新疆富蕴地区希勒库都克铜钼矿床含矿斑岩的年代学与地球化学特征   总被引：14，自引：0，他引：14  

龙灵利  王京彬  王玉往  王莉娟  王书来  蒲克信 《地质通报》2009,28(12):1840-1851

位于新疆富蕴县境内的希勒库都克铜钼矿属于斑岩型矿床。含矿花岗斑岩和石英闪长岩为弱过铝质高钾钙碱性岩石,具有相对富集大离子亲石元素、亏损Nb、Ta、Ti元素的地球化学特征。获得含矿花岗斑岩SIMS锆石Ｕ-Pb年龄（329.6±4.1）Ma。综合分析,花岗斑岩和石英闪长岩可能为同一岩浆不同演化阶段的产物。据含矿岩石高的正εNd（t）值、低的87Sr/86Sr初始值推测,其原始岩浆起源于亏损地幔源区。  相似文献   

新疆白干湖钨锡矿田东北部花岗岩锆石SIMS U-Pb 年龄、地球化学特征及构造意义   总被引：6，自引：0，他引：6  

李国臣  丰成友  王瑞江  马圣钞  李洪茂  周安顺 《地球学报》2012,33(2):216-226

白干湖矿田东北部出露钾长花岗岩和二长花岗岩,具有相近的成岩年龄和相似的地球化学特征,表明为同源演化的复式岩体。利用SIMS方法获得二者锆石U-Pb谐和年龄是422±3Ma和421±3.7Ma,为晚志留世。岩石主量元素地球化学特征二者表现为弱过铝质(A/CNK为0.99～1.02)或准铝质(A/CNK为0.92～0.94)、高钾(K2O/Na2O分别为1.08～1.31和1.03～1.22)、高碱((Na2O+K2O)分别为8.59%～9.38%和9.54%～9.69%)、钙碱性或弱碱性(δ分别为2.39～3.17和4.02～4.22)、Fe#(TFeO/MgO分别为9.58～12.26和8.94～9.96)高。稀土元素总体含量(分别为228×10-6～448×10-6和271×10-6～392×10-6)较高,微量元素亏损Ba、Nb、Sr、Ti、P和富集La、Ce、Zr、Sm,总体显示A型花岗岩的特征。R1-R2图解显示岩体构造背景落入晚造山区域。Sr-Yb图解显示岩体落入低Sr高Yb的区域,暗示拉伸的地壳减薄的环境。Pearce图解显示构造环境为板内为主。综合区域背景资料,认为该岩体形成于加里东造山旋回的后碰撞阶段。  相似文献   

Uranium and Thorium Concentration and Isotopic Composition in Five Glass (BHVO‐2G,BCR‐2G,NKT‐1G,T1‐G,ATHO‐G) and Two Powder (BHVO‐2, BCR‐2) Reference Materials     

Kathryn A. Matthews  Michael T. Murrell  Steven J. Goldstein  Andrew J. Nunn  Deborah E. Norman 《Geostandards and Geoanalytical Research》2011,35(2):227-234

Here we report uranium and thorium isotopic ratios and elemental concentrations measured in solid reference materials from the USGS (BHVO‐2G, BCR‐2G, NKT‐1G), as well as those from the MPI‐DING series (T1‐G, ATHO‐G). Specifically created for microanalysis, these naturally‐sourced glasses were fused from rock powders. They cover a range of compositions, elemental concentrations and expected isotopic ratios. The U‐Th isotopic ratios of two powdered source materials (BCR‐2, BHVO‐2) were also characterised. These new measurements via multi‐collector thermal ionisation mass spectrometry and multi‐collector inductively coupled plasma‐mass spectrometry can now be used to assess the relative performance of techniques and facilitate comparison of U‐Th data amongst laboratories in the geoscience community for in situ and bulk analyses.  相似文献   

阿拉善地块北缘雅干花岗岩体地球化学、地质年代学及其对区域构造演化制约   总被引：4，自引：1，他引：3  

郑荣国  吴泰然  张文  冯继承  徐操  孟庆鹏  张昭昱 《岩石学报》2013,29(8):2665-2675

位于阿拉善北部中蒙边境地区的雅干花岗岩体以二长花岗岩为主,岩体的锆石离子探针U-Pb年龄为283.2±2.2Ma (n=14,MSWD=0.016).该花岗岩体具有相对较低的SiO2含量(66.96％～70.71％),和较高的A12O3(15.05％～16.05％)和(Na2O+ K2O)含量(7.24％～9.19％),且岩体钠含量稍高(Na2O/K2O＞1).雅干花岗岩体总体上表现为高钾钙碱性及偏铝质-过铝质的特征.岩体稀土元素总合量为101.9×10-6～133.1 ×1O-6,在稀土元素配分模式图中,岩体表现为轻-重稀土元素中等程度-强烈分异,同时具有明显的负Eu异常(δEu =0.59 ～0.77);在微量元素原始地幔标准化蛛网图中,岩体表现为亏损Nb、Ta、P、Ti,富集Ba、Rb、Cs、Th、K等大离子亲石元素;岩体同位素特征则表现为具有高的(87 Sr/86 Sr)i值(0.707654 ～0.710235)以及负εNd(t)值.根据雅干花岗岩体的形成时代、地球化学特征以及相关的沉积建造特征,可推断该岩体形成于后碰撞环境,表明古亚洲洋在阿拉善地块北缘北部地区的分支于早二叠世(283.2 ±2.2Ma)之前已经闭合.  相似文献   

The effect of Ca-Tschermaks component on trace element partitioning between clinopyroxene and silicate melt   总被引：19，自引：0，他引：19  

Eddy Hill  Bernard J. Wood  Jonathan D. Blundy 《Lithos》2000,53(3-4):203-215

We have studied the influence of Ca-Tschermaks (Calcium Tschermaks or CaTs) content of clinopyroxene on the partitioning of trace elements between this phase and silicate melt at fixed temperature and pressure. Ion probe analyses of experiments carried out in the system Na₂O–CaO–MgO–Al₂O₃–SiO₂, at 0.1 MPa and 1218°C, produced crystal-melt partition coefficients (D) of 36 trace elements (Li, Cl, Sc, Ti, V, Cr, Fe, Co, Ge, Sr, Y, Zr, Nb, Mo, Ru, Rh, In, Sn, Sb, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta and W), for clinopyroxene compositions between 10 and 32 mol% CaTs. Partition coefficients for 2+ to 5+ cations show, for each charge, a near parabolic dependence of log D on ionic radius of the substituting cation, for partitioning into both the M1 and M2 sites of clinopyroxene. Fitting the results to the elastic strain model of Blundy and Wood [Blundy, J.D., Wood, B.J., 1994. Prediction of crystal-melt partition coefficients from elastic moduli. Nature 372, 452–454] we obtain results for the strain-free partition coefficients of theoretical cations (D₀), with site radius r₀, and for the site's Young's Modulus (E).

In agreement with earlier data our results show that increasing ^ivAl concentration in cpx is matched by increasing D, E_M1, E_M2 and D₀ for tri-, tetra- and pentavalent cations. The degree of fractionation between chemically similar elements (i.e. Ta/Nb, Zr/Hf) also increases. In contrast, D values for mono-, di- and hexavalent cations decrease with increasing ^ivAl in the cpx. The large suite of trace elements used has allowed us to study the effects of cation charge on D₀, r₀ and E. We have found that D₀ and r₀ decrease with increasing cation charge, e.g. r₀=0.66 Å for 4+ cations and 0.59 Å for 5+ cations substituting into M1. Values of E_M1 and E_M2 increase with cation charge as well as with increasing ^ivAl content. The increase in E_M2 is linear and close to the trend set by Hazen and Finger [Hazen, R.M., Finger, L.W., 1979. Bulk modulus-volume relationship for cation–anion polyhedra. J. Geophys. Res. 84 (10) 6723–6728] for oxides. E_M1 values are much higher and do not fit the trend predicted by the Hazen and Finger relationship.  相似文献   

Red micas from basal ignimbrites of Mt. Vulture (Italy): interlayer content appraisal by a multi-methodic approach     

Fernando Scordari  Emanuela Schingaro  Gennaro Ventruti  Maria Lacalamita  Luisa Ottolini 《Physics and Chemistry of Minerals》2008,35(3):163-174

The crystal chemistry of red phlogopites from Mt. Vulture (Italy) ignimbrites has been studied by electron microprobe, secondary ion mass spectrometry (SIMS), single crystal structural investigation and Fourier transform infrared (FTIR) spectroscopy. The analysed phlogopite has Fe/(Fe + Mg) ∼ 0.35, TiO₂ (wt%): 2.8–5.0 and H₂O (wt%): 1.24–3.37. Infrared spectra revealed the presence of bands due to the NH₄⁺ and H₂O stretching and bending vibrations. The samples belong to the 1M polytype. The bimodal behaviour of several structural parameters allows red micas to be clustered into two distinct groups: K⁺ ↔ NH₄⁺, H₂O and M³⁺-vacancy substitutions dominate in the first group; M^3+,4+-oxy, in the second group. It has to be pointed out that quantitative analysis of hydrogen (via SIMS) together with the characterization of the local environment of the anionic site (via FTIR) are fundamental in assessing the correct structural formula and the substitution mechanisms in micas. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

二次离子质谱第四纪锆石年代学:台湾金瓜石英安岩定年   总被引：2，自引：0，他引：2       下载免费PDF全文

高钰涯  李献华  李秋立  锺孙霖 《地学前缘》2010,17(2):146

高精度第四纪年代学是第四纪研究的基础,对了解地球演化和发展非常关键。大型二次离子质谱(SIMS)锆石U-Th-Pb定年方法,集高空间分辨率、高精度、高效率和近无损分析等优势于一体,可以提取矿物微区中记录的丰富地质信息,在第四纪年代学研究中具有很大的应用潜力。文中对SIMS第四纪锆石原位微区年龄测定的基本原理、分析校正方法进行介绍,并报道我们测定台湾第四纪金瓜石英安岩锆石U-Pb年龄的结果((1.166±0.020)Ma)。  相似文献   

GGR Biennial Review: Key Advances in Secondary Ion Mass Spectrometry in the Geological Sciences during the Period 2008–2009     

Michael Wiedenbeck 《Geostandards and Geoanalytical Research》2010,34(4):387-394

Secondary ion mass spectrometry (SIMS or ion microprobe) remains one of the most powerful techniques in the analytical geochemist’s toolkit. The key strength of SIMS is its capacity to provide trace element and isotope data at sampling sizes which are not approached by other methods. As compared with the main competing technique of laser ablation-ICP-MS, SIMS commonly provides a total sampling mass some 10 to 500 times smaller; this feature can be the deciding factor as to whether an analytical objective is technically achievable. Additional strengths of SIMS lie in the areas of depth profiling and trace element imaging. Though perhaps not as commonly used in the geosciences, these two operational modes represent unique capabilities of SIMS.  相似文献   

大别山双河地区花岗质片麻岩锆石的离子探针定年   总被引：8，自引：0，他引：8  

吴元保  陈道公  夏群科  程昊 《矿物岩石地球化学通报》2001,20(4):298-301

对双河花岗质片麻岩的锆石进行了阴极发光分析 ,结果表明存在两种类型的锆石 (残留锆石和原岩中的岩浆锆石 )。对其进行离子探针定年显示原岩的岩浆锆石形成于 10 2 5Ma ,在超高压和后期的退变质事件中都存在铅丢失现象 ,其 197Ma变质作用的年龄不能反映超高压事件峰期变质作用的年龄。残留锆石的形成年龄为 2 86 1Ma的晚太古代年龄 ,这些锆石在超高压变质作用中发生了较严重的重结晶作用 ,对应于 2 30Ma左右的峰期变质作用的年龄 ,后期退变质作用对其影响较小。  相似文献   

Analytical Developments in Secondary Ion Mass Spectrometry 2003     

Etienne Deloule  Michael Wiedenbeck 《Geostandards and Geoanalytical Research》2005,29(1):37-40

This annual review of secondary ion mass spectrometry (SIMS) highlights significant progress in the application of the technology for the following areas: U-Pb geochronology (notably in the fields of reference material zircons), sources of uncertainty during analysis and secondary ion yields. Major publications introduced a new zircon reference sample and dealt with an intercomparison study of a suite of established calibrators, some of which have been shown to have certain limitations. Another publication claimed that the principal uncertainty in U-Pb dating is related to variations in the Pb and U relative emission yields over a complete analytical session. 2003 saw the introduction of an automated particle identification procedure applied to the analysis of a chondritic meteorite, as well as new geometries of SIMS hardware (NanoSIMS) and techniques (time-of-flight SIMS). NanoSIMS allows a two to three order of magnitude reduction in sampling volume as a result of a reduced beam diameter, and time-of-flight SIMS allows the study of sample surfaces, and can provide data for elements concurrently.  相似文献