ABSTRACT

"This award is funded under the American Recovery and Reinvestment Act of 2009
(Public Law 111-5)."
Collaborative Research: Synthesis and Integration of Magmagenetic Controls for
Subduction Factory focus sites
Intellectual Merit: The MARGINS program ends in 2009, and the organization,
synthesis, and integration of the most important results is a high priority for each of the
four experiments. This proposal outlines a 3-year collaborative effort (between 5 US and
2 Japanese scientists) to do this for key aspects of the Subduction Factory experiment.
In co-operation with the LDEO database group, geochemical and isotopic data for fresh,
young igneous rocks from the Izu-Bonin-Mariana and Central America Subduction
Factory focus sites will be compiled and filtered to generate a Subduction Factory
Geochemical Reference Library of high-quality data for each arc system. Forward
models to explain the most important differences between the chemical and isotopic
compositions of lavas erupted from the volcanic front and rear-arc volcanoes at the two
focus sites will be generated and tested against compositions in this Library. Models will
be site-specific, using all available geophysical observations to generate thermal
structure and melt distribution models appropriate for each focus site. Best estimates for
the compositions of subducted sediments and oceanic crust at each focus site will be
used as input to thermodynamic models simulating equilibrium metamorphic reactions,
dehydration, and melting of subducted sediments and oceanic crust (slab) within the
subduction zone. Interaction of these slab fluids and melts with overlying mantle
peridotite to yield primitive basalt will be modeled using the "Arc Basalt Simulator"
(ABS), an Excel macro that explicitly separates key forcing functions and is designed to
be flexible and accessible. Several improvements to ABS will also be accomplished
during this project.
Broader Impacts: This project is in response to calls for synthesis and integration efforts
by the 2004 MARGINS Review Committee. Dissemination of results and training Earth
scientists to use ABS will be accomplished at two free workshops at national scientific
meetings. A lesson plan that uses ABS and the Subduction Factory Geochemical
Library to explore the most important controls on subduction-zone magma genesis will
be developed; this will be aimed at upper division Geoscience majors and beginning
graduate students. Broader dissemination of the most important results to the general
public will be accomplished via development of a Wikipedia entry for "Subduction
Factory".
NATIONAL SCIENCE FOUNDATION
Proposal Abstract
Proposal:0840794 PI Name:Stern, Robert
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