Application of an Ion-Selective Electrode Method to the Determination of Chloride in 41 International Geochemical Reference Materials

Determinations of trace amounts (with one exception) of chloride are reported for 41 international geochemical reference standards, 12 of which have no previously reported literature values. All determinations were made by the chloride-specific ion-selective electrode method of Aruscavage and Campbell with certain refinements. Chlorine is separated from most other elements in geologic materials by acid-dissolution in a gas diffusion cell, and is subsequently determined as the chloride ion in basic solution. A statistical F-test was applied to 19 of the standards for which three bottles of each were analyzed in triplicate with no failures. All these standards, plus the other 22 for which six analyses were performed on a single bottle, exhibited a relative standard deviation of 1-6% for concentrations of chloride >50 ppm. For most samples chloride values agree well both with available, reported experimental values and with recommended or consensus values.     

地下水中微量组份H2SiO3富集的地质地球化学环境

通过对全国325处富含偏硅酸地下水点的化学测试数据、所处的地球化学环境、地质背景的分析,阐述了微量组份H2SiO3的富集特征与含水介质岩性的关系,以及富含H2SiO3地下水的地球化学特征。认为富含H2SiO3地下水的形成与不同含水介质岩性和SiO2平均丰度等地球化学环境密切相关。地下水中H2SiO3富集的最有利地质环境是中酸性侵入岩地层,其次是区域变质岩、喷出岩、碎屑岩。研究表明,地下水中的H2SiO3含量与水化学类型和pH值相关,推断出HCO3-Ca、HC03-CaNa型水和碱性、酸性水都有利于H2Si03的富集。     

Instrumental Neutron Activation Analysis of Twenty-Nine International Geochemical Reference Samples

Results of measurements of twenty-seven elements, most of them in trace amounts, by Instrumental Neutron Activation Analysis (INAA) in twenty-nine international geochemical reference samples from Canada, U.S.A., Japan, France and South Africa, are reported and compared with available literature values. In general, our data agree well with literature values. The disagreement of our results (e.g., Zr in Canadian syenites and several trace elements in USGS ultrabasic rocks) with those reported by other workers is briefly discussed and ways of improving INAA are pointed out. The present report includes data on several trace elements for which existing data are rather scarce.     

Elemental Concentrations In Japanese Silicate Rock Standards: A Comparison With The Literature

Data on seventeen Japanese geochemical reference samples are presented. Ten major and twenty-three trace element concentrations as well as the H2O + and H2O- were determined using x-ray fluorescence, colorimetry, coulometry and instrumental thermal neutron activation analysis. Error bars for the methods as well as information on some elements not previously published are presented. Good agreement was generally obtained with the recently published values of Ando.
Dix éléments majeurs et vingt éléments en traces ainsi que H₂O+ et H₂O- ont été dosés dans 17 échantillons de référence du Service Géologique du Japon. Les méthodes employées sont la spectrométrie de fluorescence-X, la coulométrie, la colorimétrie et l'activation neutronique thermique. En générale, un accord favorable est obtenu avec les valeurs publiées.     

Geochemistry analysis and evolution of a bolson aquifer,basin and range province in the southwestern united states

This paper expands significantly on the major-ion geochemical characterization, evolution, and differentiation of groundwater in the Presidio-Redford Bolson (PRB) Aquifer of Texas as presented in Chowdhury et al. (2008). For 19 groundwater samples from the PRB Aquifer, the author calculated major cation–anion balance errors, equilibrium carbon dioxide partial pressure values and saturation indices for selected minerals. Comparison of major-ion analyses for groundwater from basin margin wells with those for basin center wells is documented and illustrated with ion-concentration maps and Piper and Stiff diagrams and reveals significant increases in concentrations of chloride, sulfate and sodium coupled with notable decrease of calcium in bolson-center well samples. These geochemical changes suggest dissolution of aquifer minerals and cation exchange as groundwater migrates downgradient to the bolson center. The US Geological Survey (USGS) computer code, NETPATH, was used to interpret probable net geochemical mass-balance reactions that potentially have occurred within the PRB Aquifer along groundwater flowpaths from bolson margin to bolson center. For all four upgradient–downgradient well pairs studied, at least three NETPATH models contain cation exchange values; calcium is being exchanged for sodium. The Rio Grande Alluvium Aquifer and Rio Grande River are notably minor sources of recharge to the PRB Aquifer, based on Chowdhury et al. (2008) and geochemical evaluations of this study.     

Cd, Gd and Sm Concentrations in BCR-1, BHVO-1, BIR-1, DNC-1, MAG-1, PCC-1 and W-2 by Isotope Dilution Thermal Ionisation Mass Spectrometry

Cadmium, gadolinium and samarium concentrations were determined in seven geochemical reference materials by isotope dilution thermal ionisation mass spectrometry. The results for all three elements in BCR-1 are in excellent agreement with the compiled values as well as the literature values dete-mined by isotope dilution mass spectrometry. The agreement with compiled values on the other material is generally good except for Cd where the values for BHVO-1, BIR-1, DNC-1 and W-2 need to be revised.     

Instrumental Neutron Activation Analysis of Two French Geochemical Reference Samples - Basalt BR and Biotite Mica-Fe

Instrumental neutron activation analysis results for 20 trace elements (Sc, Cr, Co, Ni, Rb, Cs, Ba, La, Ce, Nd, Sm, Eu, Gd, Tb, Tm, Yb, Lu, Hf, Ta, Th) and for two major elements (Na and Fe) in two geochemical reference samples issued by the "Centre de Recherches Pétrographiques et Géochimiques" are reported and compared with available literature values. In general our results agree well with recommended or proposed values.     

Geochemical mapping based on geological units: A case study from the Marnoso-arenacea formation (Northern Apennines,Italy)

Geochemical maps can provide us with much information on geology, earth surface processes and anthropogenic pressure and are valuable tools for ore prospecting and land management. Stream sediments represent an integral of the various possible sources of sediments upstream from the sampling point therefore there can be multiple signal sources but generally the prevailing signal source is the one related to bedrock geology. Stream sediments collected from active second-order channels including singular geological units, were selected in order to determine the geochemical characteristics of each unit. The aim of this study was to analyse their potential for using them to integrate geological interpretation and produce a geologically-oriented geochemical map. From the 770 samples collected for a regional geochemical mapping program, we selected 149 samples whose catchment basin included only one of the members recognized within the Marnoso–Arenacea formation. This Middle-Upper Miocene (Langhian–Tortonian) turbiditic unit forms the backbone of the Romagna Apennines and has been subdivided into 14 members according to age and lithostratigraphic criteria. The results indicate that there are marked differences in the composition of the members of the Marnoso Arenecea formation which indicate the provenance of the sediment and the palaeogeographic evolution of the units. By means of univariate and multivariate statistical analyses (Factor analyses) two main types of sediment compositions are identified: Tortonian members are characterized by sialic coarse grain- sediments while the Langhian–Serravallian members are richer in carbonate fraction, slightly enriched in a mafic contribution. This study elaborated the geochemical data from a geological point of view by integrating the information available in literature to spatially extend the interpretation based on limited site observation as for petrographic studies. In general, the geochemical map based on a geological unit could be a useful tool for carrying out the geological reconstruction of a complex area.     

Geochemical processes and sedimentological characteristics of Holocene lagoon deposits,Alikes Lagoon,Zakynthos Island,western Greece

In this paper we present sedimentological, geochemical, mineralogical and ¹⁴C Accelerator Mass Spectrometry (AMS) dating data of a 21.0‐m core obtained from Alikes Lagoon, Zakynthos Island. It is the first time that sedimentological and geochemical data are presented, up to 21‐m depth, from an Holocene coastal lagoon environment of the Ionia Sea, western Greece. The sedimentological properties and the geochemical composition of sediments were studied for the time period between 8540 years bp to present. Samples were analysed for their particle size, calcium carbonate and total organic carbon (TOC) content. Moreover, bulk sample chemical analyses for major and trace elements were carried out, as well as bulk, oriented mineralogical analyses for the clay fraction (<2 µm) were determined by powder X‐Ray diffraction. The grain size characteristics, statistical parameters and TOC, for the Holocene analysed samples, suggest a coastal environment (restricted‐shallow) with reduced salinity such as a tidal flat and/or particularly marsh in a lagoon margin. Sediment characteristics as well as trace element records may contain additional new palaeoclimate information that provide important new constraint on sediment depositional environment and Holocene climate. Stratigraphic variation of geochemical indices, such as Rb/Ti, Cs/Ti, Eu/Eu*, Th/Ti, La/Ti, Ta/Ti, Yb/Ti and Y/Ti, for the sediments with ages from 8540 to 7210 years bp , remain relatively constant indicating that the provenance of the Alikes Lagoon remained similar throughout the mid Holocene. However, geochemical indices in sediments with ages from 7110 years bp to present, indicate the transition from a warm and wet climate in the middle Holocene to a relatively cold climatic conditions in modern times. Copyright © 2012 John Wiley & Sons, Ltd.     

Comprehensive Chemical and Isotopic Analyses of Basalt and Sediment Reference Materials

Geochemical studies of geological samples require the precise determination of their major and trace element contents and, when measured, of their isotopic compositions. It is now commonly accepted that the accuracy and precision of geochemical analyses are best estimated by the concomitant analysis of international reference materials run as unknown samples. Although the composition of a wide selection of basalts is relatively well constrained, this is far from being the case for sedimentary materials. We present here a comprehensive set of major and trace element data as well as Nd, Hf, Sr and Pb isotopic compositions for thirteen commonly used international reference materials – eight magmatic rocks (BHVO‐2, BR, BE‐N, BR 24, AGV‐1, BIR‐1, UB‐N, RGM‐1) and five sediments (JLk‐1, JSd‐1, JSd‐2, JSd‐3, LKSD‐1). We determined the concentrations of over forty elements in the magmatic rocks together with Sr, Nd, Hf and Pb isotopic compositions. Our trace element results were both accurate (difference ≤ 3%) and precise (reproducibility at 1s ≤ 3%) and the isotopic results were very similar to other published values. In contrast, we observed a significant chemical and isotopic variability in the sedimentary materials, which we attribute to mineral heterogeneities in the powders. Despite the limitation imposed by this heterogeneity, our work presents a complete set of data determined with a precision not yet achieved in the literature for sedimentary material. We also provide the first Nd, Hf and Pb isotopic measurements for the five sediments, which are commonly used by the geochemical community. Our study of both basalt and sediment reference materials represents a comprehensive and self‐consistent set of geochemical data and can therefore be considered as a reference database for the community.     

中天山卡瓦布拉克地区中-基性岩脉的年代学及岩石成因

中天山卡瓦布拉克地区侵入岩类广泛发育,并多处被中-基性岩脉穿插。LA-ICP-MS锆石U-Pb测年获得闪长岩和辉长岩脉年龄分别为296.1±2.5 Ma(MSWD=1.4),299.5±2 Ma(MSWD=1.07),均侵位于早二叠世。岩石学和岩石地球化学分析结果表明该区中-基性岩脉具有富集轻稀土元素(LREE)和大离子亲石元素(Rb,U,Th)、亏损高场强元素(Nb,Ta,Ti)的地球化学特征,SREE为69.19~234.62,LREE/HREE=3.97~11.18。闪长岩脉锆石(176Hf/177Hf)值为0.280 618~0.283 329,对应的εHf(t)值为-14.57^+25.06。研究数据表明,该区中-基性岩脉可能起源于亏损岩石圈地幔,原始岩浆在侵位过程中发生了分离结晶作用,同时还受到了地壳混染作用的影响。基于卡瓦布拉克地区中-基性岩脉的野外地质特征和地球化学分析结果,并结合区域地质资料,认为它们形成于南天山洋闭合之后的后碰撞伸展构造背景。     

A SELF-CONSISTENT COMPILATION OF ELEMENTAL CONCENTRATION DATA FOR 93 GEOCHEMICAL REFERENCE SAMPLES

Concentration data obtained by instrumental neutron activation analysis (INAA) are presented for up to 36 chemical elements in 93 geochemical reference samples, including some for which there are little previous data. Because all data are based on at least three independent analyses, and for many of the data the uncertainty associated with counting is an insignificant source of error, the values presented here are considered of higher precision than generally reported by INAA. Information on subsampling error (sample heterogeneity) is also presented.     

多维分形理论和地球化学元素分布规律

多维分形模型不仅采用常规的低阶矩统计, 而且采用高阶矩统计对多维分形分布进行度量, 从而能较细致地刻划正常值以及异常值.地球化学元素的正常值往往服从统计学中的大数定量, 即满足正态分布或对数正态分布, 然而异常值会服从分形分布(Preato).介绍了多维分形领域中的最新发展以及在地球化学研究中特别是研究超常元素空间分布和富集规律中的应用.结果表明, 通常的统计方法只对应于多维分形围绕均值周围的局部特征.为了有效地研究异常值的分布和富集规律, 建议采用高阶矩统计方法和多维分形方法, 并给出了两种分析地球化学元素, 并突出异常值贡献的方法.这些方法不仅可应用于研究微量元素的空间分布和富集规律, 而且可以区分地球化学背景与矿化有关的异常值.还介绍了该方法在对加拿大B.C.省西北部Mitchell-Sulphurets地区金铜矿化蚀变带研究中的应用.      

GEOCHEMICAL STANDARD REFERENCE SAMPLES GSD 9–12, GSS 1–8 AND GSR 1–6

The 18 Chinese geochemical standard reference samples GSD 9-12 (stream sediments), GSS 1-8 (soils) and GSR 1-6 (rocks) were prepared after GSD 1-8 (stream sediments) for even wider and increasing needs of geology, exploration geochemistry and geochemical analysis. Usable values of 41 trace, minor and major elements of the 18 samples were published in 1984. In the following two years, efforts were concentrated on the determination of other elements, most of which are more difficult to determine accurately and hence not many data were available in the literature. At the same time, additional data on the 41 elements already evaluated were also submitted. In all, 155 234 results were available along with the 35 284 analytical data submitted. The processing of samples, the examination of sample homogeneity, the plan of collaborative analysis of the samples, and the criteria for defining the recommended values are described. The recommended or reference values of the 72 constituents, to-gether with the 35 284 analytical data of the 18 samples are published in this paper.     

中国东部CO2气地球化学特征及其气藏分布

中国东部CO₂气田(藏)发育广泛,分布复杂。本文对中国东部松辽、渤海湾、苏北、三水、东海、珠江口、莺琼、北部湾等盆地和内蒙古商都地区以及部分现代构造岩浆活动区CO₂气田(藏)和气苗中CO₂的地球化学特征进行了分析和研究,探讨了中国东部CO₂气的成因、来源及分布。中国东部CO₂气的含量主要分布区间为0~10%,其次为90%~100%,呈现典型的U字型。δ¹³C_CO2值则呈现典型的单峰式分布,峰值区间为-6‰~-4‰。CO₂含量、δ¹³C_CO2值和R/Ra值综合表明,中国东部高含CO₂气以幔源无机成因为主,混有部分有机成因气和(或)壳源无机气。中国东部已发现的36个无机成因CO₂气田(藏)在空间分布上与新近纪及第四纪北西西向玄武岩活动带展布一致,深大断裂和岩浆活动是无机成因CO₂富集、运移和分布最重要、最直接的两大主控因素。     

Evaluating the Provenance of Metasedimentary Rocks of the Jiangxian Group from the Zhongtiao Mountain Using Whole-Rock Geochemistry and Detrital Zircon Hf Isotope

Abstract：In this study, whole-rock geochemical and Nd isotopic data, as well as detrital zircon Hf isotopes of Palaeoproterozoic metasedimentary rocks from the Jiangxian Group are presented to evaluate the characteristics of their provenance and the tectonic history. The major and trace element compositions are comparable to Post-Archean upper continental crust (PA-UCC), but have slight enrichment in the LILE, with the exception of Cs and Sr, and a slight depletion in ferromagnesian elements, HFS elements, such as Nb and Ta, and some major elements, such as CaO and Na2O. The geochemical data reveal that the collected metasedimentary rocks have experienced intermediate source weathering with chemical index of alteration values ranging from 72 to 78, varying degrees of K-metasomatism, and post-depositional loss of Na, as well as negligible sorting, and are derived from the weathering of mostly felsic and non-mafic rocks. The selected Lu–Hf isotopic analysis on detrital zircon points to both the Trans-North China Orogen and Eastern Block of the north China craton as the most likely sources for the metasedimentary rocks of the Jiangxian Group. However, a contribution of detritus from the Western Block of the north China craton can be ruled out. The sediments were probably deposited in a back-arc basin within an active continental margin setting.     

黔北白云岩红色风化壳元素地球化学特征

选取贵州高原喀斯特地区典型白云岩风化剖面作为研究对象,探讨了红土剖面元素迁移特征及其影响因素,为进一步认识红色风化壳元素地球化学特征提供依据。结果表明:（1）红土剖面中土壤样品（XPS-4~XPS-25）Fe、K、Mn常量元素及Co、Pb、Zn微量元素的分布曲线相对于其他元素靠近 UCC,元素Mg、Ca、Na、Ti和 Li、Cr、Ba、V 的数据点则显著偏离了上部陆壳的平均组成。（2）元素对协变分析得出Ti与Fe、Ba和V的积累特征一致,呈增加趋势;Ti与Mg呈反向变化特征。（3）以Ti为参比元素的剖面迁移特征表明,绝大部分元素的地球化学行为表现为迁移淋失,仅 Fe 、Cr和V 富集。K、Ba总体上呈迁出趋势,个别层段有轻微富集;Na和Co在风化原岩处有一个富集端点。元素在风化过程中的迁移聚集与土壤剖面的pH值和剖面结构变化、粘土矿物和有机质等的吸附有关。      

Report (1968–1978) on Two Mica Reference Samples: Biotite Mica-Fe and Phlogopite Mica-Mg

Since 1967–68, two mica reference samples, Biotite Mica-Fe and Phlogopite Mica-Mg, were made available to several geochemical laboratories. The analytical data reported during the past ten years by 142 geoanalysts belonging to 74 international laboratories are presented and assessed for deriving preferred values. Reaomrmended or proposed values are assigned for major, minor and several trace elements. The biotite Mica-Fe is better characterized for its chemical composition than the Phlogopite Mica-Mg. Both the samples are also proposed as geochronological standards. Because very few mica reference samples have been processed in large quantities, the international geochemiaal community is invited to contribute further useful data.     

分形奇异(特征)值分解方法与地球物理和地球化学异常重建

地球物理和地球化学异常是找矿的重要依据.地球物理和地球化学异常取决于地层、构造在成矿时间上的多样性与空间上排列、叠置的复杂性.地层、构造因素是构造、岩浆、沉积与成矿地球化学等多种动力学过程的综合反映.这些岩石和构造的因素以及动力过程相互渗透和影响决定了最终地质、地球物理与地球化学场.本文提出的在GIS环境下实现的分形奇异值分解(MSVD) 异常重建方法, 不仅可以提取地球物理和地球化学等异常, 而且能够进一步刻画其中的线性和环状构造、细微的局部纹理结构特征.该方法首先对地球物理和地球化学等网格数据进行二维矩阵的奇异值分解, 之后用左特征向量矩阵与右特征向量矩阵的直积构造一个正交完备基.地球物理和地球化学二维数据可以投影到该正交基上, 其投影系数是矩阵的奇异值.在该正交完备空间的某些子空间上对地球物理和地球化学等数据进行滤波.为了选择子空间, 本文定义了上述正交完备基中的能谱密度、能谱半径(或尺度) 与能量测度.在此基础上与空间域及频率域类比, 探讨了能量测度与能谱密度呈现分形(fractal和bifractal) 规律.利用分形关系的间断点, 设计分形奇异值重建算子, 实现对地球物理和地球化学异常的分解.以加拿大NovaScotia南部布格重力异常与As地球化学异常为例, 采用MSVD方法分解Au、Wu -Sn -U等已知矿有关的地球化学异常.发现重建异常能很好地用于解释已知矿点的分布规律.重建的地球化学异常显现了地球化学中的线状和环状异常; 重建的布格重力异常有效勾勒出原图中不易发现的纹理结构, 这些纹理结构可以合理地解释已知矿点在侵入岩体内及其周围的分布规律.应用实例表明, 该方法不仅可以从起因复杂的异常中区分出背景、异常场, 还可以识别代表了成矿源岩、流体、运移通道、赋存空间等异常因素引起的纹理、结构与构造特征.同时实现了GIS环境下交互可视化的MSVD处理与解释系统, 增强了地质异常定量分析的实用性与可操作性.