Transport of magma and gas from the mantle to the atmosphere by volcanic eruptions

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This proposal comprises six distinct projects which are linked intellectually and also in time and space. The overarching objective of this research program is to understand explosive volcanism as it is expressed in magmas and gases which transit from the mantle through the crust to the surface and atmosphere. As such, I take a general “bottom-to-top” approach within this proposal, illustrating how specific key problems can be addressed and answered within the individual research projects. Part 1 of the proposal addresses the transport, storage, and evolution of magmas from mantle depths through the crust to the surface. Particular attention is paid to distinct batches of magmas, how and where they are stored in crustal reservoirs, and the means and timing by which the different batches interact prior to and during volcanic eruptions. I will examine both small systems (Hekla in Iceland and Cerro Negro in Nicaragua) as well as larger caldera systems. Complementary to the first part of the proposal, Part 2 examines the isotopic evolution of volcanic gas from the mantle to the surface. These will be the first such isotopic measurements of their kind. The first component of the research will examine the carbon isotopic character of volcanic gas in plumes of actively degassing volcanoes. The second component will study carbon and hydrogen isotopes in melt inclusions to gain insight into isotopic gas signature of gas at deeper levels beneath a volcano. Part 3 will study the atmospheric and environmental effects and impacts of volcanic gas emissions using two new approaches. First, the bromine, iodine, and chlorine budget of caldera supervolcanoes will be calculated, to estimate the amount of these volatile species released during large explosive eruptions which may serve to deplete stratospheric ozone. Second, the sulfur isotopic signature of tree rings impacted by volcanic degassing will be used to identify periods of activity and quiescence at volcanoes. Such isotopic tree ring records offer a new means of identifying and dating activity at volcanoes which reactivate periodically. A total of 3 PhD students, 3 MSc students, 10 BSc students, and 1 postdoctoral student will be trained during the course of this 5-year research program. My mentoring philosophy is to ensure that the more junior students are mentored and trained by myself and the more senior students, in particular the postdoc and advanced PhD students. This research will contribute to my long-term goals which are a broad understanding of magma and volatile behaviour prior to and during eruptions. The knowledge gained will improve our ability to forecast volcanic eruptions.