Published: Fri, June 22, 2018
Science | By Joan Schultz

Mysterious Mars rock formation explained - and it doesn't involve UFOs

Mysterious Mars rock formation explained - and it doesn't involve UFOs

In the recent research study, scientists used gravity data from different spacecraft revolving the red planet to calculate the density of the rock.

The study, published in the Journal of Geophysical Research, reveals that Medusae Fossae was deposited when explosive volcanic eruptions occurred on Mars over 3 billion years in the past.

"The presence of a pyroclastic deposit of this scale on Mars has important implications for our understanding of the planet's volcanic history, its interior, and volatile content", the co-authors wrote in the conclusion of the study.

Called the Medusae Fossae Formation, the huge and unusual deposit of soft rock lies near Mars' equator, and consists of hills and abrupt mesas.

The Medusae Fosse Formation has baffled scientists since it was spotted by the Mariner spacecraft in the 60s (as well as inspiring lots of bonkers YouTube videos).

Medusae Fossae formation is the Solar System's largest volcanic eruption deposit that humans know of till now, say the researchers.

The formation is one-fifth the size of the United States and 100 times more massive than the largest similar formation on Earth.

"Viewed as a whole, the formation of the MFF would have marked a pivotal point in the atmospheric, surface, and interior evolution of Mars". They say that it's possible that the violent eruptions ejected water that rose up to over 4 inches high throughout Mars.

Greenhouse gases that the volcano gave out during these eruptions could have actually warmed the Martian surface enough for water to stay liquid surface level. The combination of hot atmosphere and toxic water would have likely affected the potential for Mars's habitability, explained Ojha said.

Considering the large size of the MFF, the eruptions that created this rock formation must have had a strong effect on the atmosphere and hydrosphere of Mars.

Sedimentary rock forms when rock dust and debris accumulate on a planet's surface and cement over time.

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. By combining radar and gravity data, the team found that this density rules out the presence of ice, which has always been a contender for what's down there. According to the study, the researchers noted the MFF as a "relatively porous unit" and theorized its evolution was the result of "explosive volcanic eruptions".

Ash from these explosions plummets to the ground and streams downhill.

"If you were to distribute the Medusae Fossae globally, it would make a 9.7-meter (32-foot) thick layer", Ojha said.

For the first time ever, Johns Hopkins University planetary scientist Lujendra Ojha and his colleagues were able to measure the density of rocks from MFF. "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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