A rock found on Mars contains substances that could have been produced by ancient microbes that were once alive, NASA said Wednesday.

The NASA rover Perseverance found the rock, named “Cheyava Falls,” last July. Scientists noted white spots ringed in black on the rock that, on Earth, are sometimes associated with fossilized microbes below the immediate surface of the rock. 

Samples of the rock were tested to find out whether life was involved in making the leopard spot-like rings.

Scientists “said, ’listen, we can’t find another explanation,’ so this very well could be the clearest sign of life that we’ve ever found on Mars,” interim NASA Administrator and Secretary of Transportation Sean Duffy said at a press conference Wednesday.

A paper published Wednesday in the journal Nature said the “Sapphire Canyon” sample taken from the Cheyava Falls rock contained “potential biosignatures,” substances or structures that could have biological origins but require further study before making a definitive conclusion as to whether life was involved in creating them, NASA said.

Cheyava Falls was found in the “Bright Angel” formation of rocks made up of clay and silt, both of which are known to preserve microbes on Earth.

“The combination of chemical compounds we found in the Bright Angel formation could have been a rich source of energy for microbial metabolisms,” said Joel Hurowitz, lead author of the paper and Perseverance researcher.

In particular, the sample contained the iron-rich minerals vivianite and greigite, NASA said, which can be produced by microbes but can also be created abiotically, meaning without the presence of life.

The paper found that the Bright Angel formation did not show signs of the sustained heat and acidity needed for the abiotic creation of those minerals.

“Astrobiological claims, particularly those related to the potential discovery of past extraterrestrial life, require extraordinary evidence. … while abiotic explanations for what we see at Bright Angel are less likely given the paper’s findings, we cannot rule them out,” said NASA Jet Propulsion Laboratory scientist Katie Stack Morgan, who works on the Perseverance team.

• Brad Matthews can be reached at bmatthews@washingtontimes.com.