Kinetics and detectability of the bridgmanite to post-perovskite transformation in the Earth's D″ layer.

摘要: Bridgmanite, the dominant mineral in Earth’s lower mantle, crystallizes perovskite structure and transforms into post-perovskite at conditions relevant for D$${}^{{\prime\prime} }$$ layer. This transformation affects dynamics of lowermost mantle can explain a range seismic observations. The thickness over which two phases coexist, however, extend 100 km, casting doubt on assignment observed boundaries. Here, experiments show that bridgmanite to transition (Mg$${}_{0.86}$$,Fe$${}_{0.14}$$)SiO$${}_{3}$$ is fast geological timescales. kinetics, reflection coefficients $$P$$ $$S$$ waves by more than one order magnitude. Thick layers coexisting hence be detected using reflections. Morever, detection wave period dependence reflections used constrain significant features such as coexistence layer, obtain information temperature grain sizes. layer involves discontinuity often assigned phase post-perovskite, this occurs broad region boundaries remains unclear. authors find due kinetics transformation, thick reflections, unlike previously thought.