Mercury stable isotope compositions in magmatic-affected coal deposits: New insights to mercury sources, migration and enrichment
Mercury stable isotope compositions in magmatic-affected coal deposits: New insights to mercury sources, migration and enrichment
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受岩浆影响的煤矿床中的汞稳定同位素组成：对汞来源、迁移和富集的新见解
DOI：
10.1016/j.chemgeo.2017.12.032
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发表时间：
2018-02
期刊：
影响因子：
3.9
通讯作者：
Sonke Jeroen E.
中科院分区：
文献类型：
--
作者：
Zheng Liugen;Sun Ruoyu;Hintelmann Holger;Zhu Jianming;Wang Ruwei;Sonke Jeroen E.
汞（Hg）通常以痕量水平存在于煤炭矿床中。地质作用，特别是岩浆侵入和含煤地层中的热液循环可以显着增加煤中的汞含量。然而，在岩浆作用煤盆地中，热应力、岩浆组分、岩浆-热液流体、低温热液流体对Hg富集的影响是相互混淆的。在这里，我们展示了使用稳定的汞同位素，以了解控制因素的汞富集在两个著名的中国煤矿受岩浆活动的影响：乌兰图嘎低温热液蚀变煤存款和卧龙湖岩浆侵入型煤存款，乌兰图嘎6号煤层是汞的极端富集，从中部煤层的0.37 μg/g到最上部和最下部煤层的40-90 μg/g。观测到的质量分馏变化约为2.5‰（δ 202 Hg的δ =-3.07 ‰ ~-0.58 ‰）。δ 202 Hg-1/[Hg]图解表明，成煤过程中存在原始热液、分馏热液和天然成煤物质三种Hg端元的混合物。乌兰图嘎煤的同位素组成均表现出正的质量无关分馏效应，Δ 199 Hg和Δ 201 Hg分别高达0.87‰和0.66‰。Δ 199 Hg/Δ 201 Hg比值在1.3 - 3.3之间，表明大部分光降解甲基汞可能已进入煤存款。岩浆侵入的卧龙湖8号煤层中Hg仅为轻-中度富集，富集范围为0.10 - 0.40 μg/g。接触岩床附近的煤（≤ 5 cm，− 1.81‰ ~ − 1.52‰）的δ 202 Hg值与岩浆岩床岩（− 2.05‰ ~ − 1.80‰）的δ 202 Hg值相似，但两者的MIF值都不显著。远离接触岩床（≥ 15 cm）的煤δ 202 Hg值变化在-3.40 ‰ ~-1.61 ‰之间，Δ 199 Hg值变化在0.26‰ ~ 0.58‰之间，轻、奇Hg同位素明显富集。远离接触岩床的卧龙湖煤的Δ 199 Hg和Δ 201 Hg在量值和Δ 199 Hg/Δ 201 Hg比值上与大气沃茨和海水相似。我们的两个案例研究表明，显着的汞同位素，这告知汞迁移和封存在岩浆岩和煤矿床，大气降水和热液流体循环的作用。
Mercury (Hg) is commonly present at trace levels in coal deposits. Geological processes, particularly magmatic intrusion and hydrothermal cycling in coal-bearing strata can significantly increase Hg levels in coals. However, the effects of thermal stress, magmatic components, magmatic-hydrothermal fluids, low-temperature hydrothermal fluids on Hg enrichment are confounded in a magmatic-affected coal basin. Here, we demonstrate the use of stable Hg isotopes to understand the controlling factors on Hg enrichment in two well-known Chinese coal deposits affected by magmatic activities: Wulantuga low-temperature hydrothermal-altered coal deposit and Wolonghu magmatic-intruded coal deposit.The Wulantuga No. 6 coal seam is extremely enriched in Hg, varying from 0.37 μg/g in middle coal benches to 40–90 μg/g in the upper most and lowest coal benches. Approximately 2.5‰ variation in mass dependent fractionation (MDF, − 3.07‰ to − 0.58‰ in δ202Hg) is observed. δ202Hg vs. 1/[Hg] diagram suggests a mixture of three Hg end-members: original hydrothermal fluids, fractionated hydrothermal fluids and native coal-forming materials. In addition, Wulantuga coals all show positive mass independent fractionation (MIF) of odd isotopes, up to 0.87‰ in Δ199Hg and 0.66‰ in Δ201Hg. The Δ199Hg/Δ201Hg ratios range from 1.3 to 3.3, suggesting that a large fraction of photodegraded methylmercury was likely incorporated into the coal deposit. The magmatic-intruded Wolonghu No. 8 coal seam is only slightly to intermediately enriched in Hg, varying from 0.10 μg/g to 0.40 μg/g. The coals near the contact sill (≤ 5 cm, − 1.81‰ to − 1.52‰) have similar δ202Hg as the magmatic sill rocks (− 2.05‰ to − 1.80‰), both with insignificant MIF values. Coals far from the contact sill (≥ 15 cm) have δ202Hg values varying from − 3.40‰ to − 1.61‰ and Δ199Hg varying from 0.26‰ to 0.58‰, which are significantly enriched in light and odd Hg isotopes compared to coals near the contact sill. Δ199Hg and Δ201Hg in Wolonghu coals far from the contact sill resemble those of meteoritic waters and seawater in both magnitude and Δ199Hg/Δ201Hg ratio. Our two case studies show significant MDF and MIF of Hg isotopes, which inform on Hg migration and sequestration in the magmatic rocks and coal deposits, and on the roles of meteoric water and hydrothermal fluid circulation.
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影响因子：
5.3
作者：
L. Sherman;J. Blum;D. Nordstrom;R. McCleskey;T. Barkay;C. Vetriani
通讯作者：
L. Sherman;J. Blum;D. Nordstrom;R. McCleskey;T. Barkay;C. Vetriani
影响因子：
5.6
作者：
Ketris, M. P.;Yudovich, Ya. E.
通讯作者：
Yudovich, Ya. E.
中国贵阳降水中汞同位素的质量相关和质量无关分馏
影响因子：
1.4
作者：
Cai HongMing;Huang Qiang;Wang ShuXiao;Wang FengYang
通讯作者：
Wang FengYang
影响因子：
11.4
作者：
L. Lefticariu;J. Blum;J. Gleason
通讯作者：
L. Lefticariu;J. Blum;J. Gleason
DOI：
10.1016/j.crte.2015.04.001
发表时间：
2015-11
期刊：
--
影响因子：
--
作者：
M. Štrok;P. Baya;H. Hintelmann
通讯作者：
M. Štrok;P. Baya;H. Hintelmann