安徽淮南群四顶山组燧石Sm-Nd年龄测定

The Sm-Nd Age of Cherts from Sidingshan Formation of the Huainan Group of Anhui Province

在对苏皖北部的上前寒武系进行了矿物学研究基础上 ,选择安徽北部淮南群四顶山组燧石作为测定对象 ,系统测试 Rb- Sr和 Sm - Nd同位素 ,应用 Sm- Nd等时线方法进行了定年。本次研究表明 ,安徽淮南群四顶山组燧石可能是在海洋环境中形成 ,主要反映了陆源物质特征 ,其形成时代约为 80 0 Ma。这为苏皖北部地区上前寒武系是位于华北区青白口系和扬子区震旦系之间的一套地层提供了一个新的证据 。

Based on researches on mineralogy of the Upper Precambrian System of Anhui Province, the cherts from the Sidingshan Formation of the Huainan Group of Anhui Province were selected to determine Rb-Sr and Sm-Nd isotopes. The five chert samples yield a Sm-Nd isochron age of 801±46 Ma. This study suggests that the cherts of Sidingshan Formation of Huainan Group of Anhui Province may be formed in an oceanic environment and reflect the nature of materials derived from the continental crust. The Sm-Nd age of cherts provides new evidence that the Upper Precambrian System of Anhui is composed of a set of strata between the Qingbaikou System of North China and the Sinica System of the Yangzi Region of South China.