Correlation between the shear-speed structure and thickness of the mantle transition zone

Abstract

The 410 and 660 kmseismic discontinuities that bound the mantle transition zone (TZ) are attributed to phase transformations in olivine structure. This implies that variations in TZ thickness (HTZ) should correlate with those in TZ temperature. Pertinent seismic evidence has so far been ambiguous, however. We show that the transformations in olivine structure give rise to the 410 and 660 km discontinuities globally.