On the viscosity and creep mechanism of Earth's inner core
On the viscosity and creep mechanism of Earth's inner core
复制标题
地球内核的粘度和蠕变机制
DOI：
10.1029/2004gl021209
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发表时间：
2004
影响因子：
5.2
通讯作者：
J. Orman
中科院分区：
文献类型：
--
作者：
J. Orman
[1] 地球内核的粘度和蠕变机制是根据高压高温、低应力和大晶粒尺寸下铁的流动特性的微观物理模型来评估的。哈珀-多恩蠕变（一种牛顿粘性位错机制）被证明是可能的变形过程，并且粘性预计为 ∼1011 Pa s，处于先前估计的低端。如此低的粘度意味着内核可以在大约一分钟的时间尺度上调整其形状，以与地幔施加的重力场保持一致。它还意味着足以产生显着晶格择优取向的应变可能会在几年到几百年内发展起来，这表明内核的地震各向异性是主动变形的产物，并且没有初级结晶的记忆。
[1] The viscosity and creep mechanism of Earth's inner core are evaluated based on microphysical models of the flow properties of iron under high pressure and temperature, low stress and large grain size. Harper-Dorn creep, a Newtonian-viscous dislocation mechanism, is shown to be the likely deformation process, and the viscosity is predicted to be ∼1011 Pa s, at the low end of previous estimates. Such a low viscosity implies that the inner core can adjust its shape to maintain alignment with the gravitational field imposed by the mantle on a timescale of approximately one minute. It also implies that strain sufficient to produce significant lattice preferred orientation could develop in a few years to a few hundred years, which suggests that seismic anisotropy of the inner core is the product of active deformation and has no memory of primary crystallization.