摘要
大别山东部榴辉岩同位素地质年代学研究反映出三方面的问题:(1)Sm - Nd 两点等时线的不确定性;(2) 部分高压- 超高压变质年龄实际是片麻岩的分析结果;(3) 首批发表的“C型榴辉岩”Sm - Nd 年龄,测定岩石不是榴辉岩。大别山东部榴辉岩年龄反映的是加里东期高压- 超高压变质的年代学信息。进一步研究应着重于榴辉岩锆石成因及Sm - Nd 体系适用性。岩相学是研究榴辉岩锆石成因的重要方法。
Three main problems are revealed from the geochronological data of eclogites in the eastern Dabie Mountains.(1)It is difficult to evaluate the geological significance of Sm_Nd internal isochrons because of their two_point nature.(2)Some data of gneiss are interpreted as high_to ultrahigh_pressure metamorphic ages;(3)The first batch of Sm_Nd ages of “C type eclogites”was actually dated on garnet pyroxenites.Which three misleaded the geochronological studies of eclogites in the area.\;The ages on eclogites reflect the Caledonian high_ to ultrahigh metamorphic event of the eastern Dabie monuntains.The further geochronological study should focus on origins of zircons and the behavious of Sm-Nd system of eclogites.Petrographical observation provides and important method in studying the origions of zircons from eclogites.
基金
国土资源部同位素地质研究开放实验室基金
关键词
榴辉岩
同位素体系
变质作用
大别山东部
eastern Dabie mountains eclogites the relationship between isotopic systems and metamorphism
