黔西玄武岩铂族元素赋存状态及地质意义   总被引：2，自引：1，他引：2  

来雅文  王林根  肖国拾  甘树才  段国正 《吉林大学学报(地球科学版)》2005,35(5):607-610,631

在地球化学系统中,元素的亲合性是制约元素地球化学行为的基本属性,而赋存状态则反映元素质的属性.对黔西基性玄武岩原岩与流体包体中Pt、Pd的赋存状态进行研究,结果说明了利用元素亲合性对指导其赋存状态查定的重要性,同时表明了研究该地区玄武岩中同生流体包体中铂族元素对重演古流体中元素迁移与富集具有重要的理论与实际意义.  相似文献   

Solid-solute phase equilibria: From thermodynamic basis information to multicomponent systems     

Heinz Gamsjäger 《Aquatic Sciences - Research Across Boundaries》1993,55(4):314-323

Solubility equilibria in aqueous media are a powerful source of information on Gibbs energy functions of pure ionic compounds and solid-solutions. Because solid-solid phase transformations and/or recrystallizations are often much slower than equilibration between solids and solutes, it is sometimes possible to obtain reliable data from measurements on metastable systems.Thermodynamic quantities of geochemically and industrially important sparingly soluble metal oxides, hydroxides, carbonates and sulfides have been determined by solubility techniques. Activity coefficient variations of the reacting species are either minimized by the method of constant ionic media, or else corrected for by using the Pitzer equations. Measurements carried out at various fixed ionic strengthsI may be used to calculate the value of the solubility constantK _s ⁰ at infinite dilution. Given the availability of Pitzer parameters of sufficient quality, values ofK _s ⁰ extrapolated by this method lead to accurate Gibbs energies of formation. Moreover, when Pitzer parameters are known up to saturation, solubilities of highly soluble salts can easily be exploited for the calculation of Gibbs functions.A consistent set of equilibrium constants for the homogeneous and heterogeneous reactions occurring in the systems under investigation is used in the general Gibbs energy minimizing program ChemSage. Master variables for the depiction of the pertinent solid-solute phase diagrams are deduced from generalized Gibbs-Duhem equations. Application of the resulting data to geochemical and industrial problems is discussed.  相似文献   

Seasonal variations of adsorption/desorption equilibrium concentrations of P at water-sediment interface in different trophic states of Taihu Lake, China     

Xiangcan JIN Xia JIANG Dongmei LIU 《中国地球化学学报》2006,25(B08):164-164

Sediment from three different trophic states （Meiliang Bay, Xukou Bay and Gonghu Bay） in spring, summer, autumn and winter were collected and analyzed in Taihu Lake. At the same time, seasonal variations in adsorption/desorption equilibrium were investigated with corresponding sediments from these three trophic states, including adsorption efficiency, adsorption/desorption equilibrium concentration and equilibrium adsorption quantity. Variations of TP and P fractions＇ concentrations in the initial and end of adsorption experiment were also documented in order to find the most active P fractions. The following conclusions were obtained： （1） Concentrations of total phosphorus （TP） and its fractions in the sediments were coincided with the trophic state of corresponding overlying water, Meiliang Bay〉Gonghu Bay〉Xukou Bay. The Meiliang Bay located in the north of Taihu Lake is in the eutrophic state and belong to alga-type lake; the Xukou Bay located in the northeast of Taihu Lake is relatively clean lake region; the Gonghu Bay is located in the east of Taihu Lake is in the meso-trophic state. Fe-P concentrations in the Meiliang Bay, Gonghu By and Xukou Bay account for 35.1%-70.9%, 19.6%-26.8%, 16.5%-34.3% of TP, Ca-P account for 20.6%-43.7%, 40.7%-45.0%, 23.0%-41.1% and OP accounts for 15.3%-20.2%, 28.4%-37.4%, 23.6%-54.3%, which changes obviously in different seasons. Fe-P is the major fraction in the eutrophic lake region, which is significantly correlated with the TP concentrations. （2） Adsorption and desorption processes in these three lake regions varied with season.  相似文献   

我国氧化矿石银的赋存状态研究     

王静纯  余大良 《矿物岩石地球化学通报》2006,25(2):129-132

通过我国氧化矿石伴生银赋存特征的系统研究后指出,银以独立银矿物为主,少量为离子吸附银和类质同象银。银矿物组合及矿化系列、产出形态、结构、粒度及嵌布类型与原矿的成矿溶液性质和氧化程度有关。铅、锌、铁氧化物和残留的硫化物是银的主要载体矿物。银的配分受矿石氧化强度、矿物组合及嵌布形式控制。这一研究成果为有效提高银的回收率提供了科学依据。  相似文献   

Stages in gully evolution and self‐organized criticality     

Aleksey Sidorchuk 《地球表面变化过程与地形》2006,31(11):1329-1344

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Paramètres statistiques de la houle au large de la côte sud-aquitaine     

Stéphane Abadie  Rémi Butel  Hélène Dupuis  Christophe Brière 《Comptes Rendus Geoscience》2005,337(8):769-776

Statistical parameters of waves on the south Aquitaine coast have been determined by comparison of two datasets: in situ local measurements on a short duration and numerical simulation outputs from the WAVEWATCH III model over a period of 6 years and 9 months. Data and simulation results are well correlated in the case of the significant wave height, whereas in the case of the peak periods $(T_{\mathrm{p}})$ and directions $(D_{\mathrm{p}})$, this correlation is lower. This is due respectively to the intrinsic unstable nature of $T_{\mathrm{p}}$ and the narrow distribution of $D_{\mathrm{p}}$. An adjustment of simulation data on measurement is then used to give an evaluation of the wave statistics for the southern fraction of the French Atlantic coast. Eventually, the relationships between the three statistical variables $(H_{\mathrm{s}},T_{\mathrm{p}},D_{\mathrm{p}})$ are analysed in order to determine representative sea states. The classification obtained shows the predominance of swell regimes, distributed on a very narrow angular sector over wind sea regimes. To cite this article: S. Abadie et al., C. R. Geoscience 337 (2005).  相似文献   

Insights into oxygen-cation bonding in fresnoite-type structures from O <Emphasis Type="Italic">K</Emphasis>- and Ti <Emphasis Type="Italic">L</Emphasis><Subscript>23</Subscript>-electron energy-loss spectra and ab initio calculations of the electronic structure     

P. A.?van AkenEmail author  T.?H?che  F.?Heyroth  R.?Keding  R.?Uecker 《Physics and Chemistry of Minerals》2004,31(8):543-552

O K- and Ti L₂₃-core-loss spectra of fresnoite Ba₂TiSi₂O₈ (BTS) and Sr₂TiSi₂O₈ (STS), which is isotypic to BTS, have been measured by electron energy-loss spectroscopy (EELS). The energy-loss near-edge structures (ELNES) of the O K edge have been identified on the basis of theoretical simulations and interpretations of the X-ray absorption near-edge structures (XANES), which have been modelled in the framework of self-consistent full multiple-scattering (FMS) theory using FEFF8. Herewith, the K-absorption spectra of oxygen (E) and the local partial electron density of states (DOS) of all atoms have been calculated. For BTS, the observed spectral features in the O K-edge spectra are interpreted in terms of mixing between the central O p and neighbouring Ba 5d and 4f, Si 3p and 3d, and Ti 3d orbitals. The observed differences in the O K-edge spectra for STS and BTS can mainly be attributed to three properties: (1) The lack of high local partial Sr unoccupied DOS with 4f symmetry near the Fermi level compared to the high Ba 4f unoccupied DOS results in differences of overlapping O 2p – cation orbitals. (2) The differences in the ionic radii of Sr and Ba result in a larger unit cell for BTS and, thus, in larger oxygen-cation bonding distances. (3) In comparison to STS, the strength of the incommensurate 2-D structural modulation is significantly weaker in BTS, i.e. distortions of coordination polyhedra occur to a much lesser extent. All these effects alter the oxygen-cation hybridization and, hence, result in a variation of the O 1s p transition and consequently of the O K-edge spectral shape. The observed peak broadening in Ti L₂₃ ELNES of STS compared to BTS is correlated with strong displacive modulations hosted in STS.  相似文献   

Phonon density of states in iron at high pressures and high temperatures     

G. ?ShenEmail author  W. ?Sturhahn  E. E. ?Alph  J. ?Zhao  T. S. ?Tollenner  V. B. ?Prakapenka  Y. ?Meng  H.-R. ?Mao 《Physics and Chemistry of Minerals》2004,31(6):353-359

The phonon density of states (DOS) in iron has been measured in situ by nuclear resonance inelastic X-ray scattering (NRIXS) at high pressures and high temperatures in a resistively heated diamond anvil cell. The DOS data provide a variety of thermodynamic and elastic parameters essential for characterizing iron at depth in the Earth interior, such as average sound velocity, Debye temperature, atomic mean square displacement, average kinetic energy, vibrational entropy and specific heat. The NRIXS data were collected at 6, 20, and 29 GPa and at temperatures up to 920 K. Temperatures were directly determined from the measured spectra by the ratio of intensities of the phonon creation/annihilation side bands that are determined only by the Boltzmann factor. The change of the DOS caused by the structural transition from -Fe to -Fe is small and not resolvable within the experimental precision. However, the phonon energies in -Fe are clearly shifted to lower values with respect to - and -Fe. The temperature dependence of derived thermodynamic parameters is presented and compared with those obtained by Debyes model. The Debye temperatures that best describe the data decrease slightly with increasing temperature.  相似文献   

粤西水东弧形海岸海滩剖面的地貌状态     

陈子燊  李春初 《热带海洋学报》1993,(2)

对粤西水东弧形海岸长时段重复测量海滩剖面的因子分析说明了各特征岸段剖面的主要地貌状态。频域分析反映了各岸段海滩体积的月周振动峰值和对波能的响应特征。实测海滩剖面波动过程的计算则指示了当前各剖面的蚀积状态。  相似文献   

Optimal Precursors Triggering the Kuroshio Extension State Transition Obtained by the Conditional Nonlinear Optimal Perturbation Approach     

Xing ZHANG  Mu MU  Qiang WANG  Stefano PIERINI 《大气科学进展》2017,34(6):685-699

In this study, the initial perturbations that are the easiest to trigger the Kuroshio Extension(KE) transition connecting a basic weak jet state and a strong, fairly stable meandering state, are investigated using a reduced-gravity shallow water ocean model and the CNOP(Conditional Nonlinear Optimal Perturbation) approach. This kind of initial perturbation is called an optimal precursor(OPR). The spatial structures and evolutionary processes of the OPRs are analyzed in detail. The results show that most of the OPRs are in the form of negative sea surface height(SSH) anomalies mainly located in a narrow band region south of the KE jet, in basic agreement with altimetric observations. These negative SSH anomalies reduce the meridional SSH gradient within the KE, thus weakening the strength of the jet. The KE jet then becomes more convoluted, with a high-frequency and large-amplitude variability corresponding to a high eddy kinetic energy level; this gradually strengthens the KE jet through an inverse energy cascade. Eventually, the KE reaches a high-energy state characterized by two well defined and fairly stable anticyclonic meanders. Moreover, sensitivity experiments indicate that the spatial structures of the OPRs are not sensitive to the model parameters and to the optimization times used in the analysis.  相似文献