超大陆裂解与中国大规模成锰作用的耦合关系探讨

Discussion about the coupling relationship between the breakup of supercontinent and the large-scale manganese accumulation in China

中国沉积型菱锰矿赋存时代跨度大,分布广泛。成矿时代集中于中元古代蓟县纪,新元古代南华纪、震旦纪,早古生代寒武纪、奥陶纪,晚古生代泥盆纪、石炭纪、二叠纪和中生代三叠纪。沉积型菱锰矿分布于伸展背景下的裂谷型盆地区,包括华北中元古代燕辽坳拉槽,华南南华纪—奥陶纪南华裂谷、南华纪扬子北部陆内裂谷、震旦纪—寒武纪扬子北部大陆边缘裂谷、晚古生代—三叠纪右江盆地和湘桂拗拉槽、扬子西部(水城—遵义)陆内裂陷槽和扬子西北缘裂陷槽。菱锰矿的锰质主要来源于地球深部热液,沉积于弱氧化—弱还原的较深水的浅裂谷环境。裂谷型盆地形成于哥伦比亚超大陆、罗迪尼亚超大陆、冈瓦纳大陆的裂解期。沉积型菱锰矿的发育与超大陆裂解存在明显的耦合关系。

Sedimentary Mn carbonate deposits in China are accumulated in a large time scale and widely distributed.The metallogenic peaks are Mesoproterozoic Jixianian,Neoproterozoic Nanhuan and Sinian,Early Paleozoic Cambrian and Ordovician,Late Paleozoic Devonian,Carboniferous and Per mian,and Mesozoic Triassic.Sedimentary Mn carbonate deposits are mainly distributed in stretching rift basin,including the Mesoproterozoic Yan-Liao Aulacogen in North China,the Nanhuan-Ordovician Nanhua Rift Basin,the Nanhuan intracontinental rift in northern Yangtze Block,the Sinian-Cambrian con tinental margin rift in northern Yangtze Block,Late Paleozoic-Triassic Youjiang Basin and the Xiang-Gui Aulacogen,the intracontinental trough in the western Yangtze Block(Shuicheng-Zunyi)and the trough in northwestern Yangtze Block.The source of the Mn carbonate deposit mainly comes from the deep hydrothermal fluid,which are then deposited in the shallow rift environment of suboxic deep water.The rift-type basins were formed during the breakup periods of the Columbia Supercontinent,the Rodinia Supercon tinent and the Gondwana continent.There is an obvious coupling relationship between formations of the sedimentary Mn depo sits and the breakup of supercontinents.