Reference Materials in Geoanalytical Research -Review for 2004 and 2005     

Klaus Peter Jochum  Matthias Willbold 《Geostandards and Geoanalytical Research》2006,30(3):143-156

This review gives an overview of the use and development of reference materials of geochemical and environmental interest in the literature of the years 2004 and 2005. In these years the performance of existing methods has been improved and new geochemical applications using new techniques have been developed. Accordingly, there was an increasing need for new reference materials, especially for in situ microanalysis and for precise stable isotope measurements. In addition, there was a notable trend for further characterisation of existing reference materials, mainly for the platinum-group elements. This review focuses on five topics: reference materials for platinum-group elements, reference glasses for in situ microanalysis, zircon reference materials, isotopic reference materials, and the development and certification of reference materials.  相似文献   

2004–2005 Analytical Developments in Secondary Ion Mass Spectrometry     

Etienne Deloule 《Geostandards and Geoanalytical Research》2006,30(3):175-182

This review of the literature from 2004 and 2005 concerning secondary ion mass spectrometry (SIMS) highlights the contribution the technique has made in the fields of petrology, geochronology, cosmochemistry and material sciences. In petrology, much research was devoted to the measurement of stable isotopes and trace elements by developments in multicollection acquisition, with emphasis on low atomic mass number elements. Elements studied in particular were S (in sulfides), O (in garnets), C (in sedimentary organic matter), Cl (in glasses) and Si. Novel applications of SIMS to geochronology have included the measurement of young zircon grains by the U-Pb and U-Th decay methods. An increasing number of studies have combined U-Pb geochronology with the measurement of trace elements or stable isotopes in zircon.  相似文献   

林草复合经营模式养分动态关系   总被引：2，自引：0，他引：2  

王海明  李贤伟  陈治谏  王海娥 《山地学报》2006,24(2):156-160

林草复合经营模式在目前的退耕还林工程中起着重要的作用，研究林草复合模式的林与草之间的营养元素关系，通过对不同林草养分的研究得出林木、草、土壤之间的养分动态关系，对矿质养分相互关系的研究为合理搭配林草提供重要依据，为退化山地生态系统的恢复和重建提供重要的模式。模式Ⅰ在退耕还林初期，土壤养分供给氮素虽未亏缺，但从三者问的消长关系看出：氮磷素供应并不富足，特别是水解性氮。土壤交换性钙供应不足，引起杉木与黑麦草对钙质竞争。而土壤全钙含量很高，钙质向交换性钙转化的速度缓慢。模式Ⅱ与模式Ⅰ得到相似结果，所以在这两种模式中应加强人为管理，在退耕初期应适当增施氮磷钙肥，辅以土壤结构改良，加速土壤养分向植物可利用态转化。模式Ⅲ牛鞭草的生物量极高，磷、钙索相对缺乏。由于牛鞭草被不断的采割用于牲畜的饲料，对该模式中必须进行一定养分的输入，以保持杂交竹与牛鞭草这一林草生态系统的养分平衡。  相似文献   

长白山锦北雨养泥炭剖面元素富集规律分析   总被引：3，自引：2，他引：3  

贾琳  王国平  刘景双 《湿地科学》2006,4(3):187-192

为了揭示长白山锦北泥炭沼泽区泥炭沉积环境和重金属元素的历史变化及其对环境的指示意义,利用荷兰W ardenaar泥炭采样器采取泥炭样品并对样品进行高分辨率切割。用原子吸收分光光度计和等离子体发射光谱仪测定不同深度剖面Ca,Mg,Na,K,A l,Ti,Cu,Zn,Fe,Mn,Pb,Cr,N i和Co的浓度。研究分析了Ca,Mg,Na,K,A l,Ti,Mn,Zn,Cu,Pb,Cr,N i和Co在泥炭剖面的分布趋势并对其进行了相关分析和富集分析,得出Mn,Zn,Cu,Pb,Cr,N i和Co呈显著相关且在泥炭表层明显累积,揭示出泥炭表层重金属元素的大气沉降来源,表明近年来人类重金属消耗量及排放量的增加是大气沉降重金属元素的主要释放源,而且环境中重金属污染有加重的趋势。  相似文献   

The distribution of radiogenic heat production as a function of depth in the Sierra Nevada Batholith, California   总被引：4，自引：0，他引：4  

Robert J. Brady  Mihai N. Ducea  Steven B. Kidder  Jason B. Saleeby 《Lithos》2006,86(3-4):229-244

Geochemical analyses and geobarometric determinations have been combined to create a depth vs. radiogenic heat production database for the Sierra Nevada batholith, California. This database shows that mean heat production values first increase, then decrease, with increasing depth. Heat production is 2 μW/m³ within the 3-km-thick volcanic pile at the top of the batholith, below which it increases to an average value of 3.5 μW/m³ at 5.5 km depth, then decreases to 0.5–1 μW/m³ at 15 km depth and remains at these values through the entire crust below 15 km. Below the crust, from depths of 40–125 km, the batholith's root and mantle wedge that coevolved beneath the batholith appears to have an average radiogenic heat production rate of 0.14 μW/m³. This is higher than the rates from most published xenolith studies, but reasonable given the presence of crustal components in the arc root assemblages. The pattern of radiogenic heat production interpreted from the depth vs. heat production database is not consistent with the downward-decreasing exponential distribution predicted from modeling of surface heat flow data. The interpreted distribution predicts a reasonable range of geothermal gradients and shows that essentially all of the present day surface heat flow from the Sierra Nevada could be generated within the 35 km thick crust. This requires a very low heat flux from the mantle, which is consistent with a model of cessation of Sierran magmatism during Laramide flat-slab subduction, followed by conductive cooling of the upper mantle for 70 m.y. The heat production variation with depth is principally due to large variations in uranium and thorium concentration; potassium is less variable in concentration within the Sierran crust, and produces relatively little of the heat in high heat production rocks. Because silica content is relatively constant through the upper 30 km of the Sierran batholith, while U, Th, and K concentrations are highly variable, radiogenic heat production does not vary directly with silica content.  相似文献   

Monazite behaviour and age significance in poly-metamorphic high-grade terrains: A case study from the western Musgrave Block, central Australia     

Nigel M. Kelly  Geoffrey L. Clarke  Simon L. Harley 《Lithos》2006,88(1-4):100-134

Integrated, in situ textural, chemical and electron microprobe age analysis of monazite grains in a migmatitic metapelitic gneiss from the western Musgrave Block, central Australia has identified evidence for multiple events of growth and recrystallisation during poly-metamorphism in the Mesoproterozoic. Garnet + sillimanite-bearing metapelite underwent partial melting and segregation to palaeosome and leucosome during metamorphism between 1330 and 1296 Ma, with monazite grains in leucosome recording crystallisation at 1300 Ma. Monazite breakdown during melting is inferred to have occurred in the palaeosome. During a subsequent granulite facies event at 1200 Ma, deformation and metamorphism of leucosome and palaeosome resulted in partial disturbance of ages and potential minor growth on 1300 Ma monazite in leucosome. Growth of new, high-Y (+HREE) monazite in palaeosome domains occurred during garnet breakdown in the presence of sillimanite to cordierite and spinel, as a result of post-peak isothermal decompression. Diffusive enrichment of resorbed garnet rims in Y + HREE suggests garnet breakdown occurred slower than volume diffusion of REE. Monazite in both palaeosome and leucosome were subsequently partially to penetratively recrystallised during a retrogression event that is suggested to have occurred at 1150–1130 Ma. The intensity of recrystallisation and disturbance of ages appears linked to proximity to retrogressed garnet porphyroblasts and their occurrence in the relatively reactive or ‘fertile’ local environments provided by the palaeosome/mesosome volumes, which caused localised changes in retrogressive fluids towards compositions more aggressive to monazite. Like reaction textures, it is apparent that domainal equilibrium and reaction may control or at least strongly influence monazite REE and U–Th–Pb chemistry and hence ages.  相似文献   

Biological and Geochemical Record of Anthropogenic Impacts in Recent Sediments from Lake Pupuke, Auckland City, New Zealand     

Paul Augustinus  Michael Reid  Sofia Andersson  Yanbin Deng  Mark Horrocks 《Journal of Paleolimnology》2006,35(4):789-805

Frozen sediment cores from Lake Pupuke in Auckland City, New Zealand, contain a high resolution decadal to annual scale record of changing lake paleoenvironments and geochemistry that reflects changing landuse and hydrology in the catchment over the past c. 190 years. A reliable chronology is available from AMS ¹⁴C and ²¹⁰Pb dating of the sediments, with the timing of the older part of the record supported by the first appearance of pollen of introduced Pinus and Plantago lanceolata associated with European settlement of Auckland in the early 1840s. Diatom stratigraphy, sediment elemental and carbon isotope geochemistry reflect changes in sediment sources and lake conditions commensurate with European development of the Lake Pupuke catchment, in particular enhanced algal productivity controlled by the influx of nutrients after c. 1920 AD. Attempts to prevent nuisance algal blooms in 1933, 1934 and 1939 using CuSO₄ addition produced Cu spikes in the sediment that allowed confirmation of the accuracy of the ²¹⁰Pb chronology. Hence, the elemental and isotopic composition of the Lake Pupuke sediments reflect the timing of significant anthropogenic activities, rather than climatic variations, that have occurred within the watershed over the past c. 190 years. The comparison of records of land use change in the catchment with the multi-proxy record of changes in the sediments usually allowed unambiguous identification of the signatures of change and their causes.  相似文献   

Petrology, geochemistry and the mechanisms determining the distribution of platinum-group element and base metal sulphide mineralisation in the Platreef at Overysel, northern Bushveld Complex, South Africa     

David A. Holwell  Iain McDonald 《Mineralium Deposita》2006,41(6):575-598

Platinum-group element (PGE) mineralisation within the Platreef at Overysel is controlled by the presence of base metal sulphides (BMS). The floor rocks at Overysel are Archean basement gneisses, and unlike other localities along the strike of the Platreef where the floor is comprised of Transvaal Supergroup sediments, the intimate PGE–BMS relationship holds strong into the footwall rocks. Decoupling of PGE from BMS is rare and the BMS and platinum-group mineral assemblages in the Platreef and the footwall are almost identical. There is minimal overprinting by hydrothermal fluids; therefore, the mineralisation style present at Overysel may represent the most ‘primary’ style of Platreef mineralisation preserved anywhere along the strike. Chondrite-normalised PGE profiles reveal a progressive fractionation of the PGE with depth into the footwall, with Ir, Ru and Rh dramatically depleted with depth compared to Pt, Pd and Au. This feature is not observed at Sandsloot and Zwartfontein, to the south of Overysel, where the footwall rocks are carbonates. There is evidence from rare earth element abundances and the amount of interstitial quartz towards the base of the Platreef pyroxenites that contamination by a felsic melt derived from partial melting of the gneissic footwall has taken place. Textural evidence in the gneisses suggests that a sulphide liquid percolated down into the footwall through a permeable, inter-granular network that was produced by partial melting around grain boundaries in the gneisses that was induced by the intrusion of the Platreef magma. PGE were originally concentrated within a sulphide liquid in the Platreef magma, and the crystallisation of monosulphide solid solution from the sulphide liquid removed the majority of the IPGE and Rh from it whilst still within the mafic Platreef. Transport of PGE into the gneisses, via downward migration of the residual sulphide liquid, fractionated out the remaining IPGE and Rh in the upper parts of the gneisses leaving a ‘slick’ of disseminated sulphides in the gneiss, with the residual liquid becoming progressively more depleted in these elements relative to Pt, Pd and Au. Highly sulphide-rich zones with massive sulphides formed where ponding of the sulphide liquid occurred due to permeability contrasts in the footwall. This study highlights the fact that there is a fundamental floor rock control on the mechanism of distribution of PGE from the Platreef into the footwall rocks. Where the floor rocks are sediments, fluid activity related to metamorphism, assimilation and later serpentinisation has decoupled PGE from BMS in places, and transport of PGE into the footwall is via hydrothermal fluids. In contrast, where the floor is comprised of anhydrous gneiss, such as at Overysel, there is limited fluid activity and PGE behaviour is controlled by the behaviour of sulphide liquids, producing an intimate PGE–BMS association. Xenoliths and irregular bands of chromitite within the Platreef are described in detail for the first time. These are rich in the IPGE and Rh, and evidence from laurite inclusions indicates they must have crystallised from a PGE-saturated magma. The disturbed and xenolithic nature of the chromitites would suggest they are rip-up clasts, either disturbed by later pulses of Platreef magma in a multi-phase emplacement or transported into the Platreef from a pre-existing source in a deeper staging chamber or conduit.  相似文献   

Environmental and health risk assessment in abandoned mining area, Zlata Idka, Slovakia   总被引：1，自引：0，他引：1  

S. Rapant  Z. Dietzová  S. Cicmanová 《Environmental Geology》2006,51(3):387-397

The Zlata Idka village is a typical mountainous settlement. As a consequence of more than 500 years of mining activity, its environment has been extensively affected by pollution from potentially toxic elements. This paper presents the results of an environmental-geochemical and health research in the Zlata Idka village, Slovakia. Geochemical analysis indicates that arsenic (As) and antimony (Sb) are enriched in soils, groundwater, surface water and stream sediments. The average As and Sb contents are 892 mg/kg and 818 mg/kg in soils, 195 mg/kg and 249 mg/kg in stream sediments, 0.028 mg/l and 0.021 mg/l in groundwater and 0.024 mg/l and 0.034 mg/l in surface water. Arsenic and Sb concentrations exceed upper permissible limits in locally grown vegetables. Within the epidemiological research the As and Sb contents in human tissues and fluids have been observed (blood, urine, nails and hair) in approximately one third of the village’s population (120 respondents). The average As and Sb concentrations were 16.3 μg/l and 3.8 μg/l in blood, 15.8 μg/l and 18.8 μg/l in urine, 3,179 μg/kg and 1,140 μg/kg in nails and 379 μg/kg and 357 μg/kg in hair. These concentrations are comparatively much higher than the average population. Health risk calculations for the ingestion of soil, water, and vegetables indicates a very high carcinogenic risk (>1/1,000) for as content in soil and water. The hazard quotient [HQ=average daily dose (ADD)/reference dose (RfD)] calculation method indicates a HQ>1 for groundwater As and Sb concentrations.  相似文献   

华南地区晚二叠和晚三叠世煤中稀土元素特征研究   总被引：2，自引：0，他引：2  

杜美霞  庄新国 《中国煤田地质》2006,18(2):22-26

在华南地区贵州六盘水、江西乐平、露庆和湖北黄石矿区晚二叠和晚三叠世煤层的稀土元素ICP—MS分析数据的基础上，系统研究了研究区煤中稀土元素的含萤分布特征、赋存特征、配分模式以及地质控制因素。含量分布表明晚二叠世稀土元素含量总体高于晚三叠世；煤中稀土元素与灰分成正相关关系，部分煤样品由于有富稀土元素的重矿物组合的存在而出现稀土元素的异常高值；同一矿区、同一时代煤中稀土元素的配分模式具有一定的相似性，而不同地区同一时代和同一地区不同时代煤中稀土元素的配分模式具有较大差异；煤的沉积环境，煤中无机矿物组成以及海水的影响是控制煤中稀土元素含量和配分模式的主要地质因素。  相似文献