Modern precipitation of hydrogenetic ferromanganese minerals during on-site 15-year exposure tests
Modern precipitation of hydrogenetic ferromanganese minerals during on-site 15-year exposure tests
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现场 15 年暴露试验期间氢化铁锰矿物的现代沉淀
DOI：
10.1038/s41598-020-60200-5
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发表时间：
2020
影响因子：
4.6
通讯作者：
Yamaoka K.
中科院分区：
文献类型：
--
作者：
Usui A.;Hino H.;Suzushima D.;Tomioka N.;Suzuki Y.;Sunamura M.;Kato S.;Kashiwabara T.;Kikuchi S.;Uramoto G.-I.;Suzuki K.;Yamaoka K.
对氧化还原敏感的金属元素锰和铁在深海沃茨中被氧化，并以极低的增长率在世界洋底形成丰富的铁锰结壳和结核。这种氧化过程和沉淀机制尚不清楚。本文介绍了第一次成功的、长期的、现场的矿物沉淀实验的结果，该实验证实了现代的、正在进行的氧化物材料的水成沉积，这些氧化物材料来自水深900-4500米的地质活动和非活动环境。我们成功地在海底原位沉淀实验，并采用高分辨率和亚微米尺度的化学，矿物学和结构分析的沉淀物的特点。安装的玻璃、陶瓷和塑料人造板产生了直径从1微米到几微米不等的散布颗粒，球形不规则形状，暴露12-15年后最多为1，000 - 10，000个单个颗粒/mm 2/年。结果表明，如果Mn和Fe同时供给底层沃茨，则水成矿物会持续大量生长。沉淀物的矿物学、化学和结构特性与海底天然沉淀物相似，后者由水成铁锰结壳和结核以及沉降沉积物、悬浮的热液颗粒或培养的锰氧化细菌的微生物沉淀物组成。我们的工作提出了新的现实的见解，提出了现代不同的海洋环境中的海洋水成铁锰矿床的成因模式。
Redox-sensitive metallic elements, Mn and Fe, are oxidized in deep sea waters and form abundant ferromanganese crusts and nodules on the world’s ocean floors at ultraslow rates of growth. This process of oxidation and the mechanism of precipitation are yet unknown. In this paper, the results of the first successful, long-term, on-site experiment of mineral precipitation that ascertains modern, ongoing hydrogenetic deposition of oxide materials from normal seawaters at water depths of 900–4500 m of geologically active and inactive environments are presented. We succeeded in thein-situprecipitation experiment on the sea floor and characterized the precipitates using high-resolution and submicron-scale chemical, mineralogical, and structural analyses. The installed artificial plates of glass, ceramics, and plastic yielded spread-out particles of sizes varying from one to a few micrometers in diameter, of coccoid-like irregular shapes, with a maximum of 1,000–10,000 individual particles/mm2/year after 12–15 years of exposure. The results indicated a continuous substantial growth of the hydrogenetic minerals if both Mn and Fe are supplied to the bottom waters. The mineralogical, chemical, and structural properties of the precipitates are similar to those of the natural precipitates on the seabed that are made up of hydrogenetic ferromanganese crusts and nodules, together with settling sediments, suspended hydrothermal particles, or microbial precipitates from cultivated Mn-oxidizing bacteria. Our work presents new realistic insight into proposed genetic models of marine hydrogenetic ferromanganese deposits in modern diverse ocean environments.