Mars formed over a longer time than previous estimates suggest

Posted Feb 21, 2020 by Tim Sandle
How old is Mars? Certainly older than previous estimates according to scientists who have conducted simulations of the impacts that produced the mixed Mars mantle during the early years of the formation of our Solar System.
An artist’s impression shows how Mars may have looked about four billion years ago. The young plan...
An artist’s impression shows how Mars may have looked about four billion years ago. The young planet Mars would have had enough water to cover its entire surface in a liquid layer about 140 metres deep, but it is more likely that the liquid would have pooled to form an ocean occupying almost half of Mars’s northern hemisphere, and in some regions reaching depths greater than 1.6 kilometers.
ESO/M. Kornmesser/N. Risinger (
During the formation of the Solar System Mars, the fourth planet from the Sun, was repeatedly struck by planetesimals (these are small protoplanets no larger than 1,200 miles in diameter). A few became moons, such as with Phobos and Deimos (the moons of Mars).
Simulating this bombardment activity, using a combination of materials examination and computer modelling, has enabled scientists to make a new estimate as to how hold Mars is (or at least when the planet began to form). the experiments involved the mixing of materials of a similar nature to Mars and the hunks of space matter, recreating the impacts.
The research also has implications for scientists who study the history of Earth. To date some 61,000 meteorites have been found on Earth, and of these around 200 are assumed to be of Martian origin, ejected from Mars as the result of the early collisions from the planetesimals.
According to lead researcher, Dr. Simone Marchi, from the Southwest Research Institute: "Based on our model, early collisions produce a heterogeneous, marble-cake-like Martian mantle. These results suggest that the prevailing view of Mars formation may be biased by the limited number of meteorites available for study."
From the modelling, the researchers have indicated that instead of the prevailing view that Mars was formed some 2-4 million years after the Solar System began to form, the large, early time-point collisions support the view that Mars was formed over a far longer timescale of up to 20 million years. This is evidence from an assessment of the tungsten isotopic balance, drawn from the materials based models. This approach allows an assessment of heterogeneous mixture of materials found within the early Martian mantle.
The research has been published in the journal Science Advances. The research paper is titled "A compositionally heterogeneous Martian mantle due to late accretion."