The experimental studies on electrical con-ductivities and P-wave velocities of anortho-site at high pressure and high temperature   总被引：1，自引：0，他引：1  

白利平  杜建国  刘巍  周文戈 《地震学报(英文版)》2002,15(6):667-676

Introduction The measurements of the compressional wave velocity and electrical conductivity of minerals and rocks are of fundamental importance to look into the earths interior, including composition, geotherm, generation and distribution of fluids and melts. Hydrous minerals formed by metamatu-siom are abundant within the earth. Previous studies have been carried out on the dehydration effect on the electrical conductivity and wave velocity of rocks such as serpentine, amphibole, most of whi…  相似文献   

区域可持续发展评价:进展与展望   总被引：55，自引：4，他引：55  

李利锋  郑度 《地理科学进展》2002,21(3):237-248

可持续发展的评价是目前可持续发展研究的热点和前沿。当前评价可持续发展的单项指标和指标体系在指标与可持续性的关系、指标权重的选择、指标的定量化、可持续性的总体判别方法、资本替代性与替代速度、指标阈值的确定等方面具有不同的局限性 ,这也是可持续发展评价的主要难点。可持续发展的评价必然要落实到不同尺度的空间地理单元上 ,区域发展是评价的对象 ,因而可持续发展的评价必然具有显著的区域性 ,不同区域的评价指标或指标体系必然会有所不同。社会、经济与人口的发展是人类社会发展的主要目标 ,而发展的可持续性依赖于自然环境的质量 ,包括自然资源的再生或替代、生命支持系统与生物多样性的维持或改善。据此 ,论文构建了区域可持续发展评价的理论框架和发展——可持续性二维评价坐标体系 ,并提出了“自上而下”和“自下而上”的指标遴选方法。  相似文献   

Uniform postglacial slip-rate along the central 600 km of the Kunlun Fault (Tibet), from ²⁶Al, ¹⁰Be, and ¹⁴C dating of riser offsets, and climatic origin of the regional morphology     

Jerome Van Der Woerd  Paul Tapponnier  Frederick J. Ryerson  Anne-Sophie Meriaux  Bertrand Meyer  Yves Gaudemer  Robert C. Finkel  Marc W. Caffee  Zhao Guoguang  Xu Zhiqin 《Geophysical Journal International》2002,148(3):356-388

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Oxydation expérimentale de Fe-tourmalines et corrélation avec une déprotonation des groupes hydroxyleAnnealing in oxidising conditions of Fe-tourmalines and correlated deprotonation of OH groups     

Yves Fuchs  Martine Lagache  Jorge Linares 《Comptes Rendus Geoscience》2002,334(4):245-249

Annealing at 400?T?600 °C (40?P?60 MPa and HM buffer-controlled f(O₂)) of tourmalines synthesised at the same T and P with NNO buffer induces an oxidation of Fe²⁺ into Fe³⁺ in some Y sites only (Mössbauer Spectroscopy data). Annealing in the same conditions of natural tourmalines is consistent with these results. FTIR spectroscopy shows that oxidation of Fe²⁺ into Fe³⁺ is charge-balanced by deprotonation of the external OH₍₃₎ groups. To cite this article: Y. Fuchs et al., C. R. Geoscience 334 (2002) 245–249.  相似文献   

Structure cristalline d'une ménéghinite naturelle pauvre en cuivre,Cu_0,58Pb_12,72(Sb_7,04Bi_0,24)S₂₄Crystal structure of a Cu-poor natural meneghinite,Cu_0.58Pb_12.72(Sb_7.04Bi_0.24)S₂₄     

Yves Moëlo  Pierre Palvadeau  Nicolas Meisser  Alain Meerschaut 《Comptes Rendus Geoscience》2002,334(8):529-536

Cu-poor meneghinite from La Lauzière Massif (Savoy, France) has the composition (electron microprobe) (in wt%): Pb 59.50, Sb 20.33, Bi 1.19, Cu 0.87, Ag 0.05, Fe 0.03, S 17.62, Se 0.05, Total 99.64. Its crystal structure (X-ray on a single crystal) was solved with R1=0.0506, wR2=0.1026, with an orthorhombic symmetry, space group Pnma, and a=24.080(5) Å, b=4.1276(8) Å, c=11.369(2) Å, V=1130.0(4) Å³, Z=4. Relatively to the model of Euler and Hellner (1960), this structure shows a significantly lower site occupancy factor for the tetrahedral Cu site (0.146 against 0.25). Among the five other metallic sites, Bi appears in the one with predominant Sb. Developed structural formula: Cu_0.15Pb₂(Pb_0.53Sb_0.47)(Pb_0.46Sb_0.54)(Sb_0.75Pb_0.19Bi_0.06)S₆; the reduced one: Cu_0.58Pb_12.72(Sb_7.04Bi_0.24)S₂₄. The formation of such a Cu-poor variety seems to be related to specific paragenetic conditions (absence of coexisting galena), or to crystallochemical constraints (minor Bi). To cite this article: Y. Moëlo et al., C. R. Geoscience 334 (2002) 529–536.  相似文献   

青藏公路铁路沿线生态系统特征及道路修建对其影响   总被引：36，自引：2，他引：36  

陈辉  李双成  郑度 《山地学报》2003,21(5):559-567

根据2001—08和2002—08月野外调查数据及2001年1：100万中国植被图、1996年1：400万青藏高原植被区划图和2000年青藏铁路沿线自然保护区分布及功能区界调整图，以青藏公路铁路沿线植被生态系统为研究对象，运用ARCVIEW和ARC／INFO软件研究青藏公路铁路建设对沿线生态系统结构的影响，结论如下：①青藏公路铁路南北跨越9个纬度，东西跨越12个经度，共穿越青东祁连山地草原地带、柴达木山地荒漠地带、青南高寒草甸草原地带、羌塘高寒草原地带、果洛那曲高寒灌丛草甸地带和藏南山地灌丛草原地带6个自然区，对植被类型的统计结果显示了地带性。②青藏公路铁路的建设对生态系统产生直接的切割，使景观更加破碎。③青藏公路铁路的建设直接破坏沿线植被生态系统(主要为50m缓冲区内)，年损失总净初级生产量为30504．62t，损失总生物量432919．25～1436104．3t／a。损失总净初级生产量占1km缓冲区年净初级生产量535005．07～535740．11t／a的百分比为5．70％，占10km缓冲区年净初级生产量3408950．45～3810480．92t／a的0．80～0．89％；损失生物量占1km缓冲区生物总量7502971．85～25488342．71t／a的5．70％，占10km缓冲区总生物量43615065．35～164150665．37t／a的0．80％～0．89％。  相似文献   

单道扫描电感耦合等离子体发射光谱法测定地质样品中的微量稀土元素     

郭振华  张立英  杜百娟 《化工矿产地质》2003,25(1):57-60

采用Na_2O_2熔融矿样,水提取,加三乙醇胺、EGTA做掩蔽剂。经氢型阳离子交换树脂交换分离富集稀土元素,由于选择了合适的仪器条件及测定波长,有效地消除了电感耦合等离子体发射光谱法(ICP-AES)测定过程中的基体干扰和光谱干扰。应用于地质样品中的稀土元素分析,获得了满意的准确度、精密度及检出限。  相似文献   

Integration and Sharing of Geo-spatial Data Based on Data Engine     

WUXiaofang CAIZhongliang WUGuofeng DUQingyun 《地球空间信息科学学报》2003,6(4):27-31

Through analyzing the principle of data sharing in the database system, this paper discusses the principle and method for integrating and sharing GIS data by data engine, introduces a way to achieve the high integration and sharing of GIS data on the basis of VCT in VC , and provides the method for uniting VCT into RDBMS in order to implement a spatial database with object-oriented data model.  相似文献   

高原交通干线对土地利用和景观格局的影响——以兰州至格尔木段为例   总被引：12，自引：1，他引：12  

阎建忠  张镱锂  刘林山  沈振西  刘燕华  郑度 《地理学报》2003,58(1):34-44

运用景观生态学方法和Arc/Info软件，研究1995年至2000年兰州至格尔木铁路沿线的区域土地利用和景观格局变化，分析交通干线（公路和铁路）的影响程度与范围。主要结果如下：（1）东线土地利用和景观格局没有发生显著变化，西线土地利用和景观格局变化较大；（2）东线缓冲带土地利用程度综合指数没有显著变化，西线缓冲带土地利用程度综合指数明显升高。缓冲带综合土地利用动态度的变化反映了交通干线的轴向影响规律；兰州至西宁铁路对土地利用变化的显著影响范围是5km，青藏铁路对土地利用变化的显著影响范围是7km；（3）9个城市缓冲带的土地利用变化分析表明：城市扩展主要发生在1km缓冲带内。  相似文献   

Rivers, chemical weathering and Earth's climate   总被引：4，自引：0，他引：4  

Bernard Dupr  Cline Dessert  Priscia Oliva  Yves Goddris  Jrme Viers  Louis Franois  Romain Millot  Jrme Gaillardet 《Comptes Rendus Geoscience》2003,335(16):1141-1160

We detail the results of recent studies describing and quantifying the large-scale chemical weathering of the main types of continental silicate rocks: granites and basalts. These studies aim at establishing chemical weathering laws for these two lithologies, describing the dependence of chemical weathering on environmental parameters, such as climate and mechanical erosion. As shown within this contribution, such mathematical laws are of primary importance for numerical models calculating the evolution of the partial pressure of atmospheric CO₂ and the Earth climate at geological timescales. The major results can be summarized as follow: (1) weathering of continental basaltic lithologies accounts for about 30% of the total consumption of atmospheric CO₂ through weathering of continental silicate rocks. This is related to their high weatherability (about eight times greater than the granite weatherability); (2) a simple weathering law has been established for basaltic lithologies, giving the consumption of atmospheric CO₂ as a function of regional continental runoff, and mean annual regional temperature; (3) no such simple weathering law can be proposed for granitic lithologies, since the effect of temperature can only be identified for regions displaying high continental runoff; (4) a general law relating mechanical erosion and chemical weathering has been validated on small and large catchments. The consequences of these major advances on the climatic evolution of the Earth are discussed. Particularly, the impacts of the onset of the Deccan trapps and the Himalayan orogeny on the global carbon cycle are reinvestigated. To cite this article: B. Dupré et al., C. R. Geoscience 335 (2003).  相似文献