Citizen / General public
Researcher
Student / Future student
Company
Public partner
Journalist
Teacher / Pupil

A subtle chemical tipping point governs the eruption style of rhyolitic magmas

A team of researchers from the Institut de Physique du Globe de Paris and the University of Munich have just revealed in Nature that nanoscale changes in magma can cause catastrophic changes in the dynamics of volcanic eruptions, which can alternate between effusive and explosive eruptions.

A subtle chemical tipping point governs the eruption style of rhyolitic magmas

Publication date: 08/01/2018

Press, Research

Related teams :
Geomaterials

Related themes : Natural Hazards

What if certain major climate catastrophes were the result of changes in the eruptive style of rhyolitic volcanoes, which can alternate between effusive and explosive eruptions? An international team of researchers from the Institut de Physique du Globe in Paris and the University of Munich has revealed that changes that can occur on a nanoscale can cause major changes in eruptive dynamics. Three key factors combine to modify the structure and viscosity of a magma, leading to changes in eruptive dynamics:

  • an increase in the ratio, RK=K/(Na+K) causes an increase in viscosity of several orders of magnitude (Le Losq et al, 2017 Scientific Report)
  • the agpaititic rheological index, RAI=(Na2O+K2O+MgO+CaO+FeO)/(Al2O3+Fe2O3) for which values below 1 are correlated with high viscosities
  • the presence of iron oxide nanolite will also increase viscosity
Transition from effusive to explosive eruption, as seen by RAI versus RK diagrams

By observing how RAI and RK ratios vary over dozens of volcanic eruptions, both effusive and explosive, the Franco-German team has just shown that the most explosive eruptions are observed for RAI ratios of less than 1 and RK ratios of more than 0.5. This work shows that minute changes in the chemical composition of a rhyolitic magma have a first-order effect on viscosity, unlike water content or the presence of crystals.

Ref : “A compositional tipping point governing mobilization and eruption style of rhyolitic magma” – D. Di Genova, S. Kolzenburg, S. Wiesmaier, E. Dallanave, D. R. Neuville, K. U. Hess & D. B. Dingwell. Nature. doi:10.1038/nature24488

Latest news
Soil erosion in mountain environments accelerated by agro-pastoral activities for 3,800 years
Soil erosion in mountain environments accelerated by agro-pastoral activities for 3,800 years
Over the last 3,800 years, agro-pastoral activities have accelerated alpine soil erosion at a pace 4-10 times faster than their natural formation.
Submarine Volcanism: The Case of Mayotte in the Spotlight in Our Next Twitch Live!
Submarine Volcanism: The Case of Mayotte in the Spotlight in Our Next Twitch Live!
After a first live dedicated to space missions and sample returns, and a second exploring the world of deep-sea microorganisms, the IPGP invites you o...
Release of the IPGP's 2024 Annual Report
Release of the IPGP's 2024 Annual Report
The IPGP annual report, in both French and English, aims to share our enthusiasm for all the research we conduct with as many people as possible. It p...
Director position of the Institut de physique du globe de Paris (IPGP)
Director position of the Institut de physique du globe de Paris (IPGP)
The position of Director of the Institut de Physique du Globe de Paris (IPGP) is vacant as of March 24, 2026.