Volcanic eruptions manifest the exceptional nature of Earth in the solar system. Below solid surface, currents of hot planetary interior
drive plate tectonics, which constrain the surface conditions of the Earth. Occasionally, catastrophic volcanism occurs and millions of
cubic kilometres of ash and lava are formed. Why and how these large volcanic provinces are generated is a hotly debated issue.
We have discovered exceptionally primitive volcanics in the Karoo province. These globally rare rocks provide unique insights into the
origin of great volumes of magma in this and other large volcanic provinces. These volcanics originated in the upper mantle, but under
extremely high pressure and temperature. Yet they have high water contents atypical of such sources.
Using geochemistry we scrutinise the magma source indicated and address its significance in the Karoo province. The results are
expected to increase our understanding of Earth's mantle and the origin of supereruptions.