A newly released study conducted in part by a team of UCSB scientists has discovered a series of ancient underwater volcanoes off the Santa Barbara coast, roughly 700 feet below the sea level.
What’s more, they’re made completely of asphalt.[media-credit name=”Illustration Courtesy of Jack Cook” align=”alignleft” width=”150″][/media-credit]
The scientists, who worked in conjunction with researchers from Woods Hole Oceanographic Institution, UC Davis, University of Sydney and University of Rhode Island, have found that the 30,000 to 40,000-year-old volcanoes may hold some clues about life during the Ice Age as well as shed light on previously unexplainable patterns in oil and natural gas emissions.
“Previous studies have implicated massive releases of methane — a potent greenhouse gas — in major climatic events,” Chris Farwell, a UCSB graduate student and co-author of the study, said. “The timing of formation as well as the location of these structures coincides with previously reported evidence for one such massive methane release between 35,000 to 40,000 years ago. This study provides evidence that methane was released in large amounts at the same time these volcanoes were formed, leaving large pits adjacent to the volcanoes characteristic of methane bubbling from the subsurface.”
Farwell was aboard the initial research cruise to the site, located 10 miles off the Santa Barbara coast, in 2007, which was the first investigation into a series of unusual bumps on the sea floor. While the depth was far too great for divers, the research submarine Alvin was able to see what no one else could: a massive, six-story asphalt volcano as long as a football field — the biggest of the underwater volcano range.
UCSB earth science professor David Valentine, lead author of the National Science Foundation-funded study, said the discovery may explain records of Ice Age-era emissions of petroleum and methane that previously baffled the scientific community. Today, however, the volcanoes lie extinct — a far cry from their active records of years past.
“In the past, they may have had a very dramatic effect,” Valentine said. “Large emissions of both oil and natural gas probably contributed to very poor water quality of the channel at that time, perhaps even driving all of the oxygen out of some of the water. But now, they’re virtually extinct; there’s no oil emanating from them anymore, just a small amount of residual gas that’s still bubbling. Today, they actually serve as a hard sea floor that allows organisms to latch onto it, so it actually provides quite a bit of diversity; it acts like a deep-sea reef in some ways.”
Valentine and his colleagues, including students from Geology 181: Field Studies in Marine Geophysics and 182: Field Studies in Marine Geochemistry, returned to the site to collect more samples with the submarine’s robotic arm. In 2009, the team also sent Sentry, an autonomous underwater vehicle, to photograph the volcanoes from roughly nine feet above the sea floor.
As of now, the team has hundreds of pounds of samples that they will continue to test. While Valentine is pleased with the research, he said he desired to further investigate the depths of the volcano in the history of aquatic life.
“The nature of these features is unusual,” Valentine said. “They act somewhat like the La Brea Tar Pits in that they trap organisms of the time, and there may be some very interesting molecular remains inside of them. I’d like to be able to see the progression of how they formed and when they formed; I imagine there’s a whole history of eruptions and flows that lie on top of other flows, so there could be a very detailed history as you drill down into the features. I’m also very interested in fossilized remains of organisms that may have been thriving, eating away at many of the components that made up the oils that flowed; it would be pretty cool to be able to look back [30,000 to] 40,000 years at the DNA of trapped microorganisms that could be in there.”