松辽盆地徐家围子断陷无机成因天然气及其成藏模式

通过对徐家围子地区天然气组分、同位素资料以及气体包裹体资料的综合分析认为 ,该地区存在无机成因天然气。烃类气体中具有重碳同位素异常 ( >- 2 0‰ )和负碳同位素系列(δ13C1>δ13C2 >δ13C3)的同位素分布特征 ,表现出无机成因烃类气体的特点。高含量的无机CO2 气体和幔源氦的发现 ,指示着该区无机成因天然气主要来自于地球的深部。地幔热柱上升在地壳不同圈层中引起的岩浆火山活动是无机天然气的主要来源 ,而由此形成的地壳“网状”结构和基底大断裂是无机气上升运移至浅部聚集成藏的主要运移通道。构造活动间歇期和活动期分别以渗流方式和幕式涌流方式向上运移可能是深部流体运移的两种主要方式。古隆起带、岩浆侵入带以及基底大断裂带是无机成因天然气的有利聚集带。     

THE INFLUENCE OF GREENHOUSE WARMING ON THE ATMOSPHERIC COMPONENT OF THE HYDROLOGICAL CYCLE

An atmosphere–ocean climate box model is used to examine the influence of cloud feedback on the equilibria of the climate system. The model consists of three non-linear ordinary differential equations, which are simplified forms of the first law of thermodynamics for the atmosphere and ocean and the continuity equation for the atmospheric component of the hydrological cycle. The mass continuity equation expresses the cloud liquid water content as a function of the evaporation rate from the ocean surface and the precipitation rate. Cloud formation releases latent heat. The model clouds also absorb solar energy at a rate consistent with recent findings. The model simulates snow–ice albedo feedback, water vapour feedback and cloud feedback. The global mean precipitation and surface temperature are analysed as they respond to enhanced greenhouse warming. Model results show that cloud feedback can lead to the occurrence of multiple climate equilibria. Some of these are warmer than the present equilibrium, with increased precipitation, while others are colder, with reduced precipitation. If the cloud feedback is weak, enhanced greenhouse forcing leads to a small alteration of the present equilibrium. If the cloud feedback is strong enough, the climate system can be forced into a warmer and wetter equilibrium.     

温室性气体地质处置研究进展及其问题

温室性气体地质处置的机理有3个:①将深部含水地层作为容器封闭CO2;②含水(油)介质,即岩石矿物与CO2发生化学反应而消耗掉CO2,使CO2长期安全保存于地下介质中;③在低渗透含水层中,CO2的运移与滞留时间较长,属于水力学控制CO2的机制.尽管CO2的地质处置存在费用和安全稳定性问题,但国际上已开展的研究表明,地质处置温室性气体是人类积极解决全球环境问题极具前景的方法之一.     

Infiltration of river water to a shallow aquifer investigated with H/He, noble gases and CFCs

Noble gas isotopes (³He, ⁴He, Ne, Ar, Kr, Xe), tritium (³H), chlorofluorocarbons (CFCs) and dissolved oxygen (O₂) were seasonally measured in a small groundwater system recharged by infiltration of river water at Linsental, northeastern Switzerland. All Groundwater samples contained an excess of atmospheric noble gases (‘excess air’) usually with an elemental composition equal to air. The concentrations of atmospheric noble gases in the groundwater were used to calculate the excess air component and the water temperature at recharge. The noble gas temperatures (NGTs) in the boreholes close to the river vary seasonally, however, the average NGT of all samples lies close to the mean annual temperature of the river water. Groundwater ages were calculated using the tritium/helium-3 (³H/³He) dating method. The water ages of the samples obtained near the river depend on the amount of recently infiltrated river water and are young during times of active river discharge. In contrast, the mean water age of about 3 years of the deep aquifer remained nearly constant over the sampling period. The observed CFC-11 (CFCl₃) and CFC-12 (CF₂Cl₂) concentrations are significantly higher than the atmospheric equilibrium concentrations and therefore CFCs do not provide any direct information on the residence time of the groundwater. Nevertheless, the CFC excess in the groundwater shows a linear increase with the ³H/³He age. Additionally, both accumulation of radiogenic He (⁴He_rad) and O₂ consumption are strongly correlated with residence time. All these correlations can be interpreted either in terms of mixing of recently infiltrated river water with older groundwater or in terms of accumulation/consumption rates.     

蛇绿岩的地球化学研究

蛇绿岩有不同的地球化学类型,但基本的是岛弧拉斑玄武岩（IAT）和洋脊玄武岩（MORB）两种。蛇绿岩的玄武岩大多数是LREE亏损型,如NMORB和IAT。EMORB的LREE略富集是NMORB与OIB混合造成的。文中讨论了变质作用和水岩交换作用对蛇绿岩的改造,鉴于变质岩区蛇绿岩地球化学研究往往出现多解性,作者认为,当前至关重要的是在研究思路和方法学上要有一个突破。     

Tritium and stable isotopes of magmatic waters

To investigate the isotopic composition and age of water in volcanic gases and magmas, we analyzed samples from 11 active volcanoes ranging in composition from tholeiitic basalt to rhyolite: Mount St. Helens (USA), Kilauea (USA), Pacaya (Guatemala), Galeras (Colombia), Satsuma Iwo-Jima (Japan), Sierra Negra and Alcedo (Ecuador), Vulcano (Italy), Parícutin (Mexico), Kudryavy (Russia), and White Island (New Zealand). Tritium at relatively low levels (0.1–5 T.U.) is found in most emissions from high-temperature volcanic fumaroles sampled, even at discharge temperatures >700°C. Although magmatic fluids sampled from these emissions usually contain high CO₂, S_total, HCl, HF, B, Br, ³He R/R_A, and low contents of air components, stable isotope and tritium relations of nearly all such fluids show mixing of magmatic volatiles with relatively young meteoric water (model ages≤75 y). Linear δD/δ¹⁸O and ³H/δ¹⁸O mixing trends of these two end-members are invariably detected at arc volcanoes. Tritium is also detected in fumarole condensates at hot spot basalt volcanoes, but collecting samples approaching the composition of end-member magmatic fluid is exceedingly difficult. In situ production of ³H, mostly from spontaneous fission of ²³⁸U in magmas is calculated to be <0.001 T.U., except for the most evolved compositions (high U, Th, and Li and low H₂O contents). These values are below the detection limit of ³H by conventional analytical techniques (about 0.01 T.U. at best). We found no conclusive evidence that natural fusion in the Earth produces anomalous amounts of detectable ³H (>0.05 T.U.).     

气候变化减缓技术：国际现状与发展趋势

介绍了当前国际主要气候变化减缓技术,并以国际能源署（IEA）、世界自然基金会（WWF）、全球能源技术战略计划（GTSP）、世界资源研究所（WRI）和欧盟（EU）、美国等国际组织、机构与国家发布或拟议中的有关气候变化减缓技术的报告为框架,对全球的气候变化减缓技术部署进行了概述。在此基础上,分析了主要的气候变化减缓技术对减缓气候变化的预期贡献。最后,对减排技术的效果、安全性、对环境的影响以及公众的认可程度等进行了讨论。     

苏北朱家墩气田气源的新证据

针对盐城朱家墩气田的气源问题,在前人研究基础上重点补做了天然气和源岩的对比,油气混合及凹陷底部源岩展布等研究,研究再次证实天然气来自古生界,并明确主要是二叠系栖霞组灰岩,同时查明了尽管在数量上不足道,但属于上白垩统泰州组来源的凝析油的组成面貌,盐城册陷底部出露的海相古生界地层可能是一大型背斜的南翼,由北向南地层时代逐渐变新,栖霞组灰岩位于册陷南侧,古生界天然气主要从盐（2）断层通过垂向,侧向运移进入储层,在朱家墩构造聚集成藏,盐（3）断层起到了很好的侧向封堵作用。     

Variations in trace gas concentrations in different environments in India

Observations of trace gases (SO₂, NH₃, NO₂ and O₃) were made during the period 1981 to 1984 at 6 different locations representative of urban industrial, urban, nonurban, thermal power plant and marine environment. Diurnal variations of the trace gases were studied in an urban environment. Except in the urban industrial environment, the concentration of NH₃ was found in the range of background values. Also, the average concentrations of NO₂ and O₃ at the different environments were in the order of background values. However, the concentrations of SO₂ were substantially higher by about 7 times, in urban industrial and thermal power plant environments. The diurnal variations of SO₂, NH₃ and NO₂ showed anitphase relationship with surface temperature at the urban environment station which is relatively free of industrial pollution. Discussion is centred on trace gas variations in different environments in India together with the values reported for various countries in the world.     

Peut-on évaluer le rôle de la sédimentation sur l'effet de serre à l'échelle de temps des cycles orbitaux ?Can the role of sedimentation in the greenhouse effect at the time scale of orbital cycles be evaluated?

The evolution of the atmospheric CO₂ content is partly a response to the lack of balance between oceanic sedimentation and continental weathering, because the oceanic C reservoir tends to balance net inputs or losses from slow processes by rapid exchanges with the atmospheric reservoir. This response strongly depends on both amplitudes and time scales of the related processes. At Milankovitch or lower time scales, global models generally do neglect organic matter fossilisation, but such an assumption is only valid for oligotrophic systems. In eutrophic or mesotrophic systems, organic matter is not negligible and should be considered relatively to the carbonate sedimentation in order to know whether the impact of the sedimentation was a source or a sink for atmospheric CO₂. To cite this article: P. Bertrand, C. R. Geoscience 334 (2002) 521–528.