New timeline for water-forged terrain on Mars proposed, days before Perseverance rover landing

A scientist has proposed an update to the chronological model of Mars, suggesting that the terrain on Mars shaped by ancient water activity on the planet may be hundreds of millions of years older than previously thought. This finding could be timely to consider, with NASA’s Perseverance rover gearing up to make its landing on the Red Planet on 18 February. The age of Earth’s terrains are usually ascertained by calculating the natural radioactivity of rocks, scientists use a different process to determine the chronology of Mars. For the Red Planet, impact craters on its surface are counted instead. Describing the process, Dr Simone Marchi of the Southwest Research Institute said, “The idea behind crater dating is not rocket science; the more craters, the older the surface”. Marchi, who authored the study, explained that craters form on any celestial body when an asteroid or comet strikes the surface. It is difficult to translate the number of craters to the age of the terrain, since “the rate of these cosmic crashes over the eons is uncertain”. Marchi has, instead, adopted a fresh approach to analysing the available data with the new findings. [caption id=“attachment_9077761” align=“alignnone” width=“1280”]  A vertically exaggerated, false-color view of a large, water-carved channel on Mars called Dao Vallis. Image: ESA/DLR/FU Berlin/Lujendra Ojha[/caption] Marchi focused intentionally on the Jezero Crater on Mars, the chosen landing site for the Mars 2020 Perseverance rover. “These surfaces could have formed over 3 billion years ago, as much as 500 million years older than previously thought,” she said. Now, as NASA’s rover lands on the crater to gather samples to be brought back on Earth for radiometric dating and ,  Marchi is hopeful that the data will use “vital ground-truth data” so that the current existent chronology models can be developed. Scientists also expect to find out if Mars can serve as a habitable environment in the future, given the Jezero Crater most likely hosted a lake many years ago. The new paper titled ‘A new Martian crater chronology: Implications for Jezero crater’ has been published in The Astronomical Journal.