摘要:

The distribution coefficients of alkali, alkaline earth, rare earth and a series of other elements between solid and liquid natural aluminosilicate systems can be estimated by a semi-empirical equation which can be derived by extension of Schuetze's incremental method for calculating oxygen isotope effects in silicate systems. This equation is used for investigating the partial melting of mantle wedge and subducted oceanic crust as potential sources of magmas giving rise to continental growth and for evaluating the history of igneous rocks. A series of geochemical criteria are derived for attributing igneous rocks to common parent magmas and for contributing to the estimation of the length of intrusive pathways. Particular attention is devoted to the evaluation of the geochemical behaviour of the rare earth elements.

ISSN:0021-1915    

DOI:10.1080/10256018508623476

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0021-1915    

DOI:10.1080/10256018508623477

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The distribution coefficients D of yttrium and the lanthanides between solid and liquid natural aluminosilicates can be described in terms of an extension of Schuetze's [1] incremental method for calculating oxygen isotope effects in silicate systems: log D = k + S · ΔI, where, ΔI the difference of the18O indices of the liquid and the solid phase and k and S coefficients to be determined empirically. The coefficient k accounts for the effect of the aggregational state, particularly the water content, S accounts for the effect of the degree of linking of the (Si, Al)O4tetrahedrons in the phases being in equilibrium on the distribution coefficients. The dependence of D, k and S on the atomic number can be understood in terms of the radii of the hydrated and not hydrated lanthanide ions. The constraints on the structural properties of magmas are discussed.

ISSN:0021-1915    

DOI:10.1080/10256018508623478

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

It is shown that the share of mantle, crustal and sedimentary substances in rocks and ore formations may be determined by isotope methods. On an example of Yakutian kimberlites a prove of mixing processes of mantle and crustal substances by means of strontium isotopes is delivered. Due to the high sensitivity of strontium to hydrothermal disturbances, the combined use of neodymium and strontium isotopes is believed to be a more perfect approach to the problem of determining the share of mantle substances. This is demonstrated by an application of isotopes to REE-minerals and alkaline rocks of Eastern Siberia and the Peoples Republic of Mongolia.

ISSN:0021-1915    

DOI:10.1080/10256018508623479

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Some new trends in the mathematical modelling of the lead isotope evolution in connection with the dynamic development of the earth's crust and with the exchange of materials between the crust and the mantle are discussed. The mathematical modelling of the derivatives with respect to time of U/Pb and Th/Pb ratiosinstead of μ and W give the possibility to describe a wider variety in change of μ and W with less unknown parameters. It is possible from the isotopic ratios of the lead in a sample to determine the two model ages (uranogenic and thorogenic) and a model parameter. The values of this parameter indicate the time of enrichment (ancient or younger) in U/Pb, which is an extremely important index for identifying the lead source-type. The differences in the uranogenic and the thorogenic model ages, due to the different geochemical behaviour and migration abilities of U and Th at metamorphic processes, provide additional information about the genesis of ores and the source-type of the lead.

ISSN:0021-1915    

DOI:10.1080/10256018508623480

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The electronic measuring system for radiotracer investigations of dynamic phenomena in industrial technological processes and environment protection has been described. The versatile and multi-functional system together with a digital minicomputer is a basic equipment of the specially designed mobily laboratory. The measuring system is currently being provided with the correlation analyses apparatus and the radio remote control system for communication between detectors and the central recording unit.

ISSN:0021-1915    

DOI:10.1080/10256018508623481

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

In order to investigate the adsorption of astatine and radon on a palladium surface some on- and off-line thermochromatographic experiments were carried out with2l0At- and220Rn-traccrs. The partial molar adsorption enthalpy for zero covering was experimentally found to beand. The results are compared with the theoretical and experimental values for other elements of the sixth period. The adsorption behaviour of At is in conformity with that of the p-metals on a palladium surface.

ISSN:0021-1915    

DOI:10.1080/10256018508623482

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Methods of separation of uranium and plutonium from irradiated nuclear fuels by extraction and ion exchange are described as well as methods of the determination of the element concentration or isotopic composition by spectrophotometry, coulometry, potentiometric titration, mass spectrometry, alpha spectroscopy and liquid scintillation counting. Advantages and disadvantages of the methods are discussed.

ISSN:0021-1915    

DOI:10.1080/10256018508623483

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0021-1915    

DOI:10.1080/10256018508623484

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor