• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Surveys in Geophysics: An International Review Journal of Geophysics and Planetary Sciences >Laboratory Electrical Conductivity Measurement of Mantle Minerals
【24h】

Laboratory Electrical Conductivity Measurement of Mantle Minerals

机译：地幔矿物的实验室电导率测量

获取原文
获取原文并翻译 | 示例
       
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Electrical conductivity structures of the Earth's mantle estimated from the magnetotelluric and geomagnetic deep sounding methods generally show increase of conductivity from 10(-4)-10(-2) to 10(0) S/m with increasing depth to the top of the lower mantle. Although conductivity does not vary significantly in the lower mantle, the possible existence of a highly conductive layer has been proposed at the base of the lower mantle from geophysical modeling. The electrical properties of mantle rocks are controlled by thermodynamic parameters such as pressure, temperature and chemistry of the main constituent minerals. Laboratory electrical conductivity measurements of mantle minerals have been conducted under high pressure and high temperature conditions using solid medium high-pressure apparatus. To distinguish several charge transport mechanisms in mantle minerals, it is necessary to measure the electrical conductivity in a wider temperature range. Although the correspondence of data has not been yet established between each laboratory, an outline tendency of electrical conductivity of the mantle minerals is almost the same. Most of mineral phases forming the Earth's mantle exhibit semiconductive behavior. Dominant conduction mechanism is small polaron conduction (electron hole hopping between ferrous and ferric iron), if these minerals contain iron. The phase transition olivine to high-pressure phases enhances the conductivity due to structural changes. As a result, electrical conductivity increases in order of olivine, wadsleyite and ringwoodite along the adiabat geotherm. The phase transition to post-spinel at the 660 km discontinuity further can enhance the conductivity. In the lower mantle, the conductivity once might decrease in the middle of the lower mantle due to the iron spin transition and then abruptly increase at the condition of the DaEuro(3) layer. The impurities in the mantle minerals strongly control the formation, number and mobility of charge carriers. Hydrogen in nominally anhydrous minerals such as olivine and high-pressure polymorphs can enhance the conductivity by the proton conduction. However, proton conduction has lower activation enthalpy compared with small polaron conduction, a contribution of proton conduction becomes smaller at high temperatures, corresponding to the mantle condition. Rather high iron content in mantle minerals largely enhances the conductivity of the mantle. This review focuses on a compilation of fairly new advances in experimental laboratory work together with their explanation.
机译：根据大地电磁和地磁深测方法估算的地幔电导率结构通常显示电导率从10（-4）-10（-2）到10（0）S / m随深度的增加而增加到下部的顶部地幔。尽管下地幔的电导率变化不大，但根据地球物理模型，已在下地幔的底部提出了高导电层的可能存在。地幔岩石的电学性质受热力学参数控制，例如主要成分矿物的压力，温度和化学性质。地幔矿物的实验室电导率测量已使用固体介质高压设备在高压和高温条件下进行。为了区分地幔矿物中的几种电荷传输机制，必须在较宽的温度范围内测量电导率。尽管尚未在每个实验室之间建立数据的对应关系，但地幔矿物电导率的概貌趋势几乎相同。形成地球地幔的大多数矿物相都表现出半导体行为。如果这些矿物包含铁，则主要的传导机理是小的极化子传导（亚铁与三价铁之间的电子空穴跳跃）。橄榄石至高压相的相变由于结构变化而提高了电导率。结果，沿着绝热地热，电导率按橄榄石，沃兹利特石和林伍德石的顺序增加。在660 km处不连续地过渡到尖晶石后，可以进一步提高电导率。在下地幔中，由于铁的自旋跃迁，电导率曾经在下地幔中部降低，然后在DaEuro（3）层的条件下突然增加。地幔矿物中的杂质强烈控制着载流子的形成，数量和迁移率。标称无水矿物（例如橄榄石和高压多晶型物）中的氢可通过质子传导增强电导率。但是，与小的极化子传导相比，质子传导具有较低的活化焓，对应于地幔条件，在高温下质子传导的贡献变小。地幔矿物中较高的铁含量会大大提高地幔的电导率。这篇综述着重于实验实验室工作中相当新的进展及其解释的汇编。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号