Geoscientists have traditionally believed that water and shallow magma were the primary drivers of volcanic eruptions. However, recent research from Cornell University reveals that gaseous carbon dioxide can also trigger explosive eruptions. The study proposes a new model suggesting that basaltic volcanoes, typically found within tectonic plates, are supplied by deep mantle magma located 20 to 30 kilometers below Earth's surface.
Published in the Proceedings of the National Academy of Sciences on August 7, 2023, this research sheds light on the inner dynamics and composition of our planet, with significant implications for improving volcanic-hazards planning. The senior author of the study, Esteban Gazel, explains that the magma responsible for these eruptions comes directly from the mantle, propelled by the process of carbon dioxide exsolution.
This groundbreaking discovery challenges the previous assumption that water was the primary eruption driver. Gazel and his team developed innovative tools, including a high-precision carbon dioxide densimeter and Raman spectroscopy, to analyze microscopic carbon dioxide-rich bubbles trapped in volcanic crystals. These tools allowed them to gain insights into magma storage and behavior, even tested during the 2021 eruption in Las Palmas, Canary Islands.
By examining volcanic deposits from the Fogo volcano in Cabo Verde, the researchers found that the magma contained high concentrations of volatiles, particularly carbon dioxide. This finding indicates that the magma was stored deep within the mantle, rather than within the Earth's crust. The study also establishes a link between this deep mantle source and the supply of magma to these volcanoes.
Understanding this magma storage process is crucial for enhancing our ability to prepare for future volcanic eruptions. By pinpointing where eruptions originate and what triggers them, scientists can develop more effective strategies for managing volcanic hazards and safeguarding communities.
Source: Cornell University