地球物理学进展 ›› 2019, Vol. 34 ›› Issue (1): 1-5.doi: 10.6038/pg2019CC0028

• 固体地球物理及空间物理学(大气、行星、地球动力学、重磁电及地震学、地热学) • 上一篇    下一篇

地球内部存在低应力长时间作用的黏性破坏吗?

陈祖安1,李明1,2   

  1. 1. 中国科学院地质与地球物理研究所地球与行星内部物理院重点实验室, 北京 100029
    2. 中国科学院大学,北京 100049
  • 收稿日期:2018-06-17 修回日期:2018-11-22 出版日期:2019-02-20 发布日期:2019-04-15
  • 作者简介:陈祖安,男,1963年生,博士,副研究员,主要从事岩石力学和地球动力学数值模拟工作.(E-mail: zachen@mail.iggcas.ac.cn)
  • 基金资助:
    国家自然科学基面上项目资助.(41474083);国家自然科学基面上项目资助.(41574089)

Is there any rheological failure for material inside earth interior due to long time action at low stress?

CHEN Zu-an1,LI Ming1,2   

  1. 1. Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences,Beijing 100029,China
    2. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2018-06-17 Revised:2018-11-22 Online:2019-02-20 Published:2019-04-15

摘要:

根据变形耗散理论,本文提出了一个长期以来被忽略的问题:地球内部低应力长时间作用下超塑性蠕变会导致黏性流变破坏吗?一些实验表明在纳米相合金和陶瓷中观察到高应变率下的超塑性,因而推断如果存在高应变率和高温在非常细粒的地质材料中也将发现超塑性.事实上对于碳酸盐的实验表明了这一点.从已有大理岩的实验结果,总结出围压在0~500 MPa,温度在0~600 ℃范围的临界耗散能公式.表明这样的黏性流变破坏是存在的.值得注意的是,超塑性达到破坏阶段,它的微观结构将发生变化,因而物理性质也会变化.这就意味着地球内部一些地质现象可能与黏性流变破坏存在一定的关系.如果上地幔的确存在着黏性流变破坏,结合水和熔体作用,就可解释上地幔低速高导层种种争议问题.

关键词: 超塑性流变, 流变破坏, 临界耗散能, 低应力, 局部化

Abstract:

Based on dissipative theory of deformation, a question neglected long term before is proposed in the paper: under long time action at low stress, can super plastic creep result in rheological failure of rock inside earth interior? Some experiment results indicate that superplasticity has been observed at high strain rates for arrange of nano-phase alloys and ceramics, and could potentially occur in fine-grained geological materials, if deformrd at high strain rates and temperatures. The experiment about carbonate also supports the guess. From the experimental results with temperature from 0~600 ℃ and pressure from 0~500 MPa on marble, we estimated the formula of critical dissipative energy with pressure and temperature. It indicates the rheological failure may exist. It is noteworthy that as soon as deformation of rock reaches failure phase, its microstructure will change, therefore property of rock will change. This means that there is the possible relationship between physical phenomenon inside earth interior and rheological failure at low stresses. If indeed rheological failure at low stresses exists in upper mantle, combining water and melt hypothesis, some dispute questions about low wave velocity and high conductivity layer in upper mantle could be explained better.

Key words: Superplastic rheology, Rheological failure, Critical dissipative energy, Low stress, Localization

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