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| 1 | 扬子板块北缘下志留统龙马溪组重晶石结核特征及其成因机制分析显示文摘在扬子板块北缘城口明中剖面及巫溪徐家坝剖面下志留统龙马溪组底部的硅质岩、泥岩中发现椭球状重晶石结核。其矿物组成主要为重晶石颗粒与作为'基质'的黄铁矿、粘土矿物和石英。通过重晶石岩石学、矿物学及锶同位素分析表明,重晶石结核形成于早期成岩阶段松软沉积物的孔隙水中。上升洋流带来丰富的营养及富钡物质,表层海水的高初始生产力促使生物繁盛,海水中的钡通过生物作用富集形成生物钡,生物钡(bio-barite)在埋藏过程中的硫酸盐耗竭区(sulfate depleted zones)通过硫酸盐细菌作用(BSR)溶解被激活提供了钡的来源。围岩岩性(黑色泥岩和硅质泥岩)表明重晶石结核形成于缺氧的环境中。上述研究对深入理解早志留世时期扬子板块北缘古海洋环境有一定的启示作用。 | 昝博文 刘树根 冉波 叶豪 杨迪 黄瑞 夏国栋 焦堃 | 2017 | 岩石矿物学杂志2017，36，2： | 9 |
| 2 | 秭归地区震旦系陡山沱组碳酸盐岩结核成因新认识及其地质意义显示文摘扬子克拉通秭归地区震旦系陡山沱组第四段黑色泥页岩中广泛发育具明显δ^(13) C负异常的碳酸盐岩结核,其是否与古甲烷天然气水合物渗漏有关值得深入研究.对该碳酸盐岩结核开展的沉积结构构造、岩相学和地球化学研究表明,碳酸盐岩结核具典型韵律环带结构,普遍发育有亮晶球体结构、草莓状黄铁矿,以及与渗漏系统有关的凝块组构,δ^(13) C具明显负异常(-5.65‰^-6.76‰),U、Mo元素强烈富集(U_(EF)=8~26,Mo_(EF)=99~320),Y/Ho比值为31.05~37.31,稀土配分型式为平缓左倾,主微量元素K、Sc、V、Cr、Co、Ni、Rb、Sr、Ba、Th、U和Mo等总体显示为缺氧-硫化环境,与冷泉碳酸盐岩的形成环境和特征一致.碳酸盐岩结核环带SiO_2、MgO、CaO、CO_2等地球化学元素含量呈阶段性连续增减变化,显示碳酸盐岩结核形成经历了初始形成、成岩-交代、成岩后改造3个连续演化阶段.据此,提出碳酸盐岩结核是新元古代末噶斯奇厄斯冰期(582~551Ma)结束温度回暖,黑色泥页岩中低温封存固态天然气水合物发生分解释放和成岩-交代形成的冷泉碳酸盐岩结核,也是古天然气水合物存在的重要地质记录和标志,这一新认识为华南扬子克拉通在震旦系和下古生界沉积盖层中寻找页岩气(甲烷天然气)储集层位提供了重要地质依据. | 张明正 彭松柏 张利 方家松 张先进 韩庆森 | 2016 | 地球科学(中国地质大学学报)2016，41，12： | 7 |
| 3 | 三峡地区埃迪卡拉系至下寒武统地层中硒的含量分布富集规律显示文摘分析了三峡地区埃迪卡拉系至下寒武统(E-ε_1)地层中硒(Se)的含量分布富集规律,探讨了Se的显著和非显著富集层的元素地球化学特征.结果表明,Se为E-ε_1地层中最富集(浓集)的元素,其富集系数EF(与上地壳平均元素含量相比)和浓集系数CC(与同类岩性相比)均值分别为26.97和48.04.富集系数EF′(Al标准化之后的EF)指示.Se为第二富集的元素(Se^(EF′)=218.73),低于Cd(Cd^(EF′)=288.46),远高于第三富集的微量元素As(As^(EF′)=97.49).Se在E-ε_1地层中含量范围为<10.5~30.08ppm,算数均值为1.35ppm.相对于南沱组(Se^(EF)=2.29),E-ε_1地层中Se^(EF)值增加11.78倍.其EF均值呈现为水井沱组(92.58)>岩家河组(54.45)>陡山沱组(24.72)>灯影组(2.48)>石牌组(1.95)>天河板组下部(1.24).E-ε_1地层中Se的含量较服从自然对数正态分布,表现出正偏态分布类型.Se显著富集(EF>10)的层位主要包括陡II下部、陡II上部、陡III顶部、陡IV、岩家河组底部和上部、水井沱组下部和上部.元素地球化学特征表明:Se显著富集层中Se含量普遍受陆源碎屑的影响,还受热液、火山碎屑、深部物源等单一或多因素的共同作用.此外,黄铁矿对部分层位(陡II上部、陡IV和水井沱组上部)及有机质对部分层位(陡II下部和水井沱组上部)中Se的富集具有促进作用.Se的非显著富集层(除陡I、水井沱组中部、石牌组和天河板组下部外)中Se含量仍受陆源碎屑影响,而其他的因素(热液、火山碎屑和深部物源等)的活动普遍较弱. | 田兴磊 雒昆利 | 2017 | 中国科学:地球科学2017，47，8： | 5 |
| 4 | Distribution and enrichment patterns of selenium in the Ediacaran and early Cambrian strata in the Yangtze Gorges area, South China显示文摘The distribution and enrichment patterns of selenium(Se) in the E-?1 strata in the Yangtze Gorges area of South China were obtained. The geochemical characteristics of the significantly and non-significantly enriched strata of Se were analyzed.The observed enrichment factor(EF, relative to the upper continental crust) and concentration coefficient(CC, relative to the similar lithology in Eastern China) both suggest that Se is the most enriched/concentrated(SeEF=26.97, SeCC=48.04) among the analyzed23 trace elements the E-?1 strata. The normalized enrichment factor(EF′, EF after Al or Th normalized) shows Se is secondly enriched(SeEF′=218.73), which is slightly lower than cadmium(CdEF′=288.46) but significantly higher than the third enriched trace element arsenic(AsEF′=97.49). Se concentrations in the E-?1 strata vary from <10.5 to 30.08 ppm with an arithmetic mean value of 1.35 ppm. Compared to the Nantuo Formation, Se increased 11.78 times in the whole E-?1 strata and the average EF values are displayed as Shuijingtuo(92.58)>Yanjiahe(54.45)>Doushantuo(24.72)>Dengying(2.48)>Shipai(1.95)>lower Tianheban(1.24)Formations. Se concentrations in the E-?1 strata are best displayed on natural logarithm normal quantile-quantile(Q-Q) plots and shown as a positive-skewed distribution pattern. The Se significantly enriched(EF>10) strata sequences mainly include the lower and upper Doushantuo member II(DST-II), top DST-III, DST-IV, the basal and upper Yanjiahe Formation, and lower and upper Shuijingtuo Formation. Geochemical characteristics indicate that Se concentrations in the significantly enriched strata were generally influenced by terrigenous detrital as well as the combined action of single or multiple factors, such as hydrotherm,volcanic debris and deep source. Moreover, pyrite and organic matter promoted the enrichment of Se in the upper DST-II, DST-IV,upper Shuijingtuo Formation and lower DST-II, upper Shuijingtuo Formation, respectively. The Se concentrations in the not significantly enriched strata(except for DST-I, middle Shuijingtuo Formation, Shipai Formation and lower Tianheban Formation)were also influenced by terrigenous detrital, but other enrichment activities(e.g., hydrothermal, volcanic debris, and deep source)were generally insignificant. | TIAN XingLei LUO KunLi | 2017 | Science China Earth Sciences2017，60，7： | 0 |
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