2003 Fiscal Year Final Research Report Summary
Computer simulation of the densities and the seismic velocities of the mantle transition zone
| Project/Area Number |
13640482
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Petrology/Mineralogy/Science of ore deposit
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| Research Institution | Himeji Institute of Technology |
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Principal Investigator |
MATSUI Masanori Himeji Inst.Tech., Fac.Sci., Prof., 大学院・理学研究科, 教授 (90125097)
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| Co-Investigator(Kenkyū-buntansha) |
HAGIYA Kenji Himeji Inst.Tech., Fac.Sci., Res.Assoc., 大学院・理学研究科, 助手 (70237907)
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| Project Period (FY) |
2001 – 2003
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| Keywords | mantle transition zone / seismic velocity / computer simulation molecular dynamics method / mantle minerals / high temperature and high pressure / マントル鉱物 |
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| Research Abstract |
The following results are obtained from the present project.
1.The MD simulation for a pyrolite composition(60 vol% spinel) is compatible with a recent model SF99 (Shearer and Flanagan, 1999) within the 16 limit for both density and sound. velocity jumps. The MD simulated bulk sound velocity jump for a piclogite composition(40 vol% spinel) is also consistent with SF99 within 16, while the MD density jump for the piclogite lies outside the SF99 data. Our MD computed density and sound velocity jumps, either for the pyrolite or the piclogite composition, differ substantially from the values by the PREM or the ak135 model.
2.We applied the MD simulation to pyrope, majorite, and grossular, and found that the MD simulated crystal symmetry and elastic constants for each of the three garnets reproduce the observed values very accurately.
3.Based on breathing-shell-model MD simulations with quantum correction, we calculated the temperature-pressure-volume (T-P-V) equation of state(EOS) of γ-Mg_2SiO_4 to be used as a reliable pressure calibration standard at temperatures up to 2000 K and pressures up to 25 〜 30 GPa. We found that the MgO EOS previously given by Matsui et al.[2000] and the present γ-Mg_2SiO_4 EOS agreed very well, with the average differences in the estimated pressures between the two EOS's being less than 0.3 GPa at T between 1500 and 2000 K and P between 19 and 23 GPa.
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