The 13 km crater is filled with a formation called Medusae Fossae Formation
A new study indicates that explosive volcanic activity, firing jets of hot ash, rocks and gas into the sky, is the probable source of the mysterious Martian mountain cover.
The formation of Medusae Fossae Formation is a massive and unusual deposit of soft rock at the Martian equator with hills. For the first time, the feature was able to observe the NASA Mariner spacecraft in the 1960s. But it is still unclear how it was formed.
A new study suggests that the formation was precipitated during the period of explosive volcanic eruptions on the Red Planet more than 3 billion years ago. The formation is 1/5 more of the continental part of the USA and 1000 times more massive than the largest explosive volcanic deposit on Earth. That is, we face the most explosive volcanic sediment in the entire solar system.
The creation of Medusae Fossae Formation could be a turning point in Martian history. The eruptions that had erected could eject a huge amount of climate-changing gas and throw out enough water to cover Mars with a global ocean more than 9 cm thick. The greenhouse gases created by the eruption could also warm the Martian surface, and toxic gases like hydrogen sulphide and sulfur dioxide would be able to change the chemistry of the surface of the atmospheric layer. These processes affect the adaptability of the planet to habitability.
Source of rock
The formation of Medusae Fossae Formation is represented by hills and mounds of sedimentary rock surrounding the Martian equator. Sedimentary rock is formed when rock dust and debris accumulate on the surface of the planet. Over time, they become hard.
Global geographical map of Mars with Medusae Fossae Formation location (red circle)
Scientists have known about the existence of Medusae Fossae Formation for decades, but could not understand what exactly precipitated the rocks in this place. Early location measurements of the Martian surface suggested that Medusae Fossae Formation had an unusual composition, but it was difficult to understand whether there was a highly porous rock or a mixture of rock and ice. The new study repelled the gravitational data of various spacecraft to measure the formation density for the first time.
It turned out that the stone is incredibly porous: approximately 2/3 in density coincides with the rest of the Martian crust. Radar and gravity were also used to prove that the density of Medusae Fossae Formation cannot be explained by the presence of ice. Everything indicated an explosive volcanic eruption. The ash from the explosions is on the surface and flows down the hill. After a certain period, ash is cemented into rock.
New findings indicate that the Martian interior is more complex than scientists thought. The crust of Mars contains water and carbon dioxide, but the inner space would need a huge amount of volatile gases to create a field of this size. If you place Medusae Fossae Formation around the world, the layer would have reached a thickness of 9.7 m.