A team of geologists from the University of British Columbia (Canada) has proposed rethinking our understanding of the origin of volcanic lava erupting in hot spots on Earth such as Hawaii, Iceland and Samoa. The researchers concluded that all the lava must have come from a single reservoir in the planet’s mantle.

The results of the study were published in the journal Natural Geology, He noted that the Earth’s mantle is more homogeneous than previously thought, and that lava acquires its unique chemical signatures as it rises to the surface.

As a reminder, the Earth’s mantle is a layer of solid rock located between the iron core and the crust, making up about 84% of the planet’s volume. Despite the high temperatures, the mantle remains mostly solid due to the high pressure. Lava is magma released from the mantle, passing through the crust and rising to the surface.

Hotspots are areas on the planet’s surface where magma from deep in the mantle erupts upwards, forming volcanic islands and mountain chains. The chemical diversity of lava erupted in these regions is traditionally thought to be due to the heterogeneity of sources in the deep mantle, containing components of different composition, origin, and age.

As part of the study, geologists analyzed trace elements and isotopes in hotspot lava flows to determine the composition of the parent magmas and sources. The results show that the chemical heterogeneity of the lava flows is a result of processes that occur as the magma rises to the surface.

The team found that the parent magmas of hotspot lavas, as well as kimberlites and basalts from large igneous provinces, have uniform elemental and isotopic compositions, suggesting a single reservoir deep in the mantle despite visible differences at the surface.

The discovery suggests a simpler model of Earth’s mantle evolution, in which a single mantle reservoir that was depleted and degassed became enriched with incompatible elements during the Archean Eon (about 2.5 to 4 billion years ago) and has remained relatively unchanged since then.

If the conclusions of the authors of the new scientific study are correct, then the Earth’s mantle is more uniform than previously thought. The research results provide a better understanding of the processes observed in the early history of our planet.