Thermodynamically consistent decompression: implications for lower mantle composition

M. S.T. Bukowinski, G. H. Wolf

Research output: Contribution to journalArticle

32 Scopus citations

Abstract

Estimates of the composition of the lower mantle are commonly obtained by a process of adiabatic decompression, in which zero-pressure mantle parameters are determined with a least squares fit of an equation of state to mantle densities. It is shown that this procedure may lead to biased estimates of the zero-pressure density and compressibility of the mantle. The bias can be eliminated or minimized by subjecting the equations of state that are compatible with the lower mantle as well as the thermal properties of selected mineral models. This method was used to evaluate assemblages containing (Mg, Fe)SiO3 perovskite and (Mg, Fe)O, with Fe/(Fe + Mg) ratios as high as 0.2. Results suggest that unless the mantle is homogeneous in its major oxide components, the lower mantle is likely to be enriched in Fe by at least several percent. -from Authors

Original languageEnglish (US)
Pages (from-to)12,583-12,593
JournalJournal of geophysical research
Volume95
Issue numberB8
StatePublished - Jan 1 1990
Externally publishedYes

    Fingerprint

ASJC Scopus subject areas

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

Cite this