Indian Ocean volcano erupts magma preserving 4.5-billion-year-old primordial mantle signatures

Researchers sampled historic flows from the Indian Ocean hotspot and measured extremely high 3He/4He ratios alongside 182W anomalies that match predictions for early mantle domains isolated since magma-ocean solidification. The study design combined high-precision noble-gas mass spectrometry on olivine-hosted melt inclusions with tungsten isotope analysis on bulk lavas from 20 distinct eruptions. These data indicate that large low-shear-velocity provinces can sequester and later return chemically primitive material formed within the first 100 million years of Earth history.

The preservation of such signatures challenges models assuming efficient convective mixing and instead supports long-term isolation of dense, iron-rich cumulates at the core-mantle boundary. This finding links directly to habitability questions because primordial reservoirs may control the long-term flux of volatiles and heat that sustain plate tectonics and surface oceans. Routine coverage overlooked how these geochemical fingerprints constrain the timing of late accretion and the delivery of life-essential elements.

Future work requires targeted drilling of additional hotspot chains and integration with seismic tomography to map the spatial extent of these domains. Expanded datasets could test whether similar reservoirs exist beneath other major plumes within the next decade.