MARGINS: Collaborative Research: Synthesis and Integration of Magmagenetic Controls for Subduction Factory Focus Sites

点击翻译按钮获取中文摘要

"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 forSubduction Factory focus sitesIntellectual 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 thefour experiments. This proposal outlines a 3-year collaborative effort (between 5 US and2 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 SubductionFactory focus sites will be compiled and filtered to generate a Subduction FactoryGeochemical Reference Library of high-quality data for each arc system. Forwardmodels to explain the most important differences between the chemical and isotopiccompositions of lavas erupted from the volcanic front and rear-arc volcanoes at the twofocus sites will be generated and tested against compositions in this Library. Models willbe site-specific, using all available geophysical observations to generate thermalstructure and melt distribution models appropriate for each focus site. Best estimates forthe compositions of subducted sediments and oceanic crust at each focus site will beused as input to thermodynamic models simulating equilibrium metamorphic reactions,dehydration, and melting of subducted sediments and oceanic crust (slab) within thesubduction zone. Interaction of these slab fluids and melts with overlying mantleperidotite 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 tobe flexible and accessible. Several improvements to ABS will also be accomplishedduring this project.Broader Impacts: This project is in response to calls for synthesis and integration effortsby the 2004 MARGINS Review Committee. Dissemination of results and training Earthscientists to use ABS will be accomplished at two free workshops at national scientificmeetings. A lesson plan that uses ABS and the Subduction Factory GeochemicalLibrary to explore the most important controls on subduction-zone magma genesis willbe developed; this will be aimed at upper division Geoscience majors and beginninggraduate students. Broader dissemination of the most important results to the generalpublic will be accomplished via development of a Wikipedia entry for "SubductionFactory".NATIONAL SCIENCE FOUNDATIONProposal AbstractProposal:0840794 PI Name:Stern, RobertPrinted