An international team of researchers have identified the mud volcanoes at Isua in southwest Greenland as a possible birthplace for life on Earth by studying 3.8 billion-year-old formations.

According to the study which was published this week in the Proceedings of the National Academy of Sciences, almost four billion years ago these volcanoes released chemical elements which are indispensable to the formation of the first biomolecules which created an environment that met all the requirements for the emergence of life.

The scientists focused their studies on serpentinites from Isua which dated back some 3.8 billion years. Using isotopes of zinc as indicators of the basic or acid nature of an environment, the researchers were able to highlight the basic character of the thermal fluids that permeated the Isua serpentinites, demonstrating that these minerals formed a favorable environment for amino-acid stabilization.

Comparing these serpentinites with recent equivalents from the mid-oceanic ridge of the Artic Ocean, the Alps and Mexico, the researchers found out that the Isua rocks are markedly depleted in heavy isotopes of zinc compared to the latter whereas their zinc is isotopically similar to that from mud volcanoes of the Marianas Trench.

Nearly four billion years ago, at a time when the continents only occupied a very small part of the surface area of the globe, the oceanic crust of Isua was permeated by basic hydrothermal fluids, rich in carbonates, and at temperatures ranging from 100 to 300°C. Phosphorus, another indispensable element to life, is abundant in environments where serpentinization takes place.

According to the researchers, as this process generates mud volcanoes, all the necessary conditions were gathered at Isua for organic molecules to form and be stable. The mud volcanoes at Isua thus represent a particularly favorable setting for the emergence of primitive terrestrial life.

The research team was headed by researchers from the Laboratoire de Geologie de Lyon: Terre, Planetes et Environnement (CNRS/Universite Claude Bernard Lyon 1/ENS de Lyon).