Elemental and Sr-Nd-Pb isotopic compositions of late Cenozoic Abaga basalts, Inner Mongolia: Implications for petrogenesis and mantle process

摘要

The Abaga volcanic field is one of the largest and least known areas of late Cenozoic intraplate igneous activities in eastern China. Twenty-seven Abaga basaltic rocks were analyzed for major and trace element contents, Sr-Nd-Pb isotopic compositions, and K-Ar dating. These basalts predominantly consist of alkali basalt with subordinate transitional olivine tholeiite and rare quartz tholeiite. Combining our data of ten K-Ar dates with previously published data showed that the time of the principal volcanic eruption was from the Miocene to the Quaternary (14.57-0.19 Ma), A large amount of volcanic activity is believed to have begun in the northwestern portion of the AVF and gradually migrated southeast-wards with geological time.