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An Ancient Meteorite Is The First Chemical Evidence of Volcanic Convection on Mars

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For many years, we thought Mars was dead. A dusty, dry, barren planet, where nothing moves but the howling wind. Recently, however, pieces of evidence have started to emerge, hinting that Mars is both volcanically and geologically active.

 

Well, the idea of a volcanically active Mars just got a little more real. A meteorite that formed deep within the belly of Mars has just provided the first solid chemical proof of magma convection within the Martian mantle, scientists say. 

Crystals of olivine in the Tissint meteorite that fell to Earth in 2011 could only have formed in changing temperatures as it was rapidly swirled about in magma convection currents – showing that the planet was volcanically active when the crystals formed around 574 to 582 million years ago – and it could still be intermittently so today.

“There was no previous evidence of convection on Mars, but the question ‘Is Mars a still volcanically active planet?’ was previously investigated using different methods,” explained planetary geologist Nicola Mari of the University of Glasgow to ScienceAlert.

“However, this is the first study that proves activity in the Mars interior from a purely chemical point of view, on real Martian samples.”

Olivine, a magnesium iron silicate, isn’t rare. It crystallises from cooling magma, and it’s very common in Earth’s mantle; in fact, the olivine group dominates Earth’s mantle, usually as part of a rock mass. On Earth’s surface, it’s found in igneous rock.

 

It’s fairly common in meteorites. And olivine is also fairly common on Mars. In fact, the presence of olivine on the surface of Mars has previously been taken as evidence of the planet’s dryness, since the mineral weathers rapidly in the presence of water.

But when Mari and his team started studying the olivine crystals in the Tissint meteorite to try to understand the magma chamber where it formed, they noticed something strange. The crystals had irregularly spaced phosphorus-rich bands.

We know of this phenomenon on Earth – it’s a process called solute trapping. But it was a surprise to find it on Mars.

magma olivine(Mari et al., Meteoritics & Planetary Science, 2020)

“This occurs when the rate of crystal growth exceeds the rate at which phosphorus can diffuse through the melt, thus the phosphorus is obliged to enter the crystal structure instead of ‘swimming’ in the liquid magma,” Mari said.

“In the magma chamber that generated the lava that I studied, the convection was so vigorous that the olivines were moved from the bottom of the chamber (hotter) to the top (cooler) very rapidly – to be precise, this likely generated cooling rates of 15-30 degrees Celsius per hour for the olivines.”

 

The larger of the olivine crystals were also revealing. Traces of nickel and cobalt are in agreement with previous findings that they originated from deep under the Martian crust, a depth of 40 to 80 kilometres (25 to 50 miles).

This supplied the pressure at which they formed; along with the equilibration temperature of olivine, the team could now perform thermodynamic calculations to discover the temperature in the mantle at which the crystals formed.

They found that the Martian mantle probably had a temperature of around 1,560 degrees Celsius in the Martian Late Amazonian period when the olivine formed. This is very close to the ambient mantle temperature of Earth of 1,650 degrees Celsius during the Archean Eon, 4 to 2.5 billion years ago.

That doesn’t mean Mars is just like an early Earth. But it does mean that Mars could have retained quite a bit of heat under its mantle; it’s thought that, because it lacks the plate tectonics that help to dissipate heat on Earth, Mars may cool more slowly.

“I really think that Mars could be a still volcanically active world today, and these new results point toward this,” Mari told ScienceAlert.

“We may not see a volcanic eruption on Mars for the next 5 million years, but this doesn’t mean that the planet is inactive. It could just mean that the timing between eruptions between Mars and Earth is different, and instead of seeing one or more eruptions per day (as on Earth) we could see a Martian eruption every n-millions of years.”

We’ll need more research to confidently say this hypothesis checks out. But these results also mean that previous interpretations of the planet’s dryness based on surface olivine may need to be revisited. (Although let us be clear, Mars is still extremely dry.)

The ongoing NASA InSight mission that recently found evidence of Marsquakes, measures – among other things – the heat flux from the Martian crust. If Mars is still volcanically active, we may know more about it really soon.

The research has been published in Meteoritics & Planetary Science.

 



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Intriguing New Research Indicates Volcanoes Might Still Be Active on Venus

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Despite the similarities our world has with Venus, there is still much don’t know about Earth’s “sister planet” and how it came to be.

Thanks to its super-dense and hazy atmosphere, there are still unresolved questions about the planet’s geological history. For example, despite the fact that Venus’ surface is dominated by volcanic features, scientists have remained uncertain whether or not the planet is still volcanically active today.

 

While the planet is known to have been volcanically active as recent as 2.5 million years ago, no concrete evidence has been found that there are still volcanic eruptions on Venus’ surface.

However, new research led by the USRA’s Lunar and Planetary Institute (LPI) has shown that Venus may still have active volcanoes, making it the only other planet in the Solar System (other than Earth) that is still volcanically active today.

This figure shows the volcanic peak Idunn Mons (at 46 degrees south latitude, 214.5 degrees east longitude) in the Imdr Regio area of Venus. The colored overlay shows the heat patterns derived from surface brightness data collected by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS), aboard the European Space Agency's Venus Express spacecraft.(NASA)

Figure above shows the volcanic peak Idunn Mons in the Imdr Regio area of Venus. The coloured overlay shows the heat patterns derived from surface brightness data collected by the Visible and Infrared Thermal Imaging Spectrometer, aboard the ESA’s Venus Express spacecraft.

This research, which appeared recently in the journal Science Advances, was led by Justin Filiberto – a staff scientist with the LPI.

He was joined by fellow-LPI researcher Allan H. Treiman, Martha Gilmore of Wesleyan University’s Department of Earth and Environmental Sciences, and David Trang of the Hawai’i Institute of Geophysics and Planetology.

The discovery that Venus once experienced a great deal of volcanic activity was made during the 1990s thanks to NASA’s Magellan spacecraft. The radar imaging it provided of Venus’ surface revealed a world dominated by volcanoes and lava flows.

 

During the 2000s, the ESA followed up on this with their Venus Express orbiter, which shed new light on volcanic activity by measuring infrared light coming from the planet’s surface at night.

This data allowed scientists to examine the lava flows on Venus’ surface more closely and differentiate between the ones that were fresh and those that were altered.

Unfortunately, the ages of lava eruptions and volcanoes on Venus were not known until recently since the alteration rate of fresh lava was not well constrained.

For the sake of their study, Filiberto and his colleagues simulated Venus’ atmosphere in their laboratory in order to investigate how Venus’ lava flows would change over time.

These simulations showed that olivine (which is abundant in basalt rock) reacts rapidly with an atmosphere like Venus’ and would become coated with magnetite and hematite (two iron oxide minerals) within days.

They also found that the near-infrared signature emitted by these minerals (which are consistent with the data obtained by the Venus Express mission) would disappear within days.

From this, the team concluded that the lava flows observed on Venus were very young, which in turn would indicate that Venus still has active volcanoes on its surface.

venus volcanoes mainbody 1Volcanoes and lava flows on Venus. (NASA/JPL)

These results certainly bolster the case for Venus being volcanically active, but could also have implications for our understanding of the interior dynamics of terrestrial planets (like Earth and Mars) in general. As Filiberto explained:

“If Venus is indeed active today, it would make a great place to visit to better understand the interiors of planets. 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.”

 

In the near future, a number of missions will be bound for Venus to learn more about its atmosphere and surface conditions. These include India’s Shukrayaan-1 orbiter and Russia’s Venera-D spacecraft, which are currently in development and scheduled to launch by 2023 and 2026, respectively.

These and other missions (which are still in the conceptual phase) will attempt to resolve the mysteries of Earth’s “sister planet” once and for all.

And in the process, they might be able to reveal a thing or two about our own!

This article was originally published by Universe Today. Read the original article.

 



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Astronomers Have Detected Hints of a Hellish Volcanic Exomoon

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Given the extravagant profusion of moons in our own Solar System, it seems likely that there are way more exomoons out there in the Universe than there are exoplanets. We’re yet to conclusively find one – but astronomers just found a signal that could mean the presence of an exomoon.

 

Not just any exomoon, either, but something akin to a jacked-up version of the Jovian moon Io, the most volcanically active object in the Solar System.

And we really do mean jacked. Not only would the exomoon itself be covered in volcanoes spewing lava, it would be orbiting a hot planet – WASP-49b, a massive gas giant planet known as a hot Jupiter, hurtling around yellow dwarf star WASP-49 once every 2.8 days.

“It would be a dangerous volcanic world with a molten surface of lava, a lunar version of close-in Super Earths like 55 Cancri-e,” said astrophysicist Apurva Oza of the Physics Institute of the University of Bern.

But don’t go packing your lava suits just yet. The team didn’t detect the exomoon directly. They have inferred it exists based on data from the planet itself – from stuff detected in its upper atmosphere.

When a paper describing the atmosphere of WASP-49b was published in 2017, researchers noted the presence of a thick layer of sodium at unusually high altitudes free of clouds. This sodium layer made Oza’s international team look more closely.

 

“The neutral sodium gas is so far away from the planet that it is unlikely to be emitted solely by a planetary wind,” he said.

We know, based on observations closer to home, that volcanic activity on Io produces pretty hefty amounts of potassium and sodium (among a few other things). These do not cling in significant quantities to the moon, but get swept up into Jupiter’s complex magnetosphere, resulting in a torus of material ringing the planet.

We also know that, without the intense gravitational interplay between Io and Jupiter generated by the moon’s elliptical orbit – the varying tidal forces that create friction and thus heat in the moon – it would not be volcanically active.

In 2006, a different team of researchers extrapolated that the presence of a torus of material around a planet could imply the presence of a moon or other orbiting body.

So, the team crunched some numbers. And they found that a volcanically active exomoon could actually release more potassium and sodium than the planet it orbits.

The sodium and potassium around WASP-49b, in the quantities and at the strange altitude detected, Oza’s team concluded, could have plausibly been spewed out by a volcanic hell-moon. But it’s also plausible that other processes or phenomena are responsible – a ring of ionised gas, for example.

Once again, more observation would help find answers – analysing the planet’s spectrum in greater detail. Sodium and potassium lines on the spectrum are both very strong; by searching more closely, the researchers hope to find the weaker signals of other volcanic volatiles in the planet’s atmosphere, such as sulphur and oxygen.

In addition, it provides yet another excellent reason to probe the atmospheres of exoplanets – a task at which we hope the next generation of telescopes will excel.

“While the current wave of research is going towards habitability and biosignatures, our signature is a signature of destruction,” Oza said. “The exciting part is that we can monitor these destructive processes in real time, like fireworks.”

The research has been accepted into The Astrophysical Journal, and is available on arXiv.

 



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