关于辽南及苏皖地区震旦系与青白口系的关系

通过对辽南苏皖地区晚前寒武纪地层的同位素年龄及生物化石的研究,及对辽南复州地区海岛子—袁家沟剖面的研究,认为该区原确定为晚前寒武纪地层的层序有叠接的错误。重新厘定的地层层序为永宁组(曹店组)、钓鱼台组(八公山组)、南芬组(刘老碑组)、桥头组(寿县组)、高家屯组(九里桥组)、洼里组和金山组(四顶山组)。震旦系与青白口系无空缺存在。

THE RELATIONSHIP BETWEEN THE SINIAN AND QINGBAIKOU SYSTEMS OF SOUTH LIAONING AND JIANGSU-ANHUI AREA

The original sequence of Late Precambrian in south Liaoning is incorrect. The incorrectness lies in that the strata of different positions were taken as within the same position and those of the same position were considered in the form of superimposed strata of different positions. The similar mistake was also made about the sequence of Late Precambrian in the north parts of Jiangsu and Aahui provinces. The above opinions axe reconformed by the fact that the original sequences are inconsistent with their biogenic fossils and isotopic ages available. So the author thinks it does not hold water that there is an absence between the Sinian and Qingbaikou systems.The revised sequences of Late Precambrian in south Liaoning and the north parts of Jiangsu and Anhui provinces are, in an ascending order, Yongning Formation (Caodian Formation), Diaoyutai Formation (Bagongshan Formation), Nanfen Formation (Liulaobei Formation), Qiaotou Formation (Shouxian Formation), Gaojiatun Formation (Jiuliqiao Formation), Wali Formation and Jinjia Formation (Sidingshan Formation). The study of Haidaozi-Yuanjiagou section in the Fuzhou area of south Liaoning shows that Yongning and Diaoyutai formations can be correlated with Changlong-shan Formation, while Nanfen Formation with Jingeryu Formation. The discovery of Sabelliditidae in Gaojiatun Formation proved that Qiaotou, Gaojiatnn, Wali and Jinjia formations belong to the Sinian. Then the formations from Yongning up to Jinjia, and Changlongshan and Jingeryu formations are believed to be of Sinian based on the finding of Sabelliditidae and Vendotanides in Liulaobei formation which corresponds to Jingeryu and Nanfen formations. Therefore it is superimposition instead of absence that exists between the Sinian and Qingbaikou systems. In other words, Nantuo Formation of moraine, Doushantuo Formation and Dengying Formation are of Sinian, with the former one being the lower part and the latter two being the upper part; Changlongshan and Jingeryu formations which were originally considered to be Qingbaikou system, are actually the lower part of the Sininan;The Sinian belongs to the Paleozoic and is the oldest sedimentary cover which was formed at the time when the Proterozoic platform replaced the geosyncline; and Liantuo Formation which is thought to correspond to Maling and Xiangyangxi formations and be molasse formation caused by the inversion of the geosyncline, belongs to the Qingbaikou system of the upper part of the Proterozoic.