A Nasa rover has found possible signs of ancient life on Mars from rock samples it collected from a geologically rich area.

The Perseverance rover collected two samples from an ancient river delta in the Jezero Crater, a site scientists believe was full of life billions of years ago.

Nasa hopes to bring these samples back to Earth on a return mission it plans to carry out later this decade in partnership with the European Space Agency.

The rocks may have organic matter, or building blocks of life, with a wide variety of compounds made up of carbon, hydrogen and oxygen atoms.

“We picked the Jezero Crater for Perseverance to explore because we thought it had the best chance of providing scientifically excellent samples ― and now we know we sent the rover to the right location,” said Thomas Zurbuchen, Nasa’s associate administrator for science.

“These first two science campaigns have yielded an amazing diversity of samples to bring back to Earth by the Mars Sample Return campaign.”

The rover landed on Mars early last year and has been collecting rocks from various locations. So far, it has collected 12 samples.

It has been carrying out its science campaign at the Jezero Crater, which features a delta that formed about 3.5 billion years ago at the convergence of a Martian river and a lake.

Perseverance is currently investigating the delta’s sedimentary rocks, formed when particles of various sizes settled in the once-watery environment.

During its first science campaign, the rover explored the crater’s floor, finding igneous rock, which forms deep underground from magma or during volcanic activity at the surface.

Ken Farley, a Perseverance project scientist, said that the campaign is helping scientists study the geological history of Mars.

“The delta, with its diverse sedimentary rocks, contrasts beautifully with the igneous rocks ― formed from the crystallisation of magma ― discovered on the crater floor,” he said.

“This juxtaposition provides us with a rich understanding of the geological history after the crater formed and a diverse sample suite."

This is not the first time a Nasa rover has found evidence of organic matter on Mars.

In 2013, the Curiosity Mars rover found evidence in rock samples, and Perseverance detected organics in the Jezero Crater before.

This time, however, the rover made the discovery in an area where sediment and salts were deposited into a lake under conditions in which life could potentially have existed./agencies