贵州遵义二叠系茅口组锰矿成矿建造、盆地原型及锰矿相带特征*

为提高勘查效率,降低找矿勘查风险及成本,需建立贵州遵义二叠系锰矿深部找矿预测模型。近年来通过“贵州遵义锰矿整装勘查区矿产地质调查与找矿预测”项目4个1︰50000图幅专项地质填图工作,总结了贵州遵义二叠系茅口组锰矿成矿建造、盆地原型及锰矿相带特征及标志。根据不同的岩性组合和结构构造等,将锰矿成矿期沉积(茅口组三段)划分为6个建造类型,分别为富锰建造、贫锰建造、含锰建造、黏土岩建造、硅化岩建造、生物灰岩建造,并划分出中心相、过渡相和边缘相3个锰矿相带;依据地层厚度、硅化角砾岩、特殊沉积构造、AMT地球物理标志,对盆地原型进行了分析。以上述理论为指导开展找矿预测工作,在研究区圈定了3个全隐伏找矿靶区,为钻探工程部署提供依据。2018—2019年在谢家坝找矿靶区施工了4个验证钻孔,均揭露厚层富锰矿体,初步探获新增锰矿资源量逾2200×10⁴ t,显示该理论方法运用在遵义锰矿区深部找矿预测是有效的,对勘查工作指导效果显著。

Characteristics of metallogenic formation,basin prototype and manganese facies belt of the Permian Maokou Formation in Zunyi area,Guizhou Province

In order to improve the exploration efficiency and reduce the risks and costs of prospecting and exploration,a prediction model for deep prospecting of the Permian manganese deposit in Zunyi area,Guizhou Province was established in this paper. In recent years,four geological maps with the scale of 1︰50000 were established through the project of “Mineral Geological Survey and Prospecting Prediction in Zunyi Manganese Mine Integral Exploration Area,Guizhou”,and the manganese ore formation,basin prototype,and manganese facies belt characteristics of the Permian Maokou Formation in Zunyi,Guizhou have been summarized. In this paper,according to different lithological combinations,structural structures,six types of deposition combinations were found in the manganese mineralization period of the Third Member of Maokou Formation,including manganese-rich formation,manganese-poor formation,manganese-bearing formation,clay rock formation,silicified rock formation and biological limestone formation. Furthermore,the characteristics of central facies,transition facies and marginal facies of the manganese ore are summarized. The prototype of the basin was analyzed from the thickness of stratum,silicified breccia,special sedimentary structure,and AMT geophysical signs. The theories mentioned above were used to guide the manganese prospecting. Three fully hidden prospecting target areas have been delineated,which provide a basis for drilling projects. From 2018-2019,four boreholes were constructed in the Xiejiaba prospecting target area and thick manganese ore bodies were found in all boreholes,and more than 22 million tons manganese ore have been detection. This shows that the theoretical and methods presented in this paper are effective for deep prospecting of manganese ore in Zunyi area.