Earth scientist Antoine Bracco Gartner shows where the unusual, potassium-rich magma that has erupted in central Italy over the past few million years comes from. This type of magma forms deep within the Earth, where a subducted tectonic plate has released fluids and melts that chemically altered the mantle rock. He studied microscopic droplets of ancient magma trapped inside crystals of the mineral olivine, allowing him to determine how this process unfolded and what sources feed the magma.
Bracco Gartner’s analysis shows that the origin of the potassium-rich magma is not the same everywhere: its composition varies from place to place. This is because the mantle rock was influenced in different ways by material from the subducted plate. Moreover, some of the studied magma droplets contain chemical traces that point to previously unknown minerals in the magma source.
These discoveries provide new insight into how volcanism works and how the Earth’s mantle forms and evolves. Bracco Gartner’s research not only improves our understanding of the origin of potassium-rich magma but also contributes to a broader picture of the cycle of materials between the Earth’s crust and mantle. Ultimately, this fundamental research is important for volcanic regions worldwide and provides knowledge that, in the long term, contributes to better climate models, since volcanism affects the balance of greenhouse gases such as CO₂.
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