French researchers find clues to Mars' history in rare meteorite

French scientists have examined a rare meteorite that contains fragments of the Martian crust dating back more than 4 billion years and found clues as to how Mars was able to sustain liquid water on its surface during that period.

Frederic Moynier heads the cosmochemistry department at the IPGP. © Dhananjay Khadilkar

Scientists from the Institut de Physique du Globe de Paris (IPGP) at the Université de Paris analysed the meteorite ‘NWA 7533’ also called ‘Black Beauty’ which is a part of the Martian rocks that was ejected during an impact. It was discovered in 2011 in Morocco.

“Observations by space missions have shown that liquid water in the form of rivers, canals and deltas was present on Mars around 4 billion years ago. However, the presence of liquid water was a mystery as at that time our Sun produced 30 percent less energy than today. This implies the temperature on Mars would have been too low for water to exist in a liquid state,” Fréderic Moynier who heads the cosmochemistry department at IPGP told RFI.

#Communiqué 🗞️ | Dans une étude menée par @IPGP_officiel @CNRS @Univ_Paris, une équipe scientifique int. a montré qu’il y a 4,4 milliards d’années la jeune atmosphère de #Mars était suffisamment chaude pour maintenir de l’eau à l’état liquide.

➡️ https://t.co/116ti1s7tg pic.twitter.com/DTTzkTLxkf

— Centre national de la recherche scientifique 🌍 (@CNRS) November 2, 2020

On conducting a chemical and isotopic analysis of the meteorite sample, Moynier and his team found that the Martian crust was oxidised during its fusion by impacts in the presence of water.

“The analysis showed the oxidation of the Martian crust by water led to the release of di-hydrogen, a greenhouse gas, into the Martian atmosphere. A combination of high quantity of di-hydrogen and an atmosphere with CO2 caused the Martian to warm up, thus allowing it to sustain liquid water,” he said.

Among the hundreds of Martian meteorites found so far, the ‘Black Beauty’ stands out because of its chemical composition and very old age. It bears the signature of rocks from the southern hemisphere of Mars and contains the oldest fragments of the known Martian crust.