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| 1 | Characteristics of authigenic pyrites in shallow core sediments in the Shenhu area of the northern South China Sea: Implications for a possible mud volcano environment显示文摘Distinct pyrites have been recovered from a shallow sediment core from Site 4B in the Shenhu area of the northern South China Sea. Based on the lithology, texture and structure of sediments, the stable sulfur isotope of pyrite and the total organic carbon (TOC) concentration of the sediments, a distinctive sediment interface is identified at a depth of about 1 m below the seafloor in the core sediments. The pyrites only accumulate in the lower part of the core as rods and foraminifera-infillings, and mainly within three intervals marked by high pyrite concentrations. The amount of pyrite in the sediments shows no remarkable correlation with TOC in the Site 4B core sediments. The stable sulfur isotopes of the pyrite have extremely negative values ranging from 41.69‰ to 49.16‰. They are considered to be the mutual product of sulfate bacterial reduction and sulfur bacterial disproportionation. Our research proposes that Site 4B might be located in or near a possible mud volcano sedimentary environment; a large amount of methane could migrate from deep to shallow sediments in an active mud volcano and thereby play a key role in the intensity of sulfate bacterial reduction and the amount of pyrite formed at Site 4B. Further, the variation in flux of deep methane fluid by intermittent mud volcanic eruptions might result in the deposition of authigenic pyrite intervals. | XIE Lei WANG JiaSheng WU NengYou WU DaiDai WANG Zhou ZHU XiaoWei HU Jun CHEN HongRen LIN Qi | 2013 | Science China Earth Sciences2013，56，4： | 14 |
| 2 | 神狐海域Site4B表层沉积物中脂肪酸组成及其碳同位素分布特征显示文摘通过对神狐海域表层5个沉积物样品进行脂肪酸组成及其碳同位素分布特征测试和研究,结果表明总脂肪酸含量分布为5.14~8.99μg/g,碳数分布范围从C1z到Csz,类型包括正构饱和脂肪酸、支链脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸和类异戊二烯酸等计48种;样品中饱和的短链脂肪酸主要来自细菌与浮游生物,而长链饱和脂肪酸来自陆源高等植物,其比例表明研究海域中海洋细菌与浮游生物输入量远远大于陆源高等植物的输入。支链脂肪酸10me16:0与单不饱和脂肪酸18:l009、16:1ω9主要来自硫酸盐还原菌,而单不饱和脂肪酸16:1ω7很大可能来源于硫氧化菌,比较相对含量得出神狐海域表层沉积物为还原环境。样品中检测出8种类异戊二烯酸,主要是植烷酸和17,21-印二升藿烷酸,及少量的姥鲛酸,推测为叶绿素a和细菌微生物的共同贡献。 | 朱小畏 茅晟懿 吴能友 孙永革 管红香 | 2013 | 海洋学报2013，35，6： | 6 |
| 3 | 南海北部陆坡NH-1孔沉积物中碳酸盐碳同位素特征及其地球化学意义显示文摘源于深部天然气藏渗漏或天然气水合物分解释放的甲烷,可导致海洋沉积物中生成δ13C明显负偏的碳酸盐矿物。对NH-1孔沉积物样品的碳酸盐含量、全岩碳酸盐及生物碳酸盐δ13C、有机碳含量等参数进行了分析。结果表明:沉积物中碳酸盐含量较高(平均6.90%);全岩碳酸盐δ13C(-6.09‰^-0.48‰)与正常海相碳酸盐相比明显负偏;浮游有孔虫(G.rube)壳体碳酸盐δ13C(-0.834‰~0.004‰)明显低于正常值。结合海域的地质特点,认为这很可能是沉积物中较高甲烷通量背景条件下自生碳酸盐的形成所导致的。有机碳、氮数据与全岩碳酸盐δ13C的相关性分析指示了有机质也可能是全岩碳酸盐δ13C偏低的根源之一。因此,NH-1孔碳酸盐碳同位素特征是较高甲烷通量背景下甲烷缺氧氧化-硫酸盐还原及有机质缺氧氧化-硫酸盐还原等地球化学过程的综合反映。全岩碳酸盐δ13C含量可用于指示沉积物中自生碳酸盐矿物及较高甲烷通量的存在。 | 蒲晓强 钟少军 李艳 于雯泉 刘刚 姜在兴 | 2009 | 中国石油大学学报(自然科学版)2009，33，2： | 5 |
| 4 | 南海神狐海域自生黄铁矿分布、形貌特征及其对甲烷渗漏的指示显示文摘自生黄铁矿是渗漏甲烷发生甲烷厌氧氧化和硫酸盐还原作用的产物之一,是海底甲烷渗漏活动的有效示踪剂。南海神狐海域是我国天然气水合物研究的重点区域,对神狐海域柱状沉积物中自生黄铁矿含量、分布、形貌等特征进行研究,结果发现自生黄铁矿的含量随深度增加而递增,存在两个异常富集峰段:在第一个黄铁矿富集峰段,黄铁矿以长条状为主,外形较粗,微晶形态以草莓状黄铁矿为主,且粒径均一;在第二个峰段主要以细长的条状黄铁矿为主,由带外壳结构的草莓球颗粒组成,晶粒大小不一,存在二次生长现象。另外还发现胶黄铁矿与自生黄铁矿共生。这些特征反映神狐海域沉积物中存在多期次的甲烷渗漏事件,高通量的甲烷渗漏发生在较浅的层位,可能发生甲烷的有氧氧化而变成缺氧环境,有利于黄铁矿富集在第一个峰段;较低的甲烷渗漏发生在较深的层位,甲烷厌氧氧化和硫酸盐还原作用而形成大量的黄铁矿保存在第二个峰段。因此,神狐海域沉积物中自生黄铁矿的异常富集可以作为地质历史时期甲烷渗漏通量和期次的指示矿物之一。 | 张美 陆红锋 邬黛黛 刘丽华 吴能友 | 2017 | 海洋地质与第四纪地质2017，37，6： | 5 |
| 5 | Characteristics of authigenic pyrite and its sulfur isotopes influenced by methane seep at Core A, Site 79 of the middle Okinawa Trough显示文摘The anaerobic oxidation of methane(AOM) has strongly developed at Core A, Site 79 of the middle Okinawa Trough, East China Sea, and a large amount of authigenic pyrite is preserved in the surface sediment. In this study, we analyze the characteristics of the authigenic pyrite and its sulfur isotopic values. The authigenic pyrite is stripy and tubular, and there were foraminifera compartments filled with pyrite. The pyrite is extracted using chromium reduction, and the values of ? 34 S are found to lie between ?41.20‰ and 8.92‰ V-CDT. The bulk pyrite tends to be more enriched in 34 S with increasing depth. Particularly, the ? 34 S value of the pyrite lies between ?32.73‰ and ?41.20‰ V-CDT above 278 cmbsf, but it quickly increases below this depth(?21.49‰–8.92‰ V-CDT). At the same time, the total sulfur content of the pyrite shows an abrupt increase above 100 cmbsf but is otherwise stable between 1.04% and 0.55% below 100 cmbsf. The stable and negative values of ? 34 S and the decreasing values of total sulfur above 278 cmbsf indicate reduced AOM activities in 17.18–5.3 ka. In addition, the increasing ? 34 S and pyrite content indicate strong AOM development and methane seep below 278 cmbsf in 18.8–17.18 ka. In particular, the highest positive value of ? 34 S occurring in 18.78 ka indicates the most intense AOM activity. The shallow sulfate-methane interface(SMI) and high methane flux below marine sediments also strongly support this activity. | WANG Meng CAI Feng LI Qing LIANG Jie YAN GuiJing DONG Gang WANG Feng SHAO HeBin HU GaoWei | 2015 | Science China Earth Sciences2015，58，12： | 4 |
| 6 | Calcium isotope fractionation and its controlling factors over authigenic carbonates in the cold seeps of the northern South China Sea显示文摘In this study, we analyzed stable calcium isotope results of authigenic carbonates from two cold seep areas of the Dongsha area and the Baiyun Sag in the northern South China Sea. The stable isotopes of carbon and oxygen as well as the mineral composition of authigenic carbonates were used to investigate control calcium isotope fractionation. The δ44/40Ca ratios of the southwestern Dongsha area samples ranged from 1.21‰ to 1.52‰ and the ratio of the Baiyun Sag sample was 1.55‰ of the SRM915a isotope standard. X-ray diffraction analysis showed that the carbonate samples consisted of dolomite, calcite and aragonite, with small amounts of high-Mg calcite and siderite. The δ13C values of the carbonates of the southwestern Dongsha area varied between δ49.21‰ and δ16.86‰ of the Vienna PeeDee Belemnite (VPDB) standard and the δ18O values ranged from 2.25‰ to 3.72‰ VPDB. The δ13C value of the Baiyun Sag sample was 2.36‰ VPDB and the δ18O value was 0.44‰ VPDB. The δ13C values of the carbonates of the southwestern Dongsha area revealed there is methane seeping into this area, with a variable contribution of methane-derived carbon. The sampled carbonates covered a range of δ13C values suggesting a dominant methane carbon source for the light samples and mixtures of δ13C values for the heavier samples, with possibly an organic or seawater carbon source. The δ18O values indicated that there is enrichment in 18O, which is related to the larger oxygen isotope fractionation in dolomite compared to calcite. The results of the Baiyun Sag sample exhibited normal seawater carbon and oxygen isotopic values, indicating that this sample is not related to methane seepage but instead to precipitation from seawater. The relatively high δ44/40Ca values indicated either precipitation at comparatively high rates in pore-water regimes with high alkalinity, or precipitation from an evolved heavy fluid with high degrees of Ca consumption (Raleigh type fractionation). The dolomite samples from the Dongsha area revealed a clear correlation between the carbon and calcium isotope composition, indicating a link between the amount and/or rate of carbonate precipitation and methane contribution to the bicarbonate source. The results of the three stable isotope systems, mineralogy and petrography, show that mineral composition, the geochemical environment of authigenic carbonates and carbon source can control the calcium isotope fractionation. | WANG ShuHong YAN Wen MAGALHAES H Vitor CHEN Zhong PINHEIRO M Luis GUSSONE Nikolaus | 2012 | Chinese Science Bulletin2012，57，11： | 4 |
| 7 | Autotrophic potential in mesophilic heterotrophic bacterial isolates from Sino-Pacific marine sediments显示文摘Microbial carbon fixation is a paramount process in the ocean especially below the photic zone both in water and sedimentary ecosystems. Autotrophic microbes that fix carbon dioxide are renowned. However, the question whether heterotrophs can also fix carbon is intriguing. Ten heterotrophically grown, identified bacterial isolates from the Sino-Pacific marine sediments were tested for autotrophic uptake potential with and without addition of electron donors. Nine of the ten isolates showed carbon uptake capacity without addition of any substrate at very low rates in the order of 10^(-8) to 10^(-4) fmol/(cell·h). The addition of manganese and ammonium at 1 mmol/L final concentration enhanced the uptake potential. Addition of 1 mmol/L final concentrations of reduced iron(10^(-6) to10^(-5) fmol/(cell·h) and sulfide(10^(-5) fmol/(cell·h) decreased the uptake potential significantly at p<0.1. Bacterial tolerance to formaldehyde suggested propensities of anaplerotic chemical reactions that form metabolic intermediates of C-1 metabolism pathways. The isolates displayed high metabolic flexibility. With the changes in electron donors, the isolates metabolically toggled between relatively anoxic reductive iron/sulfur cycles and the oxidative cycles of manganese/ammonium and vice-versa. This property makes these microbes successful survivors in the highly dynamic Sino-Pacific sediments. | CAO Wenrui DAS Anindita SAREN Gaowa JIANG Mingyu ZHANG Hongjie YU Xinke | 2017 | Acta Oceanologica Sinica2017，36，2： | 0 |
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