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在 Kawai-1000型多顶砧压机上,利用橄榄石相变人工合成地幔转换带矿物 wadsleyite 和 ringwoodite,其含水量从0.03wt%到2.0wt%变化不等。在压力14～16GPa,温度873K～1273K,通过 Mo:MoO_2固体反应控制氧逸度的条件下,利用阻抗谱分析方法,测量获得了这些样品的电导率。实验结果显示:wadsleyite 的电导率与 C_H~(0.66)呈正比,ringwoodite 的电导率与C_H~(0.69)呈正比,水极大地增强了样品的电导率;在我们的实验条件下,含水 wadsleyite 和 ringwoodite 样品的主要电荷载体是自由质子。另外,结合大地电磁反演获得的电导率结果和我们的实验数据,我们推断中国东北地区地幔转换带中的水含量约为0.1～0.3wt%,远远高于上地幔中的水含量,这或许表明在410km 处可能发生了部分熔融。
On the Kawai-1000 multi-apex press, wadsleyite and ringwoodite, which are synthetic synthetic mantle transition belts, vary in water content from 0.03 to 2.0 wt%. The conductivity of these samples was measured by impedance spectroscopy under conditions of pressure 14 ~ 16GPa, temperature 873K ~ 1273K, and oxygen fugacity controlled by Mo: MoO_2 solid reaction. The experimental results show that the conductivity of wadsleyite is proportional to C_H ~ (0.66), the conductivity of ringwoodite is proportional to C_H ~ (0.69), and the water greatly enhances the conductivity of the sample. Under our experimental conditions, wadsleyite and The main charge carrier for ringwoodite samples is free protons. In addition, combining the conductivity results obtained from MT and our experimental data, we infer that the water content in the mantle transition zone in northeastern China is about 0.1 ~ 0.3wt%, which is much higher than the water content in the upper mantle Perhaps indicating that partial melting may occur at 410 km.