Iron-rich silicates in the Earth's D″ layer
AUTOR(ES)
Mao, Wendy L.
FONTE
National Academy of Sciences
RESUMO
High-pressure experiments and theoretical calculations demonstrate that an iron-rich ferromagnesian silicate phase can be synthesized at the pressure–temperature conditions near the core–mantle boundary. The iron-rich phase is up to 20% denser than any known silicate at the core–mantle boundary. The high mean atomic number of the silicate greatly reduces the seismic velocity and provides an explanation to the low-velocity and ultra-low-velocity zones. Formation of this previously undescribed phase from reaction between the silicate mantle and the iron core may be responsible for the unusual geophysical and geochemical signatures observed at the base of the lower mantle.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1174998Documentos Relacionados
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