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Spectroscopic Study of Natural Diamonds in China 总被引:2,自引:0,他引:2
It has become clear in recent years that the important substitutional impurities in diamond are nitrogen,hydrogen and boron(Bibby,D.M.,1982).The physical and chemical properties of diamond are determined by the content and form of occurence of nitrogen based on which diamonds are generally classified.The well-known experiments concerning the mutual transformation of the forms the origin of diamond.by Evans.T.Et al.(1982) have provided a theoretic basis for the origin of diamond.Since 1979,spectroscopic investigation of natural diamonds from different areas in china has been carried out using UV-visible and IR spectrophotometer,EPR and cathodoluminescence techniques.We have conducted the classification of natural cathodoluminescence techniques.We have conducted the classification of natural diamonds in China and studies on the forms of nitrogen and hydrogen,the radiation damage and their geological implications.Spectroscopic characteristics of natural diamonds in china and their geological implications are discussed in this paper. 相似文献
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正 We owe to Davis the conception that a landform is the function of processes, structure and time. Among these three independent variables, process is a dynamic variable, structure a spatial variable and time a time variable. 相似文献
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《International Geology Review》2012,54(5):419-423
While the initial activity of a natural disaster event may directly injure or kill a number of people, it is possible that a significant number of individuals will be affected by disease outbreaks that occur after the first effects of the disaster have passed. Coupling the epidemiologist's knowledge of disease outbreaks with geographic information systems and remote sensing technology could help natural disaster relief workers to prevent additional victims from disease aftershocks. 相似文献
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INTRODUCTIONAs early as 1644 , Ren啨Descartes proposed thatsilver-,gold-,and lead-bearing veins were producedby the condensation of vapors emanating from theearth' s interior ( Williams-Jones et al ., 2002) . Butthe solubility of many metals is higher in liquid thanin vapor andtherefore the focus of research on hydro-thermal ore deposits was placed on hydrothermal sys-tems (Barnes ,1997) ,considering the fact that ore-forming elements may exist as complexes in hydro-thermal solutions . T… 相似文献
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华仁民 《中国地球化学学报》1990,9(3):231-243
The Dongchuan-type copper deposits have long been studied and well reported because of their great economic significance.The present paper proposes a “sedimentation-reworking“ origin for this type of deposits to challenge the current “sedimentation-metamorphism“ model which has been widely asscpted since 1970s.According to the new idea,orebodies were not directly deposited in the Luoxue dolomite where they are hosted.Instead,copper was preliminarily concentrated in the Yinmin Formation.During or after diagenesis,copper in the Yinmin Formation was mobilized and leached by hydrothermal solutions derived from the interstitial water of sediments under the high geothermal gradient of rift environment,Thus,copper was transported from the source bed(the Yinmin Formation)upward to the Luoxue algal dolomite where sulfur was produced by the reduction of sulfates.The copper sulfides were formed through replacement of initial sulfides by Cu-bearing solutions. 相似文献
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Study on Inclusions in Natural and Synthetic Gems 总被引:4,自引:0,他引:4
李兆麟 《中国地球化学学报》2001,20(4):324-332,T001
The characteristics of inclusions in natural and synthetic gems are distinct owing to their different forming mechanisms and can be utilized to distinguish gems from different localities.In addition,intensive studies on inclusion characteristics of natural gems could identify their geographical origins and provide valuable information on gem synthesis,In this paper synthetic gems (synthetic star-spangled sapphire and emerald)and natural gems from various locations including natural sapphire from Thailand and Australia,and natural aquamerine from Mufushan,Hunan Province,and Ailoshan,Yunnan Province,were selected for the comparative study of inclusion.Significant research results have been achieved,thus providing the important basis for distinguishing natural from synthetic gems. 相似文献
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<正>1 Introduction Studies of marine sedimentary phosphate rock have lasted decades,scholars proposed some standpoints about mineralization,however,the genesis of mineral deposits remains to be a controversial question(She et al.,2013).There are many viewpoints of mineralization about the Doushantuo phosphorites,Central Guizhou,including biological mineralization(Mi et al.,2010;Shi et al.,2005), 相似文献
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The powder XRD analysis of ringwoodite(γ-Fe2SiO4),which was synthesized in a II-stage anvil high-pressure capsule,was made,Its unit-cell parameter was calculated:a=8.219A,After the refinements,for several cycles,of the oxygen parameter x and the occupancy rate of Si in octahedron site,i.e.,the iversion degree u,the final result is R=0.077,when x=0.379A and u=27.5%,with the structural formula (Fe1.725 Si0.275)VI(Si0.725Fe0.275)IV O4 and atomic distances(Fe,Si)VI-O=2.022 A and (Si,Fe)IV-O=1.836A,Meanwhile,the Moessbauer spectroscopic analysis of the sample was conducted and the results obtained are in good agreement with those of X-ray structural analysis ,This paper focuses on the phase transformation and the properties of bonds of α-Fe2SiO4→γ-Fe2SiO4. 相似文献
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Please?refer?to?the?attachment(s)?for?more?details. 相似文献
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In the Phanerozoic, there are three major geological boundaries: Precambrian/Cambrian.Permian/Triassic and Cretaceous/Tertiary. Studies of these boundaries in China and over the world stronglysuggest that they have the following similar features: mass extinctions of many taxa, positive anomalies ofplatinum-group metals, and abrupt changes of stable isotopes (δ~(13)C). It is quite probable that these were theconsequences of some rare catastrophic events of extraterrestrial origin. Hence, the three above-mentionedmass extinction events may be regarded as key indicators for the division of the geological history of thePhanerozoic. 相似文献
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Study on the Sr,Nd,Pb and O Isotopes of Basic Dyke Swarms in the Wudang Block and Basic Volcanics of the Yaolinghe Group 总被引:1,自引:1,他引:1
The Sr,Nd and Pb isotopic characteristics of the Wudang basic dyke swarms and basic volcanics of the Yaolinghe Group show that they were derived from the same multi-component mixing source in the mantle.The Wudang basic dyke swarms have(^87Sr/^86Sr)i=0.6905-0.7061,εNd(t)=-1.9-5.0,△^208Pb/^204Pb=35.49-190.26,△^207Pb/^204Pb=Th/Ta and a wide range of La/Yb ratios;and the basic volcanics of the Yaolinghe Group have(^87Sr/^86Sr)i=0.6487-0.7075,εNd(t)=0.11-3.94,△^208Pb/^204Pb=-81.58-219.95,△^207Pb/^204Pb=4.44-16.68and higher Th/Ta and La/Yb ratios,indicating that their source is a mixture of DM and EMⅡ,and the basic volcanics of the Yaolinghe Group were contaminated by crust materials en rout to the surface.Based on the geochemical features of continental tholeiitic basalts and being products of differen tacies derived from the same source,it can be concluded that an important rifting event in the South Qinling basement block occurred during Neoproterozoic,followed by a setting of oceanic basic in the Early Paleozoic. 相似文献
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《Chemie der Erde / Geochemistry》2014,74(4):735-747
In recent years, voices in Jordan became lauder to exploit the fresh to brackish deep groundwater overlain by fresh groundwater bodies. In this article the implications of such a policy on the existing fresh water bodies are worked out through studying the sources of salinity in the different aquifer systems and the potentials of salinity mobilization by artificial changes in the hydrodynamic regimes. It is concluded that extracting the groundwater of deep aquifers overlain by fresh water bodies, whether the deep groundwater is fresh to brackish, brackish or salty, is equivalent to extracting groundwater from the overlying fresh groundwater bodies because of the hydraulic connections of the deep and the shallow aquifers’ groundwaters. The consequences are even more complicated and severe because exploiting the deep groundwater containing brackish or salty water will lead to refilling by fresh groundwater leaking from the overlying aquifers. The leaking water becomes salinized as soon as it enters the pore spaces of the emptied deep aquifer matrix and by mixing with the deep aquifer brackish or saline groundwater. Therefore, the move to exploit the deep groundwater is misleading and damaging the aquifers and is unjust to future generation's rights in the natural wealth of Jordan or any other country with similar aquifers’ set-up. In addition, desalination produces brines with high salinity which cannot easily be discharged in the highlands of Jordan (with only very limited access to the open sea) because they will on the long term percolate down into fresh water aquifers. 相似文献
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The new type of copper deposits concerned with in this paper are vein copper deposits found in the Lanping-Simao Rift Basin, Yunnan,China. As is indicated by H,O,C,S,Pb and Sr isotopes, water and mineralizers in the ore-forming fluids were derived from heated meteoric water and mantle, respectively.The metallic elements(Cu,Ag,Pb,Zn,As,Sb,Fe,REE,etc.)are characterized by a mixed source from the crust and the mantle. 相似文献
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XU Jiandong QU Guosheng Institute of Geology China Seismological Bureau Beijing PRCand Robert D. JACOBI Department of Geology State University of New York at Buffalo USA 《《地质学报》英文版》1999,73(4)
The Cantor's dust theory is applied to investigate the scaling properties of the spatial distribution of natural fractures obtained from detailed scanline surveys of 27 field sites in the Appalachian Plateau of western New York, USA. The results obtained in this study indicate: 1) fracture spacing is characterized by fractal and multifractal properties. On small scales analyses yield an average fractal dimension of 0.15, which suggests a very high degree of clustering. In contrast, on large scales, fractures tend to be more regular and evenly distributed with an average fracture dimension of 0.52; 2) fractal dimension varies with different sets in different orientations, which can be attributed to interactions between pre-existing fractures and younger ones, as well as variations of the intensity of the stresses under which the fractures were formed; 3) a time sequence of fracture set formation can be proposed based on fractal and multifractal analyses, which consists of (from old to young): N-S, NW, EN 相似文献
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Xu Ruisong Guangzhou New Technology Institute of Geology Academia Sinica Jiang Minxi 《《地质学报》英文版》1992,66(4)
The vegetation has been poisoned by gold in the western Guangdong-Hainan region. The gold content ofthe leaves there is as high as 10-1961 times the abundance, the chlorophyll content is 10%-30% lower thanthat of the vegetation in metamorphic terrains and 10%-20% higher than that in granite terrains, and thecarotenoid content is 10%-44% lower than the background value. The water content of leaves is 10% to 20%lower than the background value. The cells of leaves are deformed and broken. The leaf surface shows colourspots and becomes yellow or dark green. The spectral reflectance of the leaf surface is 5%-30% higher than thebackground value: the spectral shape has shifted 5-15 nm to the short wavelength. The gray scales of eanopyon images of Landsat TM and airborne imaging scanner (AIS) are 10%-100% higher than the backgroundvalues. On Landsat TM and AIS false colour images, plants poisoned by gold display a yellow color, whichdisinguishes them from background plants. According to the spectral and image features of goldbiogeochemical effects, the author has constructed a gold information system and expert prediction system,and thus two gold target areas and two gold prospect areas have been identified rapidly, economically andaccurately in the western Guangdong-Hainan region which is extensively covered by vegetation. 相似文献
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Zavodchikova Maria 《中国地质大学学报(英文版)》1994,(1)
BasicFactsConcerningStrengthofSandstone¥ZavodchikovaMaria(Sankt-PetersburyMiningInstitute,Sankt-Petersburg199026;)(Eepartment... 相似文献