中文摘要：

为分析碳酸盐岩地球化学特征对地层及层序界线、沉积环境的影响,选取冀北宽城中元古界杨庄组剖面进行了实测。冀北宽城中元古界杨庄组常量、微量元素和碳、氧同位素在纵向上具有特征的演变规律,特别是在岩石地层界线与层序界面附近变化明显。CaO含量从杨庄组一段到二段为21.07%～16.45%,从二段至三段则为16.45%～24.21%,Sr、Ba含量分别从杨庄组底部向上由44.59×10-6突变至98.16×10-6和0.51×10-6至10.45×10-6,δ13C值在0‰～-1.5‰之间变化,δ18O在-3.5‰～-8.5‰之间变化。上述常量、微量元素及碳、氧同位素组成、变化与同时期海平面变化基本一致,表明地球化学特征可作为划分地层界面或层序界面的标志,特别是可以优化地层界线或层序界线。杨庄组CaO/MgO、Sr/Ba及V、Rb、Be、B等组成和演化研究表明,杨庄组形成于干热气候下的近岸浅水环境。

英文摘要：

The study area is located in the northeast of the North China Craton and geographically belongs to the middle and northern Yanshan area.In this area,Mesoproterozoic and Neoproterozoic strata are well developed and constitute the type section of Mesoproterozoic and Neoproterozoic strata in China.Over ten thousand meters of Mesoproterozoic and Neoproterozoic strata recorded paleogeography and paleoenvironment,paleo-ocean geochemistry and the history of life development and sedimentary evolution.The Kuancheng area of northern Hebei has great thickness of Mesoproterozoic and Neoproterozoic sediments,with ideal outcrops.Previous researchers had conducted fairly detailed investigation in this area.Geochemical studies of Mesoproterozoic and Neoproterozoic strata in Jixian County started in the late 1970＇s,with the emphasis placed on major elements.In the middle of the 1980＇s,Liu Baoquan et al.（1985） carried out organic geochemical researches on Mesoproterozoic,Neoproterozoic and Lower Paleozoic carbonate rocks in North China.Wang Songshan et al.obtained an age of dark banded chert （1 317 Ma） at the top of Yangzhuang Fomration.The multiple stratigraphic division method was also introduced into the division and correlation of Mesoproterozoic and Neoproterozoic strata.The Yangzhuang formation has a total thickness of 322.37 m and consists mainly of carbonate rocks which include micritic dolomite,sand-bearing micritic dolomite and chert striped dolomite as well as local corrugated stromatolite dolomite,arenaceous dolomite and gravel lithic silicalite.In these rocks,horizontal laminae and birdeye structures are widespread.In order to analyze the influence of geochemical characteristics of carbonate rocks on stratigraphic and sequence boundaries as well as sedimentary environment,the authors chose the geological section of Mesoproterozoic Yangzhuang Formation in Kuancheng to conduct in-situ measurement.Along this section,there exists obvious vertical characteristic evolutionary regularity of major and trace elemen