Meeting room "Glova", 4 floor, Integrated Research Building
Abstract
Subductions of granitic materials by tectonic erosion, sediment-trapped subduction, and direct subduction of immature oceanic arcs are indicated by recent geological and geophysical surveys. Geological studies have estimated the volume of subducted tonalite-trondhjemite-granodiorite (TTG) materials is 7 times larger than the volume of the present continental crust. Such a huge volume of subducted granitic materials have a large influence on the chemical evolution of the Earth, and therefore their destination in the mantle has long been debated.
A recent study indicates the TTG materials are gravitationally stable in a depth between 300km and 750km. [Kawai et al., in press]. Capacity of this layer is large enough to reserve subducted continental crust, which might control the mantle convection to some extent. However, it is unclear how and how much they subduct dynamically through the mantle under the lithosphere.
In this study, we conducted a numerical and an analytical approach on a flow that mimics a subduction channel of granitic materials on a slab. Sustainable thickness of the subduction channel and supply rate of the granitic materials to 300km depth are estimated.
For inquiry：Taku Tsuchiya TEL:（089）927-8198
E-mail takut@sci.ehime-u.ac.jp
