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Electric conductivity measurement of the Earth's materials

地球材料的电导率测量

基本信息

批准号：
13440164
负责人：
KATSURA Tomoo
金额：
$ 9.6万
依托单位：
OKAYAMA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

项目摘要

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.

对日本北海道日高变质带麻粒岩的电导率进行了测量。根据实验结果，我们估计深度为10-30 km的高阻区温度为600℃。我们通过电导率测量的方法进行了实验，以估计铁-铁硫化物熔体在白云石和橄榄岩基质中的连通性。从这一系列的实验中，我们发现当铁-铁硫化物的体积比大于5%时，铁-铁硫化物熔体就会发生连接。因此，地核物质与地幔的分离应该很容易发生在地球的早期历史中。在压力为25、35和40 GPa，温度为500 ~ 1000 K的条件下，测量了SiO_3钛铁矿（Mg_<0.93>Fe_<0.07>）的电导率。我们发现指数前项在所有压强下都是常数3×10 S/m。活化体积和活化能分别为-0.90±0.10 cm^3/mol和0.69±0.04 eV。因此钛铁矿的压力依赖性很大。我们还测量了（Mg_<0.93>Fe_<0.07>）SiO_3钙钛矿在35和40 GPa压力和500 ~ 1100 K温度下的电导率。我们发现指数前项在两个压强下都是常数1×10 S/m。活化体积和活化能分别为-0.06±0.04 cm^3/mol和0.39±0.02 eV。因此，钙钛矿的压力依赖性比钛铁矿小一个数量级。