Electronic transitions in perovskite: possible nonconvecting layers in the lower mantle.
Science
; 305(5682): 383-6, 2004 Jul 16.
Article
em En
| MEDLINE
| ID: mdl-15256667
ABSTRACT
We measured the spin state of iron in magnesium silicate perovskite (Mg(0.9),Fe(0.1))SiO(3) at high pressure and found two electronic transitions occurring at 70 gigapascals and at 120 gigapascals, corresponding to partial and full electron pairing in iron, respectively. The proportion of iron in the low spin state thus grows with depth, increasing the transparency of the mantle in the infrared region, with a maximum at pressures consistent with the D" layer above the core-mantle boundary. The resulting increase in radiative thermal conductivity suggests the existence of nonconvecting layers in the lowermost mantle.
Buscar no Google
Base de dados:
MEDLINE
Idioma:
En
Ano de publicação:
2004
Tipo de documento:
Article