吉辽徐淮地区新元古代地层对比格架

根据层序地层学最大海泛,Sr、C同位素测年,地质事件,生物化石和古地磁资料对吉辽徐淮地区新元古代地层进行了时代界定和对比。研究表明吉辽徐淮地区震旦纪海平面变化趋势基本一致,旋回层序基本上可以对比,其沉积主体除辽南兴民村组和淮北史家组的2个数据小于750Ma之外,相互之间的Sr、C同位素比值对比性很好,沉积时限在750—860Ma之间,为北方青白口系之后的沉积。吉南的八道江组、辽南的十三里台组和徐淮的魏集组可作为三地的对比标志,并提出了新的地层对比方案。

THE NEOPROTEROZOIC STRATIGRAPHIC CORRELATION FRAMEWORK IN THE JILIN-LIAONING-XUZHOU-HUAIYANG AREA

Based upon the Sr and C isotope dating, maximum marine flooding event in terms of sequence stratigraphy, geological events, fossils and paleogeomagnetism, the Neoproterozoic strata are correlated between the South Jilin, South Liaoning, and Xuzhou-Huaiyang area of Jiangsu and Anhui. This study indicates that Neoproterozoic sea-level change is consistent, and cyclic sequences can well be correlated. Correlation of Sr and C isotopic ratio suggests that strata in the study areas may be younger than the Qing-baikou System of North China,and 750-860Ma may be their chronological interval except two topmost units, namely the Xingmincun Fro. in South Liaoning and the Shijia Fro. in North Anhui younger than 750Ma. The Badaojiang Fm. in South Jilin,the Shisanlitai Fro. in South Liaoning, the Weiji Fm. in Jiangsu and Anhui are the key sequences for correlation of Neoproterozoic strata in the study areas. On the basis of this research a new correlation of Neoproterozoic strata is suggested.