摘要
1:5万仙下幅区域地质调查在江西于都县沙坝黄组底部发现一套似层状或透镜状的变流纹质熔结凝灰岩,其为造山晚期陆相裂隙式火山喷发,浅海陆棚边缘斜坡水下结晶形成。通过采集变流纹质熔结凝灰岩同位素年龄样,采用锆石(LA-ICPMS) U-Pb定年法获得加权平均年龄值为744 ±5 Ma,显示沙坝黄组地层形成时代为南华纪早世,改变了以往普遍认为沙坝黄组地层形成时代为南华纪中–晚世的认识。
A set of stratoid or lenticular metamorphosed rhyolitic welded tuff was identified out in the re-gional geology survey of 1:50,000 Xianxiao Sheet,which was formed from continental fissure type volcanic eruption of late-orogenic and underwater crystallization on a marginal slope of neritic shelf.A 744±5 Ma weighted mean age of isotopic age samples collected from the me-tamorphosed rhyolitic welded tuff,obtained by zircon(LA-ICPMS)U-Pb method dating,shows Shabahuang Formation was in Early Epoch of Nanhua Period,having changed the recognition that Shabahuang Formation was widely believed to be formed in Middle-Late Epoch of Nanhua Period.
出处
《地球科学前沿（汉斯）》
2019年第3期138-147,共10页
Advances in Geosciences
基金
国家地质大调查项目:江西1:5万仙下、于都县、梓山幅区域地质矿产调查项目(项目编号:121201140 24401)。
