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Thermal conductivity measurments of earth materials under high pressure and high temperature

高压高温下土体材料的导热系数测量

基本信息

批准号：
09640511
负责人：
OSAKA Masahiro
金额：
$ 2.11万
依托单位：
National Science Museum
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09640511/
关键词：
MANTLE MATERIALS THERMAL CONDUCTIVITY THERMAL DIFFUSIVITY HIGH-PRESSURE DEEP INTERIOR OF THE EARTH 高圧

项目摘要

To investigate the thermal state of the earth's mantle, the author measured the thermal conductivity and the thermal diffusivity of mantle candidate minerals under high pressure and at high temperature.A pulse method using one-dimensional heat flow has been applied to simultaneous thermal diffusivity and thermal conductivity measurements. The sample, made in the form of three identical thin disks, is heated by a pulse current in a thin heater inserted into one interface of the stacked disks. Change of temperature is detected by a thermocouple on the other interface. Thermal diffusivity is determined from decay time of the temperature profile, and thermal conductivity is calculated from the rise of temperature and an electric power for the known thickness of the sample.Experiments were performed using a uniaxial split-sphere high-pressure apparatus. A magnesia octahedron with a edge length of 18 mm was used as a pressure medium in tungsten carbide anvils with a truncation of 11 mm. Size … More s of the samples were 4 mm in diameter and 1 mm in height. A pair of metallic planar furnaces in the octahedron was used for experiments at high temperatures.Measurements were made on fused silica, garnet and olivine under pressures up to 8.2 GPa. Extrapolated values of thermal conductivity or thermal diffusiivity to zero pressure agree with those obtained by other methods. Reproducibilities of measurements are within 7 per cent for thermal diffusively and within 15 per cent for thermal conductivity.Pressure dependences on thermal diffusively or thermal conductivity of mantle minerals are tow or three per cent increase per 1 GPa for garnets and five per cent increase per 1 GPa for the b-axis direction of olivine.Garnet and olivine were measured at temperatures up to 1000 K under 8.2 GPa. The thermal diffusively or the thermal conductivity of garnet decreases moderately with temperature increase unlike normal insulators in the T-inverse law of thermal conductivity. This is the same effect as seen in previous results under zero pressure. Less

为了研究地幔的热状态，作者在高压和高温下测量了地幔候选矿物的热导率和热扩散率。采用一维热流的脉冲方法已应用于同时热扩散率和热导率测量。该样品由三个相同的薄盘制成，通过插入堆叠盘一个界面的薄加热器中的脉冲电流进行加热。另一个接口上的热电偶检测温度变化。热扩散率是根据温度分布的衰减时间确定的，热导率是根据已知厚度的样品的温度上升和电功率计算的。实验是使用单轴分流球高压装置进行的。边长为 18 mm 的氧化镁八面体在截断为 11 mm 的碳化钨砧中用作压力介质。样品尺寸为直径 4 毫米、高度 1 毫米。八面体中的一对金属平面炉用于高温实验。在高达 8.2 GPa 的压力下对熔融石英、石榴石和橄榄石进行测量。零压力下的热导率或热扩散率的外推值与通过其他方法获得的值一致。热扩散测量的重复性在 7% 以内，导热系数在 15% 以内。地幔矿物的热扩散或导热系数的压力依赖性对于石榴石来说每 1 GPa 增加 2% 或 3%，对于橄榄石 b 轴方向每 1 GPa 增加 5%。石榴石和橄榄石是在 8.2 下在高达 1000 K 的温度下测量的。 GPa。与导热系数 T 逆定律中的普通绝缘体不同，石榴石的热扩散或导热系数随着温度的升高而适度降低。这与之前在零压力下的结果中看到的效果相同。较少的