Scientists opened a meteorite from Mars and got a big surprise

Opening a Martian meteorite that fell to Earth revealed an unexpected treasure. Researchers almost missed the discovery… but decided to take a closer look.

Hidden inside a rock fragment, a team of scientists found some garnet grains — a mineral that has never been identified before in a sample from Mars.

These tiny points raise huge questions.

On Earth, garnets often form under conditions of intense heat, pressure high or chemical change. Until now, the right conditions for the formation of this mineral had never been identified on Mars.

Therefore, this meteorite, kept in the collection of the Royal Ontario Museum, leaves much unexplained. The grenade formed on Mars? If so, what process produced it and when? And, if it didn’t form there, Where did it come from and how did it get to Mars??

“This discovery will expand our knowledge about the geological processes that are possible on this planet”, he states. Kizovski askedplanetary geologist at Brock University, Canada, and the University of Portsmouth.

“This new type of garnet rock could give us clues about how Mars has changed throughout its history and new information about the ancient environments that may have formed garnet and associated minerals”, adds the researcher, first author of the discovery, published on Tuesday in the journal Geochemical Perspectives Letters.

When we think of garnets, we tend to imagine the form of this mineral highly valued for its deep, blood-red hue. But the Martian version it doesn’t look anything like that.

As with many minerals, garnet doesn’t always look like that we could expect.

In particular, an iron-rich formknown as andraditeoften presents a color yellowish-greenishvery similar to that of other minerals often found in meteorites, so it does not stand out in the same way.

For this reason, researchers almost missed the discovery. “This small section of the meteorite it looked very interestingand the chemical composition was a little strange,” says Kizovski.

“At first glance, we thought it was a mineral called pyroxenewhich is very common, but after we decided to look more closely”.

The following analyzes confirmed that the mineral was andradite. Just a few grains were found in a tiny rock fragment measuring about 0.8 by 0.5 millimeters — smaller than a poppy seed.

The meteorite, called NWA 8171was already arousing great interest among planetary scientists. It is composed of basaltic breccia — a type of rock that forms when magma cools and solidifies around other mineral fragments.

Its composition Reminds me of a fruit cake: basalt is the mass, while the other mineral inclusions are fruits and nuts.

Between the basalt and these inclusions, NWA 8171 has a lot to reveal about Martian geology, from ancient magma flows to information that may be preserved within the grains.

That’s what makes it so exciting discovery of garnet in NWA 8171: these minerals are particularly valuable narrators. Grenades preserve excellent records of geological processes past, keeping unique portraits of the temperature and pressure conditions in which they were formed.

They can also be used to date these conditionsand often contain traces of other minerals, capable of revealing the chemistry of the environment in which they formed, notes .

The researchers They still don’t know what this training environment was likewhether it involved an unusual type of magma not yet identified on Mars or whether it resulted from a metamorphic process.

“The grenade is a classic example of a frequently found mineral in metamorphic rocks on Earth. The process of metamorphism transforms igneous or sedimentary rocks into a new form through exposure to extreme heat, high pressure or hot fluids,” explains Kizovski.

“On Marsthe heat and pressure required to produce garnet by metamorphism may have been generated by impact of a meteorite on the Martian surface, by the rise of magma to the crust of Mars, or both”, says the researcher.

Investigators also still cannot exclude the possibility that the grenade not having graduated from Mars. As NWA 8171 is a breccia containing several types of material, it remains theoretically possible that the fragment originated elsewhere and was crashed on Mars before being incorporated into the breach.

To investigate this hypothesis, the next step will be to analyze the isotopic proportions of the mineral. If they are similar to those of other minerals Martians, this will indicate that the garnet formed on Mars — which, in turn, will shed new light on the deep geological history of the red planet.