山东邹平青山下亚组玄武安山岩源区性质及成因

本文通过岩石的显微观察、全岩元素地球化学及Sr-Nd-Pb同位素组成等综合研究,参照前人的研究成果,探讨邹平火山岩盆地内青山下亚组玄武安山岩的岩石地球化学性质、物质来源及岩石成因。研究表明,岩石富钠、富镁,具有大离子亲石元素(Rb、Sr、Ba)和轻稀土元素(LREE)富集,高场强元素(Nb、Ta、Ti)相对亏损的地球化学特征。全岩Sr同位素初始比值(87 Sr/86 Sr)i为0.705674~0.705876;全岩Nd同位素初始比值εNd(t)为-10.0~-10.2,Nd同位素二阶段模式年龄T2DM为1.74~1.75Ga;全岩铅同位素初始比值(206Pb/204Pb)i介于16.917~17.095之间,(207Pb/204Pb)i介于15.306~15.396之间,(208Pb/204Pb)i介于36.750~37.208之间;较低的Sr-Nd初始比值及较均一的低放射性铅同位素组成,可能为EMI型富集地幔的部分熔融所致。晚中生代加厚的华北岩石圈发生大规模拆沉作用,拆沉的大陆中下地壳部分熔融形成富硅熔体与古生代岩石圈地幔相互作用形成富集地幔,随后在岩石圈伸展与区域热异常作用下减压部分熔融,形成的玄武安山质岩浆沿着深大构造侵入地壳上部或喷发至地表,形成青山下亚组玄武安山岩,但是岩浆上侵过程中地壳物质混染不强。该研究对深化鲁西地区晚中生代构造-岩浆作用的认识有一定的理论意义。     

熔融制样X射线荧光光谱法测定锑矿石中的锑和14种微量元素

锑矿石分析通常分别采用酸分解系统和碱熔系统,萃取分离后应用容量法、原子吸收光谱法、原子荧光光谱法等分析手段进行单项测定,样品处理繁琐、操作复杂,分析过程常因熔矿不完全而导致结果偏低或失真,难以满足地质测试的需要。本文建立了玻璃熔融制样,波长色散X射线荧光光谱测定锑矿石中的锑及14种次量元素与伴生元素(Cu、Pb、Zn、As、Co、Ni、W、Ba、S、SiO₂、Al₂O₃、TFe、CaO、MgO)的快速分析方法。用国家标准物质和人工合成标准参考物质拟合校准曲线,对熔融条件进行了研究。确定样品与四硼酸锂-偏硼酸锂-氟化锂复合熔剂的熔融稀释比例为1:20,以硝酸铵为氧化剂,碳酸锂为保护剂,700℃预氧化,在1050℃温度下熔融完全,有效地防止了As、S的挥发损失,解决了化学法测试样品处理复杂、不能同时测定多元素、测试元素偏少的问题。一些元素的检出限为Sb 0.14%,Cu 0.0027%,Pb 0.0025%,Zn 0.0046%,As 0.0028%,S 0.021%;方法精密度(RSD,n=12)小于5%;选用合成标准物质和实际生产锑矿试样进行验证,测定结果与参考值或化学值一致性良好。本法大部分元素检出限都要稍高于粉末压片法,但操作简单,测试范围更宽,适用于实验室对不同锑矿矿种批量样品中多元素快速、准确检测的需要。     

鄂东南铁山地区土壤-植物系统中重金属元素分布及富集特征

采用原子荧光光谱法和等离子体质谱法(ICP-MS)对鄂东南铁山地区主要河流流经区土壤、植物中重金属元素质量分数及其富集特征的研究表明,研究区西港河流域下游局部地段形成Cu、Zn、Ni、Cd、As重金属元素的土壤污染,东港河流域下游局部地段形成Cd、Cu、As、Pb、Zn重金属元素的土壤污染,植物中已经形成Cd、Zn元素的超量富集.其中土壤中重金属元素的富集主要与冶炼厂废水和尾矿坝渗漏水有关,而植物中重金属元素的富集则受土壤中重金属元素质量分数和植物吸收性能的双重控制.     

成都盆地平原区浅层土壤Cd、Pb、Zn分布特征及其成因初探

通过多目标地球化学调查在成都盆地平原区浅层土壤内发现呈面状分布的Cd、pb、Zn等元素高值区.为了研究它们的成因,应用多元统计方法分析了这些元素在不同景观区及不同环境介质中的分布特征及相关关系,利用参考元素对Cd、Pb、Zn的富集含量进行了定量估算.结果表明,平原区浅层土壤内Cd、Pb、Zn元素的分布明显不同于物源区及平原区深层土壤,在元素之间的典型相关关系及元素富集的分布特征上,均表现出明显的人为源特征.Cd、Pb、Zn元素的富集主要出现在平原区中部的城镇及农田区,与成都盆地浅层样地球化学图上的高值区一致.Cd、Pb、Zn元素的富集,是在自然背景的基础叠加了人为源含量,但尚未达到危害程度.     

青岛城区土壤重金属环境地球化学研究

为研究青岛城区土壤的环境地球化学特征,对青岛市南区、市北区、四方区、李沧区、崂山区5区进行了广泛的土壤地质调查。在每1km2一个样品的取样密度下取得表层土样(0～10cm深度)319个,经前期处理后,利用多种仪器如X射线荧光光谱(XRF)、等离子体发射光谱(ICP-OES)和等离子体质谱(ICP-MS)等分析测得所有样品的72种元素的含量,本文探讨了重金属元素Cd、Cr、Cu、Ni、Pb和Zn及类金属元素As的含量分布。结果表明,人类活动导致表层土壤中元素Cd、Cu、Pb和Zn含量的增加,而元素As、Cr和Ni主要是地质起源,但也会受到人类活动的影响。其中Zn的含量值变化较大,Zn元素含量值增高的地区是工业、交通密集处等人类活动频繁的地区。     

辽宁沈抚污灌区土壤重金属环境质量评价

辽宁省沈抚污灌区自上世纪60年代以来开始接受污水灌溉,直到2000年左右才停止.由于长期接受污水灌溉,土壤污染比较严重.通过分析污灌区的土壤中4种重金属元素Zn、Cu、Pb、Cd含量,采用地质累积指数评价方法,对其地球化学特征及空间分布进行了探讨.结果表明：元素Cu和Zn的污染范围最广,元素Cd的污染程度最高,4种重金属元素污染程度排序为Cu > Zn > Cd > Pb.各元素在空间上造成的污染排序如下：李石寨（样点7） > 三宝屯（样点1） > 刘尔屯（样点5）> 四方台（样点8） > 小瓦村（样点15）.     

LA-ICP-MS在地质全岩样品元素分析中的应用

激光剥蚀电感耦合等离子体质谱法(LA-ICP-MS)作为一种原位微区分析方法,已被广泛的应用于地质研究的各个领域。LA-ICP-MS法避免了传统溶液进样分析中繁琐、费时的湿法化学消解过程,并且具有低背景、低氧化物和氢氧化物干扰的特点,因此适用于地质全岩样品的元素分析。本文阐述了LA-ICP-MS用于全岩样品元素分析现状,在总结了现有研究成果的同时,对目前存在的问题进行了评述,并展望了该方面研究的发展方向。     

LA-ICP-MS工作参数优化及在锆石U-Pb定年分析中的应用

将激光器(LA)和电感耦合等离子体质谱仪(ICP-MS)联用避免了溶液分析繁琐、耗时的前处理操作,减少了样品制备过程中可能带来的污染,同时又具备分析成本低、测试速度快、分析数据精度高等优势。本文将LA与ICP-MS联接使用,通过激光能量密度和剥蚀频率组合来讨论较低的元素分馏效应,同时匹配RF功率、采样深度、载气及He气流速等主要工作参数以获得较高的元素信号灵敏度和稳定性,从而得到仪器最优工作参数组合,建立了可靠的锆石U-Pb定年方法。通过对锆石标样91500、GJ-1及Ple2ovic互测结果表明,其206Pb/238U加权平均年龄分别为1063.9±6.0 Ma(2σ,n=20)、600.3±2.6 Ma(2σ,n=27)及337.6±1.7 Ma(2σ,n=20),测试结果准确度和精度均在1%范围内,与前人报道的误差范围一致。使用优化后的仪器参数对来自鄂东南铜绿山矿区石英正长闪长玢岩岩体中的实际锆石样品进行测试,获得其206Pb/238U年龄与前人研究结果基本一致,表明本法能准确地对锆石进行定年分析。     

硼酸盐熔融制样法测定辉绿岩中10种常量元素的准确度

对硼酸盐熔融制样法中溶剂、样品配比和熔融过程等进行优化,可以提高SiO_2、TiO_2、Al_2O_3、TFe_2O_3、MnO、MgO、CaO、Na_2O、K_2O和P_2O_5等10种氧化物的测试精度和熔融制样效率。利用岩石、土壤等标准样品,采用经验系数法进行基体校正,建立涵盖辉绿岩中10种常量元素浓度范围的标准曲线。优化后的硼酸盐熔融制样法参与了国际地质分析家协会组织的Geo PT第43期地质能力分析能力测试。经能力测试比对,SiO_2浓度偏差为0. 23%,TiO_2浓度偏差为0. 003%,Al_2O_3浓度偏差为0. 06%,TFe_2O_3浓度偏差为0. 01%,MnO浓度偏差为0. 002 4%,MgO浓度偏差为0,CaO浓度偏差为0. 05%,Na_2O浓度偏差为0. 01,K_2O浓度偏差为0. 009 4%,P_2O_5浓度偏差为0. 003%。本次测试结果为-0. 21 Z 0. 26,远优于Geo PT规定的"合格"范围:-2 Z 2。优化后的硼酸盐熔融制样法在测定辉绿岩中10种常量元素的精准度较高,达到测试预期结果。     

河南新县花岗岩岩基的岩石成因、来源及对西大别构造演化的启示

本文对新县花岗岩岩基进行了系统的锆石U-Pb定年,全岩元素地球化学、Sr-Nd-Pb-Hf同位素测试,研究探讨其成岩年龄、岩石成因、物质来源以及地球化学动力学背景。锆石U-Pb年龄为125.5±1.5Ma,属于早白垩世产物。全岩元素地球化学成分表现为高硅、富碱,贫镁、铁和钙,富集轻稀土元素、大离子亲石元素（Rb、K、Th、U）和Pb,亏损重稀土元素、高场强元素(Nb、Ta、Ti)和Sr、Ba。全岩同位素具有中等略偏高的Sr 初始比值(87Sr/86Sr)i=0.706949~0.707086;低的放射性Pb同位素组成[ (206Pb/204Pb)i=16.611～17.152,(207Pb/204Pb)i=15.304～15.432,(208Pb/204Pb)i=37.316～37.702]; 低的Nd初始比值（εNd(t)=-13.65～-13.51）和老的Nd模式年龄（TDM2=2.12～2.13Ga）。锆石原位Hf同位素具有较低的初始比值（εHf(t)=-22.92～-19.40）和老的Hf二阶段模式年龄（TDM2=2.39~2.61 Ga）。综合以上元素地球化学特征、锆石U-Pb定年结果及Sr-Nd-Pb-Hf同位素组成,新县花岗岩岩基应属于分异的高钾钙碱性I型花岗岩,是化学成分类似于扬子板块北缘新元古代TTG型岩浆岩的扬子下地壳在非加厚下地壳（深度小于35km）环境下部分熔融的产物。     

LA-ICP-MS微区原位准确分析含水硅酸盐矿物主量和微量元素

通过描述一种利用LA-ICP-MS准确测定含水硅酸盐矿物主量元素和微量元素含量的多外标、无内标分析方法.总结出该方法基于矿物化学计量式计算含水硅酸盐矿物中挥发分的相对含量,再将全部分析元素归一化到总金属氧化物含量(100%减含水量)的原理,利用多种天然成分的岩石标准玻璃(如MPI-DING玻璃和USGS玻璃)作为外标进行校正计算.利用该方法对角闪石、绿帘石、电气石和透闪石等含水硅酸盐矿物进行了分析,并与利用电子探针和微钻(直径300 μm)取样溶液-ICP-MS分析的结果进行了对比研究.研究结果表明:对于组成均一的主量元素的分析结果与电子探针分析数据一致,相对偏差集中在5%以内.除了那些分布异常不均一的元素(在300 μm尺度上),对微量元素的分析结果与溶液-ICP-MS分析结果具有很好的一致性,二者之间的相对偏差大部分集中在10%以内.研究结论为采用归一化校正策略,选择MPI-DING和USGS玻璃作为外标,利用LA-ICP-MS微区分析方法可以准确测定含水硅酸盐矿物中的主、微量元素含量.      

Laser Ablation ICP-MS Analysis of Geological Materials Prepared as Lithium Borate Glasses

A simple, rapid and precise method is described for determining trace elements by laser ablation (LA)-ICP-MS analysis in bulk geological materials that have been prepared as lithium borate glasses following standard procedures for XRF analysis. This approach reliably achieves complete sample digestion and provides for complementary XRF and LA-ICP-MS analysis of a full suite of major and trace elements from a single sample preparation. Highly precise analysis is enabled by rastering an ArF excimer laser (λ= 193nm) across fused samples to deliver a constant sample yield to the mass spectrometer without inter-element fractionation effects during each analysis. Capabilities of the method are demonstrated by determination of twenty five trace elements (Sc, Ti, V, Ga, Rb, Sr, Y, Zr, Nb, Cs, Ba, REE, Hf, Ta, Pb, Th and U) in a diverse range of geological reference materials that includes peridotites, basalts, granites, metamorphic rocks and sediments. More than 90% of determinations are indistinguishable from published reference values at the 95% confidence level. Systematic bias greater than 5% is observed for only a handful of elements (Zr, Nb and U) and may be attributed in part to inaccurate calibration values used for the NIST SRM 612 glass in the case of Zr and Nb. Detection limits for several elements, most notably La, are compromised at ultra-trace levels by impurities in the lithium borate flux but can be corrected for by subtracting appropriate procedural blanks. Reliable Pb analysis has proved problematic due to variable degrees of contamination introduced during sample polishing prior to analysis and from Pt-crucibles previously used to fuse Pb-rich samples. Scope exists for extending the method to include internal standard element/isotope spiking, particularly where integrated XRF analysis is not available to characterise major and trace elements in the fused lithium borate glasses prior to LA-ICP-MS analysis.     

Trace Element Analysis of Fused Whole-Rock Glasses by Laser Ablation-ICP-MS and PIXE

The concentrations of fifty trace elements, including relatively volatile elements and transition metal elements, in fused glasses of Geological Survey of Japan rock reference materials GSJ JR-2, JA-1, JA-2, JB-1a, JB-3, JGb-1 and JF-1 were determined by particle (proton) induced X-ray emission (PIXE) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The fused glasses were prepared by rapid fusion and subsequent quenching in welded platinum capsules and were found to be homogeneous for major elements and for trace elements with concentrations of more than 1 μg g^-1 within the observed precision (± 10% mean) on a 70 μm sampling scale. The values obtained by PIXE and LA-ICP-MS for the transition elements (Cr, Mn, Fe, Ni and Cu), the relatively volatile elements (Zn, Ga, Rb and Pb) and the refractory elements (Y, Zr, Nb and Th) with concentrations greater than a few μg g^-1 showed good agreement (within 10 % relative difference). The values for almost all the elements detected at concentrations higher than 1 μg g^-1 as determined by LA-ICP-MS also agreed well with the reference values (mean relative difference < ± 10%), except for B and Cu. The good agreement confirmed the appropriateness of the NIST SRM 600 series glass calibration reference material for LA-ICP-MS analysis of glasses with variable major-element compositions for almost all elements. The concentrations of Cu in all the samples were lower than the reference values, which was attributed to adsorption of the transition metals onto the platinum capsule during preparation.     

Chemical Characterisation of the USGS Reference Glasses GSA-1G, GSC-1G, GSD-1G, GSE-1G, BCR-2G, BHVO-2G and BIR-1G Using EPMA, ID-TIMS, ID-ICP-MS and LA-ICP-MS

The USGS reference glasses GSA-1G, GSC-1G, GSD-1G, GSE-1G, BCR-2G, BHVO-2G and BIR-1G were investigated by different analytical techniques. All these materials have a geological (basaltic) matrix and are therefore useful in igneous geochemistry as matrix-matched reference materials for microanalytical techniques. The new GS glasses have trace elements in groups at concentration levels of about < 0.01, 5, 50 and 500 μg g^-1. Their major element compositions have been determined by EPMA, and trace elements have been analysed by LA-ICP-MS and two isotope dilution techniques using TIMS and ICP-MS. EPMA and LA-ICP-MS analyses indicated that the USGS reference glasses are homogeneous at the μm to mm scale with respect to major (variations < 1-2%) and most trace elements (variations 1-4%). Trace element data obtained from the different analytical techniques agreed within an uncertainty of 1-5%, indicating that between method results are comparable. Therefore, the preliminary working values for the four USGS GS glasses calculated from these data have a low level of uncertainty.     

非破坏性开放式激光剥蚀电感耦合等离子体质谱法原位测定大尺寸陶瓷样品主微量元素组成

激光剥蚀电感耦合等离子体质谱法(LA-ICP-MS)通常采用体积固定的封闭剥蚀池,大尺寸样品要经过切割或破碎,能够放入剥蚀池后才可以再进行LA-ICP-MS分析,因此,这种常规密闭式LA-ICP-MS难以应用于无法破碎的珍稀大尺寸样品分析.为实现大尺寸样品的非破坏性微区原位主微量元素分析,本文基于自行设计的开放式样品采...     

High-Resolution LA-ICP-MS for Accurate Determination of Low Abundances of K, Sc and Other Trace Elements in Geological Samples

Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was used to determine K, Sc, Ti, V, Cr, Mn, Co, Ni and Zn in geological samples. Because the isotopes of these elements and the internal standard element (Ca) often have interferences from molecular ions when determined using quadrupole or sector-field ICP-MS in low mass resolution mode, ion intensities were measured at a high mass resolution of 4000. We investigated dynamic element fractionation, type and abundance of molecular ions using different geological reference materials. Highly resolved mass spectra were especially important for accurate low-abundance measurements. As a result, maximum "critical" concentration limits for each isotope were obtained, where a mass resolution of 4000 was necessary for reliable LA-ICP-MS analysis. To test the LA-ICP-MS technique, different international reference material glasses and powdered rock reference materials were analysed. Rock powders were fused to glass beads using an Ir-strip heater. Nearly all concentration values for the reference materials agreed with the reference values at the 95% confidence level. To demonstrate routine LA-ICP-MS analysis at a mass resolution of 4000, trace element data for Hawaiian basalts are also presented.     

LA-ICP-MS原位分析白钨矿稀土元素

白钨矿是各类矿床中较为常见的副矿物,通过分析白钨矿的稀土元素质量分数及其标准化配分模式图,可为矿床成矿流体特征及演化提供重要的判别依据。本文对东北地区羊鼻山矽卡岩型矿床和杨金沟热液脉型矿床两个典型钨矿床的白钨矿样品中的稀土元素进行了激光剥蚀-电感耦合等离子体质谱（LA-ICP-MS）原位分析。其中：羊鼻山矽卡岩型矿床白钨矿LA-ICP-MS分析方法所获得的稀土元素配分曲线模式与前人用传统的溶液-ICP-MS分析方法所获得的结果完全吻合,表明采用剥蚀束斑44 μm和剥蚀频率7 Hz的193 nm ArF激光器,NIST 610作外部标样,Ca作内标元素,对基体效应影响最小,所获数据可靠,方法可行;而杨金沟热液脉型矿床白钨矿溶液-ICP-MS分析方法与LA-ICP-MS分析法所获得结果既具有相似性又具有差异性。原因在于羊鼻山白钨矿的成因类型为矽卡岩型、粒度较小且形成时间短,因此不同矿物颗粒间、同一矿物不同部位间稀土元素的配分模式一致;而杨金沟白钨矿的成因类型属于热液脉型、粒度较大、沉淀结晶时间长,因此同一矿物不同部位的稀土元素的配分模式因成矿流体早晚阶段不同而不同。基于以上对比研究发现,无论是在取样和测试过程方面,还是数据准确度方面,相比传统溶液-ICP-MS分析法,LA-ICP-MS原位分析法均具有明显的优势,主要表现在样品形式简单、粒度和质量分数要求低、测试周期短、费用低且结果精确度高;同时其可对不同成矿阶段或白钨矿不同部位成分进行精细测定,从而得出不同成矿阶段或白钨矿不同部位的稀土元素质量分数,以及在更高的空间分辨率下获得更详细准确的数据信息。此外,对白钨矿（尤其是无明显环带者）进行LA-ICP-MS原位分析时,既可采用电子探针微量分析（EPMA）准确测定Ca的质量分数,也可直接采用标准化学式计算Ca的质量分数,分析所得数据同样可以获得合理的地质解释。     

Application of High Spatial Resolution Laser Ablation ICP-MS to Crystal-Melt Trace Element Partition Coefficient Determination

In this contribution we evaluate the capabilities of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) using a 12 μm spot size. Precision, accuracy and detection limits were assessed on the USGS BCR-2G reference material. We demonstrate that the 12 μm LA-ICP-MS analyses of experimentally-grown amphibole and garnet are in excellent agreement with secondary ion mass spectrometry (SIMS) trace element determinations on the same crystals. The 12 μm spot size configuration was subsequently used to determine trace element crystal-melt partition coefficients (D_c/m) for a wide range of trace elements in amphibole in equilibrium with a basanitic melt. The following strategy to determine accurately and evaluate D_c/m is proposed. One or more major elements determined previously by electron probe microanalysis (EPMA) was used to ensure consistency between EPMA and the composition of the aerosol produced by the laser ablation. Measured D_c/m values were successively evaluated using the lattice strain model. The use of this strategy significantly improved the precision and accuracy of D_c/m determination when a LA-ICP-MS configuration with a high spatial resolution was employed.     

New X.R.F. data retrieval techniques and their application to U.S.G.S. standard rocks

Accurate and consistent X-ray fluorescence analysis of major and trace elements using a single pressed pellet for each sample has been achieved with a wide variety of rock compositions. Counting techniques for use with data reduction and correction programs in Standard Fortran IV are described; the latter depend throughout on data developed from a wide range of standard rock compositions. A comparison of ten major and fifteen trace element analyses for U.S.G.S. standard rocks with averages taken from the literature testifies to the precision of these techniques.     

SIMS测定玻璃固化样品中铀分布的分析方法研究

玻璃固化是一种常用的高放废液固化方法,其优点在于具有较高的抗化学介质侵蚀的能力和很好的辐照稳定性、热稳定性和机械稳定性,其不足之处在于抗水浸出等性能有所下降而使其安全性需要进一步通过抗浸出实验来进行衡量和确认。使用二次离子质谱(SIMS)分析玻璃固化体中的放射性成分(如铀元素)的分布及浸出行为等各项指标,是一种评估玻璃固化体抗浸出性能的分析手段。本文应用SIMS测试模拟玻璃固化体,以碳作为镀膜材料通过真空蒸发镀碳的方法优化样品制备条件,有效地解决了样品导电性差的问题,~(235)U/~(238)U同位素测定结果约为7.9‰±0.395‰,基本符合制作模拟样品时所使用的天然铀的同位素特征(~(235)U/~(238)U参考值约7.3‰)。研究表明,建立的方法实现了铀元素同位素丰度的测量,能直接显示铀的分布情况,该方法可为研究玻璃固化体中放射性元素的浸出行为提供一定的技术支持。