古天然气渗漏沉积型锰矿床成矿系统与成矿模式——以黔湘渝毗邻区南华纪“大塘坡式”锰矿为例  

Ancient natural gas seepage sedimentary-type manganese metallogenic system and ore-forming model:A case study of 'Datangpo type' manganese deposits formed in rift basin of Nanhua Period along Guizhou-Hunan-Chongqing border area

作　　者：周琦[1] 杜远生[2] 覃英[3] 

机构地区：[1]贵州省地质矿产勘查开发局,贵州贵阳550003 [2]中国地质大学地球科学学院,湖北武汉430074 [3]贵州省地质矿产勘查开发局103地质大队,贵州铜仁554300

出　　处：《矿床地质》2013年第3期457-466,共10页Mineral Deposits

基　　金：中国地质调查局成都地质调查中心项目"黔东地区大塘坡期锰矿成矿地质背景综合研究"(编号:基[2011]01-02);中国科学院地球化学研究所矿床地球化学国家重点实验室开放基金研究项目"黔东古天然气渗漏沉积型锰矿(大塘坡式)黄铁矿地球化学特征研究"(编号:201207);贵州省2011年度公益性;基础性地勘基金项目"贵州区域构造与重要矿产成矿区带研究"的联合资助

摘　　要：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。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 313C（ - 7%0 to - 10%） and high 334S（ ＋ 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.

关 键 词：地质学 锰矿床 天然气渗漏沉积 成矿模式 南华纪 黔湘渝 

分 类 号：P618.32[天文地球—矿床学]