Researchers from the French National Centre for Scientific Research (CNRS) have discovered 4.5 billion-year-old volcanic material beneath the Indian Ocean, providing direct evidence of the Earth’s earliest composition. Recovered from the Fani Maoré underwater volcano near Mayotte, these samples suggest that deep-mantle reservoirs have remained undisturbed since the planet’s formation, challenging long-held assumptions about how the Earth’s interior mixes over time.
The Discovery at Fani Maoré
The Fani Maoré volcano, located about 50 kilometers east of Mayotte, was first identified in 2018 following a series of seismic events that shook the region between Madagascar and Africa. According to findings published in the journal Nature, the subsequent eruption was the largest underwater eruption ever documented, creating a volcanic cone of over 800 meters.
By applying high-precision measurement techniques to the fresh lava samples, the CNRS team identified a unique chemical signature. Catherine Chauvel of the CNRS stated that the discovery proves materials from the very beginning of Earth’s history exist in sufficient quantities to be sampled today. This indicates that the Earth’s mantle is far less homogeneous than previous geological models suggested.
The eruption at Fani Maoré was so significant that the island of Mayotte actually subsided by several centimeters.
Evidence of a Molten Origins
The chemical traces found in the Fani Maoré samples point to a reservoir that dates back to the aftermath of a massive collision in the early solar system. Scientists theorize that a Mars-sized body struck the young Earth, melting the entire planet. As the resulting magma ocean cooled, it formed distinct layers of rock.
For decades, geologists assumed that the slow, convective currents within the Earth’s mantle would have thoroughly mixed these early materials with younger rock. The new data suggests that instead of a uniform “stirring” process, the mantle contains deep, shielded chambers that have preserved primordial material for billions of years. This discovery echoes previous, albeit fainter, signals detected in volcanic rock from Hawaii and Iceland.
Underwater Volcanoes as Carbon Sinks
Beyond their geological value, underwater volcanoes are emerging as potential tools for climate mitigation. A study published in the journal Geology highlights that dormant undersea volcanoes can act as carbon sequestration sites by binding carbon dioxide and turning it into solid carbonate rock.
The Fontanelas volcano off the coast of Portugal serves as a prime example. Researchers suggest it could potentially store up to 8.6 million tons of CO2—a figure equivalent to decades of industrial emissions for the country. This process of mineral carbonation offers a path for the ocean floor to potentially play a role in long-term climate strategies.
Frequently Asked Questions
- How old is the material found at Fani Maoré? The chemical signatures identified by CNRS researchers date back 4.5 billion years, to the earliest stages of the Earth’s formation.
- Why is this discovery important for geology? It provides proof that deep, ancient reservoirs of material exist in the mantle, contradicting models that suggested the Earth’s interior had been thoroughly mixed over time.
- Can volcanoes help fight climate change? Yes, some dormant underwater volcanoes can chemically bind CO2 and transform it into stable carbonate rock, effectively trapping the gas.
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