| 王勇,文春华,曹创华,谭静强,曾广乾,邹光均,王灵珏,张进富.湘西民乐地区大塘坡组锰矿沉积古盐度特征及其成矿过程的指示[J].矿产勘查,2025,16(6):1311-1321 |
| 湘西民乐地区大塘坡组锰矿沉积古盐度特征及其成矿过程的指示 |
| The paleosalinity characteristics of manganese deposits in the Datangpo Formation in Minle area, western Hunan and their implications for metallogenic processes |
| 投稿时间：2025-04-12 |
| DOI：10.20008/j.kckc.202506002 |
| 中文关键词: 新元古代 Sturtian冰期 大塘坡组 沉积型锰矿 成矿机理 |
| 英文关键词: Neoproterozoic Sturtian glaciation Datangpo Formation sedimentary manganese ore metallo. genic mechanism |
| 基金项目:本文受国家重点研发项目(2017YFC0601506)和湖南省自然科学基金项目(2024JJ8357，2024JJ8366，2025JJ80026，2025JJ80052)联合资助。 |
|
| 摘要点击次数: 1151 |
| 全文下载次数: 1355 |
| 中文摘要: |
| 湘西地区大塘坡式锰矿床的形成与盆地底水氧化密切相关，明确其驱动机制有助于深入理解成矿过程，并为找矿工作提供理论指导。本文以民乐地区大塘坡组剖面为研究对象，开展全岩主、微量元素地球化学分析，利用 Mo含量、V/(V+Ni)和 V/Cr等氧化还原指标及古盐度参数(B/Ga)，建立化学地层，探讨沉积氧化还原条件与古盐度的演化关系。结果显示，黑色页岩多沉积于缺氧的半咸水—海水环境，而优质锰矿则形成于氧化或贫氧的淡水—半咸水环境。沉积环境由缺氧向氧化转变时，B/Ga比值急剧下降，反之则升高，表明淡水输入通量对水体氧化还原状态起到关键性控制作用。近岸浅水盆地的底水氧化可能由陆地富氧淡水注入驱动，有别于深水区由冰盖融水下沉引发的氧化机制。因此，在近岸浅水区找矿工作中，应重视古河道和三角洲等淡水输入主控体系的识别。 |
| 英文摘要: |
| The formation of the Datangpo-type manganese deposit in western Hunan is closely related to theoxidation of bottom waters in the basin. Clarifying its driving mechanisms is essential for a deeper understanding ofthe metallogenic process and provides theoretical guidance for mineral exploration. This study focuses on theDatangpo Formation section in the Minle area, conducting whole-rock major and trace element geochemical analy.ses. Redox-sensitive indicators such as Mo content, V/(V+Ni), and V/Cr, as well as paleosalinity parameters (B/Ga),were used to establish a chemostratigraphy and to investigate the relationship between the evolution of redox condi.tions and paleosalinity. The results indicate that black shales were primarily deposited in aNOxic, brackish to marineenvironments, in contrast to high-quality manganese ores, which formed under oxic to dysoxic conditions in freshwa.ter to brackish settings. During transitions from aNOxic to oxic depositional environments, B/Ga ratios decreasedsharply, and conversely increased during shifts toward more reducing conditions, suggesting that freshwater influxplayed a key controlling role in regulating the redox state of the water column. In nearshore shallow-water basins,the oxidation of bottom waters may be driven by the influx of oxygenated freshwater from terrestrial sources, differ.ing from deepwater oxidation driven by the downward penetration of glacial meltwater. Therefore, in the explorationof nearshore areas for Datangpo-type manganese deposits, identifying freshwater-controlled depositional systemssuch as paleochannels and deltas should be a key focus. |
|
查看全文
查看/发表评论 下载PDF阅读器 |
| 关闭 |
|
|
|