Geochronology and geodynamic implications of the felsic granulite xenoliths from the Hannuoba Basalt
LIU Yong- sheng1, GAO Shan1,2, ZHOU Lian1, ZHANG Li1, JIN Shu- yan1 (1. Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China; 2. Department of Geology, Northwest University, Xi an 710069, China)
Many felsic granulite xenoliths including some granulite- facies metasediments occur in Zhouba area, Hannuoba Basaltic Field at the northern margin of the North China craton. The U- Pb and Pb- Pb zircon ages and whole rock Sm- Nd isotopic compositions suggest that they could be old residua in the lower crust. A mineral separate- whole rock Sm- Nd isochron age of (424± 10) Ma was obtained for one granulite- facies metasedimentary xenolith, which implies that the re- emplacement and metamorphism of the granulite- facies metasedimentary xenoliths were related to the Palaeozoic subduction of Mongolia oceanic crust under the North China craton during Caledonian orogeny.