Once-hot rocks hold old secrets, pushing first life back eons
New research could shake our understanding of the origins of life on Earth, setting the date back about a billion years.
A provocative paper suggests that oceanic plate subduction was happening much earlier in Earth’s history, meaning conditions for the formation of life may have existed 900 million years earlier than commonly thought.
‘Subduction’ is a process where an oceanic plate descends beneath another plate, a common characteristic of modern plate tectonics.
The movement of plates is known to produce the chemicals and conditions needed for life to erupt, and so the earliest evidence of this movement is likely to also indicate the origin of life.
The findings came from a report by team of Australian researchers, who have analysed similarities between modern-day subduction zones and early-Earth rock sequences.
Lead author of the latest report; Macquarie University’s Professor Simon Turner, says “modern subduction settings, such as the Mariana arc, have all the right chemical ingredients to grow and sustain primitive life forms.”
“From the similarities of our research into the earlier deposits from Canada, it follows that the conditions for the formation of life may have existed much earlier, with subduction starting far longer ago than we’d thought previously.”
The early Earth’s geological processes remain a fundamental question for the earth sciences and the scarcity of rocks from this time period make exploration a significant challenge.
“We expect that this research will result in a lot of debate across the discipline, as there’s much that is yet to be discovered in the processes and earliest records of subduction,” Dr Turner said.
“Our next steps are to investigate zinc isotopes which could show whether high pH fluids were present to stabilise amino acids, and we’ll continue to explore the secrets under the Earth’s crust.”
The findings have been published in the journal Geology, and are accessible here.