华北板块边缘深地壳构造岩的基本特征和变形环境

BASIC CHARACTERISTICS AND DEFORMATION CONDITIONS OF DEEP-CRUSTAL TECTONITES ON THE BORDERS OF NORTH CHINA PLATE

本文描述华北板块南缘构造混杂岩带和北缘构造堆叠带中深地壳构造岩的结构构造和主要造岩矿物的变形特征,讨论了变形残斑和新晶的化学成分变化以及变形条件;并强调指出,在变形过程中辉石的同构造新晶和残斑的化学成分基本相同,其塑性变形条件高于斜长石、钾长石和角闪石。辉石参与塑性变形的深地壳构造岩形成于下地壳麻粒岩相环境。

This paper deals with The texture and structure of three types of deepcrustal tectonites taken from the stacked zone on the northern border and the tectonic melange zone on the southern border of North China plate,and with the deformation characteristics of rock-forming minerals,variation of chemical composition of deformed minerals and neocrystals and deformation conditions for the tectonites. It emphasize3 that the ductile deformation of Pyr in tectonites is the highest deformation facies in the lower crust,where syntectonic neocrystals (or subgrains) and residual deformation crystals are the same in composition. According to the P-T conditions for formation of the neocrystals, as known from the result of triaxial-high-temperature-creep experiment of Pyr,the P-T conditions under which Pyr is deformed ductilely are higher than those for Pl, Or and Hb. It is recognized that the tectonites were formed in the lower crust or layer of granulitic facies.