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Effect of iron on density and sound velocity of ringwoodite at high pressure and high temperature
  • +6
  • lei liu,
  • Fengxia sun,
  • hong liu,
  • li yi,
  • Chaowen xu,
  • Jianguo Du,
  • xiaoyu gu,
  • hanyu wang,
  • guangshu yang
lei liu
institute of earthquake forecasting, CEA

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Fengxia sun
institute of earthquake forecasting, CEA
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hong liu
institute of earthquake forecasting, CEA
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li yi
institute of earthquake forecasting, CEA
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Chaowen xu
Institute of Earthquake Forecasting, China Earthquake Administration (CEA)
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Jianguo Du
Institute of Earthquake Forecasting, CEA
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xiaoyu gu
institute of earthquake forecasting, CEA
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hanyu wang
institute of earthquake forecasting, CEA
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guangshu yang
Faculty of Land Resources Engineering, Kunming University of Science and Technology
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Abstract

As the most enriched composition of the lower part of mantle transition zone, properties of bearing-Fe ringwoodite are important to deduce the composition and structure of the mantle. For understanding the properties of Fe-bearing ringwoodite under condition of the lower mantle transition zone, the density and seismic wave velocity (Vp and Vs) of ringwoodite with different Fe content (0, 12.5, 25, 50, and 100 at%) were calculated under 300-2000K and 0-26 GPa by forcefeild combined with molecular dynamic method. Changes of density, Vp and Vs of ringwoodite containing different Fe content with pressure and temperature were fitted by the binary linear equation. Density of ringwoodite linearly increases with increasing Fe content, however relationship between increase of Vp and Vs and increasing Fe content show quadratic. The calculated densities of ringwoodite show that the Fe content of ringwoodite shall be 55-64 at% to match the lower mantle transition zone’s density. Therefor existence of ringwoodite may result in a low-density zone or gravity anomaly in the lower part of the mantle transition zone. The Vp and Vs of ringwoodite along the Earth’s typical temperature and pressure profile are higher than the Earth’s wave velocity model at the lower mantle transition zone (510-660 km) and the Vp and Vs of ringwoodite with 12.5 at% Fe along the Earth’s typical temperature and pressure profile are 31.3-33.7%% and 22.9-27.7% higher. The calculated results provide new data to explore composition and structure of the mantle.