Collaborative Research: Advanced modeling for understanding fluid and magma migration in subduction zones

Lead PI: Prof. Peter B. Kelemen , Marc Spiegelman , , Dr. Cian R. Wilson

Unit Affiliation: Seismology, Geology and Tectonophysics, Lamont-Doherty Earth Observatory (LDEO)

March 2014 - February 2018
Project Type: Research

DESCRIPTION: The interactions of fluids and solids control some of the most critical geochemical and geodynamic processes in subduction zones. These include flux melting of the mantle and geochemical transport by fluids and magma, possible rheological weakening of the mantle wedge, and control of seismicity and fault mechanics. Quantitative models for the solid mantle flow have been developed but there has been relatively little work to numerically simulate the production, transport, and coupled interactions of fluids and melts with the solid. This requires a more general computational framework that can deal with a wide range of uncertainty both in the physical model and input parameter space. This project continues the development of TerraFERMA (the Transparent Finite Element Rapid Model Assembler), which will be used to: quantify potential fluid and solid flow paths at subduction zones; develop a better understanding of reactive, open system flux melting; and investigate the effects of fluids on solid-state rheology. Model predictions will be tested against a suite of observations from the relatively robust location of arc volcanism to the compositions of lava samples produced at these sites. Broader impacts of this project include support of an early career scientist working at the interface between computational and Earth science and the development of a new computer code for integrating geochemical and geochemical dynamics in subduction zones. The resulting computer code will be incorporated into holdings of Computational Infrastructure for Geosciences, which provides open access to software for scientific purposes. Increased understanding of mantle deformation, magmatism, and thermal structure of the Earth at subduction zones could lead to improved knowledge of where brittle behavior (earthquakes) is more or less likely along the megathrust fault that marks the boundary between the downgoing plate and the surrounding mantle.