The rover came across an intriguing arrowhead-shaped rock called Cheyava Falls |
However, after scientists examined the unusual markings, they discovered they were packed with organic carbon, iron, phosphorus and sulphur, which are all key chemicals for sustaining life.
The researchers were even more astonished to detect the presence of two rare minerals, vivianite and greigite.
On Earth, both form through redox reactions, which is the same chemical processes behind photosynthesis, respiration and microbial life deep beneath the ocean floor.
The discovery has reignited hopes that Mars may once have harboured the same complex chemistry that made life possible on Earth.