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1.
《Organic Geochemistry》2011,42(12):1476-1488
The specific features of the nano-scale secondary ion mass spectrometry (NanoSIMS) technology with the simultaneous analysis of up to seven ion species with high mass and lateral resolution enables us to perform multi-element and stable isotope measurements at the submicron scale. To elucidate the power of this technique, we performed an incubation experiment with soil particles of the fine silt and clay fractions (from an Albic Luvisol), with occluded particulate organic material and intact soil aggregates (from a Haplic Chernozem), using a 13C and 15N labelled amino acid mixture as tracer. Before and during 6-day incubation after the addition of the label, samples were consecutively prepared for NanoSIMS analysis. For this purpose, two different sample preparation techniques were developed: (i) wet deposition and (ii) the sectioning of epoxy resin embedded samples. Single soil particles (fine silt/clay fraction) showed an enrichment of 13C and 15N after label addition that decreased over time. On aggregates of particulate organic matter, re-aggregated during the 6-day incubation experiment, we could show a spatially heterogeneous enrichment of 13C and 15N on the particle surface. The enrichment in 15N demonstrated the diffusion of dissolved organic matter into intact soil aggregate interiors. The prospects of NanoSIMS for three dimensional studies of stable C and N isotopes in organo-mineral associations is demonstrated by the recorded depth profiles of the organic matter distribution on mineral particles.  相似文献   

2.
The specific features of the nano-scale secondary ion mass spectrometry (NanoSIMS) technology with the simultaneous analysis of up to seven ion species with high mass and lateral resolution enables us to perform multi-element and stable isotope measurements at the submicron scale. To elucidate the power of this technique, we performed an incubation experiment with soil particles of the fine silt and clay fractions (from an Albic Luvisol), with occluded particulate organic material and intact soil aggregates (from a Haplic Chernozem), using a 13C and 15N labelled amino acid mixture as tracer. Before and during 6-day incubation after the addition of the label, samples were consecutively prepared for NanoSIMS analysis. For this purpose, two different sample preparation techniques were developed: (i) wet deposition and (ii) the sectioning of epoxy resin embedded samples. Single soil particles (fine silt/clay fraction) showed an enrichment of 13C and 15N after label addition that decreased over time. On aggregates of particulate organic matter, re-aggregated during the 6-day incubation experiment, we could show a spatially heterogeneous enrichment of 13C and 15N on the particle surface. The enrichment in 15N demonstrated the diffusion of dissolved organic matter into intact soil aggregate interiors. The prospects of NanoSIMS for three dimensional studies of stable C and N isotopes in organo-mineral associations is demonstrated by the recorded depth profiles of the organic matter distribution on mineral particles.  相似文献   

3.
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   

4.
Although electron probe microanalysis and secondary ion mass spectrometry are widely used analytical techniques for geochemical and mineralogical applications, metrologically rigorous quantification remains a major challenge for these methods. Secondary ion mass spectrometry (SIMS) in particular is a matrix‐sensitive method, and the use of matrix‐matched reference materials (RMs) is essential to avoid significant analytical bias. A major problem is that the number of available RMs for SIMS is extremely small compared with the needs of analysts. One approach for the production of matrix‐specific RMs is the use of high‐energy ion implantation that introduces a known amount of a selected isotope into a material. We chose the more elaborate way of implanting a so‐called ‘box‐profile’ to generate a quasi‐homogeneous concentration of the implanted isotope in three dimensions, which allows RMs not only to be used for ion beam analysis but also makes them suitable for EPMA. For proof of concept, we used the thoroughly studied mineralogically and chemically ‘simple’ SiO2 system. We implanted either 47Ti or 48Ti into synthetic, ultra‐high‐purity silica glass. Several ‘box‐profiles’ with mass fractions between 10 and 1000 μg g?1 Ti and maximum depths of homogeneous Ti distribution between 200 nm and 3 μm were produced at the Institute of Ion Beam Physics and Materials Research of Helmholtz‐Zentrum Dresden‐Rossendorf. Multiple implantation steps using varying ion energies and ion doses were simulated with Stopping and Range of Ions in Matter (SRIM) software, optimising for the target concentrations, implantation depths and technical limits of the implanter. We characterised several implant test samples having different concentrations and maximum implantation depths by means of SIMS and other analytical techniques. The results show that the implant samples are suitable for use as reference materials for SIMS measurements. The multi‐energy ion implantation technique also appears to be a promising procedure for the production of EPMA‐suitable reference materials.  相似文献   

5.
Atom probe tomography (APT) is an analytical technique that provides quantitative three‐dimensional elemental and isotopic analyses at sub‐nanometre resolution across the whole periodic table. Although developed and mostly used in the materials science and semiconductor fields, recent years have seen increasing development and application in the geoscience and planetary science disciplines. Atom probe studies demonstrate compositional complexity at the nanoscale and provide fundamental new insights into the atom‐scale mechanisms taking place in minerals over geological time. Here, we provide an overview of APT, including the historical development and technical aspects of the instrumentation, and the fundamentals of data acquisition, data processing and data reconstruction. We also review previous studies and highlight the potential future applications of nanoscale geochemical studies of natural materials.  相似文献   

6.
This GGR biennial critical review covers developments and innovations in key analytical methods published since January 2014, relevant to the chemical, isotopic and crystallographic characterisation of geological and environmental materials. In nine selected analytical fields, publications considered to be of wide significance are summarised, background information is provided and their importance evaluated. In addition to instrumental technologies, this review also presents a summary of new developments in the preparation and characterisation of rock, microanalytical and isotopic reference materials, including a précis of recent changes and revisions to ISO guidelines for reference material characterisation and reporting. Selected reports are provided of isotope ratio determinations by both solution nebulisation MC‐ICP‐MS and laser ablation‐ICP‐MS, as well as of radioactive isotope geochronology by LA‐ICP‐MS. Most of the analytical techniques elaborated continue to provide new applications for geochemical analysis; however, it is noted that instrumental neutron activation analysis has become less popular in recent years, mostly due to the reduced availability of nuclear reactors to act as a neutron source. Many of the newer applications reported here provide analysis at increasingly finer resolution. Examples include atom probe tomography, a very sensitive method providing atomic scale information, nanoscale SIMS, for isotopic imaging of geological and biological samples, and micro‐XRF, which has a spatial resolution many orders of magnitude smaller than conventional XRF.  相似文献   

7.
地球早期生命的个体极其微小,又因遭受了漫长地质年代中各种地质作用的破坏,现今保存下来的生命记录往往不完整,很难用常规分析手段对其进行原位分析.而纳米离子探针(Nano-SIMS)具有极高的空间分辨率,在使用Cs+一次离子源来获得非金属元素或同位素信息的条件下,其空间分辨率可达到50 nm,能有效地解决在地球早期生命研究中所面临的难题.基于选取的5个实例,介绍了NanoSIMS在寻找地球早期生命中发挥的重要作用.通过NanoSIMS获得的生命元素(C,N,S等)分布图像能够直观地观察到生命元素在待研究区域内的分布情况,在排除了无机成因的前提下,C,N,S等生命元素所呈现出的紧密联系可以用来指示生物成因;而获得的微区原位的C,S等同位素信息能够进一步帮助判断所谓的“生物体”或“生物遗迹构造”等是否是真正的生物或由生物活动造成的.  相似文献   

8.
Over 1400 electron probe and 700 ion probe microanalyses were performed on eleven mineral separates to evaluate their potential as reference materials for in situ Li isotopic determination. Our results suggest the homogenous distributions of major elements, Li and its isotopes for each sample. Hence, these samples are suitable to be used as reference materials for in situ measurements of Li abundance and Li isotopes by secondary ion mass spectrometry (SIMS) or laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS). These samples have the advantage of mitigating probable matrix effects during calibration owing to the wide range of compositions. The effect of composition on the δ7Li of olivine measured by SIMS is a linear function of composition, with δ7Li increasing by 1.0‰ for each mole per cent decrease in forsterite component.  相似文献   

9.
离子探针能在单矿物颗粒内进行微区原位直接分析工作,主离子束斑大小可聚焦在5μm以内,可以检测到10^-9级的微量元素,同位素分析的精度高达1‰,在地球科学领域有着广泛的应用。详细叙述了离子探针的工作原理以及微量元素成分和同位素组成的测试方法,列举了其在天体化学和地球化学研究领域的主要应用,总结了一系列的研究成果,并首次公开发表离子探针微量元素测试技术研发工作中取得的一些实验结果。  相似文献   

10.
High spatial resolution multiple sulfur isotope studies undertaken by multi‐collector secondary ion mass spectrometry (SIMS) commonly use well‐characterised sulfide reference materials that do not (or are assumed not to) exhibit mass‐independent fractionation in 33S and 36S, taking advantage of the three‐isotope plot to evaluate the extent of such fractionation in unknown targets. As a result, few studies to date have used a mass independently fractionated reference sulfide to demonstrate accuracy of measurement and/or data reduction procedures. This article evaluates two mass independently fractionated sulfides, a pyrite from the 3.7 Ga Isua greenstone belt and a pyrrhotite from a 2.7 Ga gold deposit in Minas Gerais, Brazil, which may be used to provide additional confidence in the obtained multiple sulfur isotope data. Additionally, the article presents a method for measuring quadruple sulfur isotopes by SIMS at a comparable spatial and volume resolution to that typically employed for triple sulfur isotopes. This method has been applied to the Isua pyrite as well as to a sample of 2.5 Ga pyrite from the Campbellrand, Transvaal, South Africa, previously investigated using SIMS for triple sulfur isotopes, illustrating its potential for quadruple sulfur investigations.  相似文献   

11.
NanoSIMS is a relatively new technology that is being applied to ancient carbonaceous structures to gain insight into their biogenicity and syngeneity. NanoSIMS studies of well preserved organic microfossils from the Neoproterozoic (0.8 Ga) Bitter Springs Formation have established elemental distributions in undisputedly biogenic structures. Results demonstrate that sub-micron scale maps of metabolically important elements (carbon [C], nitrogen [measured as CN ion], and sulfur [S]) can be correlated with kerogenous structures identified by optical microscopy. Spatial distributions of C, CN, and S in individual microfossils are nearly identical, and variations in concentrations of these elements parallel one another. In elemental maps, C, CN, and S appear as globules, aligned to form remnant walls or sheaths of fossiliferous structures. The aligned character and parallel variation of C and CN are the strongest indicators of biogenicity.Nitrogen/carbon atomic ratios (N/C) of spheroids, filaments, and remnants of a microbial mat suggest that N/C may reflect original biochemical differences, within samples of the same age and degree of alteration. Silicon (Si) and oxygen (O) maps illustrate that silica is intimately interspersed with organic carbon of the microfossils. This relationship is likely to reflect the process of silica permineralization of biological remains and thus may be an indicator of syngeneity of the fossilized material with the mineral matrix.The NanoSIMS characterization of Bitter Springs microfossils can be used as a baseline for interpreting less well preserved carbonaceous structures that might occur in older or even extraterrestrial materials. An example of such an application is provided by comparison of Bitter Springs results with NanoSIMS of Archaean carbonaceous structures from Western Australia, including a spheroid in the 3 Ga Farrel Quartzite and material in a secondary vein in the 3.43 Ga Strelley Pool Chert. Results reinforce a biogenic, syngenetic interpretation for the Archaean spheroid.NanoSIMS has several advantages in the study of ancient organic materials: the technique allows characterization of extremely small structures that are present in low concentrations; organic matter does not have to be isolated by acid treatment but can be analyzed in polished thin section; preparation is simple; samples are minimally altered during analysis; results provide sub-micron scale spatial distribution coupled with concentration information for at least five elements; the biologically important elements of carbon and nitrogen can be assessed; and the ability to study organic remains in situ permits petrographic assessment of spatial relationships between organic matter and mineral constituents. These advantages could be of significant benefit for interpretation of poorly preserved and fragmentary carbonaceous remains that might occur in some of Earth's oldest samples as well as in meteorites or extraterrestrial material brought to Earth in future planetary missions.  相似文献   

12.
This paper focused on the zircon sensitive high resolution ion micro-probeU-Pb geochronology of the tourmalinites from boron-bearing series of borate deposits in Eastern Liaoning. The zircons commonly have core-rim structures, most cores show oscillatory zoning in cathodoluminescence and plane polarized light images, suggesting a magmatic detrital origin. Ages of the magmatic detrital zircons from the hyalotourmalite samples (N13) and (N14) are 2175?±?5??Ma and 2171?±?9??Ma, respectively. Moreover, metamorphic zircon from the sample (N13) shows an age of 1906?±?4??Ma. Zircon core and rim from the hyalotourmalite sample (N02) record ages of 2171?±?6??Ma and 1889?±?62??Ma, which are explained as indicating the formation and metamorphic ages. Combined with the geological and geochemical studies, it can be concluded that the tourmalinites are formed during sedimentary exhalative mineralizations in the mid-Paleoproterozoic (~2170?Ma) and underwent the metamorphism in the late-Paleoproterozoic (~1900?Ma). The tourmalinites are the products of submarine acid volcanism in the extension rifting phase of the Liaoji Paleoproterozoic Rift, the rock-forming materials of which are derived from the mantle sources with recycling crustal contamination. The emergence of tourmalinites not only indicates the mid-Paleoproterozoic tectonic-magmatic processes, but also provides impetus, heat and material sources for the mineralization of borate deposits in Eastern Liaoning.  相似文献   

13.
The Pulan-Xiangquanhe ophiolite in the western Yarlung Tsangpo suture zone of Tibet is investigated for its geochemistry,geochronology,and tectonic implications in detail.Sensitive high resolution ion micro-probe zircon U-Pb dating reveals that diabases in the ophiolite from the three locations of Xugugab,Mapam Yum Co and La'nga Co are dated at 122.3±2.5 Ma,118.8±1.8 Ma and 120.5±1.9 Ma,respectively.These early Cretaceous mafic rocks have Na_2O+K_2O,rare earth element patterns,trace elemental spider diag...  相似文献   

14.
We present an improved method for the determination of the boron isotopic composition of volcanic glasses with boron concentrations of as low as 0.4–2.5 μg g?1, as is typical for mid‐ocean ridge basalt glasses. The analyses were completed by secondary ion mass spectrometry using a Cameca 1280 large‐radius ion microprobe. Transmission and stability of the instrument and analytical protocol were optimised, which led to an improvement of precision and reduction in surface contamination and analysis time compared with earlier studies. Accuracy, reproducibility (0.4–2.3‰, 2 RSD), measurement repeatability (2 RSE = 2.5–4.0‰ for a single spot with [B] = 1 μg g?1), matrix effects (? 0.5‰ among komatiitic, dacitic and rhyolitic glass), machine drift (no internal drift; long‐term drift: ~ 0.1‰ hr?1), contamination (~ 3–8 ng g?1) and machine background (0.093 s?1) were quantified and their influence on samples with low B concentrations was determined. The newly developed set‐up was capable of determining the B isotopic composition of basaltic glass with 1 μg g?1 B with a precision and accuracy of ± 1.5‰ (2 RSE) by completing 4–5 consecutive spot analyses with a spatial resolution of 30 μm × 30 μm. Samples with slightly higher concentrations (≥ 2.5 μg g?1) could be analysed with a precision of better than ± 2‰ (internal 2 RSE) with a single spot analysis, which took 32 min.  相似文献   

15.
<正>Precambrian tectonic history of Zhejiang,Fujian,and Jiangxi provinces of south China is important for understanding the tectonic evolution of South China but its magmatic activity, petrogenesis,stratigraphic sequence of the Mamianshan Group is still strongly controversial.Here we present new sensitive high resolution ion micro-probe(SHRIMP) U-Pb zircon geochronological data for the Mamianshan Group and petrographical data to constrain the tectonic framework of the regions.Our results showed that the SHRIMP U-Pb zircon age of green schists of the Dongyan Formation is 796.5±9.3 Ma,the Daling Formation is 756.2±7.2 Ma,and mica-quartz schist of the Longbeixi Formation is 825.5±9.8 Ma.These data indicate that the Mamianshan Group was formed not in the Mesoproterozoic,but in the Neoproterozoic and its stratigraphic sequences should be composed of Longbeixi,Dongyan,and Daling Formations from the bottom to the top.Rocks from this Group, from Zhejiang,Fujian and Jiangxi provinces,constituted the upper basement of the Cathaysia Block that overlay the lower basement of the Mayuan Group.Detailed petrographic studies demonstrate that the amphibole schists of the Dongyan Formation in the Mamianshan Group were formed within an intra-arc rift setting rather than a continental rift as previously suggested.Rather,this island-arc type formation was developed by collision and/or subduction between various blocks resulting from the breakup of the supercontinent Rodinia at c.850-750 Ma.The Zhuzhou conglomerate,distributed near Dikou Town,Jian'ou City,Fujian Province and previously considered as evidence of the Mesoproterozoic Dikou movement,is shown here not to be the basal conglomerate above the angular unconformity between the upper and lower basements.Our conclusions have important implications for understanding the Precambrian tectonics of South China.  相似文献   

16.
Photo‐induced force microscopy (PiFM) is a new‐frontier technique that combines the advantages of atomic force microscopy with infrared spectroscopy and allows for the simultaneous acquisition of 3D topographic data with molecular chemical information at high spatial (~ 5 nm) and spectral (~ 1 cm?1) resolution at the nanoscale. This non‐destructive technique is time efficient as it requires only conventional mirror‐polishing and has fast mapping rates on the order of a few minutes that allow the study of dynamic processes via time series. Here, we review the method’s historical development, working principle, data acquisition, and evaluation, and provide a comparison with traditional geochemical methods. We review PiFM studies in the areas of materials science, chemistry and biology. In addition, we provide the first applications for geochemical samples including the visualization of faint growth zonation in zircons, the identification of fluid speciation in high‐pressure experimental samples, and of nanoscale organic phases in biominerals. We demonstrate that PiFM analysis is a time‐ and cost‐efficient technique combining high‐resolution surface imaging with molecular chemical information at the nanoscale and, thus, complements and expands traditional geochemical methods.  相似文献   

17.
《Gondwana Research》2009,15(4):587-596
We developed a 238U–206Pb⁎ and 207Pb⁎–206Pb⁎ zircon dating method using a Cameca NanoSIMS NS50 ion microprobe. A 7-to 9-nA O− primary beam was used to sputter a 15-μm crater, and secondary positive ions were extracted for mass analysis using the Mattauch–Herzog geometry. The multicollector system was modified to detect 90Zr+, 204Pb+, 206Pb+, 238U16O+, and 238U16O2+ ions simultaneously. A mass resolution of about 4000 at 10% peak height and with a flat peak top was attained, and the sensitivity of Pb was about 4 cps·nA− 1·ppm− 1. A multicrystal zircon standard (QGNG) from South Australia with a U–Pb age of 1842 Ma was used as a reference for Pb+/UO+–UO2+/UO+ calibration, and on the basis of the positive correlation between these ratios, we determined the sample 206Pb/238U ratios. 207Pb/206Pb ratios were measured by magnetic scanning in single-collector mode. The standard zircons 91500, from Canada, and SL13, from Sri Lanka, were analyzed against QGNG. Observed 238U–206Pb⁎ and 207Pb⁎–206Pb⁎ ages agreed well with published ages within experimental error. Then, 16 zircon grains in a metamorphic rock from Nagasaki, Japan, were analyzed. Observed ages were compatible with SHRIMP ages, suggesting that the NanoSIMS with a 15-μm probe diameter is suitable for ion microprobe U–Pb zircon dating.  相似文献   

18.
The Zhashui-Shanyang district is one of the most important sulfide deposits in the Qinling Orogen where the formation of porphyry-skarn Cu-Mo deposits has a close genetic link with the Yanshannian magmatism. Laser Ablation-Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) U-Pb zircon dating of two granodiorite intrusions (Xiaohekou and Lengshuigou deposits) was investigated in the Zhashui-Shanyang district and the rock-forming ages obtained from 148.3±2.8?to 152.6±1.2?Ma, averaging 150.5 Ma, accompanied by a younger disturbance age of 144.3±1.7?Ma in the Lengshuigou intrusion, which is in excellent agreement with published sensitive high resolution ion micro-probe (SHRIMP) zircon date on the later monzodiorite porphyry phase in the Lenshuigou deposit. Two samples were selected for molybdenite ICP-MS Re-Os isotopic analyses from the Lengshuigou granodiorite porphyry, yielding Re-Os model ages from 149.2±2.7 Ma to 150.6±3.4 Ma, with a weighted mean age of 149.7±2.1 Ma. These mineralization ages overlap rock-forming ages of the host intrusions within the error range. This implies that the mineralization occurred in the Late Jurassic, which belongs to the tectonic phase B event of the Yanshan Movement, not Cretaceous as previously thought. Therefore, the Late Jurassic mineralization of the Zhashui-Shanyang district could be connected to the large-scale Yanshan molybdenum metallogenic period, the geodynamic regime of which is attributable to the far field response of convergence of surrounding plates, perhaps the approximately westward subduction of the Izanagi plate beneath the Eurasian continent.  相似文献   

19.
Secondary ion mass spectrometry (SIMS or ion microprobe) remains one of the most powerful tools available to the analytical geochemist. Despite the impressive progress witnessed by other competing laboratory methods over recent years, SIMS remains unsurpassed in its combination of small sampling volumes with low analytical uncertainties. Although the current SIMS analytical design has existed for over three decades, the period 2006–2007 saw significant advances in instrumentation, analytical methodology and, not least, the characterisation of new reference materials upon which all analyses depend. As of the end of 2007 the SIMS geoscience literature was reporting total sampling masses down to the 10 fg range, spatial resolution of better than 100 nm and uncertainties on major element isotope ratio determinations of better than ± 0.2‰ (1s). This article intends to synthesise the progress made by the geo‐SIMS community during this two year period and will also highlight some specific research results that were only possible due to the unique capabilities provided by SIMS.  相似文献   

20.
现代地球科学研究的重大突破在很大程度上取决于观测和分析技术的创新。新世纪以来,我国地球科学领域引进了一批高性能新型微束分析仪器设备,建立了一批高规格的实验室。本文回顾了近十年来微束分析技术与方法的主要进展及其在地球科学研究中的应用实例,包括电子探针、扫描电镜、透射电镜、大型离子探针、纳米离子探针、飞行时间二次离子质谱、激光剥蚀等离子体质谱、激光诱导原子探针、原子探针技术、显微红外光谱、同步辐射等,这些分析技术的进步和广泛应用极大地提高了我们对地球和行星演化历史及许多地质过程的理解。今后,应加快微束分析的新技术、新方法和新标准的开发,特别是高水平人才队伍建设,提高创新能力并在国际学术舞台上发挥重要作用。  相似文献   

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