5:15 PM - 5:30 PM
[S16-1-04] Deep mantle heterogeneity and its relationship with deep mantle heat flow inferred from 3D spherical mantle convection with plate reconstruction system in 200 Myrs
invited
In recent progress on geodynamics modeling, a coupled plate-mantle-core system can be addressed from geodynamo model incorporating the heat flow across the core-mantle boundary (CMB) computed from numerical mantle convection simulations with plate reconstruction in 200 Myrs [Olson et al., 2013]. However, computing the heat flow across the CMB, it is strongly dependent on material properties of lowermost mantle minerals such as post-perovskite phase as well as thermo-chemical piles [Nakagawa and Tackley, 2008; Dekura et al., 2013; Ammann et al., 2014]. In previous study [Nakagawa and Tackley, 2008], simple tests on a relationship between deep mantle heat flow and thermo-chemical heterogeneity have been pointed out that such a relationship is not very simple as a heterogeneous boundary condition incorporating with geodynamo simulations, which is a linear treatment [e.g. Olson et al., 2013]. Here new scaling relationship between deep mantle heat flow and thermo-chemical heterogeneity derived from numerical mantle convection simulations with plate reconstruction data. On the thermo-chemical heterogeneity, it forms by the segregation of oceanic crust in the deep mantle plus the post-perovskite phase transition. Preliminary result suggests that no simple scaling relationship can be found between deep mantle heat flow and thermo-chemical heterogeneity, which is consistent with simple tests [Nakagawa and Tackley, 2008]. This also suggests that a linear scaling relationship between heat flow and seismic anomalies seems to be an over-simplified heterogeneous boundary condition for geodynamo modeling. This can also imply for a formation mechanism on Large-Low-Shear-Velocity-Provinces (LLSVPs), which could be either thermal plus post-perovskite phase or thermo-chemical piles plus post-perovskite phase.