MAFIC INTRUSIONS IN LONGSHENG AREA: AGE AND ITS GEOLOGICAL IMPLICATIONS
Ge Wenchun1, Li Xianhua1, Li Zhengxiang2, Zhou Hanwen3
1. Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640; 2. Department of Geology and Geophysics, University of Western Australia, Nedlands WA6009, Austral; 3. Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074
A study on single zircon U -Pb chronology and Sm-Nd isotopic tracing shows that mafic intrusions derived from a magma characteristic of longly depleted mantle source by the process of emplacement and crystallization, which had ever been contaminated by crustal materials during its ascending course at 760 Ma. This dating result has limited the upper sedimentation age of Danzhou Group, and present an important chronological constraint on the recognition about not existing ophiolite suite in Longsheng area, northern Guangxi. The formation and emplacement of mafic magma may relate to another breakup event after the breakup event of Rodinia supercontinental at ～825 Ma.