Tag Archives: lava

Icelandic eruption attracts thousands of visitors, helicopter rides, over the weekend

What were probably the tastiest hot dogs made in all of Iceland this weekend were grilled over a volcanic eruption alongside marshmallows.

Aerial photo of the eruption. Image via Wikimedia.

In case it passed by below your radar, Iceland saw a new volcano start erupting late last Friday. Despite the island nation’s long history of volcanic activity and plane-grounding eruptions, this is the first time a member of this particular volcanic system has become active in around 9 centuries.

Still, the event attracted thousands of curious onlookers, and local media has even reported on some grilling marshmallows or hotdogs — which, scientifically speaking, is the best way to enjoy a volcano.

Mount Fagradalsfjall

The hard-to-pronounce volcano is situated around 40 kilometers (25 miles) from Reykjavik, Iceland’s capital. Despite the fact that the only way to reach it is to hike for around 90 minutes from the nearest road, locals came in droves to see the incandescent lava slowly pour down Fagradalsfjall’s slopes.

Luckily for everybody, the eruption has been very calm and small in scope so far, with experts estimating that around 300,000 cubic meters of lava have poured forth from the volcano’s lip now.

“It’s absolutely breathtaking,” said Ulvar Kari Johannsson, a 21-year-old engineer who spent his Sunday visiting the scene, for AFP. “It smells pretty bad. For me what was surprising was the colours of the orange: much, much deeper than what one would expect.”

Access to the area was blocked immediately after the eruption started, to keep everybody safe. After a few hours, however, the police allowed access to the public but were strongly discouraging visits (lava tends to be dangerous). By Saturday, however, visitors were allowed free access as long as they respected strict safety guidelines.

For the most part, however, the police are keeping an eye on visitors and occasionally asking those that get too close to “step back,” according to a local police officer. Emergency teams were also involved in helping people find their way back to the road on Sunday after weather conditions and visibility at the site deteriorated rapidly. These teams also carried devices to measure gas pollution levels in the atmosphere — especially sulfur dioxide, which can pose a danger to health and even be fatal.

High pollution levels on Monday morning prompted the authorities to close the site down for visitors yet again.

A volcanic eruption takes place in Iceland roughly once every five years on average and, due to the rugged nature of the island, they’re often far-removed from population centers. But this was the first such event in the Reykjanes peninsula, which is densely inhabited, in over 800 years, and the first member of the Krysuvik volcanic system to erupt in almost 900 years.

Given its relatively close proximity to people, many visitors went to admire the event, probably happy to break the dullness of staying at home all day after 2020. By Sunday, local media reported, hikers had already beaten a visible trail up to the volcano. Helicopter rides were also organized around it over the weekend.

For now, the site remains closed due to unsafe atmospheric conditions. Experts believe the eruption will die out possibly within a few days. But that doesn’t mean you have to miss out on the fun — here’s a live stream of Mount Fagradalsfjall doing volcano things.

A new study provides our best-yet prediction of what a metallic volcano might look like

If you like volcanoes, Earth isn’t a bad place to live on. After all, our planet is quite geologically active, and that also translates into a respectable level of volcanism. But when it comes to having a variety of flavors, the Earth can be a bit lacking.

 a) Metallic flow (yellow) emerging from underneath the silicate flow (orange-black) before cooling and b) metallic flow appears gray/silver, with the silicate flow black, after cooling. Image credits A. Soldati et al., (2021), Nature.

A new paper, however, comes to estimate what one type of not-yet-seen volcanic activity might look like. Called ‘ferrovolcanism’, it is likely a hallmark of geologically active worlds whose composition is mainly metallic. The study, although still purely theoretical, could help us better understand some of the more peculiar alien landscapes out there. And even though ‘metal volcanoes’ sounds like something pretty jagged and oppressive-looking, the team’s findings suggest that they’re actually quite mellow.

Metal volcanoes

“Cryovolcanism is volcanic activity on icy worlds, and we’ve seen it happen on Saturn’s moon Enceladus,” says Arianna Soldati, assistant professor of marine, earth and atmospheric sciences at NC State and lead author of a paper describing the work. “But ferrovolcanism, volcanic activity on metallic worlds, hasn’t been observed yet.”

The study, published by researchers at the North Carolina State University, aimed to give us an idea of how volcanic activity would look on a planet made predominantly of metal.

Volcanoes are born when magma, the partially-molten material found beneath a planet’s surface, erupts. The exact nature and behavior of this magma is closely related to the chemical composition of the planet. On Earth, therefore, magmas tend to be mostly molten rock (i.e. silica molecules). On icy worlds, however, magma is in fact a mixture of fluids such as water, ammonia, or methane, all super-chilled.

What the team wanted to find out, however, is how volcanism would look on 16 Psyche, a 140-mile diameter asteroid floating merrily in the asteroid belt between Mars and Jupiter. Infrared and radar analysis of its surface suggests that 16 Psyche is formed mainly of iron and nickel. Even better, though, it’s also the target for an upcoming NASA mission. This inspired Soldati to try and determine what volcanism would look like on the asteroid.

“When we look at images of worlds unlike ours, we still use what happens on Earth—like evidence of volcanic eruptions—to interpret them,” Soldati says. “However, we don’t have widespread metallic volcanism on Earth, so we must imagine what those volcanic processes might look like on other worlds so that we can interpret images correctly.”

The team defined two types of ferrovolcanism that they believe are possible. Type 1, or ‘pure’ ferrovolcanism, occurs on bodies made entirely of metal. Type 2, or ‘spurious’ ferrovolcanism, is what we’re likely to see on bodies that have both rocky and metal elements in their chemical mix.

Together with members of the Syracuse Lava Project, the researchers then simulated the second type, in which metal separates from rock as the magma melts down, in the lab.

“The Lava Project’s furnace is configured for melting rock, so we were working with the metals (mainly iron) that naturally occur within them,” Soldati says. “When you melt rock under the extreme conditions of the furnace, some of the iron will separate out and sink to the bottom since it’s heavier.”

“By completely emptying the furnace, we were able to see how that metal magma behaved compared to the rock one.”

Metallic lava (magma becomes lava once it reaches the surface) can flow up to 10 times faster, and spreads more thinly, than rock lava, the team found. As it flows, this material also separates into an abundance of braided channels, they add. Furthermore, metal lava tended to flow largely beneath the rock one, and emerged at the leading edge of the lava body.

Another important finding of the study is that the thin, braided layers of metallic lava, once cooled, give a distinctive appearance to a planet’s surface. This is very different in nature from those produced by rocky lava flows, Soldati explains, meaning that the two types of volcanism should be easy to spot from afar.

“Although this is a pilot project, there are still some things we can say,” Soldati says. “If there were volcanoes on 16 Psyche—or on another metallic body—they definitely wouldn’t look like the steep-sided Mt. Fuji, an iconic terrestrial volcano. Instead, they would probably have gentle slopes and broad cones. That’s how an iron volcano would be built—thin flows that expand over longer distances.”

The paper “Imagining and constraining ferrovolcanic eruptions and landscapes through large-scale experiments” has been published in the journal Nature Communications.

Astronomers stunned by hellish world where it rains rocks on oceans of molten lava

Artist impression of K2-141b. Julie Roussy, McGill Graphic Design.

With its clouds of sulfuric acid and surface temperatures exceeding 400 degrees Celsius, Venus is often referred to as a sort of incarnation of hell. It could be worse, though. In a new study, astronomers have zoomed in on K2-141b, a planet that is so hot it is covered in oceans of molten lava and rocks rain down from its atmosphere.

This is truly one of the most extreme worlds scientists have found out of the more than 4,000 exoplanets identified to date. In a new study, researchers from McGill University, York University, and the Indian Institute of Science Education examined the scorching planet’s atmosphere and weather system, revealing new insights about the formation and dynamics of so-called “lava planets”.

“The study is the first to make predictions about weather conditions on K2-141b that can be detected from hundreds of light-years away with next-generation telescopes such as the James Webb Space Telescope,” says lead author Giang Nguyen, a PhD student at York University 

K2-141b, which is located hundreds of light-years away from Earth, owes its bizarre weather to its close proximity to its parent star. Being so close to the star also causes the planet to be gravitationally locked in its place — meaning the same side always faces the star just like the moon does Earth. As a result, two-thirds of the distant exoplanet experiences perpetual daylight, where surface temperatures 3,000 degrees Celsius (5,400 degrees Fahrenheit).

That’s so hot that rocks melt, covering the planet in a 96-km (60-mile) ocean of magma. It’s actually so hot that some of the molten rock is vaporized into the atmosphere.

On Earth, liquid water evaporates, rising up into the atmosphere where it condenses, ultimately returning to the surface in the form of rain. A similar cycle also occurs on K2-141b, only instead of water there’s sodium, silicon monoxide, silicon dioxide, and other vaporized rocky substances, which are carried by supersonic winds blowing in excess of 3,000 mph to the planet’s dark side.

In the part of the planet shrouded in eternal darkness, temperatures are frigid, hovering at -200 degrees Celsius (-424 degrees Fahrenheit). The cold atmosphere condenses the rocky substances, which rain back into the magma ocean, restarting the cycle.

However, unlike the water cycle on Earth, this rocky cycle is not in equilibrium since the flow of material from the dark side to the dayside is slower. Eventually, the researchers predict that the planet’s surface and atmospheric composition will be altered dramatically.

“All rocky planets­, including Earth, started off as molten worlds but then rapidly cooled and solidified. Lava planets give us a rare glimpse at this stage of planetary evolution,” said Nicolas Cowan, a professor in the Department of Earth & Planetary Sciences at McGill University.

The findings appeared in the Monthly Notices of the Royal Astronomical Society.

Some lava-like features on Mars are actually ancient mud flows

For many years, scientists have been puzzled by lava-like flows on the surface of the Red Planet. Turns out that some of these features are actually not caused by lava but by ancient mud flows instead.

Not your typical mud

It’s estimated that there are literally tens of thousands of lava-like landforms on the surface of Mars. Most are situated right in the vicinity of massive channels carved into the crust billions of years ago by fluid flowing downstream.

These channels — which can be hundreds of kilometers in length and dozens of kilometers wide — are believed to be the result of huge floods that caused water to seep into the subsurface, only to reemerge as mud.

In order to test this hypothesis, an international team of researchers simulated Mars-like conditions using the Mars Chamber at the Open University in the UK.

Inside the vacuum chamber, the researchers simulated the release of mud on the Red Planet in analogous conditions of low pressure and frigidly cold temperatures (-20°C). Tweaking the pressure and temperature in such a large vacuum-chamber proved highly challenging, but the authors eventually managed to mimic Mars-like conditions.

Mud flowing from a mud volcano in Azerbaijan. Credit: Petr Brož/Czech Academy of Sciences.

The free-flowing mud didn’t solidify like on Earth because the water began to boil and evaporate, causing the mud to freeze rapidly and form an icy crust.

“The main finding is that mud flows do not behave in the same way on Mars and Earth because of the very great difference in atmospheric pressure. And the difference makes mud flows on Mars have many of the same characteristics as lava flows (on Mars or Earth). This means that we have to be very careful in our interpretation when we see what look, at first sight, like lava flows on Mars,” Lionel Wilson, Emeritus Professor of Earth and Planetary Sciences at Lancaster University, told ZME Science.

Mud vulcanism

The collapsed circular crater of a mud volcano in Azerbaijan. Credit: Petr Brož/Czech Academy of Sciences.

The mud flows formed shapes similar to pahoehoe lava that is frequently encountered in volcanically active regions on Earth, such as Hawaii and Iceland.

Like pahoehoe lava, mud flows in Martian-like conditions solidified in the form of smooth undulating surfaces as liquid ruptured the frozen crust, then refroze.

Mars was no stranger to volcanic eruptions, as its largest mountain, Olympus Mons, attests. This massive Martian volcano towers 16 miles (25 kilometers) above the surrounding plains and stretches across 374 miles (624 km) — roughly the size of the state of Arizona.

However, the new study shows that many geological features on Mars that resemble evidence of volcanic activity may not actually be the result of lava, but rather mud.

“We need to find better ways to distinguish between lava and mud in remote-sensing images (visible, infra-red, and radar). Until then we need to be careful when interpreting images. There is very little doubt about the nature of the lava flows on the flanks of the great martian shield volcanoes, but I am less sure about the “lava flows” in the northern plains of Mars,” Wilson said.

In the future, the team of researchers, which included colleagues from the Institute of Geophysics at the Czech Academy of Sciences, the Rutherford Appleton Laboratory in the UK, CNRS in France, DLR and Münster University in Germany, and CEED in Norway, plan on conducting more experiments involving even larger volumes of mud.

“This reminds us that Mars is as complicated and diverse as the Earth in terms of the processes going on in its interior. And of course everyone wants to know if there was ever life on Mars; life needs water, and if some of what we currently think are lava flows are in fact mud flows, then that implies that early Mars had even more water than we currently think it had,” Wilson concluded.

The findings were reported in the journal Nature Geoscience.

Venus might still be volcanically active, according to its infrared emissions

Venus might still harbor active volcanoes, a new paper reports.

Image credits NASA.

Earth and Venus are similar enough in size and mass that they are sometimes referred to as being ‘sister planets’. But, apart from that, the two are very different. Venus is covered in a super-thick and opaque atmosphere, so we have had very few opportunities to actually see its surface. However, new research at the USRA’s Lunar and Planetary Institute (LPI) suggests that the second planet from the Sun may still be volcanically active.

So far, Earth has been the only planet in the solar system with confirmed volcanic activity. The other three bodies known to have active volcanoes are Io, a moon of Jupiter, Triton, a moon of Neptune, and Enceladus, a moon of Saturn.

Volcanoes near you

“If Venus is indeed active today, it would make a great place to visit to better understand the interiors of planets,” explains Dr. Justin Filiberto, a staff scientist with the LPI. “For example, we could study how planets cool and why the Earth and Venus have active volcanism, but Mars does not.”

“Future missions should be able to see these flows and changes in the surface and provide concrete evidence of its activity.”

Most planets and moons in the solar system show signs of ancient volcanism. Venus is no exception: readings in the 1990s showed that Venus had been volcanically active as recently as 2.5 million years ago and that its surface is littered with volcanic features to this day. However, because Venus is so hard to observe and visit, we’re not sure if its volcanoes are active or dormant.

The new study, led by Dr. Filiberto, drew on data recorded during the 2000s by ESA’s Venus Express orbiter, which measured infrared light coming from the planet’s surface at night. Through this data, the team was able to map the lava flows on Venus’ surface and, by comparing this against previous data, track how they evolved between the 1990s and 2000s. ESA’s data also allowed them to tease apart fresh lava flows from dormant ones.

One thing that prevented us from accurately determining when Venus’ volcanoes erupted was that we didn’t know how fast its (fresh) magma alters once on the surface. In order to determine this, Dr. Filiberto and his team simulated Venus’ atmosphere in their laboratory and then investigated how it impacts the evolution of lava.

They showed that olivine (a heavy, green mineral that’s very abundant in basalt rock) would rapidly react with gases in Venus’ atmosphere, becoming coated with magnetite and hematite (iron oxide minerals) within days. The near-infrared light emitted by these minerals are consistent with data obtained by the Venus Express mission, the team explains, and would disappear within days. This observation means that the lava flows seen on Venus must have only been a few days old at most, which would strongly indicate that the planet is still volcanically active

We won’t be able to fact-check the findings until we send a new craft to Venus. Several such missions are in the works for the future, including India’s Shukrayaan-1 orbiter and Russia’s Venera-D spacecraft, scheduled to launch by 2023 and 2026, respectively.

The paper “Present-day volcanism on Venus as evidenced from weathering rates of olivine” has been published in the journal Science Advances.

Swirl patterns.

Unique swirl patterns point to the Moon’s magnetic past

The unique swirl patterns may be produced by ancient magma tubes.

Swirl patterns.

An image of the Reiner Gamma lunar swirl from NASA’s Lunar Reconnaissance Orbiter.
Image credits NASA / LRO / WAC science team.

If you prop up a telescope and look at the Moon, you’re likely to see some curious-looking shapes dotting its surface. Many people take them to be craters left over from meteorite impacts, since this is, after all, the Moon.

That would be jumping to conclusions, however, according to a team from the Rutgers University. These bright, undulating shapes are known as ‘lunar swirls’ and up until now, they were somewhat of a mystery.

Cheesy swirls

One of the most striking features of these swirls is that they come hand-in-hand with powerful — but localized — magnetic fields. These swirls, as well as their strange magnetism, have been known for decades. Efforts to map magnetic activity on the Moon (it doesn’t have a magnetic field of its own) during the Apollo 15 and 16 missions were the first to identify these swirls as sources of magnetism back in 1979.

Since then, try as we might, we just couldn’t make heads or tails of the swirls. Each new tidbit of information only seemed to compound the problem further. For example, the swirls are less pronounced and less intricate at higher altitudes. Every swirl has its own magnetic signature, but there are also magnetic fields on the Moon that are completely distinct from swirls. To top it all off, the swirls show geological signs suggesting they’re new formations (they’re much less weathered than the surrounding rocks) — however, they’re definitely not new formations; we’ve seen them up there for decades now.

Reiner.

Reiner Gamma (60 km width, same swirl as above), seen by the Clementine spacecraft.
Image credits NASA.

“The cause of those magnetic fields, and thus of the swirls themselves, had long been a mystery,” said planetary scientist Sonia Tikoo of Rutgers University-New Brunswick.

“To solve it, we had to find out what kind of geological feature could produce these magnetic fields – and why their magnetism is so powerful.”

Computer modeling allowed the team to discover that, in order to fit the observed magnetic signature, each swirl has to form close to or directly above narrow structures that are close to the surface and can create a magnetic field. One structure that would fit this description are lava tubes, or lava dikes — the products of ancient volcanic activity, the team explains.

These tubes are left-overs from the same basalt lava flows which, 3 to 4 billion years ago, created the dark and wide basalt plains seen over the lunar surface. This would explain why those underground formations became magnetized. The magnetic fields generated by the tubes would also deflect incoming solar wind particles, helping to insulate the swirls from weathering effects.

When Moon rock (regolith) is heated to around 600° Celsius (875° Kelvin or 1,112° Fahrenheit) in an environment that lacks oxygen but has a magnetic field, it becomes ‘imprinted’ with this field itself — it becomes magnetized. Heat causes some minerals in the rock to break down, releasing iron, which becomes magnetized across the same direction as the surrounding field.

This process doesn’t usually take place on Earth, because there’s a lot of oxygen here. It can’t take place on the Moon today, because it lost both its lava flows and its magnetic field. However, according to some of the team’s prior research, the lunar magnetic field persisted up to 2 billion years longer. So their hypothesis fits the timeline.

“No one had thought about this reaction in terms of explaining these unusually strong magnetic features on the Moon,” Tikoo said. “This was the final piece in the puzzle of understanding the magnetism that underlies these lunar swirls.”

The team hopes that the next mission to the Moon will study these swirls directly, and confirm or disprove their hypothesis.

The paper “Lunar Swirl Morphology Constrains the Geometry, Magnetization, and Origins of Lunar Magnetic Anomalies” has been published in the Journal of Geophysical Research: Planets.

huge lava lake Io

Largest lava lake in the solar system makes massive waves

Using giant Earth-based telescopes in tandem with the movement of Jupiter’s moons, astronomers were able to peer inside a huge lava lake on Io. This is the largest lava lake in the solar system and interestingly it produces huge lava waves on its surface.

huge lava lake Io

On March 8, 2015, Jupiter’s moon Europa passed in front of Io, allowing detailed mapping of the bright volcanic crater called Loki Patera (upper left). The lower right feature is a different volcanic hotspot. Credit: UC Berkeley.

Io, the innermost of the four Galilean moons of the planet Jupiter, is the most volcanically active body in the solar system which explains Loki Patera, the huge lava lake in question. At 8,300 square miles, it’s like Lake Ontario, only made of a lava instead of water. Actually, because of tidal heating, most of Io’s crust is literally lava.

A simple glance of Io is enough to understand what I mean — hundreds and hundreds of outpouring of lava dot the moon’s surface. Some are short-lived eruptions, others are stable lava lakes like Loki Patera.

“If Loki Patera is a sea of lava, it encompasses an area more than a million times that of a typical lava lake on Earth,” said Katherine de Kleer, a UC Berkeley graduate student and the study’s lead author. “In this scenario, portions of cool crust sink, exposing the incandescent magma underneath and causing a brightening in the infrared.”

Loki Patera photo

Loki Patera is the horseshoe-shaped dark object in this exquisite photo of Io. Credit: NASA.

To study Loki Patera, scientists used high-end telescopes but also the help of a rare natural phenomenon. On the 8th of March, 2015, another of Jupiter’s moons — Europa — passed between Io and Earth blocking infrared radiation emanating from Loki Patera for a few moments. As Europa blocked extraneous light, researchers operating the Large Binocular Telescope were able to measure the temperature of different parts of the huge lava lake.

Previously, observations suggested that temperature on the surface of the lake fluctuated greatly, rising sharply every 500 days or so. These new observations help explain why this happens. Periodically, the very top layer of lava of the lake forms a crust, cools into a dense mass, then sinks flushing out and exposing hotter lava. Using data from the new measurements and knowing cooling rates of lava lakes found here on Earth, the team was able to not only figure out how hot the lava of Loki Patera is but also how old it is.

From infrared measurements, the researchers could deduce the age of the lave at the surface of the lake. The youngest is in the lower right, having overturned most recently, about 75 days before the observations. Credit: Katherine de Kleer.

From infrared measurements, the researchers could deduce the age of the lava at the surface of the lake. The youngest is in the lower right, having overturned most recently, about 75 days before the observations. Credit: Katherine de Kleer.

Apparently, the lava on the lake cools in two waves. One travels counterclockwise from the north part of the lake while the other travels clockwise. These waves of activity move slowly across the lake at a rate of about a kilometer/day. As the days go by, the waves will eventually offset despite starting at roughly the same time. According to Ashley Davies, one of the study’s authors, this may be due to the fact that there are two distinct sources of magma feeding each area of the lake. Each of these sources has a different composition of gas which ultimately makes the cooled crust sink at different rates, as reported in the journal Nature.

The video below shows a simulation of the two resurfacing waves sweeping around Loki Patera at different rates.

All of this very violent volcanic behavior is exciting for a number of reasons. Though 628 million kilometers away, Io is like a window into our own planet’s past. Earth, Mars, and Venus were all previously largely shaped and modified by eruption events that went on for millions of years. Let’s just say Earth had a very tumultuous youth.

Another important consideration is that the tidal heating that’s feeding Io’s surface with so much lava are similar to the same forces at work on Ganymede and Europa, Io’s neighbors. Not too long ago, NASA unveiled evidence of hydrogen molecules in the plumes gushing out of Europa’s surface — telltale signs of hot spots hidden beneath the moon’s icy crust which could support life. Who know what we might learn next when Europa blocks Ion again in 2021.

“This is a step forward in trying to understand volcanism on Io, which we have been observing for more than 15 years, and in particular the volcanic activity at Loki Patera,” said Imke de Pater, a UC Berkeley professor of astronomy.

How caves form and the different types of caves

Ahh, the cave, cradle of humanity since time immemorial. Early humans sought them for shelter, plastered their walls with paintings, made them into the first temples. And even after we’ve moved out, they still captivate and terrify us — unknown, but somehow familiar.

Without caves, our life might have been very different now. So how did they come about? How does a cave form? Well, in a lot of different ways, really. Caves come in different sizes and shapes, and the way they’re created depends on the type of cave. Most often, they form when water dissolves limestone, but they can also be shaped by waves, even lava.

So don your hardhats and pull your learning pants on, because I’m going to tell you all about:

The Types of Caves

Solutional caves

Son Doong Cave in Vietnam, the largest cave ever found, is a solutional cave. It’s big enough to have its own ecosystem.
Image credits Doug Knuth

These are the structures people most readily associate with the idea of a cave, and for good reason. They’re the most numerous, the largest and most often-encountered structures. If you’ve ever been spelunking or seen a cave in a movie chances are it was a solutional cave. The secret to their abundance is two-fold: for starters, the rocks that house them are found throughout the globe, and the chemical elements required to shape them are abundant. As Andrei wrote:

“Solutional caves are generally formed in limestone or other similar rock such as gypsum or dolomite. They form when acidic water dissolves the rock, seeping through the bedding planes.”

Let’s consider a geological environment of soil over a bedrock of limestone, as solutional caves are most frequently found in this type of rock. Limestone is a carbonatic rock, formed over millions of years from the remains of coral, zooplankton, shells or bones, all mashed up together. This material gets bunched up and subjected to huge pressure, fusing into solid rock.

The main mineral found in limestone is calcium carbonate, or CaCO3, a mixture of calcium and carbon trioxide, an unstable compound. While limestone is pretty resilient and nice to look at, it tends to be relatively brittle and fractures a lot due to tectonic stress. Its chemical makeup also makes it susceptible to attack by acids which break up the calcium carbonate into calcium compounds (Ca + the non-metal that forms the acid), carbon dioxide (CO2), and water (H2O).

Limestone cave in Australia.
Image credits Andrew McMillan

[panel style=”panel-info” title=”Fun geology fact” footer=””]Rubbing a diluted solution of acid onto a geological sample is still the easiest way to determine if there are any carbonatic compounds in the rock. If so, the solution will bubble and foam quite vigorously.[/panel]

These conditions work together to make limestone an ideal place for cave formation. In nature water invariably becomes acidic by mixing with carbon dioxide molecules (H2O+CO2=H2CO3) forming a solution of carbonic acid. Part of this can happen in the atmosphere as rain pours down, but most of the mixing takes place in the soil which is rich in CO2 left over from decaying organic matter.

This solution trickles down through the soil and cracks in the limestone until it reaches the water table. Here it starts to eat through the rock, forming channels. In an almost cruel twist of geological fate, while limestone dissolves it releases the exact components needed to make more carbonatic acid. This chain reaction and the extra acids that seep in from the surface keep expanding the cavern until the water table level drops. If this happens, water with dissolved calcium compounds will trickle down to the new area of dissolution, forming stalactites and stalagmites.

And looking awesome.
Image via pixabay

If on the other hand water remains mobile throughout dissolution, the caves take on the appearance of an underground drainage system, a landscape known as karst.

Something like this, but underground.
Image credits Jonathan Wilkins

It takes a few million years for a solutional cave to form.

Lava caves

While dissolution caves are formed by hollowing out preexistent packets of rock, lava caves form at the same time as the geological environment around them — and so, they’re considered to be primary caves. They’re centered around areas of volcanic activity and resemble huge underground rock pipes.

Lava River Cave in Arizona.
Image credits Volkan Yuksel

And in a way, that’s just what they are. Molten rock that reaches the surface (called lava) can form sprawling cave networks while it flows down the path of least resistance. The material is very hot initially, but as the outer layer of lava starts to cool it solidifies into a shell of rock. This process insulates the lava within and starts at the base of the flow (because the rock it’s pouring over is a better thermal conductor than air,) forming a through-like structure through which the hot lava at the center keeps on flowing. Over time, material clings to the edges of this through and solidifies, eventually closing into a pipe-like structure.

Because this shell of rock is solidified from a flowing material its inner walls are neat, almost polished, with horizontal conduits on the inner side that channel the flow. Once the lava supply starts to dwindle the cave cools down and thermal constriction starts fragmenting the walls. The pressure of volcanic gasses in the cave, however, support the roof from collapsing. As these gasses mix with air from vents in the roof resulting oxidation processes sometimes generate enough heat to re-fuse the ceiling, solidifying it. Sometimes, this process can lead to the formation of stalactites as molten material drips from the ceiling.

Long exposure picture of a lava tube near Bend, OR. The lighting is artificial. Image credits to Michael Harms.

Long exposure picture of a lava tube near Bend, Oregon. The lighting is artificial.
Image courtesy of Michael Harms.

These structures are called lava tubes, and it’s important to note that they form on the surface and are later covered with sediments. They often have lava streams solidified along their floors. The most common access points into these caves are areas with collapsed ceiling.

Similar processes form inflationary caves or vertical conduits underground, which can be big enough to qualify as caves. The former are areas where lava pushed on neighboring rock then receded, leaving domes of solid rock behind. The latter are formed in areas where lava escaped to the surface.

Sea caves

Erosion is the process by which soil or rock is removed from their original structures by surface factors. Dissolution can be viewed as a particular case of erosion, but we’ve already talked about those.

Sea caves are also formed by water. But, while dissolution caves get hollowed out through chemical reactions, sea caves are constructed by wave-powered erosion, either above or below the waterline. They can be found on the shoreline, as the name implies, but also inland, in areas that were once close to the sea but have since dried up — in parts of Norway, for example. They can form in all types of rock: igneous, metamorphic or sedimentary.

This Minecrafty beauty is named Fingal’s Cave, Scotland. It is a sea cave formed through basalt pillars.
Image via reddit user narwalmart

Waves form these structures by sheer attrition, throughout millions of years of battering with particle-rich water. As such, they tend to form in weaker areas of the rock, such as fault lines in igneous or metamorphic rocks or bedding plane contacts in sedimentary rocks. Once waves open a fissure through the rocks, the process becomes much faster — confined to a narrower space, the water and suspended particles exert more pressure on the walls and pressurize the gasses within, acting like a wedge.

Their walls are usually chunky and jagged, as erosion breaks off irregular slabs of rock from them. Some sea caves, however, have circular shapes with smooth walls and are filled with pebbles. This is caused by the waves taking on a circular motion inside the caves as they wash in and out, grinding the pebbles against the walls and smoothing them down.

Such as this beautiful cave in the Algarve region, Portugal.
Image via Imgur

Because erosion is a continuous process, removing rock bit by bit, sea caves are prone to collapse, leaving behind a “littoral sinkhole.”

Caving in

There are many other kinds of caves, each one with its own story to tell. Each one tells of how an area’s geology interacts with the world above it, being shaped by it over countless centuries. But, the paintings our ancestors adorned them with, the lines of sooth they burned into their walls stand testament to how they can, in turn, shape the world around them.

Magma is building up beneath a town in New Zealand

Known for its magnificent landscapes and spectacular volcanoes, New Zealand never disappoints. Unfortunately, this time, the volcanism seems to be expanding under inhabited areas, a new study found.

The nearby Mount Tarawera. Image: Carl Lindberg

The good news is that there’s no need to panic – an eruption is not imminent and likely won’t be for a few centuries, but when it pops, it’s gonna be pretty big. Estimates show that there’s enough magma to fill 80,000 Olympic-size swimming pools, lifting the ground beneath the coastal town of Matata by 40 centimeters.

Matata is home to only a few hundred people, and hasn’t had a history of volcanism for over 400,000 years, so geologists weren’t expecting to discover something beneath it. But a series of surprising earthquakes caught their attention.

“It was quite a big surprise,” lead researcher Ian Hamling told Nick Perry for the Associated Press (AP).

A graphic representation of what’s happening with the magma pool. Image via Ian Hamling.

The magma pool is calculated to be some 9.5 km beneath the surface, which means it may never even turn into a volcano. Instead, it may simply accumulate and subsequently cool off and harden. But monitoring this process and understanding the magmatic evolution will help us in other places on Earth, where the threat is imminent.

“Although the ultimate fate of the magma remains unclear, its presence may represent the birth of a new magma chamber on the margins of arguably the world’s most active region of silicic volcanism, which has witnessed 25 caldera-forming eruptions over the last 1.6 million years,” the researchers write in Science Advances.

Volcano facts and other pieces of hot science

Volcanoes are some of the most amazing geological features but quite often, they’re misunderstood or not understood at all. Here we’ll get to know them a bit better, starting with the basic facts and the moving onto cool and surprising facts, and of course, continuing with everyone’s favorite (from a distance): eruptions.

Basic Volcano Facts

1. Volcanoes are ruptures in the Earth’s crust. Our planet’s crust is split into 17 major tectonic plates, and almost all volcanoes occur at the edges between these plates.

2. There are three types of volcanoes: stratovolcano (conical volcano consisting of layers of solid lava), cinder cone volcano (steep hill of tephra that accumulates around the vent) and shield volcano (built entirely or almost entirely from fluid lava vents).

3. Volcanoes can be active (with eruptions in the past 10,000 years), dormant (no eruptions in the past 10,000 years, but could wake up) and extinct (unlikely to ever erupt again). However, active volcanoes can become dormant and extinct, and dormant volcanoes can wake up. Before 79 AD, Vesuvius was considered dormant and its eruption was catastrophic. Knowing whether a volcano is truly extinct is hard to determine.

4. We’re still not sure how many volcanoes there are in the world, but geologists identified about 1300 active volcanoes, not counting underwater volcanoes.

5. The biggest volcano on Earth is Hawaii’s Mauna Kea. At 33,500 feet (10,210 meters) it’s even taller than the Everest, but most of it is underwater, so its height relative to sea level is lower. However…

6. The tallest volcano in the solar system is on Mars. Olympus Mons on Mars is a shield volcano with a height of nearly 22 km (16 mi), almost three times higher than Mount Everest. It was able to grow this big because Mars doesn’t have active tectonic plates.

Volcanic eruption on Io. Image credits: NASA/JPL.

7. Earth isn’t the most active place in the solar system – Jupiter’s moon Io is the most volcanic body in the solar system. Astronomers recently witnessed two huge eruptions, possibly largest than any ever recorded on our planet.

8. The two most active volcanoes in the world are Etna in Italy and Hawaii’s Kilauea, depending on how you judge. Etna has been active in the past 3,500 years, but it’s still being used for agriculture because its slopes are so fertile. Kilauea has been in a state of constant eruption since 1993, and more than 90% of its surface is made from young lava.

Image via USGS.

9. Volcanoes can be scary, but supervolcanoes can be downright terrifying. St. Helens, one of the largest eruptions in history spewed up 0.25 cubic kilometers of volcanic material while the last known eruption from the Yellowstone caldera ejected 4000 times more – 1000 cubic kilometers.

Volcano Eruption Facts

10. There are three types of volcanic eruptions: magmatic eruptions (involving gas decompressions that propel the eruption forward), phreatic eruptions (superheating of steam via contact with magma, often with no ejected material) and phreatomagmatic eruptions (compression of gas within magma, the complete opposite of magmatic eruptions).

11. How dangerous are volcano eruptions? In 1815, the volcano Tambora exploded in Indonesia. All vegetation on the island was destroyed and projected into the sea. Uprooted trees mixed with pumice ash, washed into the sea and formed rafts up to 5 km (3.1 mi) across. The eruption sent material into the stratosphere, at an altitude of more than 43 km (27 mi). Over 10,000 people were killed directly by the eruption, but that was only the beginning.

The epic explosion of Mount Tambora in 1815 left a massive crater behind, 3.7 miles wide and 3,600 feet deep. (NASA)

Over 40,000 people were killed by hunger and disease in neighboring islands, and the effects were felt globally. The following year, 1816 was called “the year without a summer”, as snow fell in the summer in Boston and New York. Crops were destroyed, widespread famine was reported in Asia, Europe and the Americas. It’s impossible to estimate the total damage, but up to 100,000 people lost their lives following this eruption. A Massachusetts historian summed up the disaster: “Severe frosts occurred every month; June 7th and 8th snow fell, and it was so cold that crops were cut down, even freezing the roots.” Which leads us to another question:

12. What if a supervolcano erupts? Geologically, it won’t mean much for the planet. At a geological scale, supervolcanoes erupt all the time… but for humans, the effects would be ghastly. The tens or hundreds of thousands of lives lost will pale in comparison to what will happen. The world will be thrown into a nuclear-type winter, where food availability could become a luxury (because volcanic eruptions can block sunlight, lowering global temperatures). Famine and widespread disease will emerge for at least a couple of years, as no country has the food reserves to last that long; it’s extremely difficult to gauge the full impact such an eruption might have. However, you shouldn’t waste much sleep on this – it’s extremely unlikely for such an eruption to take place in the next few thousand of years.

13. The last known supervolcano eruption was the Toba eruption 74,000 years ago, when more than 2,500 cubic kilometers of magma were erupted. The largest eruption in recent human history was the 1815 eruption described above.

Chichester Canal circa 1828 by J. M. W. Turner. Image via Wikipedia.

14. But it’s not all bad. Volcanic eruptions make sunsets more vibrant. The eruptions spew hundreds, thousands or even millions of tons of dust and gaseous sulfur dioxide into the stratosphere. The finer dust particles remain in the atmosphere, sometimes for years, producing vivid sunsets and twilight effects.

In fact, a team of German and Greek researchers are studying paintings of sunsets after historical eruptions to discover clues about our atmosphere, and even study global warming.

Image via Wikipedia.

 

15. Some volcanic eruptions can create massive thunderstorms and we still don’t know exactly why. A study published in Science found that this phenomenon, also called dirty thunderstorms, appear because electrical charges are generated when rock fragments, ash, and ice particles in a volcanic plume collide and produce static charges, just as ice particles collide in regular thunderstorms.

More Volcano Facts

16. You need at least 3.35 kg of lava to boil a liter of water. Quora user Nissim Raj Angdembay calculated that for a lava of an average temperature of 950 °C, you need to use 3.35 kg of lava to boil a liter of water. Of course, this is only a theoretical calculation, and in practice, you’d need a bit more as some of the heat will be lost to the ambient.

17. There is one unique volcano, Ol Doinyo Lengai, that produces black carbonatic lava. It also isn’t as hot as other types of lava and it’s much less viscous – comparable to water.

Black carbonatic lava. Image via SwissEduc

18. The volcanic rock pumice is the only rock that can float in water. Pumice is an extrusive volcanic rock with a very high content of water and gases extruded quickly out of a volcano. The unusual foamy configuration makes it very light.

19. Volcanic energy can be harvested to warm water and even generate electric energy. Geothermal energy generates about 3% of renewable energy-based electricity.

20. The Maleo bird in the Indonesian island of Sulawesi uses volcanic heating to incubate its eggs.

21. When Paricutin in Mexico erupted from 1943-1952 (more on that a bit later), not a single person was killed by lava, rocks or flows, but three people were killed by lightning.

Paricutin. Image via Wikipedia.

 

22. Lava temperature varies between 700 to 1,200 °C (1,292 to 2,192 °F). Geologists do sometimes use a thermometer called a “thermocouple” to take a volcano’s temperature.

23. Lava chemistry greatly influences both the temperature and the type of eruption. Lava with greater silica content (more basic) tends to be hotter, more fluid, and erupt more “gently” – think of the Hawaiian lava flows. Lava with less silica (acidic) tends to have more explosive eruptions. They also form different types of rocks.

24. In 1943, a Mexican farmer named Dionisio Pulido started to notice something strange in his cornfield. It started as a slight depression, and soon started to fissure, eliminating volcanic material. By 1952, the volcano was already 424 meters high and damaged a 233 square km area with the ejection of stone, ash and lava. Three people were killed by lightning as described above. Today, Paricutin the volcano is 2,800 m (9,200 ft) high and is considered dormant.

Stunning video shows lava in all its might


Even as a geologist, I can’t help myself from looking at lava with an almost childish fascination – it’s something from the depths of the Earth (literally), with the potential to destroy everything and anything in its path, and also to create new landscapes, drastically changing the surface of the Earth. In the short film aboveLance Page managed to capture the sheer force of the Kilauea volcano in all its splendor: terrifying, mesmerizing, and inspiring all at once.

“Many in Hawaii refer to the lava as ‘Pele’, the Hawaiian goddess of fire … This six and a half minute film is my best attempt at capturing what it felt like to witness molten rock slowly burning down a dense wet rainforest or to peer into a six-hundred-foot-wide lava lake at Kilauea’s summit crater. I’ve never been anywhere else on the planet that demanded as much respect and awareness for the natural environment around me. Her unexpected beauty and unsettling sense of danger were nothing short of humbling and put so much into perspective. Kilauea really did change my life.”

Lava is the molten rock expelled by a volcano during an eruption; the less silicates the lava has, the hotter it gets, and the smoother the eruptions. The relatively slow flow of the Hawaii volcanoes indicates a basic lava (as opposed to an acidic one) with a low viscosity, flowing at very high temperatures.

For more information and awesome volcano facts, read:

 

Extremely Close-Up Footage of Lava Spilling Into Water

Lava is amazing to see (from a distance), but it’s even more awesome to get the chance to see lava going directly into the ocean. Hawaii is one of the few places in the world where this happens. In this amazing footage, Kawika Singson uses his GoPro (hopefully on a very long pole) to get up close and personal with lava spilling into the ocean water. The video was captured off the coast of Hawaii.

lava

New type of volcanic eruption described

The general classification splits volcanic eruptions in two: explosive or effusive. An explosive eruption is, well, explosive and violent (think Mount Helens), while an effusive eruption is associated with lava flows (think Hawaii). However, in a new study conducted by New Zealand and UK researchers described another, new type of eruption.

Eruption

Inside volcanoes, magma often has dissolved gases as a function of the very high pressures and chemistry of the magma. Much in the same way you open a carbonated drink – when you take the lid off, the bubbles burst out – when magma erupts as lava, the pressure is relieved and the gases exsolve (the opposite of dissolve). In explosive eruptions, this phenomena is so strong that it fragments the lava, violently ejecting it, along with anything caught along. When this happens, the ejected lava expands so quickly the resulting rock cools and degasses to form solidified pumice that can be sufficiently light to float on water.

After studying the Macauley volcano in the Pacific Ocean however, volcanologists found an entirely different story.

“By documenting the shape and density of bubbles in pumices generated by an underwater caldera volcano in the southwest Pacific Ocean – the Macauley volcano – we found large differences in the number and shape of “bubbles” in the same pebble-sized samples, different to anything previously documented,” said co-author Ian Wright, from U.K.’s National Oceanography Centre. “This range of bubble densities distinct in these pumice samples indicates that the lava erupting from the caldera was neither vigorous enough for an explosive eruption, nor gentle enough for an effusive flow,” Wright said in a statement.

 

Pumice floating

Pumice floating

In oceans, when pumice is located, it generally represents the spot of a volcanic eruption – an explosive eruption. The mechanism proposed for this special type of pumice though is more complicated; it suggests that rather exploding in the neck of the volcano, the formation and expansion of bubbles in the magma created a buoyant foam, rising to the seafloor and then buoyantly detaching itself from the volcano as molten pumice, but with cooler margins. The vesicles within the molten interior would have continued to expand as the pressure – this time from the weight of the seawater – reduced.

“These processes explain the unique bubble structure seen in the samples analysed, which could have only occurred with an intermediate eruption style and in an underwater setting,” said Professor Wright. “We conclude that the presence of widespread deposits of pumice on underwater volcanoes does not necessarily indicate large-scale explosive volcanism.”

The authors proposed that this type of eruption be named Tangaroan, the Maori god of the sea, and name of the research vessel used to collect the samples.

Source

Dinosaur extinction ocean of lava

New dinosaur extinction theory: an ocean of lava

Dinosaur extinction ocean of lava

It wasn’t just a devastating asteroid that killed off all the dinosaurs 65 million years ago. Scientists from Boston University now claim that a massive eruption of lava fronts around the world, coinciding with the asteroid impact, sealed their fate forever.

The controversial theory is betting on two unusually hot blobs of mantle 1,700 miles beneath the crust that formed just after Earth itself, 4.5 billion years ago. These mantle stores are responsible for huge amounts of lava gush from the bowels of the Earth, flooding more than 100,000 square kilometres, leaving behind distinct geological regions known as large igneous provinces (LIPs).

Matthew Jackson at Boston University and his team found 62-million-year-old basalts from the North Atlantic LIP contain isotopes of elements in ratios that reflect the chemistry of early Earth’s mantle. The scientists claim that this is hard evidence supporting the supposed fact that LIPs are fed by the 4.5-billion-year-old stores of mantle.

“There is an amazing correlation between mass extinctions and LIPs,” Andrew Kerr at the University of Cardiff says.

These ancient magma stores might actually be still active to this day. Using seismic waves to probe the mantle’s structure, scientists found two unusual areas some 2800 kilometres down, beneath Africa and the Pacific Ocean.

It’s an interesting idea – that a giant blob of hot magma might burp from near Earth’s core every now and then, causing havoc for life,” says Gerta Keller at Princeton University, but adds more work is needed to support the hypothesis.

The researchers themselves also admit that they can perfectly understand why this theory can be considered highly controversial, however they believe it’s still highly plausible.

 

The big picture on Icelandic eruption

Eyjafjallajökull (how ever you pronounce) is a volcano located in Iceland, covered by a small glacier with the same name. It’s crater has a diameter of about 3-4 kilometers, and it erupted the second time this month, causing a cloud of ash that forced authorities to stop almost all flights above Iceland.

The first fissure that opened on Fimmvörðuháls, as seen from Austurgígar. Photo by David Karnå.

The first fissure that opened on Fimmvörðuháls, as seen from Austurgígar. Photo by David Karnå.

The problem, when you have such a volcano, is that the ice on top of it melts, causing massive floods, as well as the usual shooting of smoke and gases. Thousands of people were forced to give up their homes and take cover in the face of the floods. Here we’ll present some of the most suggestive photos from the area, taken over a time span of approximately a month.

Photo by NASA.

Photo by NASA.

 

Melt rises up 25 times faster than previously believed

lava_lake_night

Scientists have for the first time determined the actual permeability of the asthenosphere in Earth’s upper mantle, which is basically responsible for how fast the melt rises towards the surface of the earth, and the results were surprising to say the least. Researchers found that it actually moves 25 times faster than previously assumed, which forces us to reconsider every volcanic model that includes melt.

A huge centrifuge measuring 2 meters in diameter was embedded in the cellar’s floor. It spins at 2800 rotations per minute and creates an acceleration about 3000 times bigger than Earth’s gravity; when at full capacity, it creates 120 decibels, which is about as loud as an airplane, according to Max Schmidt, a professor from the Institute for Mineralogy and Petrology at ETH Zurich. It can reach 850 km/h, and after it reaches this speed, if you would turn it off, it takes about an hour to stop.

This globally unique centrifuge cast a whole new light on how we perceive magmatism. The researchers used it to simulate the transport of molten lava made of basaltic glass from the mid-ocean ridge. The matrix through which the melt passed through consisted of olivine, which makes about 2/3 of the upper mantle. They applied a temperature of 1300 degrees and a pressure of 1 giga pascal. After the basaltic mass melted, they accelerated to about 700 g’s and were then able to calculate the permeability directly by microscopic analysis and were then able to correlate porosity to permeability, which is a main part for thermo-mecanical models.

In the light of these new discoveries, these models have to be revised; if the magma ascends much faster that means it interacts a lot less with the rock it penetrates. It also explains a few things, such as why volcanoes are active for only a few thousand years.

Lava versus ocean: what happens when the two meet (awesome photo alert)

Lava, the molten rock that flows from inside the Earth, can destroy everything in its path. Water, meanwhile is like an arch nemesis of lava. So what happens when the two meet?

Image credits: Robert Cudney.

Water and fire

It’s beautiful, sure — but it’s hella dangerous. When lava enters the water, a number of things happen. It’s a very dangerous environment and you should always stay very clear of such a phenomenon — if you do happen to witness such an event, be sure to witness it from very, very far away.

For starters, the lava turns the water scalding hot, and the water swells and can spew very hot drops of water. But that’s just the start of it. If the waves of near-boiling water don’t scare you, they can also be accompanied by steam plumes and rain of hydrochloric acid and small glass particles. If you’re still not afraid, this will probably do the job: the entire lava delta can (and often does) collapse with little notice.

More common than you think

Volcanoes and water seem natural enemies, but they meet more often than you’d think. For starters, there are a lot of submarine volcanoes, but we don’t really get to witness that too often. Perhaps more common is for volcanoes on the cost to erupt and spew their lava all the way to the water.

This is especially relevant for so-called hotspot volcanoes, like the ones that former Hawai’i. Unlike other volcanoes, hotspot volcanoes are directly connected to the mantle. They typically erupt in “calmer” lava flows (again, like in Hawai’i), which has a chance of ending up in water.

The coast of Hawai’i.

So what happens when lava meets water?

It’s not so much the water itself that does things to the lava, but rather its temperature. Lava flows at extremely hot temperatures of up to 1,170 degrees Celsius (2,140 degrees Fahrenheit), gradually cooling down as it is exposed to the environment. But when it meets water, it’s forced to cool down quickly.

The lava immediately blows away some of the water, mixing with it and creating the toxic fume and droplets. As the lava cools down, it solidifies — but it doesn’t form very solid rocks. Igneous rocks that cool down slowly (in geologic time) can form large crystals, but when lava cools down quickly, it doesn’t have time to form crystals, so you just end up with a sort of black rock riddled with pieces of glass.

If you’re not sold on how awesome this phenomenon is, here are a few videos that could help change your mind.

 

All images of lava versus ocean in CC BY 3.0