Seismological observations, mineral physics constraints on mineral properties including the effects of water, geodynamical modelling and geochemical measurements are all important tools in understanding the structure, dynamics and evolution of the mantle. The mantle transition zone (MTZ), from 400 to 1000 km depth, is a particularly important region for understanding the mode of convection within the Earth’s mantle as well as its chemical composition.

In this session we welcome contributions that address the structure, dynamics and evolution the whole mantle or mantle transition zone, on temporal scales ranging from the present day to billions of years, and on spatial scales from kilometers to global. Contributions may use one or more approaches including seismology, geodynamical modelling, geochemistry, mineral physics and petrology; multidisciplinary studies are particularly encouraged.
While we welcome any contributions under this general theme, of particular interest at the present time are:
(i) Determining the fine structure of the MTZ using relatively short-wavelength seismic waveforms as well as those with more conventional approaches either in forward modeling or inversion, but in particular, innovative results that take advantage of recent seismic array data.
(ii) The structure and evolution of chemical heterogeneities in the Earth's mantle, from large-scale to short-scale, and the explanation of geochemical observations in terms of consistent physical-chemical theories.
(iii) Understanding anisotropy in the upper mantle and deep mantle.
(iv) Joint mineralogical-seismological-dynamical approaches.
(v) The influence of recent discoveries such as the iron spin transition and post-perovskite transition, as well as improved knowledge of transition zone mineral properties.
(vi) The long-term thermal and chemical evolution of the mantle - plate tectonics system, including possible transitions in behaviour and possible reconciliations of heat flow and geochemical paradoxes.
(vii) The origin of plate tectonics and the interaction between continents and the mantle.