Amino acids and other molecules important to the origin of life can be enriched within networks of rocky fractures, which would have been common on the early Earth
By James Dinneen
3 April 2024
Some amino acids can become concentrated as they travel through cracks in hot rock
Sebastian Kaulitzki / Alamy
Chemical reactions key to the origin of life on Earth could have occurred as molecules moved along thermal gradients within networks of thin rock fractures deep underground.
Such networks, which would have been common on the early Earth, could have provided a kind of natural laboratory in which many of life’s building blocks were concentrated and separated from other organic molecules.
“It’s very difficult to get a more general environment where you could have these purifications and intermediate steps,” says Christof Mast at the Ludwig Maximilian University of Munich in Germany.
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He and his colleagues created a heat flow chamber about the size of a playing card to model how a mix of organic molecules might behave in such rock fractures.
They heated one side of the 170-micrometre-thick chamber to 25°C (77°F) and the other to 40°C (104°F), creating a temperature gradient along which molecules would move in a process called thermophoresis. How sensitive a molecule is to this process depends on its size and electrical charge and how it interacts with the fluid in which it is dissolved.