东太平洋海隆13°N附近沉积物中的热液活动记录

本文以东太平洋海隆13ºN附近E53沉积物岩芯为研究对象，进行了矿物学、全岩化学分析及连续提取分析，探讨了沉积物中的热液活动记录及元素存在形式，并结合已有的测年数据，对研究区域的热液活动过程进行了初步讨论。 E53岩芯分为三层，上层为红褐色沉积层，中层为棕黄色沉积层，下层为灰绿色沉积层。沉积物岩芯的X射线衍射结果显示，E53岩芯上层非晶质的铁锰氧化物含量较高，中下段方解石含量较高。根据元素在岩芯全岩及各相态间的存在状况，将常量及微量元素分组讨论。Fe、Mn元素以铁锰氧化物相为最重要的赋存相，且与全岩样品一致，呈现随深度下降趋势。Al、Ti、Ba主要存在于残留相中；K、Na、Mg主要赋存相为碳酸盐相；Ca、Sr同样主要存在于碳酸盐相中。微量元素Mo、Co、V、Cu、Zn、Ni、Y和Pb元素主要存在于铁锰氧化物相，且含量均随深度增加而下降。Th、Sc、Li和Zr的主要存在于残留相中；Cd、U主要存在于碳酸盐相中。稀土元素存在形式有以下三个特点：1、主要存在于铁锰氧化物相中，并且呈现出随深度增加含量下降的趋势；2、次要存在形式为碳酸盐相，随深度增加含量上升并一度超过残留相中的含量；3、在有机结合相和残留相中含量很低，且变化幅度不大。 根据本文讨论结果，结合前人年代数据，认为E53岩芯中记录的为程度逐步加强且在近期保持稳定的热液活动。

中国北方中新世风尘物质来源及古气候的地球化学指示

The most prominent tectonic and environmental events during the Cenozoic in Asia are the uplift of the Himalaya-Tibetan plateau, aridification in the Asian interior, and onset of the Asian monsoons. These caused more humid conditions in southeastern China and the formation of inland deserts in northwestern China. The 22 Ma eolian deposits in northern China provide an excellent terrestrial record relative to the above environmental events. Up to date, many studies have focused on the geochemical characters of the late Mio-Pleistocene eolian deposits, however, the geochemical characteristics of the Miocene loess and soils is still much less known. In this study, the elemental and Sr-Nd isotopic compositions of the eolian deposits from the Qinan (from 22.0 to 6.2 Ma) and the Xifeng (from 3.5 Ma until now) loess-soil sections were analyzed to examine the grain size effects on the element concentrations and the implications about the dust origin and climate. The main results are as follows: 1. The contents of Si, Na, Zr and Sr are higher in the coarser fractions while Ti and Nb have the highest contents in the 2-8 μm fractions. Al, Fe, Mg, K, Mn, Rb, Cu, Ga, Zn, V, Cr, Ni, LOI have clear relationships with grain-size, more abundant in the fine fraction while non significant relationship is observed for Y. Based on these features, we suggest that K2O/Al2O3 ratio can be used to address the dust provenance, and that VR (Vogt ratio = (Al2O3+K2O)/(MgO+CaO+Na2O)) can be used as a chemical weathering proxy for the Miocene eolian deposits because of their relative independence on the grain size. Meanwhile, SiO2/Al2O3 molar ratio is a best geochemical indicator of original eolian grain size, as suggested in earlier studies. 2. Analyses on the Sr and Nd isotope composition of the last glacial loess samples (L1) and comparison with the data from the deserts in northern China suggest that that Taklimakan desert is unlikely to be the main source region of the eolian dust. In contrast, these data suggest greater contributions of the Tengger, Badain Jaran and Qaidam deserts to the eolian dust during the last glacial cycle. Since the geochemical compositions (major, trace, REE and Sr, Nd isotope) of loess samples for the past 22 Ma are broadly similar with the samples from L1, these data trend to suggest relatively stable and insignificant changes of dust sources over the past 22 Ma. 3. Chemical weathering is stronger for Miocene paleosol samples than for the Plio-Pleistocene ones, showing warmer/more humid climatic conditions with a stronger summer monsoon in the Miocene. However, chemical weathering is typical of Ca-Na removal stage, suggesting a climate range from semiarid to subhumid conditions. These support the notion about the formation of a semi-arid to semi-humid monsoonal regime by the early Miocene, as is consistent with earlier studies.

内陆湖沼相和近海沼泽相沉积环境煤中微量元素和矿物的对比研究—以辽宁北票、江西建新和桥头煤研究为例

Using knowledge of geology, geochemistry, coal petrology, mineralogy, by means of a variety of advanced measuring methods such as inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled atomic emission spectrometry (ICP-AES), X-ray powder diffraction (XRD), scanning electron microscopy with energy-dispersive spectrometer(SEM-EDS), sequential chemical extract and density fractions, the characteristics of trace elements and minerals in Jurassic Beipiao coal mine under inland limnetic sedimentary environment and in late Permian Jianxin and Qiaotou coal mines under paralic swamp sedimentary environment were studied. Compared with the average concentration in the world bituminous coals, the Beipiao coal was characterized by relatively high contents of Sc, Ti, Cr, Co, Ni, Zn, Se, Sr, Zr, Y, Ba, REE and Th, and lower contents of V, Rb, Cd, Sn, Pb, Bi and U; while the Jianxin coal was relatively enriched in Li, Sc, Ga, Sr, Y, Nb, Sb, Th and U, with low concentration of Be, Co, Ni, Cu, Ge, Zr, Mo, Cd, Cs, Ba, Pb and Bi; and the Qiaotou coal was enriched in Li, Sc, Sr, Nb, Ta, Zr, REE, Hf, Th and U, with low concentration of Be, V, Co, Ni, Cu, Ge, Mo, Cd, Cs, Ba, Tl, Pb and Bi. The concentrations of Ca, Mg and K in Beipiao coal are higher than those in Jianxin coal and Qiaotou coal, while Fe, S and Ti in Beipiao coal are lower than those in Jianxin coal and Qiaotou coal. The proximate analysis of coal samples was carried out, which indicated that Beipiao coal was medium- to high- ash (5.92-60.68%) with low sulphur coal, and Jianxin coal and Qiaotou coal was medium to high ash (8.85-46.33%) with high sulphur. The reflectivity was measured, which explained that Beipiao coal belonged to high volatile bituminous coal, Jianxin coal was low volatile bituminous coal and Qiaotou coal was low volatile anthracite. Quantitative maceral analyses were studied. The characteristics of rare earth elements (REE) were investigated, which showed that the total contents of REE were higher than that of the world's average content. With the increase of coal's metamorphic grade, the total contents of REE decreased from 98.5 X 10"6 of Beipiao coal to 94.2 X 10"6 of Jianxin coal, and to 75.9 X 10"6 of Qiaotou coal, and 5Eu reduced which indicated that the element Eu depleted. The characteristics of REE was controlled by the metamorphic grade of coal. And REE were mainly absorbed in clay minerals in Beipiao coal samples, while in Jianxin and Qiaotou coal mines, REE were primarily related to clay mineral and pyrite. The variation of trace elements in vertical direction of coal seams was studied, and the results showed that different trace elements differed greatly. The correlation between trace elements and ash were determined. Four major trace elements (aluminium-silicates, sulphide, carbonate and phosphate) accounted for the occurrence and distribution of most elements studied were determined. Coal samples were separated by density fraction, which showed that Cr, Cu, Mo and Pb were closely related to inorganic matters mainly distributed in P >2.6 and dropped remarkably in the density fractions P <2.3 . The occurrences of Co, Cr, Ni, As, Se, Mo, U were studied directly and quantitatively using sequential chemical extract with six steps, which showed that Co. Ni, Mo and U were mainly in the form of mineral, and As, Se chiefly in the form of organic state, while Cr mostly in the form of organic state and mineral. Major mineral phases presented in the Beipiao coal were Kaolinite, illite, quartz, calcite, and small amount of siderite, barite. While major mineral phases in Jianxin and Qiaotou coal were pyrite, kaolinite, and small amount of marcasite, rutile, sphalerite. This is the first time that the chromite in the coal was discovered in China, which indicates that Cr occurrence appeared in the form of chromite. The ratio of Sr/Ba, Sr/Ca and V/Ni in Beipiao coal mine under inland limnetic is smaller than that of in Jianxin and Qiaotou coal mines under paralic swamp. The ratio of K/Na and Th/U of Beipiao coal mine is higher than that of Jianxin and Qiaotou coal mine, which proved that Beipiao coal was not affected by sea water and Jianxin and Qiaotou coal were affected by sea water. Trace elements such as Cr, Ni, Mo in minerals were analyzed by SEM-EDS. The factors controlling the enrichment of trace elements can be divided into syngenetic stage factors and epigenetic stage factors.

重庆城口地区早前寒武系黑色岩系研究：（3）巴山组硅质岩中PGE异常的地球化学研究

以猪草河剖面和羊儿坝剖面为例，进行硅质岩的PGE与微量元素等地球化学分析，结果表明：槽区硅质岩中的PGE异常受控于硅质岩中火山物质（蚀变成粘土矿物）的多少，PGE与Se、Rb、Cs、Ti、Cr、Zr等具有良好的相关性；猪草河剖面远离陆源区，沉积厚度大，更靠近火山活动区域，接受火山粗碎屑物质的量多；羊儿坝剖面远离火山活动中心，主要接受了火山灰等细碎屑物质，更接近陆源区，受一定量的陆源碎屑物质影响。根据Cr／Co、Nb／Ta、Pd／Ir-Ni／Cu及Ni／Pd-Cu／h对岩浆性质的约束，当时岩浆性质为基性玄武岩。根据La-Y-Nb图解和Th-Hf-Ta图解的进一步约束，表明当时的火山岩浆性质为钙碱性的火山弧玄武岩。

乌兰图嘎超大型锗矿床含锗煤的矿物学

内蒙古乌兰图嘎锗矿是我国近年来发现的产在煤层中的超大型锗矿床,锗金属储量达1600 t。以乌兰图嘎超大型锗矿床的含锗煤为研究对象,利用X射线衍射(XRD)、带能谱的扫描电镜(SEM-EDX)和电子探针(EPMA)详细研究了乌兰图嘎含锗煤及其同时代的红旗煤矿无矿煤的矿物学特征。分析结果表明,乌兰图嘎含锗煤中的主要矿物包括石英、蒙脱石;次要矿物包括长石、高岭石、伊利石;另含少量三水铝石、角闪石、叶蜡石、石膏、绿泥石、锐钛矿、黄铁矿、方解石、白云石和草酸钙石;微量的锆石、闪锌矿、白钨矿、重晶石、黄铜矿、卤化物、磷酸盐以及含Pb、Bi、Cr、As和Sb矿物。未发现含锗矿物。推测含锗煤中的锗可能主要呈有机结合,而Ba、Zn、Ti、W、Pb、Bi、Cr、Fe、As、Zr、Sb、Cu和REE可能主要与矿物相结合。此外,首次在乌兰图嘎含锗煤及红旗煤矿无矿煤中发现含银颗粒或自然银,推测胜利煤田的褐煤可能有相当规模的Ag矿化。

热带亚热带季风气候条件下表生成矿地球化学－以个旧和老挝Nameung、Boloven地区为例

在前人对热带亚热带季风型气候条件下云南个旧砂矿、老挝Xaymomboun特区Ban Nameung铜多金属矿和Champasak省Boloven高原玄武岩等研究成果基础上，采用典型表生矿床实证解剖思路，选择个旧白云岩风化剖面、锡铅砂矿、锰结核、砂矿重选流程、Ban Nameung硫化氧化矿和Boloven玄武岩风化壳等对象，通过岩矿鉴定、主量微量元素地球化学、稀土元素地球化学、人工重砂、化学物相和微区分析等研究手段，研究这些矿床表生成矿物质来源、成矿机理、矿床地球化学特征和矿物工业可利用性等内容，并探索热带亚热带季风型气候条件下典型矿床表生成矿三个问题：（1）Sn、Pb、Mn、Ag、REE、Nb、Ta、Ga和Cd等元素表生富集成矿（矿化）规律；（2）上述元素成矿机理和工业利用可能性；（3）典型矿床其他20几种元素表生贫化与富集规律。研究获得如下主要认识： 1. 个旧地区燕山期以来持续抬升和亚热带季雨林的表生环境，使个旧地区大面积出露的碳酸盐岩风化形成强烈岩溶地貌，碳酸盐岩风化过程中CaO和MgO大量淋失，为砂矿提供了巨大容矿空间，同时碳酸盐地区碱性环境有利于原生硫化矿分解。含矿或不含矿白云岩、花岗岩、玄武岩、夕卡岩和原生硫化矿石等风化形成粘土矿物和铁锰氧化物，释放出Sn、Pb、Mn、Ga、Cd、Ag、In、Cu和Zn等元素，难风化重矿物如锡石表生残留富集，而粘土矿物和铁锰氧化物对成矿元素吸附是砂矿表生成因机理之一。 2. 个旧地区岩溶型砂矿形成机理为：（1）原生重矿物残留富集成矿，如锡石、磁铁矿。（2）金属硫化物残留成矿，如砂矿中残存大量方铅矿、黄铜矿、黄铁矿，是原生硫化物残留结果。（3）表生矿物富集成矿，如白铅矿、孔雀石、自然铅和自然铜等富集。（4）铁锰氧化物吸附和包裹成矿，如铁锰氧化物吸附Pb和Ga等元素，包裹含Pb和Zn微粒矿物。（5）锰结核吸附包裹成矿，锰结核吸附和包裹Sn、Pb和Cu等元素和微粒矿物。（6）类质同象成矿，如Ga和Al类质同象，Cd和Zn等类质同象成矿。（7）岩溶作用成矿，岩溶落水洞或溶洞内水流冲刷使锡石等重矿物富集成矿。元素表生成矿不仅是单一成矿作用结果，而是综合作用结果，如Pb有表生矿物富集成矿，也有铁锰氧化物吸附成矿。 3. 砂矿中锰结核是锰铁结核，主要成分为Fe2O3 、Al2O3、SiO2和MnO等，包裹了赤铁矿、方解石、云母、石英、蒙脱石、高岭石、白云石、钾长石等和锡石、白铅矿等矿物。锰结核中Mn、Sn、Pb、Ag、Ga、Cd和In富集成矿，Cu和Zn富集矿化，锰结核比砂矿更富集Mn、Pb和REE，其成矿机理应是吸附和包裹成矿元素或矿物使其富集成矿。 4. 个旧表生砂矿共生伴生组分复杂，有用矿物有锡石、方铅矿、白铅矿、黄铜矿、自然铅、自然铜、孔雀石、软锰矿、白钨矿、磁铁矿和褐铁矿等。模拟岩溶作用自然过程中砂矿矿物流向的源兴采选车间砂矿重选流程结果表明，锡铅精矿中Pb、Ga、Mo、Cd、In、Cu和Zn等金属总实收率仅为3.03％～6.44％，绝大部分金属留在了尾矿中。一段床和矿泥床分析中，Ag和Mn回收率低于0.66％～0.29％，Ag富集在硫化物态中，没有富集在铁锰氧化物态中；Mn富集在碳酸盐态中，没有铁锰氧化物态中。整个流程中Pb、Mn、Cu和Zn等富集在碳酸盐态矿物中，没有富集在硫化物态中。选矿流程没有利用具有潜在利用价值矿物如磁铁矿。重选流程解释了岩溶过程能富集Pb、Mn、Cu和Zn的碳酸盐矿物，不能富集这些元素的硫化矿物。 5. 老挝Ban Nameung硫化矿氧化初期，风化产物中Ag、Pb、Zn和Cu淋失，SiO2、K2O和CaO富集，风化后期Ag、Fe和Mn富集。硫化矿风化过程中，Au硫化物态部分变为有机态和铁锰氧化物态；Ag硫化物态部分变为铁锰氧化物态和有机态；Cu硫化物态部分变为铁锰氧化物态和碳酸盐态；Pb硫化物态、吸附态、碳酸盐态和铁锰氧化物态部分变为铁锰氧化物态、碳酸盐态和有机态；Zn硫化物态变为部分铁锰氧化物态、有机态、碳酸盐态和吸附态矿物。随着风化作用加强，上述几种相态比例还会改变。 6. 老挝Boloven新生代亚碱性玄武岩富Nb、Ta和Ga等微量元素，风化壳中REE、Nb、Ta和Ga已富集成矿，∑REE最高775×10-6～1003×10-6，（Nb2O5＋Ta2O5）最高642×10-6~656×10-6，Ga最高81.6 ×10-6。风化壳中达到边界品位的（Nb2O5＋Ta2O5）厚度有2m以上。REE可能存在于含P和Ti矿物中，也可能形成REE独立矿物。Nb、Ta和Ga应赋存在Ti、U、Zr和Th矿物中，其成矿应是重矿物表生残留富集结果，与粘土矿物吸附和三水铝石关系不紧密。

内蒙古乌兰图嘎超大型锗矿床含锗煤的地球化学

乌兰图嘎锗矿是我国近年来发现的产在煤层中的超大型锗矿床，锗金属储量达1600吨，其成矿地质条件与成矿模式不同于临沧锗矿和俄罗斯远东地区的锗矿。本文以乌兰图嘎含锗煤的地球化学特征为重点，利用X射线衍射、扫描电镜、电子探针、ICP-MS和数理统计等多种分析方法，系统研究了乌兰图嘎含锗煤的矿物学、微量元素和稀土元素地球化学特征，结合与其他地区含锗煤地球化学特征的对比，初步探讨了乌兰图嘎锗矿的成因。论文获得以下几点主要认识： 1. 乌兰图嘎含锗煤中的主要矿物包括石英、蒙脱石；次要矿物包括长石、高岭石、伊利石；另含少量三水铝石、角闪石、叶蜡石、石膏、绿泥石、锐钛矿、黄铁矿、方解石、白云石和草酸钙石。扫描电镜和电子探针分析表明，乌兰图嘎含锗煤中还存在锆石、闪锌矿、白钨矿、重晶石、黄铜矿、卤化物、磷酸盐以及含Pb、Bi、Cr、As和Sb矿物。未发现含锗矿物。首次在乌兰图嘎含锗煤和红旗煤矿的无矿煤中发现含Ag矿物。 2. 与上地壳平均组成相比，乌兰图嘎锗矿褐煤明显富集Be、Ge、Sb、W和U，亏损Rb、Nb、Sn和Ta。乌兰图嘎锗矿褐煤中Be、Ge、Sb、W和U的平均含量明显高于乌兰图嘎砂岩和红旗煤矿褐煤，以及美国煤和世界煤的平均组成。乌兰图嘎锗矿含矿煤的稀土元素平均含量略高于美国煤或世界煤的平均组成、乌兰图嘎砂岩以及同时代的红旗煤矿无锗煤中的稀土元素含量。稀土元素与锗含量无明显的相关性。 3. 按元素组合不同，煤中微量元素可划分为4个组：Ge-Mo，Tl-Ga-Zn-Co，Rb-Cs和W-U-Cd-Y-Pb-Cu-Hf-Zr-Th-Sn-Nb-Ta-Ti-Sb-Ba-Sr-Mn-Be组合。第一组合包括与灰分呈负相关的元素，它们主要表现出有机亲合性。 剩下三组包括与灰分呈负-较高相关的元素，其主要与硫化物或铝硅酸盐矿物结合。大多数含锗煤的稀土元素含量与灰分呈高度正相关，表明含锗煤中的稀土元素主要来自陆源碎屑并主要与同沉积矿物相结合。稀土元素在少数高锗煤中的富集与存在独居石有关。 4. Ge和Mo富集在不同剖面的不同部位，其余微量元素和稀土元素或多或少地跟随灰分的分布。TiO2标准化的元素剖面揭示乌兰图嘎褐煤样品中的Be/TiO2、Ge/TiO2、W/TiO2、U/TiO2、Mo/TiO2、Sb/TiO2、Tl/TiO2和Sr/TiO2比值较乌兰图嘎砂岩和红旗煤矿褐煤中的参考值高出许多。这些元素（Be、Ge、W、U、Mo、Sb、Tl和Sr）的大部分(>90%) 可能由溶液带入煤层。稀土元素与TiO2的比值总体接近矿区砂岩以及红旗煤矿无矿煤中的对应比值。 5. 乌兰图嘎含锗煤具有与矿区砂岩和红旗煤矿无矿煤类似的、页岩式的球粒陨石或北美页岩标准化稀土元素分配模式；与上覆砂岩的稀土元素组成相比，少量含锗煤表现出轻微但明显的中-重稀土富集，表明少量的中-重稀土在后生作用中被叠加或保留在乌兰图嘎含锗煤中。乌兰图嘎锗矿的含锗煤以较高的LREE/HREE和Eu/Eu*比值以及平坦的北美页岩标准化稀土元素分配模式为特征，明显区别于临沧锗矿和俄罗斯远东地区锗矿中的含矿煤。 6. 乌兰图嘎锗矿含锗煤中大多数的微量元素和稀土元素可能来源于花岗岩源区，Be、Ge、Sb、W和U的富集可能与后生的、侧向迁移的含锗溶液有关。含锗溶液自花岗岩源区淋滤出这些元素并将其搬运至褐煤中，煤中有机质将溶液中的锗固定而聚集成矿。

季节性氧湖泊微量金属元素的界面地球化学行为

沉积物表层几厘米范围经常呈现某些微量金属元素富集的现象，过去常笼统地认为这是工业革命以来人为污染不断加剧的证据。但近来的研究却证明强烈的早期成岩作用可以在一定程度上造成微量金属元素在沉积物中的再迁移现象，使得其环境记录失真。因此沉积物中元素分布记录不能完全反映对流域输入的物质组成特征。另外，在一定条件下，沉积物中部分金属元素也可再次向上覆水体释放，造成“二次污染”问题，严重威胁到湖泊／水库的水质安全，成为埋藏在湖泊深处的一颗“定时炸弹”。各种地球化学过程在沉积物一水界面附近造成的重金属元素的源／汇效应因此日益受到人们的重视。近年来贵州红枫湖水质季节性恶化事件频繁出现，作为贵阳市饮用水源的阿哈湖水质也开始出现季节性恶化趋势。紧迫的环境问题及重要的科学意义促使我们系统开展了红枫湖、啊哈湖沉积物一水界面微量金属的地球化学行为研究。两湖都是黔中地区人工水库，具有岩溶湖泊的共性，也具有明显的区别。红枫湖湖水具有典型的岩溶水化学特征，湖水中度富营养化；而啊哈湖受矿山废水的影响，同时由于近年的人工石灰投放等原因，造成该湖湖水具有极硬水、硫酸盐型水特征，矿化度达到600tng／L。我们对上述两湖进行了详细研究，获得了如下的研究成果：1．硫酸盐还原细菌（SRB）及铁还原细菌（DIRB）的计数直观地指示了有机质早期成岩过程中各电子受体依次利用的分带性：即硫还原（锰还原）叶铁还原。孔隙水中硫酸根及溶解铁分布与SRB和D工RB的分布吻合。沉积物孔柱的模拟实验、各类还原性微生物计数及与孔隙水中铁锰、硫酸根分布的综合分析证实了微生物的作用是厌氧环境中各种还原反应的不可缺少的因素，界面附近氧含量的变化是引起水质恶化的基本外因。模拟实验的结果还解释了铁、锰、硫在季节性缺氧湖泊中的循环机理。2．微生物计数及生物大分子分析证实了上层沉积物（0-10厘米）是微生物活跃最为强烈的区域，易降解有机质在此区域被降解。红枫湖沉积物有机质降解持续的深度较深〔达到10cm），而啊哈湖沉积物有机质降解持续深度较浅，仅为4厘米，这主要是由于两湖都是季节性厌氧型湖泊，红枫湖在缺氧季节，有机质厌氧降解所需的电子受体迅速消耗，使得缺氧季节该湖有机质降解速率相对缓慢；啊哈湖受到大量煤矿废水注入，水体及沉积物中硫酸根、铁锰含量异常高，并在厌氧季节里为微生物厌氧呼吸提供充足的电子受体，因而易降解部分有机质在表层迅速被氧化，而且该湖沉积速率相对较慢，有机质有相对充裕的时间在上层被降解，避免了被掩埋的命运。3．啊哈湖沉积物孔隙水及界面水δ13CDIC及DIC浓度的分析，显示啊哈湖沉积物产甲烷过程很弱或不明显。这主要是受到硫酸盐还原作用的抑制。从δ34SSO42-SO42-相关关系及硫酸盐还原菌分布特征，可以在深度上划分为两种还原过程及硫同位素分馏过程：慢速还原阶段（6厘米以下），硫同位素分馏程度较大，最大分馏达13．71％。分馏因子约为1.024-1.026之间；快速还原阶段（0-6厘米），硫同位素具有明显分馏，最大达到38‰，这与快速还原过程硫同位素分馏较小的规律相反，主要原因是由于表层同时出现有还原态硫的氧化反应．产生较负的δ34S-so41，δ34S-SO42--SO42-的变化反映出混合过程。通过研究我们进一步还推断，采样点沉积物下部还有煤矿硫源的输入。4．两湖沉积物中铁、锰、硫的还原作用发生位置都具有季节性沿沉积深度上下迁移的特性，部分微量金属元素扩散通量因此发生季节性变化。受沉积物中铁锰含量的控制，红枫湖沉积物一水界面铁锰循环作用比啊哈湖弱。啊哈湖锰含量很高，导致界面附近锰的循环剧烈且远强于铁的循环，并在一定程度上引起部分微量金属在沉积物上层强烈富集。5．通过红枫湖后五沉积物剖面研究，我们发现各种微量元素由于其自身不同的地球化学性质差异，早期成岩过程对其在沉积物中的垂直分布特征的改造程度是不同的。①锰具有明显的向上富集趋势，铁在沉积物中的分布特征的后期改造作用就比较弱。②钻、镍分布的后期改造程度与铁相似，从总量来看再迁移程度比较弱。③铜、锌在早期成岩过程中逐渐向沉积物中上部富集，这主要是与铜锌强烈的亲硫性引起的。钥的表层富集现象最为明显，沉积后再迁移效应显著。由其含量在上层沉积物中的两重峰值，可以指示界面剧烈的锰循环及界面下硫酸盐还原作用对它的联合控制。6．与红枫湖相比，啊哈湖沉积物金属元素再迁移特征有很大的不同：①通过部分微量金属元素地球化学相态分析，各相态微量金属分布主要服从其总量分布特征。②沉积物稀土配分模式明确指示了啊哈湖成湖基底的位置，即沉积物－水界面下18-19厘米以下。③通过Ti、Zr、ΣREE＋Y等的分析也显示了成湖前原始基底的存在位置，同时它们在沉积物中的含量变化特征还反映了该湖扩容后陆源输入的减少。④在沉积深度上铁锰及部分微量金属元素出现明显的分离现象。⑤通过相关性分析，Fe与Cu，U、Mn与Pb，C0，Ni，Cd，Zn等都存在很好的相关性，表明它们之间具有相似的界面地球化学行为。Fe型元素与Mn型元素分布差异的原因可以简约的概括为：锰的界面循环极为强烈，导致再迁移程度很高；而铁的循环相对较弱，又容易受到上层硫酸盐还原作用的抑制，因此再迁移程度不高。此外，由岩溶地区湖泊较强的酸中和能力及近年来的人为石灰投放，沉淀PH不同导致微量金属元素间发生分离，引起下游大坝处金属元素的输入差异。因此，啊哈湖大坝附近沉积物中微量金属元素的分布特征应受到沉积后再迁移和受 pH控制的煤矿废水输送差异联合制约。

TiK alpha radiography of Cu-doped plastic microshell implosions via spherically bent crystal imaging

We show that short pulse laser generated Ti K alpha radiation can be used effectively as a backlighter for radiographic imaging. This method of x-ray radiography features high temporal and spatial resolution, high signal to noise ratio, and monochromatic imaging. We present here the Ti K alpha backlit images of six-beam driven spherical implosions of thin-walled 500-mu m Cu-doped deuterated plastic (CD) shells and of similar implosions with an included hollow gold cone. These radiographic results were used to define conditions for the diagnosis of fast ignition relevant electron transport within imploded Cu-doped coned CD shells. (c) 2005 American Institute of Physics.

Cartografia geoquímica da ilha de Santiago com uma densidade de amostragem média/baixa

A ilha de Santiago é a maior do arquipélago de Cabo Verde, apresenta uma área de 991 km2, com um comprimento e largura máximos de 54,9 km e 29 km, respectivamente, e 1392 m de maior altitude. As condições climáticas e a erosão são alguns dos problemas naturais do arquipélago de Cabo Verde. Além disso, a intervenção humana no ambiente superficial revela-se muitas vezes inadequada e com forte impacto. A construção em solos com aptidão agrícola ou florestal, as actividades industriais, a deposição de materiais sólidos ou líquidos de forma inadequada, as práticas agrícolas incorrectas e intensivas, o uso abusivo de pesticidas e fertilizantes, a rega com água contaminada, a sobreexploração de aquíferos que levam muitas vezes à salinização, etc. têm enorme impacto em termos de contaminação de solos, águas superficiais e subterrâneas nas áreas envolventes. Por conseguinte, o conhecimento da variabilidade geoquímica natural é fundamental para a resolução de questões de índole económica, ambiental e de ordenamento do território, médica, e jurídica. A necessidade de construir uma base de dados de geoquímica georeferenciada que caracterize o ambiente superficial da ilha de Santiago foi a principal motivação para a realização deste estudo. Realizou-se um levantamento geoquímico de 337 amostras de sedimentos de corrente e 249 amostras de solos na ilha de Santiago, tendo sido seguidas as recomendações do Projecto Internacional IGCP 259 não só na fase de amostragem, mas também nas fases seguintes de preparação, análise, tratamento dos dados e elaboração de mapas. Determinaram-se os teores, na fracção < 2 mm, para 36 elementos – 9 elementos maiores (Al, Ca, Fe, K, Mg, Mn, Na, P, Ti) e 27 elementos vestigiais (Ag, As, Au, B, Ba, Bi, Cd, Co, Cr, Cu, Ga, Hg, La, Mo, Ni, Pb, S, Sb, Sc, Se, Sr, Th, Tl, U, V, W, Zn). Efectuou-se ainda a análise textural e estudou-se a composição mineralógica de cerca de 25% das amostras. Analisaram-se, também, 103 amostras de rochas, colhidas nas várias formações da ilha de Santiago, tendo sido determinados os teores de K2O, Na2O, Fe2O3(T), MnO, Sc, Cr, Co, Zn, Ga, As, Br, Rb, Zr, Sb, Cs, Ba, Hf, Ta, W, Th e U e REE, a fim de se fazer uma comparação com os teores destes elementos encontrados nos solos e sedimentos de corrente, averiguando se a sua variação é ou não essencialmente condicionada pela geoquímica da rocha-mãe. Os padrões geoquímicos obtidos através dos mapas de distribuição espacial foram correlacionados com a natureza da rocha mãe, o tipo de solo, e ainda com algumas fontes de contaminação. A interpretação dos resultados foi realizada não só pela observação dos mapas geoquímicos, mas também após análise estatística dos conjuntos de dados obtidos, e apoiada em informação diversa disponível. A utilização da Análise de Componentes Principais permitiu distinguir associações entre elementos químicos, quer de origem geogénica quer antropogénica. Foram ainda elaborados mapas de distribuição espacial de vários índices multielementares de importância ambiental, como o Índice de Acidificação Al/(Ca+Mg+K), Índice de Combi, Índice de Avaliação de Risco Ambiental e Índices de Enriquecimento/Contaminação para vários grupos de elementos considerados como “primary pollutant metals”.

Fate Hazardous elements in soils surrounding a coal-fired power plant complex

Proceedings of the 13th International UFZ-Deltares Conference on Sustainable Use and Management of Soil, Sediment and Water Resources - 9–12 June 2015 • Copenhagen, Denmark

Trace elements biogeochemistry in high mountain lake catchments: identifying anthropogenic versus natural components from the atmospheric contamination legacy in remote natural areas

Human activities have been interfering with the natural biogeochemical cycles of trace elements since the ancient civilizations. Although they are inaccessible and remote, high mountain lake catchments are irrefutably trace-element contaminated by anthropogenic emissions, which can travel by long-range atmospheric transport before they are deposited. This has been revealed by several natural archives. High mountain lake catchments are thus excellent sentinels of long-range contamination. Continuous accumulation can lead to a build up of potentially toxic trace elements in these remote, or relatively remote, ecosystems. The thesis focuses on the biogeochemistry of a suite of trace elements of environmental concern (Ni, Cu, Zn, As, Se, Cd and Pb) in Pyrenean lake catchments, with special emphasis on discerning the “natural” components from the “anthropogenic” contributions. Five other metallic elements (Al, Fe, Ti, Mn and Zr) have also been studied to trace natural fluxes and biogeochemical processes within the lake catchment systems.

Fulvalene cyclopentadienyl titanium and zirconium(III) and -(IV) complexes. X-Ray crystal structure of [{Ti(η5-C5H5) Cl}2 (μ-O)(μ-η5-η5-C10H8)]

The reaction of the fulvalene titanium(III) hydride [{Ti(η5-C5H5)(μ-H)}2(μ-η5-η5-C10H8)] (1) with chlorine leads to [{Ti(η5-C5H5)(μ-Cl)}2(μ-η5-η5-C10H8)] (3) and [{Ti(η5-C5H5)Cl2}2(μ-η5-η5-C10H8)] (4). The reaction of 3 with azobenzene, in wet toluene, gives [{Ti(η5-C5H5)Cl}2(μ-O)(μ-η5-η5-C10H8)] (5) and 1,2-diphenyl hydrazine. The alkylation of 4 and the analogous zirconium complex [{Zr(η5-C5H55)Cl2}2(μ-η5-η5-C10H8)] (2) with LiCH2SiMe3 or LiCH3 permits isolation of the tetraalkyl derivatives [{M(η5-C5H5)(CH2SiMe3)2}2(μ-η5-η5-C10H8)] (M  Ti (6); Zr (8)) and [{Ti(η5-C5H5)(CH3)2}2(μ-η5-η5C10H8)] (7). All the new fulvalene compounds were characterized by IR, and 1H and 13C NMR spectroscope, and mass spectra and 5 by X-ray diffraction. The structure of 5 is very similar to that of the comparable TiIV compound [{Ti(η5-C5H5)2Cl}2(μ-O)] except for the smaller TiOTi angle (159.4° against 173.81°) and a significant deviation from linearity.

Microstructural, structural and dielectric properties of Er(3+)-modified BaTi(0.85)Zr(0.15)O(3) ceramics

The (micro)structural and electrical properties of undoped and Er(3+)-doped BaTi(0.85)Zr(0.15)O(3) ceramics were studied in this work for both nominal Ba(2+) and Ti(4+) substitution formulations. The ceramics were produced from solid-state reaction and sintered at 1400 degrees C for 3 h. For those materials prepared following the donor-type nominal Ba(1-x)Er(x)(Ti(0.85)Zr(0.15))O(3) composition, especially, Er(3+) however showed a preferential substitution for the (Ti,Zr)(4+) lattice sites. This allowed synthesis of a finally acceptor-like, highly resistive Ba(Ti,Zr,Er)O(3-delta)-like system, with a solubility limit below but close to 3 cat.% Er(3+). The overall phase development is discussed in terms of the amphoteric nature of Er(3+), and appears to mainly or, at least, partially also involve a minimization of stress effects from the ion size mismatch between the dopant and host cations. Further results presented here include a comparative analysis of the behavior of the materials` grain size, electrical properties and nature of the ferroelectric-to-paraelectric phase transition upon variation of the formulation and Er(3+) content. (C) 2008 Elsevier Ltd. All rights reserved.

Zr- AND Ba-RICH MINERALS FROM THE PONTE NOVA ALKALINE MAFIC-ULTRAMAFIC MASSIF, SOUTHEASTERN BRAZIL: INDICATION OF AN ENRICHED MANTLE SOURCE

Zirconium- and Ba-rich minerals are found in gabbroic rocks from the Ponte Nova alkaline mafic-ultramafic massif in southeastern Brazil. The unusual mineralogical assemblage includes zirconolite, baddeleyite, Ba-rich alkali feldspar, and Ba- and Ti-rich biotite. Zirconolite of the Ponte Nova massif has higher levels of Zr (up to 1.172 apfu) than those registered in other terrestrial rocks and a prominent enrichment in the light rare-earth elements. Baddeleyite contains small quantities of Hf, Ti, and Fe. The Ba-rich alkali feldspar and Ba- and Ti-rich biotite contain up to 9.25 and 7.35 wt% BaO, respectively, and the biotite contains up to 12.01 wt% TiO(2). In the different intrusions of the Ponte Nova massif, such an unusual assemblage typifies the residual magma after the crystallization of clinopyroxene and olivine from previously enriched basanitic parental magma. The different trends of enrichments in REE and Th + U found for zirconolite of the intrusions of the Ponte Nova massif provide a better understanding of the variable degrees of enrichment of incompatible elements of the distinct gabbroic bodies. A lithospheric mantle source enriched in incompatible elements by the metasomatic action of volatile-rich fluids and with the presence of phlogopite or amphibole (or both) and other minor accessory phases could explain the presence of the Zr- and Ba-rich minerals in this gabbroic massif.