Superheated magma can alter eruption dynamics by dissolving the microscopic crystal seeds that normally trigger solidification, a team of researchers has found after studying samples from the Tajogaite eruption on La Palma. The analysis of material erupted in 2021 indicates that exceptionally high temperatures allow molten rock to remain fluid longer as it ascends, a condition the authors link to the development of prolonged, high-reaching lava fountains observed during that event.
The investigators combined petrographic observations and geochemical measurements of erupted glass and crystals to establish the temperature-dependent behavior. They report that when magma is heated beyond the stability range of seed crystals, these nucleation sites dissolve rather than growing into larger crystals. The loss of those seeds delays the onset of crystallization, maintaining lower viscosity in the ascending melt and altering its response to decompression and volatile exsolution.
The study describes how sustained fluidity affects gas release and fragmentation processes within the conduit. With delayed crystal formation, volatile phases can separate more efficiently from the melt and drive energetic, fountain-producing ejections of lava over extended intervals. The authors link this mechanism directly to the towering lava fountains documented at Tajogaite, providing a physicochemical explanation for the sustained activity that occurred during parts of the eruption.
These findings refine understanding of how temperature controls magma rheology and eruption style, with implications for monitoring and modeling active volcanoes. By identifying superheating and seed-crystal dissolution as controls on eruption behavior, the research offers a specific process that can be incorporated into predictive frameworks and laboratory experiments. The authors note that further work, including controlled high-temperature experiments and broader sampling from diverse volcanic systems, will be needed to quantify the frequency and threshold conditions under which this mechanism operates.
