贵州镇远都坪地区大塘坡组含锰白云岩及其后期风化富集机制

周高; 胡涛; 高骏; 李信念; 李源洪; 甄鑫; 许灵通; 余文超

周高,胡涛,高骏,李信念,李源洪,甄鑫,许灵通,余文超.贵州镇远都坪地区大塘坡组含锰白云岩及其后期风化富集机制[J].贵州地质,2025,42(3):297-314

贵州镇远都坪地区大塘坡组含锰白云岩及其后期风化富集机制

Manganese-bearing Dolomite of the Datangpo Formation in the Duping Area of Zhenyuan, Guizhou and its Supergene Weathering Enrichment Mechanism

投稿时间：2025-04-21

DOI：

中文关键词: 含锰白云岩风化富集都坪镇远贵州

英文关键词:Manganese-bearing dolomite Weathering enrichment Duping Zhenyuan Guizhou

基金项目:本文受贵州省地质矿产勘查开发局地质科研项目《贵州镇远地区锰矿成矿地质条件和找矿前景研究》(编号:黔地矿科合〔2021〕4号)资助

作者	单位
周高	贵州省地质矿产勘查开发局106地质大队，贵州遵义 563000
胡涛	贵州省地质矿产勘查开发局106地质大队，贵州遵义 563000
高骏	中国地质大学武汉，地球科学学院，湖北武汉 430074 湖北楚鹏资源环境工程有限责任公司，湖北孝感 432020
李信念	贵州省地质矿产勘查开发局106地质大队，贵州遵义 563000
李源洪	贵州省地质矿产勘查开发局106地质大队，贵州遵义 563000 中国地质大学武汉，地球科学学院，湖北武汉 430074
甄鑫	中国地质大学武汉，地球科学学院，湖北武汉 430074 自然资源部基岩区矿产资源勘查工程技术创新中心，贵州贵阳 550081
许灵通	中国地质大学武汉，地球科学学院，湖北武汉 430074 自然资源部基岩区矿产资源勘查工程技术创新中心，贵州贵阳 550081
余文超	中国地质大学武汉，地球科学学院，湖北武汉 430074 自然资源部基岩区矿产资源勘查工程技术创新中心，贵州贵阳 550081

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中文摘要:

本文以贵州镇远都坪地区大塘坡组底部含锰白云岩为研究对象，通过岩石学、矿物学、元素地球化学及碎屑锆石年代学综合分析，揭示了原生含锰层的沉积环境及次生氧化锰矿体的风化富集机制。研究结果表明:含锰白云岩具有显著的Mn(026%〖XC线.TIF,JZ〗276%)与Fe(065%〖XC线.TIF,JZ〗223%)富集特征，并呈现高Ba含量(均值215%)、显著正Eu异常(Eu/Eu=256)及正Y异常(均值122)。上述地球化学特征指示该套白云岩形成于新元古代“雪球地球”冰期早期的特殊海水环境，其锰源可能与海底热液活动输入相关。冰期后海水Mn2+的富集源于冰盖覆盖期热液通量的长期累积及冰消期氧化还原条件的转变。区内锰矿体主要为表生风化作用形成的次生氧化锰矿床，含锰矿物以软锰矿和隐钾锰矿为主，Mn含量最高达2225%。风化过程中，原生碳酸锰矿物经氧化-吸附作用形成锰氧化物，且矿物序列显示隐钾锰矿向软锰矿的转变特征。碎屑锆石U-Pb年龄谱(主峰86 Ma)表明，除含锰白云岩外，区内可能存在燕山期煌斑岩体，其风化产物亦为次生锰矿提供了重要物质来源。本研究为解析区内表生锰矿的成矿机制及区域找矿方向提供了关键依据。

英文摘要:

In this paper, it takes the manganese-bearing dolomite at the bottom of the Datangpo formation in the Duping area of Zhenyuan, Guizhou as the studying object. Through comprehensive analyses encompassing petrology, mineralogy, elemental geochemistry, and detrital zircon geochronology, the sedimentary environment of primary manganese- bearing dolomite and the weathering-enrichment mechanisms of secondary manganese oxide orebodies have been revealed. The studying results shows: the manganese- bearing dolomite exhibits significant Mn (026%〖XC线.TIF,JZ〗276%) and Fe (065%〖XC线.TIF,JZ〗223%) enrichment, along with high Ba content (average 215%), obvious positive Eu anomalies (Eu/Eu = 256), and positive Y anomalies (average = 122). These geochemical signatures indicate these dolomite formed in a unique marine environment following the Neoproterozoic "Snowball Earth" deglaciation, with manganese sources potentially linked to submarine hydrothermal activity. The post-glacial seawater Mn2+ enrichment resulted from long-term hydrothermal flux accumulation during ice sheet coverage and redox condition changes during deglaciation. The manganese orebodies predominantly comprise secondary oxide deposits formed through supergene weathering, dominated by pyrolusite and cryptomelane with maximum Mn content reaching 2225%. In the weathering processes, it transformed primary manganese carbonate minerals into oxides through oxidation-adsorption, with mineral sequences revealing cryptomelane-to-pyrolusite transitions. Detrital zircon U-Pb age spectra (main peak at 86 Ma) demonstrate that besides the dolomite of the Datangpo formation, there may be Yanshanian lamprophyre rocks in the area, and their weathering products also contributed significantly to secondary manganese mineralization. This research provides critical accordance for understanding metallogenic mechanisms of supergene manganese deposits in the Datangpo formation and regional exploration targeting.

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