La estabilidad de la magnesita y su forma de alta presión en el manto más bajo
Maiko Isshiki1, Tetsuo Irifune, Kei Hirose
1Geodynamics Research Center, Ehime University, Matsuyama, Ehime 790-8577, Japan. isshiki@sci.ehime-u.ac.jp
Nature
|January 1, 2004
Resumen
La magnesita, un carbonato clave, se transforma en una nueva forma bajo condiciones extremas en las profundidades de la Tierra. Esto sugiere que puede almacenar carbono significativo en el manto inferior.
Área de la Ciencia:
- La geoquímica es la geoquímica.
- Física mineral Física de los minerales
- Ciencias de la Alta Presión Ciencias de la Alta Presión
Sus antecedentes:
- Los carbonatos en los sedimentos marinos son cruciales para el ciclo del carbono de la Tierra.
- La subducción recicla el carbono en las profundidades de la Tierra.
- Existen datos limitados sobre la estabilidad de los carbonatos a presiones inferiores del manto.
Objetivo del estudio:
- Investigar la estabilidad de la magnesita en condiciones de límite entre el núcleo y el manto.
- Modela el ciclo del carbono en las profundidades de la Tierra.
Principales métodos:
- Difracción de rayos X in situ. difracción de rayos X in situ.
- Experimentos de alta presión y alta temperatura.
Principales resultados:
- La magnesita se transforma por encima de 115 GPa y entre 2100 y 2200 K.
- La transformación ocurre sin disociación.
- Esta fase de alta presión es estable en las condiciones inferiores del manto.
Conclusiones:
- La magnesita y su polimorfo de alta presión son probablemente los principales anfitriones de carbono en el manto inferior.
- Este hallazgo impacta los modelos del presupuesto de carbono de la Tierra.
- Sugiere un significativo secuestro de carbono en las profundidades de la Tierra.
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