Ripplocations provide a new mechanism for the deformation of phyllosilicates in the lithosphere
Ripplocations provide a new mechanism for the deformation of phyllosilicates in the lithosphere
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DOI：
10.1038/s41467-019-08587-2
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发表时间：
2019-02
影响因子：
16.6
通讯作者：
J. Aslin;E. Mariani;K. Dawson;M. Barsoum
中科院分区：
文献类型：
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作者：
J. Aslin;E. Mariani;K. Dawson;M. Barsoum
地球岩石圈的变形局限于狭窄的高应变带。层状硅酸盐是一种强各向异性的层状矿物，在这些岩石中含量丰富，它们容纳了大部分的应变，在抑制或引发地震方面起着重要作用。到目前为止，人们已经认识到层状硅酸盐只能通过位错沿层滑动而变形，并且不能在不开裂和膨胀的情况下适应大的应变。在这里，我们展示了一类新的原子尺度缺陷，称为波纹，解释了层法向应变的发展而没有脆性损伤。我们使用高分辨率透射电子显微镜（TEM）来解析层状硅酸盐矿物黑云母中波纹的纳米级弯曲特征。我们证明了共轭分层阵列是由于波纹点中层向应变的积累而产生的弹性应变能释放的结果。这项工作提供了理解层状硅酸盐变形所必需的缺失机制，对含层状硅酸盐的发震断裂和俯冲带具有重要的流变学意义。
Deformation in Earth’s lithosphere is localised in narrow, high-strain zones. Phyllosilicates, strongly anisotropic layered minerals, are abundant in these rocks, where they accommodate much of the strain and play a significant role in inhibiting or triggering earthquakes. Until now it was understood that phyllosilicates could deform only by dislocation glide along layers and could not accommodate large strains without cracking and dilation. Here we show that a new class of atomic-scale defects, known as ripplocations, explain the development of layer-normal strain without brittle damage. We use high-resolution transmission electron microscopy (TEM) to resolve nano-scale bending characteristic of ripplocations in the phyllosilicate mineral biotite. We demonstrate that conjugate delamination arrays are the result of elastic strain energy release due to the accumulation of layer-normal strain in ripplocations. This work provides the missing mechanism necessary to understand phyllosilicate deformation, with important rheological implications for phyllosilicate bearing seismogenic faults and subduction zones.