Large silicic magma bodies and very large magnitude explosive eruptions

R S J Sparks,J D Blundy,K V Cashman,C J N Wilson,A Rust,M Jackson

doi:10.1007/s00445-021-01510-y

Abstract

Over the last 20 years, new concepts have emerged into understanding the processes that lead to build up to large silicic explosive eruptions based on integration of geophysical, geochemical, petrological, geochronological and dynamical modelling. Silicic melts are generated within magma systems extending throughout the crust by segregation from mushy zones. Segregated melt layers become unstable and can assemble into ephemeral upper crustal magma chambers rapidly prior to eruption. In the next 10 years, we can expect major advances in dynamical models as well as in analytical and geophysical methods, which need to be underpinned in field research.

Highlights

An enduring problem is how to generate very large silicic magma bodies capable of feeding eruptions of tens to thousands of k m3 that produce ignimbrites, tephra fall and large calderas
We define a magma reservoir as a crustal region in which melt is present, mush as a region in which melt is distributed within a crystalline framework and a magma chamber as a melt-rich region commonly containing suspended crystals and bubbles
A reference list organised into specific topics covering the last 20 years of research is supplied in the Electronic Supplementary Material (ESM)

Summary

Introduction

An enduring problem is how to generate very large silicic magma bodies capable of feeding eruptions of tens to thousands of k m3 that produce ignimbrites, tephra fall and large calderas. Such volcanism is highly episodic and invites development of conceptual models that capture this characteristic. A reference list organised into specific topics covering the last 20 years of research is supplied in the Electronic Supplementary Material (ESM). Ideas developed over the last 20 years, building on earlier studies, have highlighted silicic melt generation and storage in the crust in the form of vertically extensive magma mush reservoirs (Fig. 1; ESM-1).

Page 2 of 6

Page 4 of 6

Page 6 of 6