Abstract: The study area, geographically including Beijing, Tianjin, Shanxi and Hebei Provinces, is the main part of the North China Plate. Based on the study of outcrop and thin section observation, the distribution pattern of oolitic limestone and its ooid characteristics are presented. Olitic limestones were widely distributed in the area during the Third Series of Cambrian. Generally, the oolitic limestone elevates in strata gradually from east to west, which indicates that the oolitic limestone is diachronous. Huge oolitic shoals distribute along a western ward bulging belt from north to south, and mainly are composed of concentric ooids. In west of the belt, the thickness of the oolitic limestone decreases rapidly, and the oolitic limestone mainly is composed of radial ooids. In east of the belt, the oolitic limestone thins gradually, with majority grains of concentric ooids. The marine transgression during the Third Epoch of Cambrian took place from east to west on the North China Plate. In this background, the inner ramp ooid shoals developed in the central belt of the study area, with open sea in the east and shoal back tidal flat in the west.

Key words: North China, the Third Series of Cambrian, oolitic limestone, sedimentary environment

摘要： 京津晋冀地区是华北板块的主体, 该区寒武系第三统以鲕粒灰岩的广泛发育为特点。通过野外露头剖面和室内薄片观察, 对研究区鲕粒灰岩空间展布和鲕粒类型进行了详细研究。鲕粒灰岩从东到西出现的层位逐渐抬高, 具有明显的穿时性。大型鲕滩呈向西凸出的弧形带状分布, 鲕滩带主体由同心鲕鲕粒灰岩组成, 鲕滩带西侧鲕粒灰岩厚度迅速减小, 鲕粒以放射鲕居多, 鲕滩带东侧鲕粒灰岩厚度逐渐减小, 鲕粒以同心鲕占绝对优势。寒武纪第三世海侵方向是由东向西, 在研究区中部发育内缓坡的鲕粒滩环境, 西部为滩后潮坪环境, 东部为开阔海环境。

关键词: 华北, 寒武系第三统, 鲕粒灰岩, 环境意义