First traces of water on Mars date back 4.45 billion years

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By analyzing a Martian meteorite, scientists from the University of Lausanne and Curtin University have discovered traces of water in the crust of Mars dating back 4.45 billion years, i.e. to near the very beginning of the planet’s formation.

This new information strengthens the hypothesis that the planet may have been habitable at some point in its history.

Thanks to observations from Mars rovers and spacecraft, we’ve known for decades that the planet Mars was once home to water, and probably had rivers and lakes. However, many questions remain. When did this precious liquid first appear in the history of Mars, and did the Red Planet, in the course of its evolution, create the conditions necessary for the emergence of life?

By analyzing the composition of a mineral (zircon) found in a Martian meteorite, scientists from the University of Lausanne, Curtin University and the University of Adelaide have succeeded in dating traces of water in the crust of Mars. According to the study, published in Science Advances, hydrothermal activity dates back 4.45 billion years, just 100 million years after the planet’s formation.  

“Our data suggests the presence of water in the crust of Mars at a comparable time to the earliest evidence for water on Earth’s surface, around 4.4 billion years ago,” comments Jack Gillespie, first author of the study and researcher at the University of Lausanne’s Faculty of Geosciences and Environment. “This discovery provides new evidence for understanding the planetary evolution of Mars, the processes that took place on it and its potential to have harboured life”.

A Martian meteorite found in the desert

The scientists worked on a small piece of the meteorite NWA 7034 “Black Beauty”, which was discovered in the Sahara Desert in 2011. “Black Beauty” originates from the Martian surface and was thrown to Earth following an impact on Mars around 5-10 million years ago. Analysis focused on zircon; a mineral contained in the meteorite. Highly resistant, zircon crystals are key tools for dating geological processes: they contain chemical elements that make it possible to reconstruct the date and conditions under which they crystallized (temperature, interaction with fluids, etc.). “Zircon contains traces of uranium, an element that acts as a natural clock,” explains Jack Gillespie. “This element decays to lead over time at a precisely known rate. By comparing the ratio of uranium to lead, we can calculate the age of crystal formation.”

Through nano-scale spectroscopy, the team identified element patterns in this unique zircon, including unusual amounts of iron, aluminium, and sodium. These elements were incorporated as the zircon formed 4.45 billion years ago, suggesting water was present during early Martian magmatic activity.

These new findings further support the hypothesis that the Red Planet may have once offered conditions favorable to life at some point in its history.

“Hydrothermal systems were essential for the development of life on Earth, and our findings suggest Mars also had water, a key ingredient for habitable environment, during the earliest history of crust formation”

Aaron Cavosie from Curtin’s School of Earth and Planetary Sciences, co-author

Lead author Dr Jack Gillespie from the University of Lausanne was a Postdoctoral Research Associate at Curtin’s School of Earth and Planetary Sciences when work began on the study, which was co-authored by researchers from Curtin’s Space Science and Technology Centre , the John de Laeter Centre  and the University of Adelaide, with funding from the Australian Research Council, Curtin University, and the Swiss National Science Foundation.