Anisotropy of magnetic susceptibility of rocks and minerals
Anisotropy of magnetic susceptibility of rocks and minerals
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DOI：
10.1029/jz068i001p00279
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发表时间：
1963
影响因子：
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通讯作者：
S. Uyeda;M. Fuller;J. Belshe;R. Girdler
中科院分区：
文献类型：
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作者：
S. Uyeda;M. Fuller;J. Belshe;R. Girdler
岩石和亚铁磁性矿物磁化率各向异性的主要原因有两个：磁性物质的形状和结晶各向异性。一般来说，这些因素可能同时起作用，但在岩石磁学中，它们的影响往往是可分离的。在形状效应各向异性的情况下，人们可以通过椭球近似来预测各向异性的程度，前提是体磁化率的大小和物体的尺寸是已知的。各向异性主要是由于在立方钛磁铁矿和岩石中含有它们的形状效应，而晶体各向异性占主导地位的晶体较低的对称性（磁黄铁矿，赤铁矿，钛铁矿）。在磁性各向异性的岩石和矿物中，热释磁性的方向有时会明显地偏离外磁场的方向，而且总是系统地偏离外磁场的方向。给出了几个例子和一些理论上的考虑。
There are two predominant causes for the anisotropy of magnetic susceptibility of rocks and ferrimagnetic minerals: the shape of the magnetic material and crystalline anisotropy. In general, these factors may operate simultaneously, but in rock magnetism their effects are frequently separable. In the case of shape‐effect anisotropy, one can predict the degree of anisotropy by an ellipsoidal approximation, provided that the magnitude of the bulk susceptibility and the dimensions of the body are known. The anisotropy is chiefly due to the shape effect in the cubic titanomagnetites and in the rocks containing them, whereas crystalline anisotropy dominates in crystals of lower symmetry (pyrrhotites, hematites, ilmenites). In magnetically anisotropic rocks and minerals, the direction of thermoremanent magnetism is found to deviate sometimes markedly, and always systematically, from that of the external magnetic field. Several examples and some theoretical considerations are given.