BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Talks.cam//talks.cam.ac.uk// X-WR-CALNAME:Talks.cam BEGIN:VEVENT SUMMARY:Mantle Melting: the achievements\, promise\, and limits of thermod ynamics - Paul Asimow (CALTECH (California Institute of Technology)) DTSTART:20160215T113000Z DTEND:20160215T123000Z UID:TALK64705@talks.cam.ac.uk CONTACT:INI IT DESCRIPTION:This workshop is an opportunity to consider the state of the a rt in application of thermodynamics to mantle melting. This approach cons tructs and calibrates Gibbs free energy models for relevant phases\, enab ling predictions of equilibrium states including phase proportions\, comp ositions\, and some physical properties. We will consider the achievement s of this approach\, its unfulfilled promise\, and its theoretical limits .

Under achievements\, a body of work has applied the MELTS and p MELTS models to upper mantle magmatism in ocean ridge\, back-arc\, intrap late\, and subduction environments. From 0-3 GPa pressure\, models of mul ticomponent minerals and silicate liquid appear good enough to recover mo st experimental results\, to provide an internally-consistent forward mod el from source peridotite through melting to the observed volume and comp osition of magmas\, to constrain the potential temperature of source regi ons\, to elucidate the role of water\, and more. There have been a few fo rays into integrating this approach with magma dynamics at various scales .

Under promise\, we expect near-future\, improved versions that incorporate carbon species\, extend to substantially higher pressure\, an d account for variable speciation in the melt to achieve higher fidelity. Calibration strategies based on a flexible\, evolving\, community framew ork will liberate the enterprise from the slow progress of models based o n fixed\, internally-consistent datasets. Fully coupled\, large-scale dyn amical simulations incorporating MELTS thermodynamics are practical and c lose to implementation.

Under limits\, we must recall the limita tions of the equilibrium assumptions underlying thermodynamics. At some t ime and length scales these assumptions break down. In a heterogeneous ma ntle containing species with widely divergent mobility\, there must be im portant roles for kinetics. Progress in incorporating kinetics in major e lement models has been nearly nil and must be a major focus of our effort s.

Related Links LOCATION:Seminar Room 1\, Newton Institute END:VEVENT END:VCALENDAR