Meteorites reveal when liquid water appeared on Mars

A breakthrough discovery from an international research team led by Purdue University (USA) has determined the time when liquid water existed on Mars through analysis of the Lafayette meteorite.

The study, published in the journal Geochemical Perspective Letters, offers new insights into the geological history of the red planet.

Dr. Marissa Tremblay, a research leader in the Department of Earth, Atmospheric and Planetary Sciences at Purdue University, uses noble gases such as helium, neon and argon to study the physical and chemical processes that shape the surface of Earth and other planets. She said some meteorites from Mars contain minerals that were formed by interactions with liquid water when it was on the planet.

Lafayette meteorite. (Photo: eaps.purdue.edu).

By dating these minerals in the Lafayette meteorite , scientists have found that they formed 742 million years ago . "We don't think there was much liquid water on the surface of Mars at that time," Dr Tremblay explained.

"Instead, we think this water came from melting subsurface permafrost, caused by the volcanic activity that still occurs periodically on Mars to this day."

This research is particularly important because it is the first time scientists have been able to pinpoint exactly when liquid water was present on Mars.

Dr. Ryan Ickert, study co-author and senior scientist at Purdue University, emphasized that previous isotopic data used to estimate the timing of interactions between water and rock on Mars may have been influenced by other processes.

The team demonstrated that this result was not affected by other factors such as the impact when the meteorite left Mars, the temperature in space during the 11 million years of flight, or the heating process when passing through Earth's atmosphere.

The Lafayette meteorite has quite an interesting history.

It was discovered in a. drawer at Purdue University in 1931 for unknown reasons.

It is one of the few meteorites that can be directly traced back to Mars. Scientists have determined that it was ejected from the Martian surface by an impact about 11 million years ago.

This is demonstrated through analysis of isotopes created by cosmic ray bombardment in space.

This new discovery not only helps us better understand the geological history of Mars, but also opens up new methods for studying other meteorites.

'We have demonstrated a reliable way to date alteration minerals in meteorites,' said Dr Tremblay. 'This method can be applied to other meteorites and celestial bodies to determine when liquid water may have been present.'

The research will continue to be developed at Purdue University thanks to the Stahura Undergraduate Meteorite Research Fund, which allows undergraduate students to participate in the geochemistry and history of meteorites.