A group of gabbroic granulite/gabbro deep-seated xenoliths have been found from Mesozoic-Cenozoic basaltic rocks in southeast China. The gabbroic granulite xenoliths from Qilin Cenozoic basaltic pipe in the coastal area are studied. A comparison study is also made with the gabbro, granitic gneiss xenoliths from Daoxian Mesozoic basaltic pipe. These studies indicate that gabbroic granulite was formed by underplating of basaltic magma at the bottom of the crust, and experienced metamorphism. Underplating is an important process of crust/mantle interaction, and an essential process in the crustal evolution of the continental margin of southeast China. The Sm-Nd isotope dating shows that the crystallization age of underplating material in the continental margin of southeast China is 112.3±17.8Ma. In addition, the extent of underplating in different tectonic area may be different, which depends on the development of basaltic volcanism, wide distribution of crust-mantle type granitoids.
|Number of pages||7|
|Journal||Acta Petrologica Sinica|
|Publication status||Published - 1999|
- Isotope dating
- Lower crust