中下地壳岩石弹性波各向异性的影响因素  

THE INFLUENCING FACTOR OF ELASTIC ANISOTROPY IN MIDDLE TO LOWER CONTINENTAL CRUST

作　　者：张国苓[1] 杨晓松[1] 陈建业[1] 闫小兵[2] 

机构地区：[1]中国地震局地质研究所,地震动力学国家重点实验室,北京100029 [2]山西省地震局,太原030002

出　　处：《地震地质》2010年第2期327-337,共11页Seismology and Geology

基　　金：国家自然科学基金(40972139);地震行业科研专项(2008419012)共同资助

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。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.

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 

分 类 号：P313.1[天文地球—固体地球物理学]