Analytical solutions for the capture zone of a pumping well near a stream

The capture zone for a fully penetrating well in an aquifer with regional flow to a stream boundary under steady-state conditions was delineated using complex algebra and image well theory. Regional flow in the aquifer was allowed to take different directions relative to the stream axis. Two critical pumping rates, Q _C1 and Q _C2, produce three capture-zone pattern scenarios: (1) at low pumping rates (Q?<?Q _C1) water is solely withdrawn from the aquifer and no water from the stream enters the aquifer, (2) at medium pumping rates (Q _C1?<?Q?<?Q _C2) a portion of stream water enters the aquifer but it is not captured by the well, and (3) at high pumping rates (Q?>?Q _C2) pumped water is supplied from both the aquifer and the stream with different proportions. For the second and third scenarios, the stream length interval through which stream water enters the aquifer was determined and found to be more sensitive to pumping rate as the regional flow direction approaches the stream axis. The portion of pumped water supplied by the stream was determined in the third scenario. Finally, the capture-zone asymmetry with respect to its axial line was delineated.     

三塘湖盆地二叠系干酪根热模拟气体产物的地球化学特征

针对三塘湖盆地的主力烃源岩二叠系芦草沟组泥质烃源岩开展封闭体系和半开放体系热模拟实验,前者将干酪根密封在金管中开展实验、后者直接对烃源岩样品进行压机半开放体系热解模拟,对实验中生成气体的组分和稳定碳同位素进行分析。实验结果显示,两种热解方法以无机气体生成为主,包括CO2、H2、H2S 和 N2等,其中 CO2含量最丰富,这与样品干酪根中丰富的氧含量一致。半开放体系模拟实验温度达到480℃时,气态烃的含量达40.64%,其中甲烷含量达到26.10%,封闭体系中随着模拟温度升高烃类气体产物的碳同位素呈现先变轻后变重的趋势,但同位素分馏程度不大, CH4气体的δ13C 值分布在-40.2‰~-46.6‰之间, C2H6分布在-34.3‰~-38.0‰之间, C3H8分布在-33.6‰~-36.0‰之间,而CO2气体δ13C值分布在-32.8‰~-28.8‰之间。三塘湖盆地针对气藏的勘探已经有所发现,但有关气藏的地球化学特征报道较少,该工作中的模拟实验结果可为三塘湖盆地深入的气藏地球化学勘探提供基础数据。     

The influence of carbon source on abiotic organic synthesis and carbon isotope fractionation under hydrothermal conditions

A series of laboratory experiments were performed to investigate the relative contributions of CO and other single-carbon compounds to abiotic synthesis of organic compounds in hydrothermal environments. Experiments were conducted by heating aqueous solutions of CO, CO₂, HCOOH, or CH₄ at 250 °C under reducing conditions, and observing production of CH₄ and other hydrocarbons. Native Fe was included in the experiments as a source of H₂ through reaction with water and as a potential catalyst. Experiments with CO or HCOOH as the carbon source resulted in rapid generation of CH₄ and other hydrocarbons that closely resembled typical products of Fischer-Tropsch organic synthesis. In contrast, experiments using CO₂ or CH₄ as the carbon source yielded no detectable hydrocarbon products. Carbon isotope measurements of reaction products from the CO experiments indicate that the CH₄ and other hydrocarbons were substantially depleted in ¹³C, with CH₄ δ¹³C values 30 to 34‰ lighter than the initial CO. Most of the fractionation apparently occurs during attachment of CO to the catalyst surface and subsequent reduction to surface-bound methylene. The initial step in polymerization of these methylene units to form hydrocarbons involves a small, positive fractionation, so that ethane and ethene are slightly enriched in ¹³C relative to CH₄. However, subsequent addition of carbon molecules to the growing hydrocarbon chain proceeds with no net observable fractionation, so that the isotopic compositions of the C₃₊ light hydrocarbons are controlled by isotopic mass balance. This result is consistent with a previously proposed model for carbon isotopic patterns of light hydrocarbons in natural samples. The abundance and isotopic composition of light hydrocarbons produced with HCOOH as the carbon source were similar to those generated with CO, but the isotopic compositions of non-volatile hydrocarbons diverged, suggesting that the higher hydrocarbons were formed by different mechanisms in the CO and HCOOH experiments. The experiments indicate that CO, and possibly HCOOH, may be critical intermediates in the abiotic formation of organic compounds in geologic environments, and suggest that the low levels of these compounds present in most hydrothermal systems could represent a bottleneck restricting the extent of abiotic organic synthesis in some circumstances.     

Comparative major ion geochemistry of Piedmont streams in the Atlanta,Georgia region: possible effects of urbanization

. The major ion stream chemistry for an urbanized basin (Peachtree Creek) in the Atlanta (Georgia, USA) metropolitan region was analyzed and compared upon a time-series basis with the stream chemistry of a nearby, but far less developed basin (Sweetwater Creek). The major ion chemistry from both streams indicated that all parameters fell below safe drinking water standards as would be expected in watersheds underlain by low-solubility aluminosilicate bedrock. Base flow TDS concentrations for the urbanized basin (Peachtree Creek) were ~30% greater than Sweetwater Creek and were characterized by elevated concentrations of base cations (Ca, Mg, Na), alkalinity, sulfate, and chloride. The less-urbanized Sweetwater Creek basin is underlain by a higher percentage of more soluble amphibolite and, therefore, the higher concentration of solutes within the urban base flow can not readily be explained by differential mineral weathering. The increased inorganic solute loads might have resulted from pollution input (leaky underground sewer lines?) and/or evaporative concentration; however, these explanations are presently speculative. Major ion concentrations within the urban Peachtree Creek basin were diluted by an average of ~50% compared with only ~25% in the Sweetwater Creek basin as a result of the increased contribution of direct surface runoff. The regression correlation coefficients for the ions that evolve through mineral weathering (Ca, Mg, Na, and HCO3) are much higher in urban stream flow than in Sweetwater Creek waters. This might indicate that storm waters in the urban basin are more closely derived from a two end member mixture (groundwater and street runoff) than waters from Sweetwater Creek, which represent a more complex mixture.     

Analysis of seismic intensities observed in Israel

Macroseismic data of earthquakes felt in Israel and also recorded instrumentally are analyzed. The analysis yields the following empirical relations:

GasBenchⅡ顶空瓶内空气背景对<100μg碳酸盐中碳氧同位素在线测定的影响及校正方法初探

较为系统地研究了在特定排空时间下GasBenchⅡ顶空瓶内背景CO2的量和同位素组成变化,并检查了该空白CO2组分对碳酸盐C、O同位素在线测定的影响。结果发现,由于排空时间较短所导致的顶空瓶内剩余的空气CO2或由于排空方法不当所导致的外部空气少量回流都会对小样品量(100μg)碳酸盐C、O同位素测定结果产生显著影响。其影响程度取决于空白CO2的量和空白CO2与碳酸盐样品之间C、O同位素的差别大小。由此,对小样品量碳酸盐C、O同位素的测定结果进行了空白校正。当碳酸盐样品质量在20~100μg,校正后δ13C和δ18O值的标准偏差分别小于0.12‰和0.13‰,这证明了该空白校正方法的可行性。由于顶空瓶中空白CO2的量很小,所以对痕量CO2的量、δ13C和δ18O测定值的测定会存在一定波动,这对碳酸盐δ13C和δ18O校正值产生小于0.2‰的不确定度。采用准确测定的实验室空气CO2的δ13C和δ18O值则会大大减少该不确定度的影响。     

Microanalysis of carbon isotope composition in organic matter by secondary ion mass spectrometry

An analytical procedure has been developed for the in situ measurement of carbon isotope composition of organic matter, with a spatial resolution of 20-30 μm, using a Cameca IMS 1270 ion microprobe. Instrumental mass fractionation (IMF) of carbon isotopes was observed to be independent of primary ion beam intensity and sputtering time, but did depend on vacuum conditions and on the chemical composition of the sample. To evaluate such “matrix effects”, a set of 9 standards representative of the natural chemical variability of organic matter was prepared, with H/C atomic ratios and organic carbon contents (C_org) ranging between 0.04 and 1.74 and between 41 and 100 wt.%, respectively. Under the analytical conditions tested, IMF was not found to be influenced by the presence of silicate mineral impurities in the organic matter, but variations in IMF up to 5‰ were observed over the set of standards with the magnitude of IMF negatively correlated to the H/C ratios of samples. Aliphaticity ratios determined using Fourier transform infrared microspectroscopy provided an in situ estimation of H/C ratios with a spatial resolution barely exceeding that of the ion microprobe and permit a correction for matrix effects with a standard error of ± 0.2‰ (1σ). Taking into account all sources of uncertainty, ion microprobe δ¹³C were accurately determined with a ± 0.7‰ (1σ) total uncertainty. The mechanism for the matrix effect of H/C ratios upon IMF is still to be determined but it is likely related to the difference in proportion of atomic vs. molecular carbon ions observed between samples of different H/C ratios.     

四川九寨沟景区钙华起源初探

九寨沟风景区以绝美的景色闻名于世。钙华作为其独特景观的重要构成要素,有着重要的观赏价值和研究价值。为了弄清九寨沟钙华的起源,特别是CO2的来源,对九寨沟主要水体的水化学和碳氢氧同位素以及现代钙华的碳同位素进行了取样分析。结果发现:(1)九寨沟水体来源于大气降水的补给;(2)水体中碳酸氢根离子和钙离子浓度较低,主要来源于土壤CO2对碳酸盐岩的溶解;(3)根据碳的来源分类,九寨沟钙华应为大气成因类钙华(或表生钙华);(4)九寨沟珍珠滩钙华与碳酸氢根间较大的碳同位素分馏表明,此处生长的藻类对钙华的形成可能有重要作用。      

增强地热系统热储层-盐水-CO2相互作用

增强型地热系统(EGS)是采用人工形成地热储层的方法,从低渗透性岩体中经济地采出深层热能的人工地热系统。以CO₂为载热流体的增强地热能系统(CO₂-EGS)是实现CO₂减排和深部地热资源开发的有效手段,系统运行时的水-岩-气相互作用对热储层孔渗特征有着重要影响,最终会影响储层的产热能力。笔者利用高温高压反应釜模拟CO₂-EGS高温下的热储层-盐水-CO₂的相互作用,通过对实验中反应液离子成分变化和岩样扫描电镜进行分析,结果表明:实验后的钾长石和方解石出现溶解现象,且方解石溶蚀剧烈;岩样表面出现极少量次生方解石和钠长石,并有新矿物析出,其主要组成元素为C、O、Si、Fe,为菱铁矿的中间产物。通过TOUGHREACT建立反应性溶质运移模型,模拟上述实验的化学反应过程,模拟结果和实验数据拟合较好。该研究可为CO₂-EGS的水-岩-气作用机制提供地球化学数据。     

Seafloor hydrothermal alteration at an Archaean mid-ocean ridge

A hydrothermally metamorphosed/altered greenstone complex capped by bedded cherts exposed in the North Pole, Pilbara Carton, Western Australia, is interpreted as an accretionary complex. It is distinctive in being characterised by both duplex structure and an oceanic crust stratigraphy. This complex is shown to represent an Archaean upper oceanic crust with a mid‐ocean ridge hydrothermal metamorphism that increases in grade stratigraphically downward. Three mineral zones have been defined; Zone A of the zeolite facies, the prehnite‐pumpellyite facies or the lower‐greenschist facies at high‐X_CO2 condition, Zone B of the greenschist facies, and Zone C of the greenschist/amphibolite transition facies. In Zone A metabasites, Ca‐Al silicates including Ca‐zeolites, prehnite and pumpellyite are absent and epidote/clinozoisite is extremely rare. Instead, abundant carbonates are present with chlorite suggesting high‐X_CO2 composition in the fluid. On the other hand, in Zones B and C metabasites, where Ca‐amphibole + epidote/clinozoisite + chlorite + Ca‐Na plagioclase are the dominant assemblages, carbonate is not identified. The metamorphic conditions boundary of Zones B/C were estimated to be about 350 °C at a pressure of <0.5 kbar. Fluid compositions coexisting with Archaean greenstones at the transition between Zones B and C were estimated by thermodynamic calculation in the CaFMASCH system (T = 350–370 °C, P = 150–1000 bar) at X_CO2 of 0.012–0.140, such values are higher than present‐day vent fluids collected near mid‐ocean ridges with low‐X_CO2 values, up to 0.005. The Archaean seawater depth at the mid‐ocean ridge was estimated to be 1600 m at X_CO2 = 0.06 using a depth‐to‐boiling point curve for a fluid. The carbonation due to high‐X_CO2 hydrothermal fluids occurred near the ridge‐axis before or was coincident with ridge metamorphism.     

U-Pb Age Determination for Seven Standard Zircons using Inductively Coupled Plasma–Mass Spectrometry Coupled with Frequency Quintupled Nd-YAG (λ = 213 nm) Laser Ablation System: Comparison with LA-ICP-MS Zircon Analyses with a NIST Glass Reference Material

This paper evaluates the analytical precision, accuracy and long‐term reliability of the U‐Pb age data obtained using inductively coupled plasma–mass spectrometry (ICP‐MS) with a frequency quintupled Nd‐YAG (λ = 213nm) laser ablation system. The U‐Pb age data for seven standard zircons of various ages, from 28 Ma to 2400 Ma (FCT, SL13, 91500, AS3, FC1, QGNG and PMA7) were obtained with an ablation pit size of 30 μm diameter. For ²⁰⁷Pb/²⁰⁶Pb ratio measurement, the mean isotopic ratio obtained on National Institute of Standards and Technology (NIST) SRM610 over 4 months was 0.9105 ± 0.0014 (n = 280, 95% confidence), which agrees well with the published value of 0.9096. The time‐profile of Pb/U ratios during single spot ablation showed no significant difference in shape from NIST SRM610 and 91500 zircon standards. These results encouraged the use of the glass standard as a calibration standard for the Pb/U ratio determination for zircons with shorter wavelength (λ = 213 nm) laser ablation. But ²⁰⁶Pb/²³⁸U and ²⁰⁷Pb/²³⁵U ages obtained by this method for seven zircon standards are systematically younger than the published U‐Pb ages obtained by both isotope dilution–thermal ionization mass spectrometry (ID‐TIMS) and sensitive high‐resolution ion‐microprobe (SHRIMP). Greater discrepancies (3–4% younger ages) were found for the ²⁰⁶Pb/²³⁸U ages for SL13, AS3 and 91500 zircons. The origin of the differences could be heterogeneity in Pb/U ratio on SRM610 between the different disks, but a matrix effect accuracy either in the ICP ion source or in the ablation‐transport processes of the sample aerosols cannot be neglected. When the ²⁰⁶Pb/²³⁸U (= 0.2302) newly defined in the present study is used, the measured ²⁰⁶Pb/²³⁸U and ²⁰⁷Pb/²³⁵U ages for the seven zircon standards are in good agreement with those from ID‐TIMS and SHRIMP within ±2%. This suggests that SRM610 glass standard is suitable for ICP‐MS with laser ablation sampling (LA‐ICP‐MS) zircon analysis, but it is necessary to determine the correction factor for ²⁰⁶Pb/²³⁸U by measuring several zircon standards in individual laboratories.     

Climatic and tectonic controls on chemical weathering in the New Zealand Southern Alps

Climatic and tectonic controls on the relative abundance of solutes in streams draining the New Zealand Southern Alps were investigated by analyzing the elemental and Sr isotope geochemistry of stream waters, bedload sediment, and hydrothermal calcite veins. The average relative molar abundance of major cations and Si in all stream waters follows the order Ca²⁺ (50%) > Si (22%) > Na⁺ (17%) > Mg²⁺ (6%) > K⁺ (5%). For major anions, the relative molar abundance is HCO₃⁻ (89%) > SO₄²⁻ (7%) > Cl⁻ (4%). Weathering reactions involving plagioclase and volumetrically small amounts of hydrothermal calcite define the ionic chemistry of stream waters, but nearly all streams have a carbonate-dominated Ca²⁺ and HCO₃⁻ mass-balance. Stream water Ca/Sr and ⁸⁷Sr/⁸⁶Sr ratios vary from 0.173 to 0.439 μmol/nmol and from 0.7078 to 0.7114, respectively. Consistent with the ionic budget, these ratios lie solely within the range of values measured for bedload carbonate (Ca/Sr = 0.178 to 0.886 μmol/nmol; ⁸⁷Sr/⁸⁶Sr = 0.7081 to 0.7118) and hydrothermal calcite veins (Ca/Sr = 0.491 to 3.33 μmol/nmol; ⁸⁷Sr/⁸⁶Sr = 0.7076 to 0.7097).Streams draining regions in the Southern Alps with high rates of physical erosion induced by rapid tectonic uplift and an extremely wet climate contain ∼10% more Ca²⁺ and ∼30% more Sr²⁺ from carbonate weathering compared to streams draining regions in drier, more stable landscapes. Similarly, streams draining glaciated watersheds contain ∼25% more Sr²⁺ from carbonate weathering compared to streams draining non-glaciated watersheds. The highest abundance of carbonate-derived solutes in the most physically active regions of the Southern Alps is attributed to the tectonic exhumation and mechanical denudation of metamorphic bedrock, which contains trace amounts of calcite estimated to weather ∼350 times faster than plagioclase in this environment. In contrast, regions in the Southern Alps experiencing lower rates of uplift and erosion have a greater abundance of silicate- versus carbonate-derived cations. These findings highlight a strong coupling between physical controls on landscape development and sources of solutes to stream waters. Using the Southern Alps as a model for assessing the role of active tectonics in geochemical cycles, this study suggests that rapid mountain uplift results in an enhanced influence of carbonate weathering on the dissolved ion composition delivered to seawater.     

Organic matter sources and transport in an agriculturally dominated temperate watershed

The quality, quantity, and origin of suspended organic matter were studied in the highly agricultural Upper Scioto River in Central Ohio. Late summer baseflow conditions were compared to late autumn high flow conditions. Variables examined in the suspended matter were the total suspended solids concentration, semi-quantitative concentrations of lignin, carbohydrate concentrations, total organic C, total and organic P, and δ-¹³C. Also examined were ratios of C to N, organic C to organic P ratios and fluxes of total organic C. The primary hypothesis of this research was that the quality (or biodegradability) and quantity of organic matter in the Upper Scioto River would increase during autumn stormflow conditions due to inputs of fresh terrestrial organic matter. The autumn suspended matter was also expected to reflect C4 plant contributions from corn organic matter. Results show that the quality and quantity of organic matter were greater during summer, as reflected in low molar ratios (178:1) of organic C to organic P, and higher organic C content of the suspended matter in summer. Summer suspended matter was 3.6% organic C and autumn suspended matter was 2.3% organic C. Carbon to N molar ratios in both seasons were very close to the Redfield ratio (6.6:1 in summer and 6.7:1 in autumn). Total suspended matter and total organic C concentrations were lower in autumn (8.7 mg/l⁻¹ TOC and 17.7 mg/l⁻¹ TSS) than in summer (17.5 mg/l⁻¹ TOC and 39.0 mg/l⁻¹ TSS), but the fluxes were greater in autumn due to greater stream flow. Stable isotope analyses suggested a phytoplankton or C3 plant source (most likely corn) for summer organic C (mean δ¹³C of −24.8‰) and a phytoplankton or C4 plant source for autumn organic matter (δ¹³C=−21.5‰).     

Groundwater hydrochemistry and soil pollution in a catchment affected by an abandoned lead–zinc mine: functioning of a diffuse pollution source

The importance of polluted alluvial soils as a potential diffuse source of heavy metals was investigated in a catchment of the Matylda stream affected by an abandoned lead and zinc ore mine in Upper Silesia, southern Poland. This was attempted by means of standard groundwater analyses performed together with measurements of Cd, Pb, Zn, Fe and Mn concentrations in soil and groundwater. The Matylda stream, receiving mine water, was converted in the 20th century into a straight channel directed in its middle reach over the valley bottom. This changed the drainage direction of the Matylda stream water. During mining operations, groundwater seepage, combined with surface drainage by shallow ditches caused pollution of sandy soils exceeding over 100 mg/kg of Cd, 24% of Zn and 4% of Pb at surface or subsurface soil horizons, and reaching at least 60 cm in depth. After mine closure in the 1970s, the network of ditches appears to be a source of Ca, Mg, chlorides, carbonates and nitrates, as indicated by the more or less regular increase of these major ion concentrations in groundwater down ditches. Whereas, the ditches are a sink rather than a source of zinc, cadmium and lead in permanently dry reaches, or transition zones in reaches with surface water flowing periodically. The metal concentrations and distribution in soil and groundwater suggest the slow mobilization of heavy metals stored in the valley bottom and the minor importance of soil as a diffuse source for surface water pollution.     

Characterisation of hydrous ferric oxides derived from iron-rich groundwaters and their contribution to the suspended sediment of streams

When Fe(II) bearing groundwaters surface in streams, particulate authigenic Fe-rich material is produced by oxidation. Such freshly precipitated Fe minerals may be transported as suspended sediment and have a profound impact on the fate of trace metals and nutrients in rivers. The objective of this study was to monitor changes in mineralogy and composition of authigenic material from its source to streams of increasing order. Groundwaters, surface waters, and suspended sediment in streams of different order were sampled in the Kleine Nete catchment (Belgium), a lowland with Fe-rich groundwaters (3.5–53.8 mg Fe/L; pH 6.3–6.9). Fresh authigenic material (>0.45 μm) was produced by oxidising filtered (<0.45 μm) groundwater and surface water. This material contained, on average, 44% Fe, and smaller concentrations of C, P, and Ca. Iron EXAFS (Extended X-ray Absorption Fine Structure) spectroscopy showed that the Fe was present as poorly crystalline hydrous ferric oxides with a structure similar to that of ferrihydrite. The Fe concentration in the suspended sediment samples decreased to 36–40% (stream order 2), and further to 18–26% (stream order 4 and 5). Conversely, the concentrations of organic C, Ca, Si, and trace metals increased with increasing stream order, suggesting mixing of authigenic material with suspended sediment from a different source. The Fe speciation in the suspended sediment was similar to that in fresh authigenic material, but more Fe–Fe interactions were observed, i.e. it was increasingly hydrolysed, suggesting ageing reactions. The suspended sediment in the streams of order 4 and 5 is estimated to contain between 31% and 59% of authigenic material, but more data are needed to refine this estimate. The authigenic material is an important sink for P in these streams which may alleviate the eutrophication risk in this catchment.     

狭缝系统与伊利石结晶度Kuebler指数的测定及相关问题讨论

根据实验结果,衍射峰半高宽随接收狭缝增大而呈二次工线线性增大。扫描速度与扫描步长的确定应遵守Ｗａｎｇ（１９９４）提出的关系式,并确定在相对误差小于〈５％的范围内。固定样品条件,选定最优实验条件下使用国际标样标定系统偏差是伊利石结晶测量中必不可少的重要步骤。不固定样品条件和实验条件,同一样品的伊利石工值将因条件的变化而不同;固定样品和实验条件而不使用国际标样标定系统偏差,则无法与他人数据进行对比,其     

Arsenic speciation in surface waters and sediments in a contaminated waterway: an IC–ICP-MS and XAS based study

An integrated approach involving the use of ion chromatography–inductively coupled plasma-mass spectrometry (IC–ICP-MS), X-ray absorption spectroscopy (XAS) and sequential extraction procedures has been employed to elucidate the solution and solid phase speciation and partitioning of As in a polluted urban watercourse. Dissolved As concentrations exceeding 130 μg l⁻¹ and comprising entirely inorganic species were determined in the waters of Tinker Brook, a contaminated stream. Upon mixing with a relatively As-free stream, White Ash Brook, both the total concentration of dissolved As and the proportion of As(V) were observed to decrease dramatically below values expected for conservative mixing. This was ascribed to adsorption onto the Fe (oxyhydr)oxides that characterise White Ash Brook on the basis of sequential extraction and direct analysis of the solids via XAS . The shift in oxidation state is speculated to be due to the faster rate of adsorption of As(V) on Fe (oxyhydr)oxides than As(III) in this fast flowing stream system. During periods of reduced supply of anthropogenic As, a small, secondary input of As(III) to White Ash Brook is detectable, delivered by a small ochreous seepage. The Fe (oxyhydr)oxide As-rich deposits surrounding this discharge may also act as a significant source of As upon dissolution during stormflow conditions.     

Single-zircon evaporation combined with Pb+ emitter bedding for 207Pb/206Pb-age investigations using thermal ion mass spectrometry,and implications to zirconology

The internal precision of Pb isotope analyses using single-zircon evaporation in a double-filament solid source mass spectrometer (Kober 1986) can be improved combining the evaporation of Pb directly from the single grain with a suitable Pb⁺ emitter-bedding technique. This is most easily done by step-wise evaporating the investigated grain at temperatures of 1700–1800 K generating on the ‘cold’ ionization filament a deposit of radiogenic Pb together with further elements and compounds derived directly from the crystal. The heating of the deposit on the ionization filament to 1400–1500 K results in long-lived and stable Pb⁺ ion beams. The ‘activating reagents’ in the deposit are HfO₂ and SiO₂. Their release from the zircon grain together with the radiogenic Pb, which presumably is sited in the crystalline zircon domains as Pb⁴⁺, is probably due to disintegration reactions of trace-element silicates hosted in the grain. In the bedding deposited on the ionization filament thermally stable Pb/Hf/SiO₂ compounds are formed (PbHfSiO₅(?)). They retain the Pb isotopes on the (Re) filament up to 1400 K–1500 K and are highly efficient Pb⁺ ion emitters similar to the ‘Si-gel’-method (Cameron et al. 1969). The combined evaporation/emitter-bedding technique has been applied to natural zircons of different genesis and to isotope standards. Routinely, a Pb⁺ ion yield of 2*10^?4-1*10^?3 and a relative standard deviation of the ²⁰⁷Pb/²⁰⁶Pb ratio in the order of 1% have been obtained for sub-ng- to ng-amounts of Pb from standards and samples. The method rapidly can yield Pb isotope information on the ‘concordant’ zircon phases with a standard deviation of ±15–20 Ma of the derived ages also in the case of Paleozoic zircon populations.     

二氧化碳—水体系的拉曼光谱研究

研究了使用石英管熔融封闭法分别在酸性、中性以及碱性条件下,采用ＣａＣＯ３或Ｎａ２ＣＯ３与ＨＣｌ反应制备不同浓度的ＣＯ２标准系列,并对气相、液相中的ＣＯ２进行拉曼光谱研究,得出了定量分析气相ＣＯ２所遵循的规律,即ＣＯ２的浓度与拉曼位移（１３８８．９ｃｍ－１）强度呈线性相关,为定量分析流体包裹体中ＣＯ２的含量奠定了基础。