| Title | Spin transition of ferric iron in the calcium-ferrite type aluminous phase |
| Authors | Wu, Ye Qin, Fei Wu, Xiang Huang, Haijun McCammon, Catherine A. Yoshino, Takashi Zhai, Shuangmeng Xiao, Yuming Prakapenka, Vitali B. |
| Affiliation | Wuhan Univ Technol, Sch Sci, Wuhan, Hubei, Peoples R China. Peking Univ, MOE, Key Lab Orogen Belts & Crustal Evolut, Beijing, Peoples R China. Peking Univ, Sch Earth & Space Sci, Beijing, Peoples R China. China Univ Geosci, State Key Lab Geol Proc & Mineral Resources, Wuhan, Hubei, Peoples R China. Univ Bayreuth, Bayer Geoinst, Bayreuth, Germany. Okayama Univ, Inst Planetary Mat, Misasa, Tottori, Japan. Chinese Acad Sci, Inst Geochem, Key Lab High Temp & High Pressure Study Earths In, Guiyang, Guizhou, Peoples R China. Carnegie Inst Sci, Geophys Lab, HPCAT, Argonne, IL USA. Univ Chicago, GeoSoilEnviroCARS, Chicago, IL 60637 USA. |
| Keywords | EQUATION-OF-STATE SUBDUCTED BASALTIC CRUST EARTHS LOWER MANTLE MID-LOWER MANTLE HIGH-PRESSURE OCEANIC-CRUST CHEMICAL HETEROGENEITY SEISMIC SCATTERERS HIGH-TEMPERATURE STISHOVITE |
| Issue Date | 2017 |
| Publisher | JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH |
| Citation | JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH.2017,122(8),5935-5944. |
| Abstract | We investigated Fe-free and Fe-bearing CF phases using nuclear forward scattering and X-ray diffraction coupled with diamond anvil cells up to 80GPa at room temperature. Octahedral Fe3+ ions in the Fe-bearing CF phase undergo a high-spin to low-spin transition at 25-35GPa, accompanied by a volume reduction of similar to 2.0% and a softening of bulk sound velocity up to 17.6%. Based on the results of this study and our previous studies, both the NAL and CF phases, which account for 10-30 vol % of subducted MORB in the lower mantle, are predicted to undergo a spin transition of octahedral Fe3+ at lower mantle pressures. Spin transitions in these two aluminous phases result in an increase of density of 0.24% and a pronounced softening of bulk sound velocity up to 2.3% for subducted MORB at 25-60GPa and 300K. The anomalous elasticity region expands and moves to 30-75GPa at 1200K and the maximum of the V reduction decreases to similar to 1.8%. This anomalous elastic behavior of Fe-bearing aluminous phases across spin transition zones may be relevant in understanding the observed seismic signatures in the lower mantle. |
| URI | http://hdl.handle.net/20.500.11897/471642 |
| ISSN | 2169-9313 |
| DOI | 10.1002/2017JB014095 |
| Indexed | SCI(E) |
| Appears in Collections: | 造山带与地壳演化教育部重点实验室 地球与空间科学学院 |
