【摘要】 广西北部龙胜地区丹洲群广泛发育一套细碧岩和镁铁 -超镁铁质岩石。细碧岩具有板内和岛弧火山岩的双重地球化学属性 ,其形成时代 <82 0 Ma。本文作者综合地质学、岩石学、地球化学和同位素年代学的资料 ,提出龙胜地区丹洲群火山岩及镁铁 -超镁铁质岩石不属于蛇绿岩 ,而是新元古代 (～ 82 0 Ma)大陆裂谷进一步发展的产物 ,其形成与 Rodinia超级大陆的裂解过程相联系。这一认识对华南地区前寒武纪大地构造演化研究具有重要意义更多还原

【Abstract】 A large number of spilitic and mafic ultramafic rocks exist in the Longsheng region of northern Guangxi. These rocks were previously considered as th “Longsheng Ophiolite”. Comprehensive investigations of field geology, petrology and geochemistry for these rocks were carried out in this study. Mafic ultramafic rocks are dominantly gabbros and serpentinized olivine gabbros and olivine pyroxenolites. They show intrusive contacts with the country rocks of Danzhou Group. The spilites, interlayed within the Neoproterozoic Danzhou Group (≤ 820 Ma), are geochemically characterized by enrichment of most incompatible trace elements but depletion of Nb, Ta and Ti, indicating that they were likely generated within an intraplate environment with various degrees of crust contamination. Thus, the spilites and mafic ultra mafic intrusives in the Longsheng region are not part of a “ophiolite complex”, but the products of mantle derived magma generated during the evolution of the Neoproterozoic Nanhua rift.更多还原