HR: 15:25h
AN: V33C-08    [Abstracts]
TI: Examining Models of Melt Transport at Subduction Zones
AU: * Hall, P S
EM: hall@eps.harvard.edu
AF: Harvard University, Department of Earth and Planetary Sciences 20 Oxford Street, Cambridge, MA 02138 United States
AU: Kincaid, C
EM: kincaid@gso.uri.edu
AF: University of Rhode Island Graduate School of Oceanography, South Ferry Rd, Narragansett, RI 02882 United States
AU: Langmuir, C H
EM: langmuir@eps.harvard.edu
AF: Harvard University, Department of Earth and Planetary Sciences 20 Oxford Street, Cambridge, MA 02138 United States
AB: Several models have been proposed to describe melt transport at subduction zones, including diapiric upwellings (e.g., Marsh, 1979) and networked flow (Hall and Kincaid, 2001), flow via fracture propagation (e.g., Furukawa, 1993), and distributed porous flow (e.g., Spiegelman and McKenzie, 1987). The flow morphologies associated with each of these models have characteristic length and time scales which bear on the thermal and chemical evolution of the melt during its ascent, in particular controlling the degree to which the melt will equilibrate, both thermally and chemically, with the surrounding mantle. We use a combination of laboratory tank experiments and numerical geodynamic models of subduction to explore the thermochemical evolution of melts at subduction zones for the various melt transport models. Predicted melt characteristics are compared to geophysical and geochemical observations of arc volcanism, including the frequency and volume of eruptions and the trace element chemistry of arc rocks, to constrain the viability of the melt transport models. Of particular interest, the coexistence of large stratovolcanoes and small monogenetic volcanoes in close geographic proximity within the Central Mexican Volcanic Belt (CMVB) provides strong constraints on melt transport mechanisms.
DE: 1009 Geochemical modeling (3610, 8410)
DE: 1037 Magma genesis and partial melting (3619)
DE: 8185 Volcanic arcs
DE: 8413 Subduction zone processes (1031, 3060, 3613, 8170)
DE: 8434 Magma migration and fragmentation
SC: Volcanology, Geochemistry, Petrology [V]
MN: Fall Meeting 2005