An article published in the journal “Geochimica et Cosmochimica Acta” reports the evidence that on the planet Mars there were hydrothermal springs and an atmosphere much thicker than the current one until just over a billion years ago. A team of researchers led by planetary geologist Nicola Mari of the University of Glasgow studied 5 of the 20 Martian meteorites from the group of nakhlites identified on Earth, analyzing in particular sulfur isotopes finding traces of hydrothermal springs and a thick atmosphere of up to about 1.3 billion years ago. An environment capable of sustaining life forms similar to the the Earth’s still existed at that time, more than two billion later than previously thought.
Nakhlites are meteorites that fell to Earth over the last 10,000 years after traveling about 10.75 million years in space, where they were ejected after the impact of a large meteorite on Mars. Their name comes from the first one discovered, the Nakhla meteorite, which fell on June 28, 1911 near the Egyptian village of El Nakhla El Bahariya. Important studies about it were completed in the last 20 years, after the British Museum gave a part of the meteorite to NASA’s Johnson Space Center.
Years of tests led to the identification of an abundance of complex carbonaceous materials and even some porous formations that resemble the effects of bacterial actions. There’s no convincing evidence of biological activity but many indications were found that in the Nakhla meteorite’s place of origin there was an environment favorable to the development of life forms similar to the Earth’s.
Now the team led by Nicola Mari has reported the results of a new examination of the Nakhla meteorite and four other nakhlites, the ones cataloged as Lafayette, Miller Range (MIL) 090032, Yamato 000593, and Yamato 000749. In particular the researchers were interested in the fragments sulfur found inside them, incorporated by the lava during eruptions that occurred on Mars and consequently materials arrived from the red planet’s surface dating back to the period of those eruptions.
The examination of sulfur isotopes gave really interesting results on the Martian environment of the time. In fact they indicate that about 1.3 billion years ago on Mars there were still hydrothermal springs and a atmosphere much thicker than the current one, which is very thin. In essence, there was an environment in which life forms similar to the Earth’s could survive more than two billion years later than previously thought.
An article published in March 2019 in the journal “Science Advances” reported the results of a research on the ancient rivers that existed on the planet Mars that lead to believe that they existed until less than a billion years ago. Now another research offers other indications that Mars has been very different from the present desert for much longer than a few hundred million years. There’s still a lot of this planet’s history that still needs to be understood to reconstruct the various steps of the transformation from a planet that for a certain period was similar to the Earth to the current one.