有机质-铀矿床中铀产出形式的电子探针研究     

黄裕柱  曲延玲 《铀矿地质》1988,(2)

在富含有机质的油矿石中,铀的产出形式往往不易查清。笔者以电子探针显微分析技术为主要研究手段,辅以放射性照相、X射线粉晶分析及其它的物理、光学和化学等测试方法,对我国南方5个重要的(含)有机质铀矿床进行研究,确定了各矿床原生工业铀矿物的存在及其产出特征,进一步查明了各矿床中铀的赋存状态。在本文研究的所有矿床的富含有机质铀矿石标本中,电子探针均查出有原生铀矿物沥青铀矿和铀石存在。在各矿床中,细小铀矿物多成集合体分布在有机质条带内或以不规则浸染状产于煤岩中,也有的铀矿物呈胶结物形式产出。此外,还见有铀矿物同黄铁矿或白硒铁矿(FeSe_2)一起充填于古植物细胞腔内的现象。  相似文献   

A kind of informationon short-term and imminent earthquake precursors-research on atmospheric electric field anomalies before earthquakes     

郝建国  唐天明  李德瑞 《地震学报(英文版)》1998,(1)

Ａｋｉｎｄｏｆｉｎｆｏｒｍａｔｉｏｎｏｎｓｈｏｒｔｔｅｒｍａｎｄｉｍｍｉｎｅｎｔｅａｒｔｈｑｕａｋｅｐｒｅｃｕｒｓｏｒｓ—ｒｅｓｅａｒｃｈｏｎａｔｍｏｓｐｈｅｒｉｃｅｌｅｃｔｒｉｃｆｉｅｌｄａｎｏｍａｌｉｅｓｂｅｆｏｒｅｅａｒｔｈｑｕａｋｅｓＪＩ...  相似文献   

A kind of information on short-term and imminent earthquake precursors—research on atmospheric electric field anomalies before earthquakes     

Jian-Guo Hao  Tian-Ming Tang  De-Rui Li 《地震学报(英文版)》1998,11(1):121-131

The long-time practice of observational research on earthquake prediction has shown that the information on short-term and imminent earthquake precursors can hardly be detected, but it is very important for practical and effective earthquake prediction. The result of analysis and study in this paper has shown that the anomaly of quasi-static atmospheric electric field may be a kind of reliable information on short-term and imminent earthquake precursors. On such a basis, the 20 years’ continuous and reliable data of atmospheric electric field observed at the Baijiatuan seismic station are used to study the correlation between the anomalies in seismic activity and relative quiet periods bear on the occurrence of near earthquakes within 200 km range around Beijing after the Tangshan earthquake. The observational results recently reported before hand in written form and earthquakes that actually occurred in near field in corresponding time periods are compared and analyzed. The efficacy of these written prediction opinions about near earthquakes in the recent 10 years is tested. From the test results, the brilliant prospect that the anomaly of quasi-static atmospheric electric field may really become a reliable mark for making short-term and imminent earthquake predictions is discussed. Besides, as a preliminary step, some judgment indexes for predicting earthquakes by use of the observational data of atmospheric electric field before earthquakes are put forward. In the last part, it is pointed out that it would be possible to obtain more believable judgment indexes for determining the three elements of near earthquakes before greater earthquakes (M _S≥5) only if a relatively reasonable station network (2–4 stations every 10 000 km²) is deployed and further investigation is made. Contribution No. 97A0040, Institute of Geophysics, State Seismological Bureau, China. This subject is sponsored by Program No. 95-04-05-01-04, State Seismological Bureau, China.  相似文献   

安徽茅坦A型花岗岩研究   总被引：22，自引：1，他引：21  

吴才来  黄许陈 《地质学报》1998,72(3):237-248

安徽茅坦花岗岩体是由４次侵入的细粒花岗岩、花岗斑岩、中粒花岗岩和粗粒花岗岩组成的复式岩体。各期次岩石具有高硅,富碱,富ＬＲＥＥ、Ｙ,Ｎｂ,Ｚｒ等大离子高电价元素及低Ａｌ、Ｍｇ,Ｃａ、Ｎｉ、Ｃｒ,Ｔｉ,Ｖ的特点,与国内外Ａ型花岗岩相似。岩石中副矿物种类聚多,以含碳硅石,磷钛矿等深源矿物为特征。锆石晶形以正锥面（１１１）和四方柱面（１１０）最为发育,与一般Ｉ型花岗岩有明显的差异。研究表明,该复式岩体为  相似文献   

An averaging method to study the motion of lunar artificial satellites II: Averaging and Applications     

Daniel Steichen 《Celestial Mechanics and Dynamical Astronomy》1998,68(3):225-247

On this, the second part of a two part study (Steichen, 1998) we further develop a semi-analytical theory for a lunar artificial satellite. This theory is obtained by averaging analytically the Hamiltonian function over period up to a month. The averaged equations are then numerically integrated. The solution is free from singularities at e = 0 and I = 0 and is not expanded in powers of these variables. In the last section, the analytic work is applied to characteristic examples to validate the method used. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Periphyton metabolism along a nutrient gradient in a desert river (Truckee River, Nevada, USA)     

Urs Uehlinger  James T. Brock 《Aquatic Sciences - Research Across Boundaries》2005,67(4):507-516

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Seabird guano influences on desert islands: soil chemistry and herbaceous species richness and productivity   总被引：4，自引：0，他引：4  

D.A. Wait  D.P. Aubrey  W.B. Anderson 《Journal of Arid Environments》2005,60(4):681-695

An understanding of the effects of guano deposition on arid soil chemistry and the consequences for plant communities is lacking. This study examined patterns of herbaceous species richness and productivity, soil chemistry, soil moisture and soil respiration on 11 islands in the Gulf of California, six of which receive seabird guano deposition. Species richness was significantly lower on islands with guano (“Bird” islands) than islands without guano (“Non-bird” islands), with very little overlap in species composition; however, productivity was significantly greater on Bird than on Non-bird islands. As expected, Bird island soils had higher concentrations of NO₃⁻, NH₄⁺ and total nitrogen (N) than Non-bird island soils; and, measurements of δ¹⁵N indicate that the higher concentrations of N were derived from guano. We also found that soil moisture and respiration were significantly higher, but pH was significantly lower, on Bird than Non-bird islands. These results suggest that guano deposition in deserts stimulates productivity—even in dry years—due to elevated N and, indirectly, soil moisture. Guano deposition also results in a decrease in species richness and a change in species composition probably due to elevated N, N toxicity, or low pH. However, we also found that pH varied more on Bird than on Non-bird islands; and that salinity—while not different between island types—was significantly patchier on Bird than on Non-Bird islands. These results suggest that guano deposition affects not only the general chemical composition of soils, but also results in greater spatial variation in soil chemical composition, which may ultimately affect species richness and composition. Therefore, understanding spatial patterning in soil chemistry as a result of guano deposition is critical for understanding guano effects on plant richness and productivity.  相似文献   

REE丰度结构类型   总被引：5，自引：1，他引：5  

王志畅  汪云亮  朱西养 《矿物岩石》2002,22(4):52-58

REE燕式曲线丰度结构与REE地球化学特征的相互关系研究为基础，引入丰度坐标系（双对数坐标系），在这种准四维坐标系中一个点定量表示相应的一条燕式曲线的总形态的基础上对REE丰度结构进行系统科学分类，便于对大量样品数据进行定量地球化学研究。  相似文献   

金银铂族元素成矿机理的新探索   总被引：7，自引：1，他引：7  

郑大中  郑若锋 《四川地质学报》2002,22(4):210-218

通过对金、银、铂族元素的氢化物，羧基化合物理化性质，贵金属矿物主要和次要化学成分，贵金属矿物的共伴生矿物组合，有关矿物流体包裹体化学成分，类地行星概况，生产实验等相关问题的讨论，认为金、银、铂族元素主要呈单质及其合金氢化物，单质羧基化合物，单质羧基氢化物迁移的。它们随岩浆，热液，热气迁至地壳浅部，由于减压，降温，氧逸度显著加大，Eh、Ph值发生变化，H2，CO逃逸，氧化，形成贵金属的单质及合金矿物，有的还能与硫，硫化氢作用形成贵金属的硫化矿物和硫盐矿物。  相似文献   

初论郯庐断裂的成藏成矿效应   总被引：1，自引：3，他引：1  

赫英  张战军  毛景文  张荣华 《大地构造与成矿学》2002,26(1):10-15

郯庐断裂是多次活动的深达地幔的断裂带,在其形成与演化过程中伴随有不同类型矿产形成,古生代以来郯庐断裂性质由张裂-压扭-扭张变化,相应的岩浆活动由超基性、基性-酸性-基性、碱性演化,与之有关的矿产由金刚石、铬、镍、铜、铁等岩浆矿床→金、钼、钨、锡、铅、锌、汞、锑、银的热液矿床与石油与烃类气藏→金、银、石油、烃类气、非烃气藏及宝石矿床等演变。郯庐断裂两侧的成矿作用,表现出明显的阶段性、偏对称性、交叉性和两侧成矿的差异性特点,是郯庐断裂带本身纵横特点、郯庐断裂穿越地块性质以及与其交切的东西向褶断带性质联合控制的结果。郯庐断裂两侧不同部位、不同时期、不同类型矿产形成过程中,壳幔作用程度不同,地幔流体有不同程度的贡献,而强烈的壳幔交换作用导致的地幔流体和地壳流体的联合作用常是大规模热液矿床矿集区形成的必要条件。  相似文献