中国海水珍珠Mg、Fe、Zn和Mn含量变化及其对珍珠微观结构的影响

利用等离子体发射光谱仪(ICP)对流沙湾优劣质珍珠中微量金属元素含量进行分析,采用扫描电子显微镜(SEM)和原子力显微镜(AFM)对两种珍珠的外表面与纵截面进行系统观察,采用785 nm激发波长对两珍珠的珍珠质层和棱柱层中无机相进行原位拉曼光谱测试。结果表明:劣质珍珠中Mg、Fe、Zn、Mn和P含量比优质珠高,珍珠层外表面文石晶体有序排列程度低;阶梯状珍珠层越致密、台阶厚度越薄,其珍珠质量越好。同一直径的珍珠,优质珍珠文石板片厚度较劣质珍珠薄,劣质珍珠棱柱层结构疏松,棱柱层比优质珠厚,劣质珠棱柱层中的方解石与杂质层影响了珍珠正常矿化过程。     

应用傅里叶变换红外光谱与紫外可见吸收光谱鉴别两类海水养殖灰色珍珠

Akoya珍珠属生物矿化有机宝玉石,该类珍珠的矿物组成与微结构分析、定性与其颜色形成属性的鉴定方法尚为缺乏。本文通过光学显微镜、紫外可见吸收光谱、傅里叶变换红外光谱、能量色散X射线荧光光谱对具有白色或灰色珠核的两类Akoya灰色珍珠的珍珠层与珠核的结构特征及显色机制、紫外吸收光谱、微量金属元素赋存特征进行了对比研究。结果表明:①灰色珍珠的珠核有白色与灰色两类,两类珍珠的直径主要分布在5～9mm,珍珠层厚度约300～500μm;②两类珍珠的珍珠层和珠核的主体矿物组成均为生物文石,且两者的珍珠层中均富Sr贫Mn。③灰色的珠核具有明显的富Mn特征,且由于辐照使得Mn元素的价态升高并使得珠核致灰色,并导致整个珍珠呈现灰色;④紫外可见吸收光谱检测中,一般而言具有白色珠核的灰色珍珠在300～400nm波段可见明显的反射带,而具有灰色珠核的灰色珍珠在400～500nm波段可见明显的反射带。两类灰色珍珠皆为海水养殖珍珠,研究表明这两类珍珠的紫外吸收光谱的差异可作为初步评判灰色系珍珠是否经辐照改色的依据之一。     

湖相烃源岩Ro异常与无机元素相关性初探

对东营凹陷牛38井主力烃源岩段沙河街三段 Ro值与对应的无机元素含量进行了相关性分析,结果表明 ,牛38井沙河街组烃源岩中, K、Na、Zn、Ni、Mg、Li、Ba、Co、Rb等无机元素含量与 Ro值分布总体呈正相关性,其中 K、Na、Rb等强碱金属元素含量与 Ro值正相关性相对较强;Ca、Sr、Mn等金属元素含量与 Ro值总体呈负相关性;Fe、B含量与 Ro值相关性差.     

华北地块东南缘中生代侵入杂岩中所含榴辉岩类包体矿物微量元素地球化学特征及其意义

华北地块东南缘中生代侵入杂岩中所含榴辉岩类包体中矿物的分析结果表明, 组成榴辉岩类包体的各矿物之间元素的分配在榴辉岩相变质阶段已经达到了化学平衡;石榴石中Al、Fe、Mn, 单斜辉石中Na、Mg、Ca, 角闪石中Na、Mg、Fe等主量元素含量与其全岩之间均呈良好的正相关, 受全岩成分制约;石榴石明显富集HREE、贫LREE, 单斜辉石相对富集LREE、MREE、贫HREE, 两者轻、重稀土含量呈相互消长的互补关系, 石榴石和单斜辉石中分别富集Y、Sr, Ga和过渡族元素Sc、Ti、V、Cr、Co等含量较高, 其含量受全岩成分控制;金红石中稀土元素的含量很少, Fe、Al、Mg、Ca、Mn、Nb、Ta、Cr和Zr含量相对较高, Rb、Sr、Ba含量极低, 部分微量元素(如Nb、Cr、Fe、V、W等)含量与其原岩有继承和对应关系;部分原生或/和退变角闪石的REE配分模式分别与单斜辉石和石榴石相似, 过渡族金属元素等的含量与石榴石、单斜辉石和全岩具有一定的相关性, 角闪石容纳Na、K、Sr、Rb、Ba等元素的能力较强, 其成分除受全岩成分的制约外, 石榴石、单斜辉石对其形成也有影响。榴辉岩类包体与其寄主中生代侵入杂岩中部分高价态/高场强元素(HFSE)和重稀土元素(HREE)呈相互消长的关系。榴辉岩的形成与扬子地块和华北地块之间的俯冲-碰撞作用有关。     

东营凹陷古近系中深层湖盆演化中的无机元素响应

为查明无机元素分布与水深、盐度等沉积环境以及湖盆演化过程的关系,采用电感耦合等离子体发射光谱仪分析对东营凹陷郝科1科探井古近系深层微量元素含量进行了测试、分析,所涉及的研究层位是该凹陷的主要烃源岩层段（沙河街组三亚段、沙河街组四亚段、孔店组）,分析结果表明:在水体浅、蒸发作用强烈的孔店组—沙四下亚段强氧化性滨浅湖环境里,钙、锶含量和Ca/Mg、Sr/Ba、Sr/Ca参数值具低值响应,铁、铝、钡、钒含量和（Fe+Al）/(Ca+Mg)参数值具高值响应;在沙四中亚段膏岩、盐岩等普遍发育的盐湖环境中,钠、锶含量和Sr/Ba、Fe/Mn、Sr/Ca均出现高值响应,锰、钡、钒含量和V/Ni、(Fe+Al)/(Ca+Mg)出现低值响应;在还原性的沙四上亚段半咸化深湖环境中,钾、钠、铁含量和Fe/Mn值具低值响应,钙、锰含量具高值响应;在沙四中亚段膏盐与泥岩共生体系中元素分布离散性明显,呈现波动性特征;Sr/Ba、Sr/Ca在盐湖环境中出现显著的高值响应,被证实可以作为良好的水体盐度指标参数,Fe/Mn、(Fe+Al)/(Ca+Mg)随水体加深逐渐增大,是良好的水体深浅指标参数。元素分布受沉积环境、岩性特征等多种地质因素的影响,在利用元素含量分布及特征元素比值来判断某单个地质因素的变化时,应该应用多种参数,进行综合判断。     

东营凹陷南斜坡沙四段沉积环境的地球化学特征

东营凹陷是一个北断南超的不对称箕状断陷湖盆,湖盆中的常量元素和微量元素含量及有关元素比值呈现出明显的旋回变化特征。而其中元素的分配及比值的变化、组合都在一定程度上指示着古沉积环境的演化历程。通过分析Fe,Mn,Ca,Sr等元素含量和Fe／Mn,Sr／Ba,Sr／Ca,Mg／Ca等元素比值以及碳氧同位素的变化特征。对东营凹陷南斜坡沙四段沉积时期的沉积环境进行了系统的研究。结果反映了沙四段沉积时期的古气候、古盐度、古湖水面和古生产力基本上都显示出了旋回变化的特征。     

X荧光能谱技术鉴别淡水珍珠和海水珍珠的应用

采用X荧光能谱技术研究珍珠中微量元素的种类及其质量分数,以达到无损鉴别淡水珍珠和海水珍珠的目的。利用X射线荧光能谱仪优选适合的激发工作条件,通过设定相同的工作条件,获得珍珠主量元素和微量元素的能量色散图谱,定性分析其主量元素和微量元素的组合关系。其中,Mn的特征峰与Sr/Ca计数比率对鉴别珍珠品种有重要的指示意义。研究表明,在电压为30～35kV、电流为0.50～0.80mA、滤光片PdThick的测试条件下,淡水珍珠一般具有Ca＋Sr＋Mn的组合关系,海水珍珠具有Ca＋Sr的组合关系;淡水珍珠中的Sr/Ca介于0.14～0.37,海水珍珠中的Sr/Ca介于0.46～0.71。综合利用元素的组合关系和Sr/Ca计数比率,可快捷、无损地鉴别珍珠品种。     

东太平洋海盆沉积物间隙水地球化学研究

研究了东太平洋海盆沉积物间隙水中元素的变化趋势及组合特征。结果表明，经过成岩改造的间隙水化学组成相对于海水发生了较大的变化。其中K、Sr、B趋于亏损，Ca、Mg、Li则表现出亏损和富集两种不同的变化趋势：Si、Ba、Rb富集，Mn、Fe、Zn、Pb、Cu、Ni、Co则高度富集。R型聚类分析结果表明，间隙水中金属元素可分成K、Sr、Mg、Li、Ca和Mn、Fe、Rb、Co，Zn、Cu、Ni、Pb两组。影响间隙水元素组成变化的主要因素有火山物质的海解作用，硅质生物组分和岩成碎屑组分的成岩作用及有机物的分解作用等。     

松嫩平原西部碱尘气溶胶的元素特征分析

碱尘暴期间松嫩平原西部碱尘气溶胶的主要元素质量浓度排序为Na、Al、Fe、Ca、Mg、K、Ti、Ba、Zn,与当地盐碱化土壤的元素组成吻合,而与沙尘、城市气溶胶的元素组成有差别。风力对碱尘气溶胶元素组成有明显的影响,当风速在8.0~17.1 m/s时,元素组成的质量浓度排序为Na、Ca、Al、Fe、Mg、K、Ba、Ti、Zn。Na元素质量浓度的激增是碱尘暴元素组分的一大特征,明显富集元素为Na和B;相对于当地背景大气气溶胶的富集情况,Zn、Cu、Ba、B的富集因子值在碱尘暴期间明显降低;在各种天气情况下,B、Cu均具有较高的富集因子。碱尘中Ti元素的富集因子值均小于1,而Ca、Fe、K、Mg、Mn、Sr、V的富集因子值为1~4。两个采样点的Ca、Na、Al、Fe、Mg、Ti、Zn的富集因子近似,表明该区碱尘的主要元素具有特定的一致性;而B、Ba、Cu、V的富集因子相差较大,可以作为区分不同碱尘源的标志性元素。     

大洋磷酸盐化作用对富钴结壳元素富集的影响

中国首次对与大洋富钴结壳密切相关的磷酸盐化作用进行了研究。对取自西太平洋麦哲伦海山区一厚度为 10cm的富钴结壳样品 ,自顶至底以 5mm间距采取了 2 0个分层样品进行了成矿元素和稀土元素分析。结果表明 ,未被磷酸盐化的新结壳和磷酸盐化的老结壳间主要成矿元素的含量相差显著。老结壳中Fe、Mn、Si、Al、Zn、Mg、Co、Ni、Cu元素亏损 ,亏损次序为Co >Ni>Mg >Al>Mn >Si>Cu >Zn >Fe;而Ca、P、Sr、Ba、Pb元素含量增加 ,富集次序为P >Ca >Ba >Pb >Sr。研究认为 ,结壳中磷酸盐化作用的强弱制约着富钴结壳成矿元素含量的变化 ,磷酸盐化作用是造成老结壳中主要成矿元素Co、Ni等贫化流失的根本原因。研究还表明 ,磷酸盐化作用对富钴结壳的稀土元素丰度也产生一定影响 ,使老结壳的稀土总量和Ce含量高于新结壳 ,但未显著改变其稀土配分模式和分馏特征。研究证实 ,老结壳的Y正异常与磷酸盐化作用无关。磷酸盐化作用的研究为富钴结壳矿产资源的评价和综合利用提供了有用信息。     

Geochemistry of metals in sediments from the mainstem of the Yellow River, China

Sediment samples at 10 locations in the mainstem of the Yellow River were taken in 1994. Five forms (exchangeable, carbonate, organic, Fe/Mn oxide and residual) of metals were extracted by the Tessier method. The total contents and contents of the five forms of 16 metal elements (Li, Na, K, Ca, Sr, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, and Al) were determined by ICP-AES. In sediments of the Yellow River, except for Na, mobile elements (such as K, Ca) do not show a negative correlation with the immobile elements. Alkaline metals (Li, Na, and K), Ti, and Al exist mainly in the residual form. The exchangeable forms of alkaline-earth elements (Ca, Sr, and Ba) are the highest, and their residual forms go up with the increase of the period in the periodic table of elements. Half of Mn exists in the residual form, and its non-residual forms exist mainly in carbonate and oxide forms. Except Mn, the iron group elements (Fe, Co, Ni, V, Cr) mainly exist in the residual and oxide forms. High carbonate content of Ca does not cause high contents of other elements in carbonate form, showing that chemical weathering is not strong in the area.     

Effect of Phosphatization on Element Concentration of Cobalt-Rich Ferromanganese Crusts

1 Introduction Co-rich ferromanganese crusts occurring on submarine guyots have received much attention from scientists since the beginning of the 1980’s because they are enriched in Co, Mn, Pt, and rare earth elements (REEs), and have large potential mineral resources, occurring as they do on topographic highs relative to polymetallic nodules in the C-C (Clarion-Clipperton) zone (Halbach et al., 1982, 1989; Hein et al., 1992, 1999; Usui and Someya, 1997; Yamazaki and Sharma, 1998, 2000…     

Rare earth element geochemistry of scleractinian coral skeleton during meteoric diagenesis: a sequence through neomorphism of aragonite to calcite

Rare earth element geochemistry in carbonate rocks is utilized increasingly for studying both modern oceans and palaeoceanography, with additional applications for investigating water–rock interactions in groundwater and carbonate diagenesis. However, the study of rare earth element geochemistry in ancient rocks requires the preservation of their distribution patterns through subsequent diagenesis. The subjects of this study, Pleistocene scleractinian coral skeletons from Windley Key, Florida, have undergone partial to complete neomorphism from aragonite to calcite in a meteoric setting; they allow direct comparison of rare earth element distributions in original coral skeleton and in neomorphic calcite. Neomorphism occurred in a vadose setting along a thin film, with degradation of organic matter playing an initial role in controlling the morphology of the diagenetic front. As expected, minor element concentrations vary significantly between skeletal aragonite and neomorphic calcite, with Sr, Ba and U decreasing in concentration and Mn increasing in concentration in the calcite, suggesting that neomorphism took place in an open system. However, rare earth elements were largely retained during neomorphism, with precipitating cements taking up excess rare earth elements released from dissolved carbonates from higher in the karst system. Preserved rare earth element patterns in the stabilized calcite closely reflect the original rare earth element patterns of the corals and associated reef carbonates. However, minor increases in light rare earth element depletion and negative Ce anomalies may reflect shallow oxidized groundwater processes, whereas decreasing light rare earth element depletion may reflect mixing of rare earth elements from associated microbialites or contamination from insoluble residues. Regardless of these minor disturbances, the results indicate that rare earth elements, unlike many minor elements, behave very conservatively during meteoric diagenesis. As the meteoric transformation of aragonite to calcite is a near worst case scenario for survival of original marine trace element distributions, this study suggests that original rare earth element patterns may commonly be preserved in ancient limestones, thus providing support for the use of ancient marine limestones as proxies for marine rare earth element geochemistry.     

Trace element geochemistry of the Mt Vulture carbonatites,southern Italy

The Mt Vulture carbonatites are the only carbonatite occurrence in the southern Apennines. We present new trace element data for these rocks in order to evaluate the factors influencing rare earth element (REE) and other trace element fractionations and their REE grade. This study focuses on massive hyalo-alvikites from two lava flows and one dike, which have different relative abundances of silicate and carbonate (i.e. Si/Ca). These differences are also evident from CaO/(CaO + MgO + FeO(T) + MnO) and Sr/Ba ratios. The REE grade of the Mt Vulture carbonatites is very similar to that of the global average for calcio-carbonatites. R-mode factor analysis shows that most of the trace element variance reflects the relative roles of carbonate and silicate minerals in influencing trace element distributions. Silicates largely control heavy rare earth element (HREE), transition metal, Zr, and Th abundances, whereas carbonate minerals control light rare earth element (LREE), Ba, and Pb abundances. In addition, apatite influences LREE concentrations. Increasing silica contents are accompanied by decreases in (La/Yb)N and (La/Sm)N ratios and less marked LREE enrichment. In contrast, higher carbonate contents are associated with increases in (La/Yb)N and (La/Sm)N. The Si/Ca ratio has little influence on Eu anomalies and middle rare earth element (MREE) to HREE fractionations. Apatite has a negligible effect on inter-REE fractionations amongst the carbonatites.     

Selenium and heavy metals content in some Mediterranean soils

The study of metal contents in industrial, agricultural or/and polluted soils compared with natural or unpolluted soils is currently necessary to obtain reference values and to assess soil contamination. Nonetheless, very few works published appear in international journals on elements like Se, Li and Sr in Spanish soils. This study determines the total levels of Se, Li, Sr, As, Cd, Co, Cr, Cu, Ni, Pb, V, Zn, Fe, Mn and Ba in 14 natural (unpolluted) soils (Gypsisols, Leptosols, Arenosols and Acrisols), 14 agricultural soils (Anthrosols, Fluvisols and Luvisols), and 4 industrial–urban affected-surface soil horizons (Anthrosols and Fluvisols) of Eastern Spain. The geochemical baseline concentrations (GBC) and reference values (RV) have been established, and the relationships among elements and also between soil properties and elemental concentrations have been analysed. The RV obtained in this study were (mg kg⁻¹): Se 2.68, Li 115, Sr 298, Cd 0.97, Co 35, Cr 217, Cu 46, Ni 50, Pb 137, V 120, Zn 246, Fe 124,472, Mn 2691, and Ba 743. The RV for Se and Li were used as a preliminary approach to assess soil contamination in Spanish soils. The results confirm human impact on Sr, As, Cd, Cr, Cu, Ni, Pb and Zn soil concentrations, but evidence no deviation from natural Se, Li, Co, V, Fe, Mn and Ba concentrations. The results obtained from the statistical analysis reveal significant correlations between some elements and clay and soil organic matter (SOM) contents, indicating that metal concentrations are controlled by soil composition. One particularly interesting finding is the high correlation coefficients obtained between SOM and Se, Cd, Cr, V, Fe, and Mn, and between clay and Cd, Zn, V, Fe and Mn. Once again, these facts confirm the role of SOM and clay minerals in soil functions and that soil is an ecosystem element responsible for maintaining environmental quality.     

应用扫描电镜-红外与反射光谱研究海水灰色Akoya珍珠特异的矿化微结构特征

近年来海水灰色Akoya珍珠是珍珠类饰品的新宠,前期研究主要聚焦在对其海水属性、各结构单元的元素赋存特征、辐照处理及其鉴别方法等方面.本文借助紫外可见(UV-Vis)反射光谱仪、显微红外光谱仪、扫描电镜等技术,对具有白色内核的一类灰色珍珠的宝石学与其精细结构特征进行研究.结果表明:①在珍珠的珠核与珍珠层之间,基本存在厚...     

微量元素分布揭示腕足化石壳体原始信息保存现状

以产于四川龙门山地区泥盆系观雾山组的有铰纲腕足化石Ｉｎｄｅｐｅｎｄａｔｒｙｐａ ｌｅｍｍａ Ｃｈｅｎ为研究对象,利用激光熔样等离子质谱（ＬＡ－ＩＣＰ－ＭＳ）对其壳体棱柱层中Ｆｅ、Ｍｇ、Ｍｎ、Ｎａ、Ｂａ和Ｓｒ六种微量元素进行了就位分析。它们在壳体横切面中的对称分布特征总体上与壳体增生方式和过程相一致,表明壳体的绝大部分未经成岩作用的改造。与常用的结构判据、阴极发光判据和微量元素含量判据相比较,微量元     

广东三水盆地古近系心组生油层的元素地球化学特征

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