GyPSM: Geodynamic and Petrological Synthesis Model Example: The northern Izu-Bonin segment of the IBM arc system subduction velocity: 5 cm/yr overriding plate thickness: 20 km slab thermal age: 135 Ma dip angle: 45 degrees mantle potential temperature: 1400 deg. C olivine solubility measurements from Mosenfelder et al. (2005) mantle initial composition from Workman & Hart (2005), with 160 ppm H 2 O GyPSM is a fully-coupled, self-consistent integration of the thermodynamic model pHMELTS with the 2-D thermal and variable viscosity flow model ConMan ConMan modifications: advection of entropy and allowance for compositionally-dependent viscosity GyPSM is run on CITerra, a High-Performance Computing Cluster at Caltech There are at present three tectonic environments that are examined by GyPSM: subduction zone, mid-ocean ridge, and back- arc basin GyPSM-R GyPSM-B Laura Baker and Paula Smith, Michael Gurnis, Paul Asimow, Chad Hall California Institute of Technology GyPSM-S

explicit accounting for energy terms such as latent heat of melting, dehydration, and hydration a. b.

viscosity is variable with respect to temperature and water in nominally-anhydrous minerals a low-viscosity channel forms adjacent to the slab b.a. c. d. slab hydration allows fluid ingress, forming a hydrated envelope compositional buoyancy is accounted for predictions can be made as to the fate of the hydrated material

water-fluxed melting data to compare with real regional examples bulk sound speed, bulk modulus, gravity,dynamic topography,major and trace element composition of melt and matrix, density Future directions: accounting for trace elements in fluid reactive interactions between fluids/melts/matrix realistic melt migration model introduction of sediment Milsom, et al. (1996)