现代洋底块状硫化物矿床中金矿化及其与同类古矿床的比较

金是火山成因的块状硫化物矿石的主要副产品之一。在加拿大黄金储量>31吨的各种类型金矿床中,10％的矿床为块状硫化物矿床,平均品位为1—3ppm,有些矿床的品位稍低。最新黄金储量加上已开采的产量达930吨。 块状硫化物在现代洋底的海山脉和扩张中心地区,在热液作用下正不断形成。这些硫化物具     

岩石物理测量应用于预测岩性差异或孔隙流体的地震响应

岩类学和孔隙中流体内容的确定是综合地震、岩石物理研究的主要目的，因为缺乏一般的反演技术，正演模拟对于研究岩石学、地层学、孔隙流体内容和地震响应的关系是有用的，这个报告描述了在犹他地区对32块岩石标本两个碎屑岩层序的分析的研究，做了详细的岩类学研究，当给俏皮 和横波速度是压力的函数时用超声波作了实验室测量，在标本为干燥的、超压的、盐水饱和的和石油饱和的各种情况下，我们计算了地震频率范围内的速度，速度对孔隙度、碳酸盐的胶结作用和沉积相等是敏感的，我们制作了假设储层为不同饱和状态的速度剖面，速度剖面用于制作合成地震共炮集资料，去研究这些碎屑岩储集层的地震响应，流体饱和度严重影响地震响应，就象有煤层存在时一样，往往观测到振幅随偏移距的变化，但是，地层学对地震响应呈现了较强的影响。     

Hydrocarbon photochemistry in the upper atmosphere of Jupiter

The hydrocarbon photochemistry in the upper atmosphere of Jupiter is investigated using a one-dimensional, photochemical-diffusive, and diurnally averaged model. The important chemical cycles and pathways among the major species are outlined and a standard model for the North Equatorial Belt region is examined in detail. It is found that several traditionally dominant chemical pathways among the C and C2 species are replaced in importance by cycles involving C-C4 species. The pressure and altitude profiles of mixing ratios for several observable hydrocarbon species are compared with available ultraviolet- and infrared-derived abundances. The results of sensitivity studies on the standard model with respect to variations in eddy diffusion profile, solar flux, atomic hydrogen influx, latitude, temperature, and important chemical reaction rates are presented. Measured and calculated airglow emissions of He at 584 angstroms and H at 1216 angstroms are also used to provide some constraints on the range of model parameters. The relevance of the model results to the upcoming Galileo mission is briefly discussed. The model is subject to considerable improvement; there is a great need for laboratory measurements of basic reaction rates and photodissociation quantum yields, even for such simple species as methylacetylene and allene. Until such laboratory measurements exist there will be considerable uncertainty in the understanding of the C3 and higher hydrocarbons in the atmospheres of the jovian planets.     

Laboratory simulations of Titan's atmosphere: organic gases and aerosols

Titan, the main satellite of Saturn, has been observed by remote sensing for many years, both from interplanetary probes (Pioneer and Voyager's flybys) and from the Earth. Its N2 atmosphere, containing a small fraction of CH4 (approximately 2%), with T approximately 90 K and P approximately 1.5 bar at the ground level, is irradiated by solar UV photons and deeply bombarded by energetic particles, i.e. Saturn mangetospheric electrons and protons, interplanetary electrons and cosmic rays. The resulting energy deposition, which takes place mainly below 1000 km, initiates chemical reactions which yield gaseous hydrocarbons and nitriles and, through polymerisation processes, solid aerosol particles which grow by coagulation and settle down to the ground. At the present time, photochemical models strongly require the results of specific laboratory studies. Chemical rate constants are not well known at low temperatures, charged-particle-induced reactions are difficult to model and laboratory simulations of atmospheric processes are therefore of great interest. Moreover, the synthesis of organic compounds which have not been detected to date provides valuable information for future observations. The origin and chemical composition of aerosols depend on the nature of chemical and energy sources. Their production from gaseous species may be monitored in laboratory chambers and their optical or microphysical properties compared to those deduced from the observations of Titan's atmosphere. The development of simulation chambers of Titan's extreme conditions is necessary for a better understanding of past and future observations. Space probes will sound Titan's atmosphere by remote sensing and in situ analysis in the near future (Cassini-Huygens mission). It appears necessary, as a preliminary step to test on-board experiments in such chambers, and as a final step, when new space data have been acquired, to use them for more general scientific purposes.     

Comparison of Venusian Coronae with Giant Circumferential Dyke Swarms on Earth

正The surface of Venus features a large number(500)of quasi-circular tectono-magmatic features known as coronae.Coronae are characterized in part by their topographic characteristics,which can be diverse and     

Large Igneous Provinces,Their Giant Mafic Dyke Swarms,and Links to Metallogeny

正Giant mafic dyke swarms are a key component of the feeder system of Large Igneous Provinces(LIPs),large volume(0.1 Mkm~3;frequently above1 M km~3),mainly mafic(-ultramafic)magmatic events of intraplate affinity.     

Genesis and Distribution of Ultra-alkaline Magmatism within the East Antarctic Associated with the Kerguelen Plume Activity

正Alkaline magmatism is often associated with the initial or final stages of huge plume activity.The alkaline bodies are most often found within the boundary area of plume impact upon the continents.The initial stages of the     

Amino acids derived from Titan tholins

An organic heteropolymer (Titan tholin) was produced by continuous dc discharge through a 0.9 N2/0.1 CH4 gas mixture at 0.2 mbar pressure, roughly simulating the cloudtop atmosphere of Titan. Treatment of this tholin with 6N HCl yielded 16 amino acids by gas chromatography after derivatization of N-trifluroacetyl isopropyl esters on two different capillary columns. Identifications were confirmed by GC/MS. Glycine, aspartic acid, and alpha- and beta-alanine were produced in greatest abundance; the total yield of amino acids was approximately 10(-2), approximately equal to the yield of urea. The presence of "nonbiological" amino acids, the absence of serine, and the fact that the amino acids are racemic within experimental error together indicate that these molecules are not due to microbial or other contamination, but are derived from the tholin. In addition to the HCN, HC2CN, and (CN)2 found by Voyager, nitriles and aminonitriles should be sought in the Titanian atmosphere and, eventually, amino acids on the surface. These results suggest that episodes of liquid water in the past or future of Titan might lead to major further steps in prebiological organic chemistry on that body.