广西大新县土湖锰矿床地质特征及成矿模式研究

Geological Characteristics and Metallogenic Model of Tuhu Manganese Deposit in Daxin County,Guangxi

土湖锰矿是桂西南地区重要的锰矿床之一,目前研究程度尚浅。为服务于土湖锰矿整装勘查,在综合分析前人研究工作的基础上,通过野外地质调查和样品采集与测试分析,开展锰矿床地质特征的系统研究,综合分析提出成矿模式。研究结果表明:榴江组是土湖锰矿的重要含锰岩系,发育3个碳酸锰矿层和5个氧化锰矿层,锰矿类型划分为氧化锰矿石和碳酸锰矿石两种。碳酸锰矿石主要为微粒结构,氧化锰矿石结构主要受风化作用影响,矿石构造主要有微层状构造、条带状构造、豆状构造、土状构造、瘤状构造等。土湖锰矿床的形成经历了碳酸锰矿床形成阶段和锰帽型氧化锰矿床形成阶段两大阶段,热液为锰质主要来源,有机物分解消耗大量氧气并提供了充足碳酸根,形成碳酸锰矿。后期锰矿层经风化、淋滤致锰元素富集且被淋积于其下方的锰帽中,菱锰矿转化为软锰矿及偏锰酸矿,形成锰帽型氧化锰矿层。

Tuhu Manganese deposit is one of the important manganese deposits in Southwest Guangxi.But the research level is still not so good at present.To serve the whole exploration of Tuhu Manganese mine,we think,on basis of comprehensive analysis of previous research work,the systematic study on geological characteristics of manganese deposits has been carried out in the field geological survey and sample collection and test analysis.The metallogenic model is put forward by comprehensive analysis.The results show that Liujiang formation is an important manganese bearing rock series of Tuhu manganese deposit.There are three manganese carbonate beds and five manganese oxide beds.Manganese ore is divided into two types:manganese oxide ore and manganese carbonate ore.Manganese carbonate ore is mainly of particle structure.The structure of manganese oxide ore is mainly affected by weathering.Ore structure mainly includes the micro layered structure,including the banded structure,the bean structure,the earth structure and the nodular structure.The formation of Tuhu manganese deposit has experienced two stages:the formation stage of carbonate manganese deposit and the formation stage of manganese cap type manganese oxide deposit.Hydrothermal solution is the main source of manganese.Organic decomposition consumes a lot of oxygen and it provides sufficient carbonate.Then,manganese carbonate ore is formed.In the later stage,the manganese ore bed was enriched by weathering and leaching.Manganese is drenched in the manganese cap below it.Generally,it is known that Rhodochrosite transform is formed into Pyrolusite and Metamanganate,manganese cap type manganese oxide ore bed.