What made these rocks stand out was an unusually high concentration of a phosphorous mineral known as schreibersite.
Phosphorus is a key ingredient in many of the processes that govern life, from growth to reproduction.
On a young Earth, the phosphorous found on the planet’s surface was not soluble in water – but schreibersite was.
The findings were published today (March 16) in the journal Nature Communications.
Mr Hess said: “Many have suggested that life on Earth originated in shallow surface waters, following Darwin’s famous ‘warm little pond’ concept.