Earth's primordial magma ocean traces found in modern volcanic lava from Fani Maoré

In a groundbreaking study published in Nature, researchers have discovered traces of Earth's primordial magma ocean in lava samples from the underwater volcano Fani Maoré, located near Mayotte. The findings, reported on July 6, 2026, reveal that remnants of the Hadean eon exist in modern volcanic materials, providing insights into the planet's early geological history.

Discovery of Fani Maoré and its Significance

The underwater volcano Fani Maoré emerged in May 2018, following a series of earthquakes in the region between Madagascar and Mozambique. Subsequent scientific expeditions led to the collection of lava samples, which were analyzed by a team of researchers. They identified mineral remnants, specifically bridgmanite, believed to date back to Earth's formative years during the Hadean eon.

The significance of this discovery lies in its potential to reshape our understanding of the early Earth. The research team, led by Claudine Israel from the University of Cambridge, utilized advanced isotopic measurement techniques to analyze 13 lava samples from Fani Maoré, along with eight additional samples from eastern Mayotte.

Neodymium Isotopes as Indicators of Early Earth

One of the key elements in this study is neodymium isotopes, particularly 142Nd, which serves as a marker for Earth's early magma ocean. Approximately 4.5 billion years ago, a massive collision is thought to have ejected debris that formed the moon and triggered a global magma ocean. As this ocean gradually solidified, crystallization occurred, leading to the formation of bridgmanite and other minerals.

The researchers highlighted the importance of the Sm–Nd isotope systems in understanding silicate differentiation and the formation of continents. The short-lived isotope 146Sm decays into 142Nd, allowing scientists to trace differentiation events from the planet's earliest years.

Implications for Understanding Mantle Composition

The study's findings challenge the prevailing notion of a well-mixed mantle. The team discovered a statistically significant positive 142Nd anomaly in the lava samples, suggesting that the mantle source material originated within the first 100 million years of Earth's history. This material was depleted in light rare-earth elements, indicating early crystal-melt separation.

Modeling conducted by the researchers proposes that only 9%–11% of Hadean bridgmanite-rich material is necessary to account for the observed 142Nd signal from a deep mantle source. In contrast, a shallow model would require an implausibly high percentage of Hadean material, suggesting that some remnants of early Earth have persisted through geological time.

The authors concluded, "Recent geodynamic simulations have shown that a fraction of the earliest formed solids can be preserved over time during Hadean magma ocean crystallization and subsequent mantle convection." This study not only sheds light on the history of Earth's formation but also opens avenues for further research into the chemical memory of the mantle.