The 'Datangpo type' manganese deposits were formed in the rift basin in Nanhua Period along the Guizhou-Hunan-Chongqing border area.This type of ore deposits is controlled by the ancient fault and is mainly distributed at the center of the sedimentary basin of the secondary fault depression in the rift basin.The mineral composition mainly consists of reddingite and calcium reddingite,characterized by low δ13C(-7‰ to-10‰)and high δ34S(+ 40‰ to + 63‰).The Mn/Cr ratios of carbonaceous shale that contains manganese are close to 40.Abundant structures are observed in reddingite,and such characteristics as soft-sedimentary deformation formed by natural gas seepage,diapir structure,bubble-shaped structure,hole structure,leaky pipe structure and salse structure are well developed.The above evidence further proves that the 'Datangpo type' manganese deposits were formed by large-scale mineralization caused by the ancient natural gas seepage system.The homologous ore-forming model was built,in which the facies were divided into central facies,transitional facies and edge facies.%黔湘渝毗邻区“大塘坡式”锰矿床形成于南华纪裂谷盆地中,矿床主要分布于裂谷盆地中的次级断陷沉积盆地中心,受古断裂控制.矿物成分主要是菱锰矿和钙菱锰矿,具有低δ13C值(-7‰～-10‰)、高δ34S值(+40‰～+63‰)的特征.含锰岩系中,碳质页岩的Mn/Cr比值在40左右.结合菱锰矿体及相邻岩层中普遍发育由古天然气泄漏沉积形成的气泡状构造、底辟构造、渗漏管构造、帐篷构造、泥火山构造及相关的软沉积变形纹理等特征,提出该地区南华纪“大塘坡式”锰矿床是古天然气渗漏沉积成矿成因,并建立了古天然气渗漏沉积型锰矿床成矿系统与成矿模式.
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