Accepted in “Melting Anolmalies: Their Nature and Origin”

• Main Authors: Gsa Post-conference Book, V. C. Manea, M. Manea, V. Kostoglodov, G. Sewell
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Kamchatka subduction zone; thermal models; mantle wedge flow; blobs; tomographic imaging; Kamchatka Peninsula; Pacific; Kamchatka
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.585.5005; http://www.geociencias.unam.mx/geodinamica/upload/articles/article378.pdf

A finite element method is applied to model the thermal structure of the subducted Pacific plate and overlying mantle wedge beneath the southern part of the Kamchatka peninsula. A numerical scheme solves a system of 2D Navier-Stokes equations and a 2D steady state heat transfer equation. A model with isoviscous mantle exposed very low temperatures ( ~ 800ºC) in the mantle wedge, which cannot account for magma generation below the volcanic belt. Instead, a model with strong temperature-dependent viscosity shows a rise in the temperature in the wedge. At a temperature of more than 1300ºC beneath the active volcanic chain, melting of wedge peridotite becomes possible. Although the subducting slab below the Kamchatka peninsula is rather old ( ~ 70 Myr), some frictional heating (µ = 0.034) along the interface between the subducting oceanic slab and the overlying Kamchatka peninsula lithosphere would be enough to melt subducted sediments. Dehydration (> 5 wt % H2O release) occurs in the subducting- 1-slab because of metamorphic changes. As a consequence, hydration of the mantle