2003 Fiscal Year Final Research Report Summary
Electric conductivity measurement of the Earth's materials
| Project/Area Number |
13440164
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | OKAYAMA UNIVERSITY |
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Principal Investigator |
KATSURA Tomoo OKAYAMA UNIVERSITY, Institute for Study of the Earth's Interior, Associate Professor, 固体地球研究センター, 助教授 (40260666)
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| Co-Investigator(Kenkyū-buntansha) |
YAMASHITA Shigeru OKAYAMA UNIVERSITY, Institute for Study of the Earth's Interior, Associate Professor, 固体地球研究センター, 助教授 (30260665)
YONEDA Akira OKAYAMA UNIVERSITY, Institute for Study of the Earth's Interior, Associate Professor, 固体地球研究センター, 助教授 (10262841)
ITO Eiji OKAYAMA UNIVERSITY, Institute for Study of the Earth's Interior, Professor, 固体地球研究センター, 教授 (00033259)
URAKAWA Satoru OKAYAMA UNIVERSITY, Faculty of Science, Associate Professor, 理学部, 助教授 (30201958)
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| Project Period (FY) |
2001 – 2003
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| Keywords | electrical conductivity / Hidaka metramorphic / connectivity / iron-iron sulfide / ilmenite / activation energy / activation volume / perovskite |
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| Research Abstract |
We measured electrical conductivity of granulite from Hidaka metramorphic belt, Hokkaido, Japan. From the experimental results, we estimated the temperature of the high resistance region at depth of 10-30 km to be 600℃.
We conducted experiments to estimate connectivity of iron-iron sulfide melts in dunite and lherzolite matrixes by means of electrical conductivity measurement. From this series of experiments, we found that iron-iron sulfide melt connects if its volume proportion is more than 5 %. Therefore, segregation of core material from mantle should have easily occurred in the early history of the Earth.
We measured electrical conductivity of (Mg_<0.93>Fe_<0.07>)SiO_3 ilmenite at pressures of 25, 35 and 40 GPa and temperature of 500 to 1000 K. We found the pre-exponential term is constant of 3×10 S/m at all of these pressures. The activation energy at 0 GPa and activation volume are 0.69±0.04 eV and -0.90±0.10 cm^3/mol. Thus pressure dependence of ilmenite is quite large.
We also measured electrical conductivity of (Mg_<0.93>Fe_<0.07>)SiO_3 perovskite at pressures of 35 and 40 GPa and temperature of 500 to 1100 K. We found the pre-exponential term is constant of 1×10 S/m at both of these pressures. The activation energy at 0 GPa and activation volume are 0.39±0.02 eV and -0.06±0.04 cm^3/mol. Thus pressure dependence of pervoskite is one order of magnitude smaller than that of ilmenite.
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