Development of an experimental technique for characterizing the effects of magma flow in porous media

University Of Utah, Salt Lake City UT

Investigators

Abstract

The vast majority of magmas that erupt from volcanoes is originally produced in the mantle (material beneath the crust) and needs to travel up to hundreds of miles before reaching the surface and becoming a volcanic rock that can be collected. Volcanic rocks are then used by geochemists and petrologists to better understand geologic processes happening in the Earth's interior. During its journey, magmas will inevitably undergo many modifications through interaction with the solid mantle through which they travel, blurring the link between the volcanic rocks and the source at depth. The primary objective of this research is to develop a new experimental technique to simulate the migration of magmas through the mantle and better quantify the impact of thier migration on the chemical and physical characteristics of magmas. The experimental products will be compared to the natural volcanic rocks and will be used to understand the relation between melting processes at depths and volcanism at the surface of the Earth. Experiments will be performed in a one-atmosphere furnace. This pilot study will investigate how a silicate melt flows through a porous solid matrix in open-system, and to systematically vary the physical (melt flux, permeability, porosity) and chemical (melt composition, mineral assemblage of the porous rock matrix) properties of the system. Experimental products will be characterized by electron microprobe, LA-ICP-MS, SEM and microtomography. This setup will provide a novel approach to study both the dynamics of melt transport and its impact on the composition of the melt and the host material. The main objectives of this project are (1) the quantification of the effect of magma flow and melt-solid interaction on the range of major and trace element concentrations in oceanic basalts, (2) the determination of the required conditions for the preservation of the source signal in primary magmas, and (3) the characterization of the effect of magma flow on mantle lithologies. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.