“Why are Arc Magmas so Rich in Silica?”

by | Jul 24, 2023 | Earthquakes & Volcanoes, Natural Hazards, Uncategorized

with Suzanne Straub Oct 24, 2020
Supported by NSF EAR 19-21624

Susanne’s slide showIntroductory slide show

Magmas that are rich in silica- and volatiles (H2O, CO2, S) produce the most explosive eruptions on Earth. Most of these magmas erupt in volcanic arcs, which are chains of volcanoes that are strung along continental and ocean plate boundaries, such as for example the ‘Ring of Fire’ around the Pacific ocean. While there is wide agreement that the volatiles originate from the root regions of arc volcanoes deep in the Earth’s mantle, the origin of the silica is far less clear. Is the high silica content also a feature of the mantle source, or is it acquired only after melt formation during ascent in the crustal basement, which all arc magmas must pass? In the project we investigate this question through the composition of tiny olivine crystals that grow abundantly in the arc magmas from the Trans-Mexican Volcanic Belt.


Problem set for this Session