Rocky pillars dotting Iceland’s Skaelingar valley were projectiles tossed into the fields by warring trolls.
A lava pillar in Iceland's Skaelingar valley. A new study suggests that these pillars were formed in an unusual interaction where lava and water met on land without exploding. Credit: Tracy Gregg
That, at least, is the tale that University at Buffalo geologist Tracy Gregg heard from a tour guide and local hiker when she visited the site on two occasions.
But Gregg and a colleague have a new explanation for the presence of the lava formations — this one also unexpected.
In the Journal of Volcanology and Geothermal Research, she and former UB master’s student Kenneth Christle report that the pillars, hollow and made from basalt, likely formed in a surprising reaction where lava met water without any explosion occurring.
Their findings appeared online Aug. 15 and will be published in a forthcoming print edition of the journal.
“Usually, when lava and water meet in aerial environments, the water instantly flashes to steam,” said Gregg, a UB associate professor of geology. “That’s a volume increase of eight times — boom.”
“Formations like the ones we see in Iceland are common in the ocean under two miles of water, where there’s so much pressure that there’s no explosion,” she said. “They’ve never been described on land before, and it’s important because it tells us that water and lava can come together on land and not explode. This has implications for the way we view volcanic risk.”
Deep-sea basalt pillars form when columns of super-heated water rise between pillows of lava on the ocean floor, cooling the molten rock into hollow, pipe-like minarets. The structures grow taller as lava levels rise, and remain standing even after volcanic eruptions end and lava levels fall again.
Gregg and Christle propose that the same phenomenon sculpted the land-based lava pillars in Iceland.
It happened in the 1780s, when lava from a nearby eruption entered the Skaelingar valley, which Gregg theorizes was covered by a pond or was super-swampy.
She thinks one reason no explosion occurred was because the lava was moving so slowly — centimeters per second — that it was able to react with the water in a “kinder, gentler” manner.
“If you’re driving your car at 5 miles per hour and you hit a stop sign, it’s a lot different than if you hit that same stop sign at 40 miles an hour,” she said. “There’s a lot more energy that will be released.”The Iceland formations, some over 2 meters tall, display telltale features that hint at how they were created. For example:
The skin of the towers isn’t smooth, but gnarled with shiny drips of rock. The glassy texture suggests that the lava hardened quickly into rock, at a pace consistent with non-explosive water-lava interactions. Had the lava cooled more slowly in air, it would have formed crystals.
Each of these distinctive characteristics is also prevalent in deep-ocean pillars, said Gregg, who first saw the Icelandic formations in the mid-1990s while hiking in the valley with her husband.
“I knew as soon as I saw them what they were,” she said. “I had, at that time, been on submarine cruises and seen these things deep under the sea, so I was just hysterical, saying, ‘Look at these!’ So I ran around and started taking pictures until the light started running out.”
She didn’t have the chance to return to the site until 2010, when Christle received a student research grant from the Geological Society of America to do field work in Iceland.
The two spent four days studying the pillars in detail, confirming Gregg’s original suspicions.
In the future, scientists could hunt for land-based lava pillars near oceans to learn about the height of ancient seas, or search for such formations on Mars and other planets to determine where water once existed.
Media Contact InformationCharlotte Hsu
Charlotte Hsu | EurekAlert!
The melting ice makes the sea around Greenland less saline
16.10.2017 | Aarhus University
WSU researchers document one of planet's largest volcanic eruptions
12.10.2017 | Washington State University
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
It's possible to produce hydrogen to power fuel cells by extracting the gas from seawater, but the electricity required to do it makes the process costly. UCF...
Mercury, our smallest planetary neighbor, has very little to call an atmosphere, but it does have a strange weather pattern: morning micro-meteor showers.
Recent modeling along with previously published results from NASA's MESSENGER spacecraft -- short for Mercury Surface, Space Environment, Geochemistry and...
10.10.2017 | Event News
10.10.2017 | Event News
28.09.2017 | Event News
16.10.2017 | Physics and Astronomy
16.10.2017 | Earth Sciences
16.10.2017 | Physics and Astronomy