Researchers at the University of Hawaii at Manoa analyzed volcanic rocks from the 6,000-kilometer-long Hawaiian-Emperor seamount chain, stretching from the Big Island to the Kamchatka Trench. By measuring trace elements and isotopes in basalt samples spanning 47 million years of eruptions, they reconstructed the temperature history of the Hawaiian mantle plume — and found that it has heated up by approximately 250°C (480°F) over that period.
This contradicts the classical model, which predicts that a mantle plume rising from the core-mantle boundary should cool as it transfers heat upward. The findings suggest that the plume's source region may be drawing in hotter material from the deep mantle over time, or that the plume conduit has widened, allowing more heat to flow. Either explanation challenges fundamental assumptions about how heat circulates inside the planet.
The Hawaiian hotspot has built the world's largest volcanic mountain range — the Emperor Seamounts were once islands as large as Hawaii — and understanding its thermal evolution has implications far beyond one archipelago. Mantle plumes drive volcanic activity, influence plate tectonics, and release carbon from the deep Earth. If other plumes behave similarly, climate models that assume stable volcanic carbon emissions over geological timescales may need revision. The study was published in Earth and Planetary Science Letters.