The effect of Fe on the crystal structure of wadsleyite β-(Mg1 −xFex)2SiO4, 0.00≤x≤0.40

✍ Scribed by Larry W. Finger; Robert M. Hazen; Jinmin Zhang; Jaidong Ko; Alexandra Navrotsky

• Publisher: Springer-Verlag
• Year: 1993
• Tongue: English
• Weight: 726 KB
• Volume: 19
• Category: Article
• ISSN: 0342-1791
• DOI: 10.1007/bf00202973

✦ Synopsis

Single crystals of five wadsleyite compositions, /?-(Mg,Fe)2SiO4 with Fe/(Fe+Mg)=0.00, 0.08, 0.16, 0.25 and 0.40, have been synthesized at high temperature and pressure in a uniaxial, split-sphere apparatus. Crystal structures of these samples, determined by x-ray diffraction techniques, reveal that iron is significantly ordered: Fe is depleted in the M2 octahedron, while it is enriched in M1 and M3. The most iron-rich synthetic sample, which falls well outside previous estimates of wadsleyite stability, raises questions regarding published Mg2SiO4-Fe2SiO4 phase diagrams at transition zone conditions.