Electromagnetic induction modelling based on satellite magnetic vector data   总被引：1，自引：0，他引：1  

Zden&#;k Martinec  Heather McCreadie 《Geophysical Journal International》2004,157(3):1045-1060

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Three-dimensional imaging of shear wave velocity in the uppermost 30 m of the soil column in Anchorage, Alaska   总被引：1，自引：0，他引：1  

José Badal  Utpal Dutta  Francisco Serón  Niren Biswas 《Geophysical Journal International》2004,158(3):983-997

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The Application of ARGO Data to the Global Ocean Data Assimilation Operational System of NCC   总被引：11，自引：0，他引：11       下载免费PDF全文

LIU Yimin  ZHANG Renhe  YIN Yonghong  NIU Tao 《Acta Meteorologica Sinica》2005,19(3):355-365

1. Introduction It is well-known that the state of ocean plays very important role in the climate change. But there is a paucity of the ocean observation data. The data distri- bution in the space, time and different components is very inhomogeneous, even in some areas, there are no any observation data. Hence, it brings some diffcul- ties to the scientists to study many problems relevant to ocean. This situation has been being changed since ARGO (Array for Real-time Geostrophic Oceanogra-…  相似文献   

Sorption of Eu~(3+) onto nano-size silica-water interfaces     

HU Ping    YIN Xiulan  ZHAO Linghu & LI Dien . Department of Earth Sciences  China University of Geosciences  Wuhan  China  . Northeastern Illinois University  Chicago  IL  USA  . China Institute of Geo-Environmental Monitoring  Beijing  China  . Division of Chemistry  Los Alamos National Laboratory  Los Alamos  NM  USA 《中国科学D辑(英文版)》2005,48(11)

A large amount of nuclear wastes has been pro-duced due to nuclear weapon development and nuclear electricity generation. One possible resolution for the disposal of the nuclear wastes is to seal them in an underground repository, which requires detailed knowledge on the mobility, chemical behavior and immobilization of radionuclides in underground water. In addition, toxic heavy metals are extensively present in ground and underground water, how to immobilize and remedy these toxic heavy meta…  相似文献   

3-D modelling and analysis of Dst C-responses in the North Pacific Ocean region, revisited     

Alexei Kuvshinov  Hisashi Utada  Dmitry Avdeev  Takao Koyama 《Geophysical Journal International》2005,160(2):505-526

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3D and 4D controls on carbonate depositional systems: sedimentological and sequence stratigraphic analysis of an attached carbonate platform and atoll (Miocene, Níjar Basin, SE Spain)     

GEORG WARRLICH†  DAN BOSENCE†  DAVE WALTHAM† 《Sedimentology》2005,52(2):363-389

This study investigates the controls on three-dimensional stratigraphic geometries and facies of shallow-water carbonate depositional sequences. A 15 km² area of well-exposed Mid to Late Miocene carbonates on the margin of the Níjar Basin of SE Spain was mapped in detail. An attached carbonate platform and atoll developed from a steeply sloping basin margin over a basal topographic unconformity and an offshore dacite dome (Late Miocene). The older strata comprise prograding bioclastic (mollusc and coralline algae) dominated sediments and later Messinian Porites reefs form prograding and downstepping geometries (falling stage systems tract). Seven depositional sequences, their systems tracts and facies have been mapped and dated (using Sr isotopes) to define their morphology, stratigraphic geometries, and palaeo-environments. A relative sea-level curve and isochore maps were constructed for the three Messinian depositional sequences that precede the late Messinian evaporative drawdown of the Mediterranean. The main 3D controls on these depositional sequences are interpreted as being: (i) local, tectonically driven relative sea-level changes; (ii) the morphology of the underlying sequence boundary; (iii) the type of carbonate producers [bioclastic coralline algal and mollusc-dominated sequences accumulated in lows and on slopes of < 14° whereas the Porites reef-dominated sequence accumulated on steep slopes (up to 25°) and shallow-water highs]. Further controls were: (iv) the inherited palaeo-valleys and point-sourced clastics; (v) the amount of clastic sediments; and (vi) erosion during the following sequence boundary development. The stratigraphy is compared with that of adjacent Miocene basins in the western Mediterranean to differentiate local (tectonics, clastic supply, erosion history, carbonate-producing communities) versus regional (climatic, tectonic, palaeogeographic, sea-level) controls.  相似文献   

Directional dependence of P- and S-wave propagation and polarization in foliated rocks from the Kola superdeep well: Evidence from laboratory measurements and calculations based on TOF neutron diffraction   总被引：1，自引：0，他引：1  

T.I. Ivankina  H.M. Kern  A.N. Nikitin 《Tectonophysics》2005,407(1-2):25-42

We have measured P- and S-wave velocities on two amphibolite and two gneiss samples from the Kola superdeep borehole as a function of pressure (up to 600 MPa) and temperature (up to 600 °C). The velocity measurements include compressional (Vp) and shear wave velocities (Vs1, Vs2) propagating in three orthogonal directions which were in general not parallel to inherent rock symmetry axes or planes. The measurements are accompanied by 3D-velocities calculations based on lattice preferred orientation (LPO) obtained by TOF (Time Of Flight) neutron diffraction analysis which allows the investigation of bulk volumes up to several cubic centimetres due to the high penetration depth of neutrons. The LPO-based numerical velocity calculations give important information on the different contribution of the various rock-forming minerals to bulk elastic anisotropy and on the relations of seismic anisotropy, shear wave splitting, and shear wave polarization to the structural reference frame (foliation and lineation). Comparison with measured velocities obtained for the three propagation directions that were not in accordance with the structural frame of the rocks (foliation and lineation) demonstrate that for shear waves propagating through anisotropic rocks the vibration directions are as important as the propagation directions. The study demonstrates that proper measurement of shear wave splitting by means of two orthogonal polarized sending and receiving shear wave transducers is only possible when their propagation and polarization directions are parallel and normal to foliation and lineation, respectively.  相似文献   

Multi-dimensional Seismic Response Analysis of Base-Isolated Frame Structure with 3D Isolator   总被引：1，自引：0，他引：1  

XiongShishu HuangLiting ChenJinfeng SuJingsu 《中国地质大学学报(英文版)》2005,16(1):66-71,78

INTRODUCTIONAs a new and effective method for withstandingthe horizontal component of earthquake motion on abuilding structure, the base isolation technique hascome to the engineering application phase ( Hu,1988). However, for some important buildings andfoundation facilities in an earthquake region, it is im portant to consider the effects of 3D aseismatic analy sis, including the vertical component, due to themulti dimensional characteristics of earthquakes (Suand …  相似文献   

Whole-rock and mineralogical composition of Phanerozoic ooidal ironstones: Comparison and differentiation of types and subtypes   总被引：2，自引：0，他引：2  

Arno Mücke  Farhad Farshad 《Ore Geology Reviews》2005,26(3-4):227-262

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Geochemistry and Crustal Evolution of Volcano-sedimentary Successions and Orthogneisses in the São Gabriel Block, Southernmost Brazil — Relics of Neoproterozoic Magmatic Arcs     

K. Saalmann  M.V.D. Remus  L.A. Hartmann 《Gondwana Research》2005,8(2):143-161

Precambrian metaplutonic rocks of the São Gabriel block in southernmost Brazil comprise juvenile Neoproterozoic calc-alkaline gneisses (Cambaí Complex). The connection with associated (ultra-)mafic metavolcanic and metasedimentary rocks (Palma Group) is not well established. The whole complex was deformed during the Brasiliano orogenic cycle. Both metasedimentary and metavolcanic rocks as well as metaplutonic rocks of the Cambaí Complex have been sampled for geochemical analyses in order to get constraints on the tectonic setting of these rocks and to establish a tectonic model for the São Gabriel block and its role during the assembly of West-Gondwana. The major element compositions of the igneous rocks (Palma Group and Cambaí Complex) indicate a subalkaline character; most orthogneisses have a calc-alkaline chemistry; many metavolcanic rocks of the Palma Group show signatures of low-K tholeiitic volcanic arc basalts. Trace element data, especially Ti, Zr, Y, Nb, of most igneous samples from both the lower Palma Group and the Cambaí Complex indicate origin at plate margins, i.e., in a subduction zone environment. This is corroborated by relative enrichment in LREE, low contents of Nb and other high field strength elements and enrichment in LILE like Rb, Ba, and Th. The data indicate the possible existence of two suites, an oceanic island arc and a continental arc or active continental margin. However, some ultramafic samples of the lower Palma Group in the western São Gabriel block indicate the existence of another volcanic suite with intra-plate character which possibly represents relics of oceanic island basalts (OIB). Trace element data indicate contributions from andesitic to mixed felsic and basic arc sources for the metasedimentary rocks. The patterns of chondrite- and N-MORB-normalized spider diagrams resemble the patterns of the igneous rocks, i.e., LILE and LREE enrichment and HFS depletion. The geochemical signatures of most igneous and metasedimentary samples and their low (⁸⁷Sr/⁸⁶Sr)_t ratios suggest only minor contribution of old continental crust.A geotectonic model for the São Gabriel block comprises east-ward subduction and following accretion of an intra-oceanic island arc to the eastern border of the Rio de la Plata Craton at ca. 880 Ma, and westward subduction beneath the newly formed active continental margin between ca. 750 and 700 Ma. The São Gabriel block represents relics of an early Brasiliano oceanic basin between the Rio de la Plata and Kalahari Cratons. This ocean to the east of the Rio de la Plata Craton might be traced to the north and could possibly be linked with Neoproterozoic juvenile oceanic crust in the western Brasília belt (Goiás magmatic arc).  相似文献