Abstract: Elastic anisotropy is an important geophysical property of crustal rocks.Due to the compositional and textural complexity of crustal rocks,the potential factors influencing its elastic anisotropy are various.Microcracks preferred orientation plays an important role on elastic anisotropy in superficial crust.While at deeper crust,lattice preferred orientation(LPO)and shape preferred orientation(SPO)take over and control the elastic anisotropy.Statistic of previous experimental work shows that the content of mica and amphibole is somehow related to the anisotropy of intermediate-acid and basic rocks,respectively.Otherwise,the oriented melt can largely enhance rock's anisotropy,which is a preferable explanation to the observed high anisotropy within the middle to lower crust under Tibetan plateau.

Key words: crust elastic anisotropy, microcracks preferred orientation, crystallographic preferred orientation, shape preferred orientation, melt preferred orientation

摘要： 地壳岩石成分及其构造的复杂性使得地壳弹性波各向异性的影响因素比较复杂。在地壳浅部,裂隙广泛发育,它们的定向排列对岩石各向异性起到了很重要的作用。在地壳深部,裂隙基本闭合,岩石的各向异性主要是由矿物晶格优选方位(LPO)和形态优选方位(SPO)决定的。云母和(或)角闪石含量较高且定向排列的地壳岩石通常具有较高的各向异性。熔体的定向排列(MPO)可以显著地加强地壳各向异性。

关键词: 地壳, 各向异性, 裂隙定向排列, 晶格优选方位, 形态优选方位, 熔体定向排列