supported by the National Natural Science Foundation of China(Grant Nos.402340520,4997301 and 40172025);the Major State Basic Research Development Program from the Ministry of Science and Technology(Grant No.2002CB412600);the Key Project of QTP from MLR(Grant No.200101020404).
40Ar/39Ar ages were determined for 6 phlogopite samples from a kamafugite pipe occurring in western Qinling, yielding a time span of 22 to 23 Ma for kamafugite eruption. Together with known geochronological data for t...