In situ X-ray diffraction of pyrolite to 40 GPa using Kawai-type apparatus with sintered diamond anvils: possibility for the existence of iron-rich metallic particles in the lower mantle

Journal Article · Wed Nov 12 04:00:00 EST 2008 · High Pressure Res.

DOI:https://doi.org/10.1080/08957950802210486· OSTI ID:1006943

Kubo, A; Ito, E; Katsura, T; Fujino, K; Funakoshi, K ^[1]

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1. Hokkaido

We investigated phase relations in pyrolite at -33--40 GPa and -1800--2150 K by in situ X-ray diffraction using Kawai-type apparatus with sintered diamond anvils. The results demonstrated that MgSiO{sub 3}-rich orthorhombic perovskite (mpv), CaSiO{sub 3}-rich cubic perovskite (cpv) and (Mg,Fe)O ferropericlase (fp) are the stable phases in pyrolite bulk composition at the conditions corresponding to the lower mantle. However, chemical analyses of a run product recovered from -34 GPa by an analytical transmission electron microscope showed the coexistence of metallic iron particles with mpv, fp, and SiO{sub 2}-rich amorphous phase. Also, Fe/Mg partitioning coefficient between mpv and fp was found to be 0.66(31), which is consistent with previous results for pyrolite bulk composition at 26--30 GPa and -1900 K. These results indicate that iron-rich metallic particles can exist in the lower mantle as a stable phase to the depth of at least -900 km.

• Research Organization: Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
• Sponsoring Organization: USDOE
• OSTI ID: 1006943
• Journal Information: High Pressure Res., Journal Name: High Pressure Res. Journal Issue: (3) ; 09, 2008 Vol. 28; ISSN 0895-7959; ISSN HPRSEL
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

58 GEOSCIENCES
DEPTH
DIAMONDS
EARTH MANTLE
ELECTRON MICROSCOPES
EQUIPMENT
IRON
PARTICLES
PEROVSKITE
PEROVSKITES
PRESSURE RANGE GIGA PA
TRANSMISSION
X-RAY DIFFRACTION