Experimental evidence for a silica-enriched Earth’s lower mantle
Acoustic wave velocity measurements of iron-bearing Brigmanite for pressure of the lower mantle show that it is enriched in Fe2+ and in silica.
Acoustic wave velocity measurements of iron-bearing Brigmanite, the most abundant mineral of the lower mantle, were obtained for pressures covering the entire lower mantle using the diamond anvil cell method coupled with Brillouin spectroscopy.
Our data fit the Preliminary Reference Earth Model (PREM) model for the lower mantle suggesting that it is enriched in Fe2+ and in silica with an Mg/Si of 1.14 relative to the upper mantle.
- The findings were published in external page PNAS.
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