山东栖霞胶东群褶皱变形构造序列

出露在胶东一带的前震旦系胶东群,是一套经历了多期构造变形的变质岩系。研究这一课题,对深入认识胶东地区的地壳演化、古构造特征以及地层的划分等重大地质问题有着重要的意义。本文指出:胶东群构造旋回的褶皱序列可划分为四期变形,各期的褶皱样式、规模和方向都具有不同的特征。根据本区几期褶皱发育的特点和各期叠加干涉的型式表明,这套古老的变质岩系是经历了多期构造运动作用,其变形总趋势是由第一期的强烈的构造置换和层内塑流为特征的小型褶皱开始,演变至第四期的开阔宽缓弱塑性变形的大型褶皱而告终。这一变形过程反映出温压条件由高向低变化的递减规律。此外,本文还对塑流褶皱的成因机制、胶东群的地层划分以及褶皱露头的分析等问题进行了讨论。

THE STRUCTURAL ORDER OF FOLD AND DEFORMATION IN JIAODONG GROUP IN QIXIA,SHANDONG

The Pre-Sinian Jiaodong Group emerged in Jiaodong region is a suite of metamorphic rocks which have endured many times of tectonic deformation. To study the structure of these rocks is important for understanding thoroughly the crustal evolution of the Jiaodong region,the characteristics of palrostructures and the devision of strata.The stuctural cycle in the Jiaodong Group can be preliminarily devided into four stages, the fold style, scale, and direction of each stage have different characteristics. According to the development characteristics and the styles of refold and interference of several-stage folds, the paleo-metamorphic rocks of this suite have endured many phase tectonic movements. The general trend of deformation is that the deformation began with small-demension folds in the first stage which have the characteristics of intensive structural replacement and plastic flow in bed, and ended with large-demension, wide and smooth, weak plastic deformation folds of the fourth stage. This deformation course reflected the progressive decreases of both temperature and pressure during the process.This paper also discusses the origion mechanism of plastic folds, the statum devision of the Jiaodong Group, and the analysis method of fold crops, etc.