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Effects of a perovskite‐post perovskite phase change near core‐mantle boundary in compressible mantle convection
Author(s) -
Nakagawa Takashi,
Tackley Paul J.
Publication year - 2004
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2004gl020648
Subject(s) - geology , post perovskite , mantle convection , mantle (geology) , geophysics , transition zone , convection , downwelling , core–mantle boundary , stratification (seeds) , petrology , silicate perovskite , phase transition , thermodynamics , upwelling , subduction , physics , tectonics , seismology , seed dormancy , oceanography , germination , botany , dormancy , biology
Numerical simulations of compressible, isochemical mantle convection are used to investigate the effect of the perovskite to post‐perovskite phase transition at around 2700 km depth, which has recently been discovered by high‐pressure experiments and ab initio calculations, on the convective planform, temperature, and heat transport characteristics of the mantle. The usual phase transitions at 410 km (olivine‐spinel) and 660 km (spinel‐perovskite) are also included. The exothermic post‐perovskite phase change at 2700 km depth destabilizes the lower thermal boundary layer, increasing the heat flow, increasing interior mantle temperature, and increasing the number and time‐dependence of upwelling plumes. The resulting weak, highly time‐dependent upwellings also have a smaller horizontal spacing than the plumes that occur in the absence of the phase transition. While the influence of post‐perovskite phase change may be smaller than that of some other complexities, such as compositional stratification, it appears to have an important enough effect that it should not be ignored in dynamical studies of mantle convection.