Ancient meteorite present in drawer comprises ‘proof of water on Mars,’ new research reveals

An ancient piece of space rock has given a big clue about one of the great extra-terrestrial questions.

The sliver of rock from Mars was found in a drawer at a university in 1931 – but it is a lot older than that. The asteroid is thought to be around 742-million-year-old and has been given the name “Lafayette Meteorite”. It is understood to have interacted with water 742-million years ago, and was separated from Mars after the planet had an impact with a meteor around 11million years ago.

The impact is thought to have sent plumes of dust and dirt flying up into space, before eventually getting caught in Earth’s gravitational field and being pulled down through our atmosphere.

The penny-sized lump of rock finally crashed down to Earth in Indiana in the US. It is not known when this happened, but somehow it ended up in a Purdue University biology department desk drawer.

Some years later, in the 1980s it was given to Chicago’s Field Museum and gases found within it were matched to those found on Mars. Further research, published in Geochemical Perspective Letters, has now to the confirmation that minerals in the rock had interreacted with water.

Marissa Tremblay, an assistant professor in EAPS and study lead author, said in a university write up: “Dating these minerals can therefore tell us when there was liquid water at or near the surface of Mars in the planet’s geologic past.

“We dated these minerals in the Martian meteorite Lafayette and found that they formed 742 million years ago. We do not think there was abundant liquid water on the surface of Mars at this time. Instead, we think the water came from the melting of nearby subsurface ice called permafrost, and that the permafrost melting was caused by magmatic activity that still occurs periodically on Mars to the present day.”

She added: “The age could have been affected by the impact that ejected the Lafayette Meteorite from Mars, the heating Lafayette experienced during the 11 million years it was floating out in space, or the heating Lafayette experienced when it fell to Earth and burned up a little bit in Earth’s atmosphere.

“But we were able to demonstrate that none of these things affected the age of aqueous alteration in Lafayette.”

Ryan Ickert, senior research scientist with Purdue EAPS, is a co-author of the paper: “This meteorite uniquely has evidence that it has reacted with water. The exact date of this was controversial, and our publication dates when water was present”.

For the latest breaking news and stories from across the globe from the Daily Star, sign up for our newsletters.