贵州新元古代大塘坡期巨量锰矿成矿物质来源分析

新元古代大塘坡期，贵州松桃等地形成锰矿集聚区，并发育4个世界级锰矿床，累计探明锰资源量达7亿t。但是什么地质条件下，能导致如此巨量的锰质富集成矿，其成矿物质来源问题一直没有得到满意的解释。本文通过对含锰岩系大塘坡组基底板溪群及海底火山岩中锰含量特征、江南造山带演化以及Rodinia超大陆解体与锰矿成矿关系分析，认为基底板溪群中锰含量高，MnO含量达到0. 16%，板溪群风化壳中锰含量更高，MnO达0. 88%。板溪群中的同期岛弧玄武岩含MnO更高，达到0. 25%，它们可能是锰矿成矿的物源层，是形成巨量锰矿的基础；江南造山带造山挤压变质作用，引起板溪群和岛弧玄武岩中锰质活化、迁移富集；Rodinia超大陆解体，在650 Ma发生拉张裂谷作用，使活化富锰变质流体沿着断裂喷流出海底，形成大量锰矿。

Ore forming source analysis of huge manganese deposits in the Neoproterozoic Datangpo stage, Guizhou Province, China

The Neoproterozoic Datangpo stage manganese depositslie in the Songtao region, Guizhou Province with four world class manganese deposits.The accumulated proven manganese resources amount to 700 million tons, which formed a significant manganese ore concentrated area in China. However, the geological conditions that could lead to such a huge amount of manganese enrichment mineralization and the source of its mineralized material have not been unified for a long time. In this paper, by analyzing the background of Mn content in the Banxi Group and syngenetic submarine volcanic rocks, it is concluded that the basal Banxi Group and volcanic rocks have high Mn content (0. 16%), and the weathered crust of the Banxi Group has higher Mn content (0. 88%). Meanwhile, the contemporaneous island arc basalts in the Banxi Group contain even higher MnO (0. 25%), and they may be the source layer for manganese ore formation, which is an important basis for the formation of huge amounts of manganese deposits. Integrated the relationship between the evolution of the Jiangnan orogenic belt, Rodinia supercontinental disintegration and manganese mineralization is considered that the orogenic extrusion metamorphism of the Jiangnan orogenic belt caused the activation and migration enrichment of manganese in the Banxi Group and island arcbasalts, while the tensional rifting caused by Rodinia supercontinental disintegration (650 Ma) caused the manganese rich metamorphic fluids along the fracture entered to the seafloor and formed a large number of manganese deposits.