GMPV
Geochemistry, Mineralogy, Petrology & Volcanology

Volcanoes

Ask us (almost) anything: how is tuff formed?

Ask us (almost) anything: how is tuff formed?

Tarun Goswami, an archaeologist from India, asks: How is a tuff formed? and more specifically… Why do some deposits have more ash than others? We are paraphrasing – the questions are specifically about the tuffs formed in the Toba supereruption. So… you asked, we answer! First of all, modern definitions generally describe a tuff as a volcaniclastic rock composed of solid volcanic ...[Read More]

Can limestone digestion by volcanoes contribute to higher atmospheric carbon dioxide levels?

Can limestone digestion by volcanoes contribute to higher atmospheric carbon dioxide levels?

By Frances Deegan and Ralf Halama Carbon – the element on everyone’s lips. Carbon is unquestionably one of the most important elements on Earth – terrestrial life is carbon-based and so are many of our energy sources. From the perspective of a human time-scale, biological and anthropogenic (caused by human activity) carbon fluxes are very important (e.g. through industrial activity and burni ...[Read More]

How do crystal aggregates form in magma chambers?

How do crystal aggregates form in magma chambers?

By Penny Wieser (PhD student at the University of Cambridge) Clues into the inner workings of volcanoes can be gleamed from material which is erupted at the surface, or that which solidified at depth in the crust. Just before eruption, three main phases are present: a gas phase (containing water, carbon dioxide, sulphur, chlorine etc), a liquid melt phase (the magma), and a solid phase (consisting ...[Read More]

Fire, Fog, Frost, Famine – French Revolution? The Lakagígar eruption in Iceland, 1783-1784 [Part 2]

Fire, Fog, Frost, Famine – French Revolution? The Lakagígar eruption in Iceland, 1783-1784 [Part 2]

PART II: Were the Haze Hardships caused by Men? Famine Before the Lakagígar eruption, the population of Iceland was 48810 people; four years later, it was down to 38518. Disregarding about 1500 deaths which were caused by a smallpox epidemic, the eruption may still have killed about 1/6 of the population [5]. These deaths were not directly caused by the lava or by toxic gases. The main cause was h ...[Read More]