Transformation textures in post‐perovskite: Understanding mantle flow in the D″ layer of the Earth
Transformation textures in post‐perovskite: Understanding mantle flow in the D″ layer of the Earth
复制标题
后钙钛矿中的转变纹理：了解地球 D 层中的地幔流
DOI：
10.1029/2008gl036840
复制
发表时间：
2009
影响因子：
5.2
通讯作者：
D. Dobson
中科院分区：
文献类型：
--
作者：
N. Walte;F. Heidelbach;N. Miyajima;D. Frost;D. Rubie;D. Dobson
（Mg，Fe）SiO3后钙钛矿（PPV）中的形变和织构形成是地球D″层中强地震各向异性的一种可能解释。然而，不同的实验方法导致不同的晶格择优取向（LPO）变形的PPV，导致在解释变形的最低地幔中的模糊性。在这里，我们表明，在从钙钛矿到PPV的相变过程中的类似物质CaIrO3的变形导致的变换纹理，不同于CaIrO3 PPV变形纹理，但类似于金刚石对顶砧单元中的PPV变形实验的结果。假设物质平行于核幔边界扩散，我们的结果预测了一个广泛的剪切波分裂与快速水平S波，这是与地震研究兼容。经历相变的下涌物质可能会发展出一种转变结构，这种结构会局部地导致垂直极化的快S波。
Deformation and texture formation in (Mg, Fe)SiO3 post perovskite (ppv) is a potential explanation for the strong seismic anisotropy that is found in the D″ layer of the Earth. However, different experimental approaches have resulted in different lattice preferred orientations (LPO) in deformed ppv that have led to ambiguity in the interpretation of deformation in the lowermost mantle. Here, we show that deformation of the analogue substance CaIrO3 during a phase transformation from perovskite to ppv leads to a transformation texture that differs from the CaIrO3 ppv deformation texture but resembles the results from ppv deformation experiments in diamond anvil cells. Assuming material spreading parallel to the core‐mantle boundary, our results predict a widespread shear wave splitting with fast horizontal S‐waves, which is compatible with seismic studies. Downwelling material that undergoes a phase transformation may develop a transformation texture that would locally result in vertically polarized fast S‐waves.