摘要
本文在地质调查和141个代表性岩石化学分析、5个基性变质岩微量元素分析基础上,探讨了华北地台东南缘大别山区—连云港地区下元古界变质地层自下而上的岩石组合、化学特点,原岩组合及其形成的原始构造环境。结果表明,该区下元古界变质地层中下部为稳定陆缘沉积,中上部为活动陆缘钙碱性火山沉积,这反映华北地台东南缘早元古代从早至晚有一个从稳定至活化的构造演变过程,该过程暗示了早元古代晚期扬子地台自南往北对华北地台的俯冲作用。
Based on the geological studies and petrochemical analyses of 141 samples and trace element analyses of 5 metabasites, the present paper deals with the rock association, chemical features, protolith formation and the original tectonic settings upwards through the Lower Proterozoic metamorphic strata in the Dabieshan-Lianyungang area,in the southeast margin of the North China Platform.The results of the present study indicate that the lower and middle part of the metamorphic strata comprise terrigenous elastics, phosphoritic formation and aluminous sedimentary formation which formed under stable continental margin environments. Whereas in the middle-upper part a calc-alkaline volcano-sedimentary formation under the active continental margin is developed.The Lower Proterozoic meta-strata of sedimentary-volcano-sedimentary origin from the bottom upwards suggest that the tectonic evolution of the southeast margin of the North China Platform is a process from stabillization to mobilization.This process suggests a northward sub-duction of the Yangtze Platform under the North China Platform during the late period of the Early Proterozoic.
出处
《地球科学（中国地质大学学报）》
EI
CAS
CSCD
北大核心
1991年第6期651-659,共9页
Earth Science-Journal of China University of Geosciences
关键词
变质岩
岩石化学
早元古界
地台
North China Platform, Lower Proterozoic, metamorphic rock, petrochemistry, Dabieshan, Lianyungang.
