Scientists Reveal the Source of a Mysterious Martian Rock Formation - Pragnya IAS Academy - News Analysis.

Scientists Reveal the Source of a Mysterious Martian Rock Formation.

Explosive volcanic eruptions that shot jets of hot ash, rock and gas skyward are the likely source of a mysterious Martian rock formation, a new study finds. The new finding could add to scientists’ understanding of Mars’s interior and its past potential for habitability, according to the study’s authors.
The Medusae Fossae Formation is a massive, unusual deposit of soft rock near Mars’s equator, with undulating hills and abrupt mesas. Scientists first observed the Medusae Fossae with NASA’s Mariner spacecraft in the 1960s but were perplexed as to how it formed.
Now, new research suggests the formation was deposited during explosive volcanic eruptions on the Red Planet more than 3 billion years ago. The formation is about one-fifth as large as the continental United States and 100 times more massive than the largest explosive volcanic deposit on Earth, making it the largest known explosive volcanic deposit in the solar system, according to the study’s authors.
“This is a massive deposit, not only on a Martian scale, but also in terms of the solar system, because we do not know of any other deposit that is like this,” said Lujendra Ojha, a planetary scientist at Johns Hopkins University in Baltimore and lead author of the new study published in the Journal of Geophysical Research: Planets, a journal of the American Geophysical Union.
Formation of the Medusae Fossae would have marked a pivotal point in Mars’s history, according to the study’s authors. The eruptions that created the deposit could have spewed massive amounts of climate-altering gases into Mars’s atmosphere and ejected enough water to cover Mars in a global ocean more than 9 centimeters (4 inches) thick, Ojha said.
Greenhouse gases exhaled during the eruptions that spawned the Medusae Fossae could have warmed Mars’s surface enough for water to remain liquid at its surface, but toxic volcanic gases like hydrogen sulfide and sulfur dioxide would have altered the chemistry of Mars’s surface and atmosphere. Both processes would have affected Mars’s potential for habitability, Ojha said.
Determining the source of the rock
The Medusae Fossae Formation consists of hills and mounds of sedimentary rock straddling Mars’s equator. Sedimentary rock forms when rock dust and debris accumulate on a planet’s surface and cement over time. Scientists have known about the Medusae Fossae for decades, but were unsure whether wind, water, ice or volcanic eruptions deposited rock debris in that location.
Previous radar measurements of Mars’s surface suggested the Medusae Fossae had an unusual composition, but scientists were unable to determine whether it was made of highly porous rock or a mixture of rock and ice. In the new study, Ojha and a colleague used gravity data from various Mars orbiter spacecraft to measure the Medusae Fossae’s density for the first time. They found the rock is unusually porous: it’s about two-thirds as dense as the rest of the Martian crust. They also used radar and gravity data in combination to show the Medusae Fossae’s density cannot be explained by the presence of ice, which is much less dense than rock.
Because the rock is so porous, it had to have been deposited by explosive volcanic eruptions, according to the researchers. Volcanoes erupt in part because gases like carbon dioxide and water vapor dissolved in magma force the molten rock to rise to the surface. Magma containing lots of gas explodes skyward, shooting jets of ash and rock into the atmosphere.
Ash from these explosions plummets to the ground and streams downhill. After enough time has passed, the ash cements into rock, and Ojha suspects this is what formed the Medusae Fossae. As much as half of the soft rock originally deposited during the eruptions has eroded away, leaving behind the hills and valleys seen in the Medusae Fossae today.
Understanding Mars’s interior
The new findings suggest the Martian interior is more complex than scientists originally thought, according to Ojha. Scientists know Mars has some water and carbon dioxide in its crust that allow explosive volcanic eruptions to happen on its surface, but the planet’s interior would have needed massive amounts of volatile gases – substances that become gas at low temperatures – to create a deposit of this size, he said.
“If you were to distribute the Medusae Fossae globally, it would make a 9.7-meter (32-foot) thick layer.” Ojha said. “Given the sheer magnitude of this deposit, it really is incredible because it implies that the magma was not only rich in volatiles and also that it had to be volatile-rich for long periods of time.”
The new study shows the promise of gravity surveys in interpreting Mars’s rock record, according to Kevin Lewis, a planetary scientist at Johns Hopkins University and co-author of the new study. “Future gravity surveys could help distinguish between ice, sediments and igneous rocks in the upper crust of the planet,” Lewis said.


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Scientists Reveal the Source of a Mysterious Martian Rock Formation.

Mysterious rise in banned ozone-destroying chemical shocks scientists - Pragnya IAS Academy - News Analysis

Mysterious rise in banned ozone-destroying chemical shocks scientists.

CFCs have been outlawed for years but researchers have detected new production somewhere in east Asia.

A sharp and mysterious rise in emissions of a key ozone-destroying chemical has been detected by scientists, despite its production being banned around the world.

Unless the culprit is found and stopped, the recovery of the ozone layer, which protects life on Earth from damaging UV radiation, could be delayed by a decade. The source of the new emissions has been tracked to east Asia, but finding a more precise location requires further investigation.
CFC chemicals were used in making foams for furniture and buildings, in aerosols and as refrigerants. But they were banned under the global Montreal protocol after the discovery of the ozone hole over Antarctica in the 1980s. Since 2007, there has been essentially zero reported production of CFC-11, the second most damaging of all CFCs.
The rise in CFC-11 was revealed by Stephen Montzka, at the US National Oceanic and Atmospheric Administration (NOAA) in Colorado, and colleagues who monitor chemicals in the atmosphere. “I have been doing this for 27 years and this is the most surprising thing I’ve ever seen,” he said. “I was just shocked by it.”
“We are acting as detectives of the atmosphere, trying to understand what is happening and why,” Montzka said. “When things go awry, we raise a flag.”
Erik Solheim, head of UN Environment, said: “If these emissions continue unabated, they have the potential to slow down the recovery of the ozone layer. It’s therefore critical that we identify the precise causes of these emissions and take the necessary action.”
CFCs used in buildings and appliances before the ban came into force still leak into the air today. The rate of leakage was declining steadily until 2013, when an abrupt slowing of the decline was detected at research stations from Greenland to the South Pole.
Scientists then embarked on an investigation, published in the journal Nature, to find out the cause. The detective work began by assessing whether there had been changes in how the atmosphere distributes and destroys CFC-11 that could explain the changed measurements. But this factor was mostly ruled out and in the most recent data – 2017 – it appears to have played no role at all.
Next, the researchers looked at whether the release of CFC from older materials could have doubled, as required to explain the data. “But we don’t know of any folks who are destroying buildings at a much more dramatic rate than they were before,” said Montzka.
Lastly, the team considered whether the new CFC-11 was being produced as a by-product of some other chemical manufacturing process. But they ruled this out too, as the quantities involved are too high, representing a 25% rise in global emissions.
“You are left with, boy, it really looks like somebody is making it new,” said Montzka, who noted that the less damaging replacement for CFC-11 is more expensive to make.
“If the increased emissions were to go away [soon], it’s influence on the recovery date for the ozone layer would be minor,” he said. “If it doesn’t go away, there could be a 10-year delay, and if it continued to increase, the delay would be even longer.” The last option is a possibility, as if the new CFC-11 is being used in foams, then only a small fraction will have made it to the atmosphere so far and more could leak out for many years into the future.
Michaela Hegglin, at the University of Reading, UK, and not part of the research team said researchers had taken rigorous steps to rule out alternative explanations for the rise in CFC-11 when reaching their conclusion that new production must be occurring.
She said: “The study highlights that environmental regulations cannot be taken for granted and must be safe-guarded, and that monitoring is required to ensure compliance.” Prof Piers Forster, at the University of Leeds, UK, said: “This new study is atmospheric detective work at its finest.”
Paul Young, at Lancaster University, UK, said: “The Montreal Protocol has been rightly hailed as our most successful international environmental treaty, so the suggestion that there are possibly continued, unreported emissions of CFCs is certainly troubling and needs further investigation.”
Montzka said the world’s nations are committed to its enforcement. “I have a feeling that we will find out fairly quickly what exactly is going on and that the situation will be remedied,” he said. Even just the publicity about the new CFC-11 production could lead to its shutdown, he said: “Somebody who was maybe doing it purposefully will realise – oh, someone is paying attention – and stop doing it.”


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Mysterious rise in banned ozone-destroying chemical shocks scientists.