The Zircon U-Pb Ages of the Low-grade Metamorphic Rocks in the Southern Part of Dabie Mountain,China
大别造山带南部浅变质岩的锆石U-Pb年龄

In the southern part of Dabie Mountain,the low_grade metamorphic (LM)rocks which underwent greenschist facies metamorphism are intercalated with ultrahigh pressure(UHP) eclogites.The zircon U_Pb dates show that the protolith of LM rocks was formed in the early Jinningian period(1100±140Ma),similar to the age of some magmatic rocks in the southern margin of the Yangtze block.The lower point age of zircon U_Pb discordia of LM rock and the date of regional gneiss in UHP block show that these two sorts of rocks were both affected by the thermal event in Caledonia.The Indosinian metamorphism reset the Rb_Sr system of LM rock,but did not affect the U_Pb system.