Rhode Island—appears online today (April 25) in the Journal Nature Geoscience. The work was funded by the National Science Foundation, U.S. Department of Energy and the Seaver Institute.

"It was an amazing experience, driving along…and all of a sudden, this mountain is staring you in the face," said Christopher M. Reddy, director of WHOI's Coastal Ocean Institute and one of the study's senior authors, as he described the discovery of the domes using the deep submersible vehicle Alvin. Moreover, the dome was teeming with undersea life. "It was essentially an oasis," he said, "almost like an ."

What really piqued the interest of Reddy—a marine who studies oil spills—was the of the dome: "very unusual asphalt material," he said. "There aren't that many opportunities to study oil that's been sitting around on the bottom of the ocean for 35,000 years."

Reddy's unique chance came courtesy of UCSB earth scientist and lead author David L. Valentine, who first came upon the largest of the structures—named Il Duomo—and brought back a chunk of the brittle, black material in 2007 from an initial dive in Alvin, which WHOI operates for the US Navy. Valentine and Reddy were on a cruise aboard the WHOI-operated research vessel Atlantis, following up on undersea mapping survey by the Aquarium Research Institute (MBARI) and the work of UCSB earth scientist Ed Keller.

"The largest [dome] is about the size of two football fields, side by side and as tall as a six-story building," Valentine said. Alvin's robotic arm snapped off a piece of the unusual formation, secured it in a basket and delivered it to Reddy aboard Atlantis.

"I was sleeping," Reddy chuckled. "Somebody woke me up and wanted me to look at the rocks and test them."

It turned out to be quite an awakening. "I was amazed at how easy it was to break," Reddy recalls, "which confirmed it wasn't solid rock" and lent credence to Keller's theory that these structures might be made of asphalt.

Without access to the sophisticated equipment in his Woods Hole lab, Reddy employed a "25-cent glass tube, the back of a Bic pen and a little nail polish remover" to analyze the crusty substance. He used the crude tools like a mortar and pestle to grind the rock, "and literally within several minutes, it became a thick oil."

"This immediately said to me that this was asphalt," Reddy said. "And I remember turning to Dave [Valentine] and saying, 'We've got to back. Please take me back there'" to the dome.

Diagram showing formation of an asphalt volcano and associated release of methane and oil. Credit: Jack Cook, UCSB

After making some schedule changes, Valentine cleared the way for him and Reddy to take Alvin back to several sites in 2007. This work also set the stage for a follow-up study in September 2009, when the investigators returned to the domes with Alvin and the Autonomous Undersea Vehicle (AUV) Sentry to study the unique structures. They were joined by, among others, WHOI collaborators Dana Yoerger, Richard Camilli and Robert K. Nelson and Oscar Pizarro, now at the University of Sydney.

"With that combination, we were able to go in and do very detailed mapping of the site and very detailed sampling at the seafloor," Valentine said. Using mass spectrometers and radiocarbon dating in their respective laboratories, the scientists were able to confirm the nature and age of the domes.

"To me, as an oil-spill chemist, this was very exciting," said Reddy. "I got to find out what oil looks like after… 35,000 years."

What it looked like was "incredibly weathered," said Reddy. "That means nature had taken away a lot of compounds. These mounds of black material were the last remnants of oil that exploded up from below. To see nature doing this on its own was an unbelievable finding."

A few asphalt-like undersea structures have been reported, says Valentine, "but not anything exactly like these…no large structures like we see here." He estimates that the dome structures contain about 100,000 tons of residual asphalt and compares them to an underwater version of the La Brea Tar Pits in Los Angeles, complete with the fossils of ancient animals.

The researchers are not sure exactly why sea life has taken up residence around the asphalt domes, but one possibility is that because the oil has become benign over the years that some creatures are able to actually feed off it and get energy from it. They may also be "thriving" on tiny holes in the dome areas that release minute amounts of methane gas, Reddy says.

The scientists plan to continue studying the domed structures. "We have some very fundamental questions that remain," Valentine says. "It would be nice to know what is going on deep down under these things.

"One future direction is to try and actually drill into them," he says. "We also need to turn it over to some geologists to figure out where this oil is really coming from. More fundamentally, we're going to look at the actual degradation of the oil by microorganisms and maybe even see what organisms are trapped in this…very much like the La Brea Tar Pits."

From a chemical point of view, Reddy says he will continue to probe the question of exactly which of the chemicals that make up the domes "stayed around" all these years.

"Instead of this taking place at a refinery, nature used a variety of its own tools," he said, to manufacture the asphalt substance. With some heating and a few chemical tweaks, he added, this is essentially the same material that paves highways and parking lots. After all, it is California.

Explore further: Researchers construct a model of impact for El Nino / La Nina events

Provided by Woods Hole Oceanographic Institution

4.5 /5 (22 votes)

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User comments : 27

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Husky
4.8 / 5 (4) Apr 25, 2010
i can imagine a few oil companies read this article with much interest, there might still be a huge oil reserve under/nearby the tar domes??
Caliban
3.3 / 5 (6) Apr 25, 2010
Quite possibly, they are remnant "plugs" from oil seeps that occured due to volcanic fracturing of nearby strata, which could have allowed migration of oil toward the surface.

It would be interesting to know what the area topography is like- a depression, or valley, perhaps?
Shootist
1.8 / 5 (16) Apr 25, 2010
No drilling for oil off the California coast. Why? Because motor cars run on moonbeams in California.

All Ahnold has to do is sign an executive order opening all State owned land to petroleum and mineral exploration/exploitation, taxed it and pay off the State's debt.

Low emission unicorns running on moonbeams.
PinkElephant
4.8 / 5 (8) Apr 25, 2010
No drilling for oil off the California coast. Why?
Here's the answer:

http://en.wikiped...ftermath

Ironic, considering it's the very same Santa Barbara that's being talked about in the above article...

Incidentally, the recent explosion/fire, and subsequent gigantic oil slick, out in the Gulf of Mexico isn't helping the argument of those who want everyone to believe how much more safe, reliable, and eco-friendly modern oil rigs have become.
All Ahnold has to do is sign an executive order opening all State owned land to petroleum and mineral exploration/exploitation
California only has legal authority out to 3 nautical miles from shore. Everything beyond that (out to 200 nautical miles, I believe), belongs to the Feds as far as resource exploitation is concerned.
ormondotvos
4.5 / 5 (2) Apr 25, 2010
What microbes ate the oil?
Caliban
3.3 / 5 (3) Apr 25, 2010
What microbes ate the oil?


There are several species of petroleum-consuming bacteria. quick wiki will do it.
aufever
3.3 / 5 (4) Apr 25, 2010
Nearby there is an Estimated up to 15 Billion Barrels of oil which would go a long way to balancing the state budget. Of particular notice to those of you opposed to drilling in the Santa Barbara Channel. According to former JPL Physicist Bruce Allen that in the 38 years since the moratorium on oil drilling in the Santa Barbara Channel and off-shore California, an estimated 900 barrels of crude oil have leaked from the production platforms visible off the the coast. In contrast, he points out, the seeps have leaked an estimated two million barrels. How much is the worth in the Balance of Trade Deficit
Caliban
3.9 / 5 (7) Apr 25, 2010
@aufever

Perhaps you should ask that question of the high white republican NIMBY Santa Barbaraites who were instrumental in getting the ban imposed in the first place.

Everyone is for offshore drilling until a spill wrecks the scenery. It just wouldn't do for Babs and Muffy to get crude on their bikinis, much less the Commodore's yacht befouled, now would it?
Shootist
2 / 5 (4) Apr 26, 2010
@aufever

Perhaps you should ask that question of the high white republican NIMBY Santa Barbaraites who were instrumental in getting the ban imposed in the first place.

Everyone is for offshore drilling until a spill wrecks the scenery. It just wouldn't do for Babs and Muffy to get crude on their bikinis, much less the Commodore's yacht befouled, now would it?


There is in fact more than enough blame to spread around.
Caliban
3 / 5 (2) Apr 26, 2010
[q
There is in fact more than enough blame to spread around.

True enough.
Baseline
2.3 / 5 (3) Apr 26, 2010
Babs and Muffy thats some funny stuff right there.

I know it may be counter intuitive to say so but perhaps the best way to reign in budgets and taxes is to show a modicum of fiscal responsibility.

The leadership needs to start leading by doing more with less, eliminating fraud and waste, not simply passing the burden on to the taxpayers.

What level of taxation will it take for the taxpayers to demand reform? Most people have never even added up their total tax burden, which for most is around 60% of earned income.

Ask yourself what are you getting for your money and do you honestly believe it is a good value?
marjon
1 / 5 (1) Apr 26, 2010
Oil is being pumped off the coast of Santa Barbara now.
The rigs are easily seen from shore.
Nature spills oil into the sea. How does that compare to what humans spill?
HaveYouConsidered
1 / 5 (1) Apr 26, 2010
If it's possible that the right sort of asphalt lasts 35,000 years under the sea, then perhaps they've stumbled across a safe way to contain and store nuclear waste.
arki
5 / 5 (1) Apr 26, 2010
So then, all those tar spots that showed up on my feet while surfing there were not from nasty corporate oil platform spills, but just an expression of ancient beautiful nature?
croghan27
4.5 / 5 (2) Apr 26, 2010
According to an already included link, there are a couple of dozen rigs off California just a-producing their little hearts out.

My question is if that asphalt last 30,000 years - howcome the stuff in front on my house lasts only ten?
JayK
3.7 / 5 (3) Apr 26, 2010
My question is if that asphalt last 30,000 years - howcome the stuff in front on my house lasts only ten?

Because fish don't drive big trucks with studded snow tires.
CWFlink
3 / 5 (2) Apr 30, 2010
I've asked before... maybe the next quake in LA will answer it for me: What happens when a real volcano splits an oil or coal field?

Just as this 35,000 year old natural oil spill exists, there must have been many instances in the past where volcanic activity released vast amounts of CO2 by consuming huge deposits of oil or coal.

Where is the archiological evidence of this? What happened to the environment in the years after the events?
JayK
1 / 5 (1) Apr 30, 2010
Ice age and extinction events. When CO2 is offset by much more massive and active solar ingredients like silica then the earth receives less UV through the clouded atmosphere resulting in massive cooling and those really bad things called extinction events.

Where is the archaeological evidence? Look at the other Physorg story where you asked the same question.
k_m
2.2 / 5 (6) May 02, 2010
Because fish don't drive big trucks with studded snow tires.
Nor do most people in California.
MikeLisanke
1 / 5 (2) May 02, 2010
Does anybody know whether oil recovered from the Gulf cleanup would become the property of the salvage company?
GaryB
5 / 5 (1) May 02, 2010
> shootist
No drilling for oil off the California coast. Why? Because motor cars run on moonbeams in California.


Because you're listening to talk radio too much. You can see the very reasonably reason why with the current BP oil disaster. Because oil companies are much more nasty than the nasty liberals.

Second: Drilling is going on today -- there's a lot of production on and off the coast.

Third: These asphalt domes typically cover up ... asphalt. That's the same as the tar pits and not very useful for energy.

All that said, I think they should allow more drilling ... but regulate the hell out of the oil companies who don't care about other uses of the area such as boating, fishing, surfing, swimming, tourism and so they won't put in the extra expense of safety systems because that's not what they are paid to do ... it takes a government to force them to do it.
Quantum_Conundrum
3 / 5 (2) May 02, 2010
There was supposedly such an event in the Soviet Union in the fossil record, in which a very large coal deposit was broken through by a volcanic eruption.

As I recall, this event was, at least according to geologists, associated with a mass extinction of 90-99% of all life on earth.

===

Personally, I do not believe oil is a "fossil fuel" at all. Finding some decaying plants in oil or coal deposits is certainly not the same thing as saying decaying plants or animals produce oil or coal.

1) There is simply too much oil on the earth for it to be a fossil fuel.

2) The surface and atmosphere of Titan is covered by several types of oil-like hydrocarbons, proving these substances have nothing to do with decaying plant or animal life, and that they form huge quantities through simple, non-biological processes.

3) Methane and other hydrocarbons exist in absurd quantities in the solar system, formed through non-biological processes.

4) it probably formed the same way here...
Skeptic_Heretic
5 / 5 (2) May 02, 2010
2) The surface and atmosphere of Titan is covered by several types of oil-like hydrocarbons, proving these substances have nothing to do with decaying plant or animal life, and that they form huge quantities through simple, non-biological processes.
Not kerogen. All oil we've pumped from the earth is kerogen based. Kerogen does not have a proven abiotic vector, nor have we found it anywhere other than Earth.
3) Methane and other hydrocarbons exist in absurd quantities in the solar system, formed through non-biological processes.
Yes but that has nothing to do with terrestrial crude.

4) it probably formed the same way here...

We pretty much know that the oil of today is the fossilized remains of the biological soup inhabiting the tidal regions of the planet long, long ago. I think you're confusing the formation of coal, which is primarily decaying plant material from the carboneferous period.
jbird
not rated yet May 02, 2010
I'm pretty sure the oil of the California coast is a heavier crude (i.e. Asphalt) not suitable for vehicle use. Oil for gas comes from what is called "sweet crude", found in places like Saudi Arabia. the crude that is found off California fuels the barges carrying the "sweet crude" to refiners.
croghan27
5 / 5 (1) May 02, 2010
I'm pretty sure the oil of the California coast is a heavier crude (i.e. Asphalt) not suitable for vehicle use. Oil for gas comes from what is called "sweet crude", found in places like Saudi Arabia. the crude that is found off California fuels the barges carrying the "sweet crude" to refiners.


jbird .... Ain't nothing heavier than oil from the oil sands in Alberta Canada or Venezuela. It is fed into a 'coker' that with great heat and in the presence of a catalyst 'cracks' the long HC chains into shorter ones that can be used for more commercial products.

The synthetic crude produced in Alberta, that comes from the tar sands is 1/3 naphtha (as in like gasoline) and 2/3 gas oil - like diesel or stove oil.

While it may be a bit more expensive, current technology can hand 'thick' oils.
croghan27
not rated yet May 02, 2010


Second: Drilling is going on today -- there's a lot of production on and off the coast.



Gary - a production rig is a lot different than a drilling rig - those off California are there for producing oil - not finding oil. (Geologists are pretty sure the oil is there - or as sure an can be in advance of drilling. and finding.)
gwrede
1 / 5 (5) May 03, 2010
Personally, I do not believe oil is a "fossil fuel" at all. Finding some decaying plants in oil or coal deposits is certainly not the same thing as saying decaying plants or animals produce oil or coal.

1) There is simply too much oil on the earth for it to be a fossil fuel.

2) The surface and atmosphere of Titan is covered by several types of oil-like hydrocarbons, proving these substances have nothing to do with decaying plant or animal life, and that they form huge quantities through simple, non-biological processes.

3) Methane and other hydrocarbons exist in absurd quantities in the solar system, formed through non-biological processes.

4) it probably formed the same way here...
Well, I'll be...

First time I hear somebody else agree with what I've always thought. I couldn't have put it better.

The scientific community insists "no way", until one day, bang, everybody goes "Of course it is." Reminds me of continental drift.