The music is Nýfallið Regn by Ásgeir Trausti.
The music is Nýfallið Regn by Ásgeir Trausti.
Volcanoes are many things: spectacular, terrifying, gargantuan, and enigmatic. They free us from ice ages, destroy civilizations and build new islands from the sea as we watch. They captivateboth scientists and non-scientists alike, so whenever a new one is found, its always a cause for celebration.
These volcanoes arent on Earth this time around, however.They can be found on a peculiar southern region of our faded crimson neighbor, Mars. As reported by NASAs Jet Propulsion Laboratory (JPL), the Mars Reconnaissance Orbiter (MRO) spotted some unusually textured surfaces inSisyphi Montes, an area packed with flat-topped mountains.
The characteristic signatures revealed the presence of a collection of minerals zeolites, sulfates, and iron oxides which can only collectively form from one type of volcanic eruption, one that occurred through a layer of ice. As ice is no longer present in the region, this means that the MRO has uncovered evidence of an ancient subglacial eruption, probably from one of those suspicious, volcano-like mountains in the region.
Rocks tell stories. Studying the rocks can show how the volcano formed or how it was changed over time, Sheridan Ackiss, a graduate student at Purdue University, West Lafayette, Indiana, and one of the researchers who discovered the long-lost volcanic eruption, said in a statement.
Curious mineral patches have been identified in a region of Mars long-suspected of having volcanic activity. NASA/JPL-Caltech/JHUAPL/ASU
Volcanic activity on Mars is thought to be long-dead, but the epic volcanic monuments left behind within the geology of the Red Planet betray to us its much more violent past. A recent study revealed how one epic volcanic effusion billions of years ago actually tipped the entire planet over by 20. Olympus Mons once squeezed out floods of lava across the Martian landscape; if it grew any larger, it would be so heavy that it would sink into the crust.
The mineral patches found in the Sisyphi Montes region, which extends from 55 to 75 south, can only be formed when lava mixes somewhat explosively with ice. Today, the ice-capped south pole is around 1,600 kilometers (1,000 miles) away from this region, which means that ice sheets were once present in this region.
We have these types of subglacial volcanoes on Earth too: The Eyjafjallajkulleruption in Iceland in 2010 is a good example of this, where the meeting of hot magma and cold ice generated prolonged, huge ash-filled plumes of steam and lava blebs.
These volcanoes either erupt under or onto a volume of ice. Whereas the latter situation tends to be calm and uneventful, the former is almost always more explosive. Ice caps above magma chambers increase the pressure difference between the magma and the outside world, and a higher pressure gradient always means a more explosive eruption.
What happens when lava erupts onto ice. Science Channel via YouTube
Also, the searing heat of the magma encountering the far colder ice initiates something called a molten fuel coolant reaction (MFCI); the greater the temperature difference, the more energetically the heat from the magma is transferred to the ice, and the more explosive the eruption will ultimately be.
Curiously, magma just erupting onto ice never produces an explosion. Volcanologists think that the ice or water needs to be wrapped up inside the magma, where it will rapidly heat and expand into a gas under additional pressure, before it explodes. This mechanism is likely behind the production of these mineral patches just discovered on Mars.
Big Brother, the cat version
Over the last seven years, seismic activity at Bárðarbunga, the second highest mountain in Iceland, has been gradually increasing. On August 16, a swarm of small earthquakes signaled the movement of molten rock underground, Nature reports, and visitors were blocked from the area. Less than two weeks later on August 28, researchers flying over Vatnajökull—Europe’s largest ice cap—spotted several depressions up to 15 meters deep in the side of the volcano, BBC reports. Called cauldrons, they’re the result of melt occurring at the base of the ice.
Finally, just after midnight local time on August 29, a fissure near Bárðarbunga erupted, sending gases and steam from small lava fountains into the air above the glacial ice north of the caldera in the volcano’s crown.
The eruption occurred on an old volcanic fissure on the Holuhraun lava field, about five kilometers north of the Dyngjujökull ice margin, according to a joint report from the University of Iceland and the Icelandic Met Office, which oversees volcanoes in the country. The active fissure was about 600 meters long.
Seismic data and images from a webcam called Mila, located northeast of the site, show that the eruption peaked about 40 minutes in. It ended about four hours later. No volcanic ash was observed, and no plume was detected by radar. The threat to aviation has since been reduced to code orange. To the right is a 1973 satellite image of the Vatnajökull ice cap from NASA, with Bárðarbunga at its northwestern edge (top left).
After the swarm of small earthquakes, 0.4 cubic kilometers of magma formed a sheet of freshly cooled rock (an intrusion called a dike) that stretched for 45 kilometers north of Bárðarbunga, Nature reports. The dike interacted with cracks leading toward a volcano called Askja 20 kilometers away. If the dike had managed to make it all the way to Askja, the stress and supply of fresh magma could have caused it to erupt.
Furthermore, the sheer volume of magma involved suggests that it’s coming from the Earth’s mantle. The source is likely hundreds of kilometers below the surface of the crust, says British Geological Survey’s Evgenia Ilyinskaya, and not the shallow magma chamber beneath the volcano.
Check here for updates from the Icelandic Met Office.
Images: Icelandic Coast Guard (top) & NASA (middle) via Icelandic Met Office