Experimental evidence for wall-rock pulverization during dynamic rupture at ultra-high pressure conditions
Experimental evidence for wall-rock pulverization during dynamic rupture at ultra-high pressure conditions
复制标题
超高压条件下动态破裂过程中围岩粉碎的实验证据
DOI：
10.1016/j.epsl.2019.115832
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发表时间：
2019
影响因子：
5.3
通讯作者：
Jamtveit, B.
中科院分区：
文献类型：
--
作者：
Incel, S.;Schubnel, A.;Renner, J.;John, T.;Labrousse, L.;Hilairet, N.;Freeman, H.;Wang, Y.;Renard, F.;Jamtveit, B.
中深源地震的触发机制几十年来一直困扰着地质学家。关于这种地震是由脆性机制还是韧性机制引发的，目前还没有达成共识。在围压为3GPa、温度为583 ~ 1073 K的条件下，对人工合成的含硬铝石蓝片岩进行了变形实验。变形后，恢复的样品显示共轭剪切断裂。石榴石晶体被解剖和移位沿着这些狭窄的故障，并揭示微观和纳米结构，类似于自然粉碎结构以及部分非晶化。已知在低围压下形成这样的结构需要高的拉伸应力和应变率，并且通过动态剪切破裂的传播来解释。被粉碎的围岩中没有剪切被认为是这些结构先于随后的发热摩擦滑动的证据。与低压下的观察结果类似，我们推断，即使在施加于样品上的高压下，我们实验中的石榴石结构也是由于剪切破裂的快速传播造成的，因此表明在下地壳到上地幔深度处可能发生脆性变形。
The mechanisms triggering intermediate and deep earthquakes have puzzled geologists for several decades. There is still no consensus concerning whether such earthquakes are triggered by brittle or ductile mechanisms. We performed a deformation experiment on a synthetic lawsonite-bearing blueschist at a confining pressure of 3 GPa and temperatures from 583 to 1,073 K. After deformation, the recovered sample reveals conjugated shear fractures. Garnet crystals are dissected and displaced along these narrow faults and reveal micro- and nanostructures that resemble natural pulverization structures as well as partial amorphization. Formation of such structures at low confining pressures is known to require high tensile stresses and strain rates and is explained by the propagation of a dynamic shear rupture. The absence of shearing in the pulverized wall rock is taken as evidence that these structures pre-date the subsequent heat-producing frictional slip. In analogy to observations at low pressure we infer that the garnet structures in our experiment result from rapid propagation of a shear fracture even at the high pressure exerted on the sample and thus suggest that brittle deformation is possible at lower crustal to upper mantle depths.
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石榴石单晶的显微硬度及脆性断裂
DOI：
--
发表时间：
1984
期刊：
影响因子：
--
作者：
M. Pardavi
通讯作者：
M. Pardavi
影响因子：
5.8
作者：
Incel, Sarah;Labrousse, Loic;Schubnel, Alexandre
通讯作者：
Schubnel, Alexandre
DOI：
10.1002/2015jb012542
发表时间：
2016-04
期刊：
Journal of Geophysical Research: Solid Earth
影响因子：
--
作者：
F. Aben;M. Doan;T. Mitchell;R. Toussaint;T. Reuschlé;M. Fondriest;J. Gratier;François Renard
通讯作者：
F. Aben;M. Doan;T. Mitchell;R. Toussaint;T. Reuschlé;M. Fondriest;J. Gratier;François Renard
影响因子：
3.1
作者：
Mitchell, T. M.;Faulkner, D. R.
通讯作者：
Faulkner, D. R.
粒度减小和剪切加热引起的中深度地震发生和剪切带形成
影响因子：
5.8
作者：
M. Thielmann;A. Rozel;B. Kaus;Y. Ricard
通讯作者：
Y. Ricard