Elemental sulfur in northern South China Sea sediments and its significance
Elemental sulfur in northern South China Sea sediments and its significance
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DOI：
10.1007/s11430-015-5182-7
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发表时间：
2015-09
期刊：
影响因子：
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通讯作者：
Qixiang Lin;Jiasheng Wang;S. Fu;Hongfeng Lu;Q. Bu;Rongxiao Lin;Fei Sun
中科院分区：
文献类型：
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作者：
Qixiang Lin;Jiasheng Wang;S. Fu;Hongfeng Lu;Q. Bu;Rongxiao Lin;Fei Sun
元素硫(Es)是无机硫循环的中间体之一，对不同储集层和海洋环境中稳定硫同位素的分馏起着关键作用。本研究利用扫描电子显微镜和拉曼光谱技术，在南海北部中国海九龙甲烷礁附近的沉积物中发现了固体Es。结合硫化物的形态和分布、硫铁矿浓度和硫同位素特征，认为：(1)固体硫化物主要分布在矿物集合体表面，与黄铁矿微晶、硫化物(氧)氧化物和粘土矿物共存；(2)固体硫化物主要赋存于硫酸盐-甲烷过渡带(SMTZ)内及其附近，形态变化不大；(3)ES的形成可能与硫化氢氧化作用有关，因此与SMTZ的波动有关。在SMTZ内，由于甲烷的强化厌氧氧化和异化的硫酸盐还原，产生了硫化氢和黄铁矿。这提高了无机硫循环的效率，并为ES的形成提供了有利条件。九龙甲烷礁附近沉积物中固体Es的发现与SMTZ波动有重要关系，可能对南中国海甲烷水合物的演化具有重要意义。
Elemental sulfur (ES) is one of the intermediates in the inorganic sulfur cycle and thus plays a key role in the fractionation of stable sulfur isotopes in different reservoirs and the marine environment. In this study, solid ES is discovered in sediments near the Jiulong Methane Reef in the northern South China Sea by scanning electron microscopy and Raman spectroscopy. Combining the morphology and distribution of ES, pyrite concentrations, and sulfur isotopes, we conclude that: (1) solid ES coexists with pyrite microcrystals and sulfide (oxyhydr)oxides as well as clay minerals, and they are mainly distributed on the surface of mineral aggregates; (2) ES mainly occurs within and near the sulfate-methane transition zone (SMTZ) despite little morphological diversity; (3) ES formation might be related to hydrogen sulfide oxidation and is therefore linked with fluctuations in the SMTZ. Within the SMTZ, hydrogen sulfide is produced and pyrite precipitates because of enhanced anaerobic oxidation of methane coupled with dissimilatory sulfate reduction. This enhances the efficiency of the inorganic sulfur cycle and provides favorable conditions for ES formation. The discovery of solid ES in sediments near the Jiulong Methane Reef suggests an important relationship with SMTZ fluctuations that could have implications for the evolution of methane hydrate in the South China Sea.