But Dr Brandenburg believes they are the remnants of nuclear explosions on the surface.
'When a thermonuclear bomb is detonated, it leaves a trace of Xenon 129 in that area, which is not the normal,' Jorjani told
Jones, adding Dr Brandenburg's findings were 'alarming evidence' of life on Mars.
'And according to Dr Brandenburg, it's a very distinct signature. It's unmistakable, and it's specifically associated with thermonuclear weapons detonation.'
The 'not the normal' means higher-than-expected levels were found.
Dr Brandenburg also argued that Mars once had an Earth-like climate home to animal and plant life, and any intelligent life would have been about as advanced as the ancient Egyptians on Earth.