Scientists Say We've Finally Found the Secret Behind the Strangest Rock Formation on Mars
Back in the 1960s, scientists using NASA's Mariner spacecraft noticed something on Mars that they couldn't explain: a large and unusual soft rock deposit that was later named the Medusae Fossae Formation (MFF).
According to a new study published in the Journal of Geophysical Research: Planets, the strange formation is over 3 billion years old and is the result of cemented ash from volcanic eruptions.
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.
Previous studies showed that the rocks were different from other parts of Mars' crust, but researchers were not able to pinpoint the exact composition or to explain its origin.
Using gravity and radar data the Mariner, Ojha and his team found that the rocks were "unusually porous," which they say eliminates the possibility that it contained ice and confirms that a volcano caused the formation.
"This is a massive deposit," Ojha said in a statement, "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.
In addition to spraying enough hot ash to form the largest known explosive volcanic deposit in our solar system, the researchers believe that the volcano that made MFF released clouds of gases that changed the atmosphere of the planet, and also sprayed enough water to cover Mars in four inches of water.
"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.
"The eruptions that led to the deposition of the MFF would have contributed significantly to the Martian hydrosphere and atmosphere. Viewed as a whole, the formation of the MFF would have marked a pivotal point in the atmospheric, surface, and interior evolution of Mars."