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Global Variations of Temperature and Water Content in the Mantle
Transition Zone from Higher Mode Surface Waves
Jeannot Trampert (Utrecht University), Ueli Meier (IDSIA Lugano), Andrew Curtis (University of Edinburgh)
We estimated lateral variations of temperature and water content in Earth’s mantle transition zone from models of transition
zone thickness and S-wave velocity (Meier et al., 2009). The latter were obtained by a fully nonlinear inversion of surface wave
overtone phase velocities using neural networks. Globally we observe a broader than previously reported transition zone and
explain this by a broad olivine to wadsleyite transition at around 400 km depth where the minerals co-exist with water induced
melt. Within the transition zone we observe relatively cold subduction zones as well as relatively warm regions beneath continents
and hot spots. We find that the transition zone is wettest away from subduction zones.
References
Meier U., Trampert J., Curtis A., 2009. Global variations of temperature and water content in the mantle transition zone from higher mode
surface waves, Earth Planet. Sci. Lett., 282, 91-101.
Mean water content variation from the unknown global mean in the mantle transition zone (top) together with the corresponding standard deviations (bottom).
II-208 | 2010 IRIS Core Programs Proposal | Volume II | Upper Mantle Structure and Dynamics