Abstract
Diffusion of Si and O in single crystal stishovite was examined at pressures of 14.0–21.5 GPa and temperatures of 1673–2073 K. Self-diffusion coefficients of Si (DSi) and O (DO) were determined as DSi [m2/s]=2.4×10−12exp{−(237[kJ/mol]+6.0[cm3/mol]×P)/RT} and DO [m2/s]=7.2×10−11exp{−(263[kJ/mol]+4.8[cm3/mol]×P)/RT}, respectively, where P is pressure (in GPa), T is absolute temperature (in K) and R is the ideal gas constant. It was revealed that diffusion of Si is approximately one order of magnitude slower than that of O and, thus, Si is the rate-controlling element for plastic deformation of stishovite. Si diffusion in stishovite is assessed to be at least three orders of magnitude slower than that in bridgmanite under mid-mantle conditions. Therefore, it is anticipated that highly viscous SiO2-rich components subducted into the lower mantle persist as the seismic reflectors for long term without mixing up with the bridgmanite-dominated surrounding mantle.
| Original language | English |
|---|---|
| Pages (from-to) | 332-339 |
| Number of pages | 8 |
| Journal | Earth and Planetary Science Letters |
| Volume | 459 |
| DOIs | |
| Publication status | Published - Feb 1 2017 |
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Keywords
- diffusion
- seismic reflectors
- stishovite
- viscosity
ASJC Scopus subject areas
- Geophysics
- Geochemistry and Petrology
- Earth and Planetary Sciences (miscellaneous)
- Space and Planetary Science
Cite this
Silicon and oxygen self-diffusion in stishovite : Implications for stability of SiO2-rich seismic reflectors in the mid-mantle. / Xu, Fang; Yamazaki, Daisuke; Sakamoto, Naoya; Sun, Wei; Fei, Hongzhan; Yurimoto, Hisayoshi.
In: Earth and Planetary Science Letters, Vol. 459, 01.02.2017, p. 332-339.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Silicon and oxygen self-diffusion in stishovite
T2 - Implications for stability of SiO2-rich seismic reflectors in the mid-mantle
AU - Xu, Fang
AU - Yamazaki, Daisuke
AU - Sakamoto, Naoya
AU - Sun, Wei
AU - Fei, Hongzhan
AU - Yurimoto, Hisayoshi
PY - 2017/2/1
Y1 - 2017/2/1
N2 - Diffusion of Si and O in single crystal stishovite was examined at pressures of 14.0–21.5 GPa and temperatures of 1673–2073 K. Self-diffusion coefficients of Si (DSi) and O (DO) were determined as DSi [m2/s]=2.4×10−12exp{−(237[kJ/mol]+6.0[cm3/mol]×P)/RT} and DO [m2/s]=7.2×10−11exp{−(263[kJ/mol]+4.8[cm3/mol]×P)/RT}, respectively, where P is pressure (in GPa), T is absolute temperature (in K) and R is the ideal gas constant. It was revealed that diffusion of Si is approximately one order of magnitude slower than that of O and, thus, Si is the rate-controlling element for plastic deformation of stishovite. Si diffusion in stishovite is assessed to be at least three orders of magnitude slower than that in bridgmanite under mid-mantle conditions. Therefore, it is anticipated that highly viscous SiO2-rich components subducted into the lower mantle persist as the seismic reflectors for long term without mixing up with the bridgmanite-dominated surrounding mantle.
AB - Diffusion of Si and O in single crystal stishovite was examined at pressures of 14.0–21.5 GPa and temperatures of 1673–2073 K. Self-diffusion coefficients of Si (DSi) and O (DO) were determined as DSi [m2/s]=2.4×10−12exp{−(237[kJ/mol]+6.0[cm3/mol]×P)/RT} and DO [m2/s]=7.2×10−11exp{−(263[kJ/mol]+4.8[cm3/mol]×P)/RT}, respectively, where P is pressure (in GPa), T is absolute temperature (in K) and R is the ideal gas constant. It was revealed that diffusion of Si is approximately one order of magnitude slower than that of O and, thus, Si is the rate-controlling element for plastic deformation of stishovite. Si diffusion in stishovite is assessed to be at least three orders of magnitude slower than that in bridgmanite under mid-mantle conditions. Therefore, it is anticipated that highly viscous SiO2-rich components subducted into the lower mantle persist as the seismic reflectors for long term without mixing up with the bridgmanite-dominated surrounding mantle.
KW - diffusion
KW - seismic reflectors
KW - stishovite
KW - viscosity
UR - http://www.scopus.com/inward/record.url?scp=85006307494&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85006307494&partnerID=8YFLogxK
U2 - 10.1016/j.epsl.2016.11.044
DO - 10.1016/j.epsl.2016.11.044
M3 - Article
VL - 459
SP - 332
EP - 339
JO - Earth and Planetary Sciences Letters
JF - Earth and Planetary Sciences Letters
SN - 0012-821X
ER -