The first study of the magnetic properties of the lava and ash produced during the 2021 eruption of the Cumbre Vieja volcano (island of La Palma, Canary Islands, Spain) led by Josep M. Parés, coordinator of the Geochronology and Geology Program at the Centro Nacional de Investigaciónsobre la Evolución Humana (CENIEH), has been published in the journal Geosciences.
Aside from the tragedy and socioeconomic impact that this natural eruption phenomenon had on the island of La Palma, volcanoes are crustal material generators that provide a window into the Earth’s interior.Based on the findings of this preliminary study, which was conducted in collaboration with the Universidad de Burgos (UBU) and the Instituto de Productos Naturales y Agrobiologa (CSIC, La Laguna), a field campaign to collect samples at various points on Cumbre Vieja, a true natural laboratory for studying the unique properties of the Earth’s magnetic field, is planned.
Aside from improving our understanding of volcanism in general, the eruption provides a once-in-a-lifetime opportunity to learn which of the Earth’s properties, such as its magnetic field, are recorded at the time of formation by materials like lava, and how this occurs.
“One of the fundamental assumptions and foundations of paleomagnetism is that rocky materials acquire and retain the ambient terrestrial magnetism at the time of formation. We also know that that record, or paleomagnetic signal, is frequently imperfect “Parés, a paleomagnetism expert, comments.
It is critical to characterize the signal in materials formed under known conditions in terms of time, direction, and magnitude of the geomagnetic field in order to determine the reliability of paleomagnetic measurements. These conditions are exceedingly met by the volcanic materials ejected by Cumbre Vieja.”We have here the generation of new rocks, where on the one hand the site conditions are known and, on the other hand, we can measure the magnitude and direction of the geomagnetic field in real time,” Parés adds.
The CENIEH and the UBU worked closely together to determine the magnetic composition of the lava and ash from Cumbre Vieja, which is an essential step in determining which formations will be suitable for deeper studies of the geomagnetic field record in lavas.
To accomplish this, the twin CENIEH and UBU paleomagnetism laboratories used a vibration magnetometer to conduct coercivity studies, and plotted thermomagnetism and other property curves that, when combined, reveal the characteristics of the titanomagnetites present in those materials.