摘要
密云环斑花岗岩与华北克拉通的破坏、燕辽裂谷的启动同期,其年代学研究一直令人关注,已获得的一些数据虽然具有参考意义,但缺乏高质量的SHRIMP定年的制约。利用西澳大利亚科庭大学离子探针中心进行远程测试,首次在该花岗岩体中获得锆石SHRIMP U-Pb加权平均年龄1685Ma±15Ma。这一年龄表明燕辽裂谷最早启动于1700Ma,为准确地标定长城系底界的年龄提供了重要的参考依据。
Much attention has long been paid to the chronology of rapakivi granite in Miyun because it formed simultaneously with the destruction of the North China craton and initiation of the Mesoproterozoic Yanhao rift. High-quality SHRIMP ages were lack- ing though some data available could be used as reference. The authors for the first time obtained a weighted mean SHRIMP U-Pb zircon age for the rapakivi granite by telemetry at the Ion Microprobe Center, Curtin University, Western Australia, and got a highquality weighted-mean SHRIMP age of 1685±15 Ma. This age suggests that the Yanliao rift was initiated at 1700 Ma. This age prorides an important base for calibrating the age of the lower boundary of the Changchengian System.
出处
《地质通报》
CAS
CSCD
北大核心
2008年第6期793-798,共6页
Geological Bulletin of China
基金
科技部基础专项(编号:2006FY120300-1)
中国地质调查局项目(编号:1212010511702)
北京市教改项目
国家自然科学基金项目(编号:G0800-06-Zs-319)联合资助
