Partitioning and Surficial Segregation of Trace Elements in Iron Oxides in Hydrothermal Fluid Systems
| Autor: | N. V. Smagunov, Vladimir L. Tauson, D. N. Babkin, Taisa Pastushkova, S. V. Lipko, Nikolay V. Bryansky, Olga Yu. Belozerova |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
magnetite
lcsh:QE351-399.2 Materials science 010504 meteorology & atmospheric sciences Analytical chemistry Ni-spinel chemistry.chemical_element Electron microprobe 010502 geochemistry & geophysics 01 natural sciences hematite law.invention Crystal chemistry.chemical_compound Iron group law crystal surface Hydrothermal synthesis 0105 earth and related environmental sciences Magnetite hydrothermal solution lcsh:Mineralogy fluid composition aluminium Geology iron group elements Hematite Geotechnical Engineering and Engineering Geology trace element surficial accumulation co-crystallisation coefficient Copper chemistry visual_art visual_art.visual_art_medium Atomic absorption spectroscopy |
| Zdroj: | Minerals, Vol 11, Iss 57, p 57 (2021) Minerals Volume 11 Issue 1 |
| ISSN: | 2075-163X |
| Popis: | Partitioning experiments were done by hydrothermal synthesis of crystals containing trace elements (TEs) by internal sampling of fluid at the temperature of 450 ° C and pressure of 1 kbar. The crystal phases obtained were magnetite, hematite, and Ni-spinel, which were studied using X-ray diffraction (XRD), X-ray electron probe microanalysis (EPMA), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), atomic absorption spectrometry (AAS), and atomic force microscopy (AFM). The solutions from the sampler&rsquo s fluid probes were analysed by AAS for TEs included elements of the iron group plus aluminium. The highest co-crystallisation coefficients of TE and Fe between mineral and fluid (DTE/Fe) in magnetite were measured for V, Al, Ni and Cr (in decreasing order of n units in value), a lower value was observed for Co (2 × 10&minus 1), and still lower values for Ti, Zn, and Mn (n × 2&ndash 3). In hematite, DTE/Fe values were highest for Al and V (order of n units in value), while lower values characterised Ti, Cr, and Co (n × 1&ndash 3), and the lowest values were exhibited by Cu, Mn, and Zn (n × 5). Copper was confirmed to be the most incompatible with all minerals studied however, Cu had a high content on crystal surfaces. This surficial segregation contributes to the average TE concentration even when a thin layer of nonautonomous phase (NAP) is enriched in the element of interest. The accumulation of TEs on the surface of crystals increased bulk content 1&ndash 2 orders of magnitude above the content of structurally-bound elements even in coarse crystals. The inverse problem&mdash evaluation of TE/Fe ratios in fluids involved in the formation of magnetite-containing deposits&mdash revealed that the most abundant metals in fluids were Fe followed by Mn, Zn, and Cu, which comprised 10 to 30% of the total iron content. |
| Databáze: | OpenAIRE |
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