【摘要】 对镁铁质侵入体进行了单颗粒锆石 U- Pb年代学和 Sm- Nd同位素示踪研究。结果表明 :镁铁质侵入体是起源于长期亏损地幔源区的岩浆在 760 Ma侵位结晶的产物 ,其侵位过程中遭受地壳物质的混染。该年龄结果限定了丹洲群地层的沉积上限年龄 ,并为龙胜地区不存在蛇绿岩套的认识提供重要的年代学制约。镁铁质岩浆的形成、侵位可能与 Rodinia超大陆～ 82 5Ma裂解之后的另一次裂解事件相联系。更多还原

【Abstract】 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.更多还原