The planet Mars fascinates humans and knowledge of its composition, structure and climate is key to planning a next space mission and a future stable colony.
Therefore, in addition to the different space observations and the ships and robots sent to its surface, scientists study it from meteorite fragments of this planetary body that have reached Earth.
Now, a group of researchers from scientific institutions in the US and France analyzed remains of two types of meteorites that arrived on Earth from the red planet, revealing new details of the structures of the outer layers of Marsas published by the Scripps Institution of Oceanography.
“Mars has a distinct structure in its mantle and crust with discernible reservoirs, and this is known thanks to the meteorites that Mars scientists Scripps Institution of Oceanography, University of California in San Diego and their colleagues have analyzed on Earth,” detailed the report that is part of the NASA Solar Systems and Emerging Worlds Workswhich funded the research.
In recent decades, scientists have collected meteorites that formed about 1.3 billion years ago and were then ejected from Mars. Scripps Oceanography geologist James Day and his colleagues reported analyzes of the chemical compositions of these Red Planet samples May 31 in the journal Science Advances.
But the work was carried out from the study of a large meteorite that crashed on Mars 11 million years agoan event that caused the destruction of parts of the planet and that some of the fragments expelled by the impact landed on Earth, in places like Antarctica and Africa.
In recent decades, scientists have taken on the task of collecting these rocky remains, since they can provide important information about the evolution of what was once a potentially habitable planet. Some of them landed on Earth. The first was discovered in 1815 in Chassigny, France, and then in 1905 in Nakhla, Egypt.
Since then, more meteorites of this type have been discovered in places such as Mauritania and Antarctica. Scientists can identify Mars as their place of origin because these meteorites are relatively young, so they come from a recently active planet, have different compositions of the abundant element oxygen compared to Earth, and preserve the composition of Mars’ atmosphere measured in surface by Viking landers in the 1970s.
Today, these Martian meteorites are fundamental to understanding about the origin and formation of different types of rocks, as well as to build geochemical and geophysical models of the red planet. These allow learn details about Mars and its evolution without having to travel to that world. “The Martian meteorites are being of great help in understanding the history of that planet and they are delivered here, to the door of our house,” Day said.
And he added: “Martian meteorites are the only physical materials we have available from Mars. They allow us to make precise and accurate measurements and then quantify the processes that occurred inside Mars and near the Martian surface. “They provide direct information about its composition, which can inform the science of true missions, such as the ongoing Perseverance rover operations taking place there.”
The team analyzed the two key types of meteorites: nakhlite and chasignite. Nakhlites are basaltic, similar to the lavas that erupt today in Iceland and Hawaii, but are rich in a mineral called clinopyroxene. Chassignites are made almost exclusively from the mineral olivine. On Earth, basalts are a major component of the planet’s crust, especially beneath the oceans; while olivines abound in its mantle.
The same thing happens on Mars. The team showed that these rocks are related to each other through a process known as fractional crystallization. inside the volcano in which they were formed. Using the composition of these rocks, they also show that some of the then-molten nakhlites incorporated portions of near-surface crust that also interacted with Mars’ atmosphere.
“By determining that nakhlites and chassignites come from the same volcanic system and that they interacted with the Martian crust that was altered by atmospheric interactions, we can identify a new type of rock on Mars. With the existing collection of Martian meteorites, all of them of volcanic origin, we can better understand the internal structure of Mars,” said researcher Day.
The team was able to do this because of the Distinctive chemical characteristics of nakhlites and chassignites, as well as the characteristic compositions of other Martian meteorites. These reveal an atmospherically altered upper crust of Mars, a deeper complex crust and mantle, where columns from the depths of Mars have penetrated to the base of the crust, while the interior of the red planet, formed early in its evolution, also It has melted to produce different types of volcanoes.
“What is notable is that Mars volcanism has incredible similarities, but also differences, with Earth. For one thing, nakhlites and chassignites formed similarly to recent volcanism in places like Oahu in Hawaii. There, the newly formed volcanoes put pressure on the mantle, generating tectonic forces that produce more volcanism,” Day noted.
And he added: “On the other hand, the reserves on Mars are extremely old and separated from each other shortly after the Red Planet formed. On Earth, plate tectonics has helped remix reservoirs over time. In this sense, Mars provides an important link between what early Earth may have been and how it looks today.”
In addition to Day, Marine Paquet of Scripps Oceanography and colleagues at the University of Nevada, Las Vegas, and the French National Center for Scientific Research contributed to the study.
