Kinetics of Melt-Rock Reaction in the Mantle

Brown University, Providence RI

Investigators

Abstract

Melt-rock reaction is a fundamental and ubiquitous process that is associated with melt migration in the Earth mantle. It is responsible or partially responsible for the development of high porosity melt channels under the mid-ocean ridge, the development of dunite-harzburgite-lherzolite sequences in ophiolites, the diversity of magmas observed in island arc, and possibly the growth of continental crust through geological times. In this project, the PI will use kinetic and thermodynamic principles, mass transfer models, and laboratory experiments to better understand the kinetics of melt-rock reaction associated with melt migration in the mantle. The project will focus on three closely related themes: (1) experimental studies of the kinetics of melt-rock reaction in the mantle, (2) experimental and numerical studies of grain growth and grain size distribution during melt-rock reaction in the mantle, and (3) applications to geological field observations through computer simulations of melt-rock reaction in porous rocks and microanalysis of samples from Trinity and Josephine ophiolites. The laboratory part of the project involves reactive dissolution experiments and will be used to constrain the rate and mechanism of melt-rock reaction. Grain growth study will be used to constrain the permeability of part of the mantle that undergoes reactive dissolution. Reactive flow modeling using laboratory calibrated reaction rates and grain size data will be used to evaluate the petrologic and geochemical consequences of melt-rock reaction in the mantle and to explore the significance of concentration gradients across the dunite-harzburgite-lherzolite sequences in ophiolites. Results from this study will also provide valuable information for a diverse group of geologists, promoting cross-discipline integration in Earth Sciences. The proposed project will provide hands on experience for undergraduates, research opportunities for senior thesis, experimental and computational experience for graduate students.