构造岩研究的新进展

DEVELOPMENTS IN TECTONITE STUDY

构造岩的研究已取得很大进展。有关构造岩的分类，无论是描述性的还是按成因的分类，都各具特点，但还是以二者兼顾为好。对构造岩，尤其是糜棱岩的识别，要注意在野外区分应变梯度带和在岩相学上利用显微构造判据。构造岩的变形机制包括碎裂作用和粘性流动，而以二者之间的转换尤为重要。变形机制的交替和转换使构造岩的显微构造具一定的演化规律。由构造岩的应变局部化和力学失稳可引起成分变异、体积亏损，而流体的流动在其中也起着重要的作用。

Some developments have taken place in the study of tectonites.Any classifica-tions of tectonites based on either descriptive or genetic criteria has advantages and disad-vantages.The optimal classification should reflect both descriptive and genetic criteria. Inidentifying tectonites,especially mylonites,we should note both the different straingradient belts in the field and the microstructure of the tectonites.Of the deformationmechanisms including cataclasis and viscous flow,the most important is the transition be-tween them.The microstructure of tectonites is controlled bv the alternation and transi-tion of deformation mechanisms.Strain localization and mechanical instability may lead tochanges in the composition and also loss of volume of the tectonites. During this process,fluid flow plays a very important role.