The ancient Egyptians loved this rare gem, and scientists have just found it in a cracked meteorite that fell from Mars
Scientists have discovered a completely new type of rock on Mars, revealing a mineral never before discovered on the red planet.
The team behind the discovery say it could change our understanding of the history of Mars, giving planetary scientists a new perspective on the planet’s ancient past and its 4.5 billion-year-old geology.
They say the discovery is actually a “geological time capsule” containing information about the temperatures, pressures and processes that formed Mars billions of years ago.
A look into Mars’ past
Our solar system is about 4.5 billion years old.
Throughout Mars’ 4.5 billion year history, it has gone through many changes. In the ancient past, it was warmer and more humid than it is today.
Scientists have previously discovered evidence of ancient riverbeds and lakes on Mars that were once filled with liquid water.
This means that ancient Mars had the potential to host life, and planetary scientists are still searching for evidence of that life today.
While rovers and orbiters operating at Mars are a great way to learn more about the planet, scientists can also learn a lot from Martian meteorites that fall to Earth.
To conduct this study, an international team of astronomers at the Royal Ontario Museum in Toronto, Canada, was analyzing a piece of a Martian meteorite – known as NWA 8171 – in the museum’s collections.
They found agate, a dark red gem that was popular with the ancient Egyptians, Romans and the Victorian elite.
The team says it is a “cornerstone” mineral in geology.
On Earth, garnets can tell scientists a lot about our planet’s history, from its tectonic forces and ore-forming processes to the liquid rock interactions that form the Earth’s crust and mantle.
The research was led by Tanja Kiesowski, assistant professor of geosciences at Brock University in Canada.
“This discovery will expand our knowledge of possible geological processes on this planet,” says Kiesowski.
“This new type of garnet-bearing rock could give us clues about how Mars changed throughout its history and new insights into ancient environments that could have formed garnet and related minerals.”
How they found the puzzle piece – and why it’s big news
This discovery came about due to Kiesovsky’s decision to take a closer look at the Martian meteorite to learn about its mineralogy and chemical composition.
“This little fragment of the meteorite looked really interesting, and its chemistry was a little strange,” she says.
“At first, we assumed it was a mineral called pyroxene, which is very common, but then we decided to take a second look.”
To analyze the rock, they used the Scanning Electron Microscopy and Microanalysis Unit at the University of Portsmouth in the UK and specialized laser equipment at the Royal Ontario Museum.
“Garnet is a classic example of a mineral found mostly in metamorphic rocks on Earth,” Kiesowski says.
“The process of metamorphism transforms igneous or sedimentary rocks into a new form through exposure to intense heat, high pressure, or hot fluids.”
“On Mars, the heat and pressure required to produce garnet through metamorphism could be the result of a meteorite hitting the Martian surface, magma rising into the Martian crust, or both.”
Martian or alien?
The team says they do not yet know whether the agate-bearing rock formed on Mars or whether it reached the planet and was incorporated into its surface during a meteorite landing.
This may mean that it formed outside Mars, but then landed on the planet
The team will now study the isotopic signatures of the garnet to learn more.
“Measuring the oxygen isotopes of the garnet-bearing rock type itself would help confirm whether it is of Martian origin or from an alien meteorite,” Kiesowski says.
“Isotopes are a group of atoms with equal numbers of protons and electrons, but different numbers of neutrons.”
The only problem is that the process will involve destroying some samples.
“[We’ve avoided that] “So far, given its rarity, it may be the only Martian rock containing garnet that we have to study,” Kiesowski says.
“The results add a fascinating new dimension to our understanding of the geology of Mars, and open an exciting new window on the evolution of our planetary neighbour,” says Professor James Darling, Professor of Earth and Planetary Sciences from the University of Portsmouth.
Read the full study Expanding the rock diversity of Mars: discovery of a garnet-bearing layer in NWA 8171.
