Large meteorite and comet impacts in the sea created structures that provided conditions favourable for life on Earth, reveal geochemists from Trinity College Dublin in Ireland.
Water then interacted with impact-heated rock to enable synthesis of complex organic molecules and the enclosed crater itself was a microhabitat within which life could flourish, said the team.
It has long been suggested that the meteoritic and cometary material that bombarded early Earth delivered the raw materials - complex organic molecules and water - and the energy that was required for synthesis.
According to the researchers, impact craters were ideal environments to facilitate the reactions that saw the first "seeds of life" take root.
"The findings suggest that extensive hydrothermal systems operated in an enclosed impact crater at Sudbury, Ontario, Canada," said first study author Edel O'Sullivan in a paper published in the journal Geochimica et Cosmochimica Acta.
The Sudbury basin provides a unique opportunity to study the sediment that filled the basin as a guide to what the earlier impact craters would have looked like.
The Sudbury structure has an unusually thick basin fill and much of this is almost black in colour (due to carbon), also containing hydrothermal metal deposits.
To reach these findings, representative samples across the basin fill were analysed for their chemistry and for carbon isotopes.