Earth elemental composition

Trueman, C.N., Behrensmeyer, A.K., Potts, R. and Tuross, N. (2006). High-resolution records of location and stratigraphic provenance from the rare earth element composition of fossil bones. Geochimica et Cosmochimica Acta 70 4343 1355. 

Bright C. A., Lyons T. W., MacLeod K. G., Glascock M. D., Rexroad C. B., Brown L. M., and Ethington R. L. Arguments against preservation of primary seawater signals in the rare-earth element compositions of biogenic (conodont) apatite. J. Sedim. Res. (submitted). 

Samuel J, Purlan S, Blanc G, Clauer N (1993) Trace- and rare-earth elements composition of different types of waters by ICP-MS. 7th E.U.G. Meeting, Terra Abstracts, 4-8 Avril (1993) Strasbourg (Prance), p 643... 

Rare earth element composition [data in ppm (wt)] of loesses. (Adapted from Taylor et al. 1983.)... 

An interesting variant of Group I is the determination of thorium in monazite concentrates.73 Here the variations that may occur in the chemical composition of the matrix leave its x-ray absorbance virtually unaltered. This simplicity is possible because the principal individual rare-earth elements present in the samples lie in the range of atomic numbers from 57 to 60, a range so small as to preclude marked variations in the over-all mass absorption coefficient. 

Table 8-2 Elemental composition by atoms of the Earth s crust"...

In each of the composition diagrams in Fig. 14.2, the numbers represent a series of reactions run at a defined composition and temperature. These are isometric sulfur slices through three-dimensional K/P/RE/S quaternary phase diagrams. As just one example of what we have studied. Table 14.1 identifies the compositions at each point and the resulting phase(s). We have rigorously studied how phase formation is dependent upon the compositions of reactions for the rare-earth elements Y, Eu, and La and we have also discovered key structural relationships between the rare-earth elements, indicating a significant dependence on rare-earth and alkali-metal size for sulfides and selenides. 

The summary of the bulk chemical compositions (major elements, minor elements, rare earth elements), Sr/ Sr (Farrell et al., 1978 Farrell and Holland, 1983), microscopic observation, and chemistry of spinel of unaltered basalt clarifies the tectonic setting of Kuroko deposits. Based on the geochemical data on the selected basalt samples which suffered very weak alteration, it can be pointed out that the basalt that erupted almost contemporaneously with the Kuroko mineralization was BABB (back-arc basin basalt) with geochemical features of which are intermediate between Island arc tholeiite and N-type MORE. This clearly supports the theory that Kuroko deposits formed at back-arc basin at middle Miocene age. 

Previous studies clearly indicated that the chemical compositions of geothermal waters are intimately related both to the hydrothermal alteration mineral assemblages of country rocks and to temperature. Shikazono (1976, 1978a) used a logarithmie cation-Cl concentration diagram to interpret the concentrations of alkali and alkaline earth elements and pH of geothermal waters based on thermochemical equilibrium between hydrothermal solution and alteration minerals. 

Chemical compositions of major elements (alkali, alkali earth elements. Si) in back-arc and midoceanic ridge hydrothermal solutions are not so different (Table 2.15). This is thought to be due to the effect of water-rock interaction. For example, Berndt et al. (1989) have shown that mQ i+ of midoceanic ridge hydrothermal fluids is controlled by anorthite-epidote equilibrium (Fig. 2.37). Figure 2.37 shows that /Mca2+/m + of back-arc hydrothermal fluids is also controlled by this equilibrium. 

Geological, mineralogical and geochemical features of these deposit types (distribution, age, associated volcanism, host and country rocks, fluid inclusions, opaque, gangue and hydrothermal alteration minerals, chemical features of ore fluids (temperature, salinity, pH, chemical composition, gaseous fugacity, isotopic compositions (O, D, S, Sr/ Sr, Pb), rare earth elements)) were summarized. 

The miniaturized Mossbauer instruments have proven as part of the NASA Mars Exploration Rover 2003 mission that Mossbauer spectroscopy is a powerful tool for planetary exploration, including our planet Earth. For the advanced model of MIMOS II, the new detector technologies and electronic components increase sensitivity and performance significantly. In combination with the high-energy resolution of the SDD, it will be possible to perform XRF analysis in parallel to Mossbauer spectroscopy. In addition to the Fe-mineralogy, information on the sample s elemental composition will be obtained. 

As a result of (1) (2) and (3), the closely fixed temperature of the Earth for 4.5 x 109 years, assisted by an atmosphere, allowed water to form and remain as a liquid on the surface as the sea. Both the atmosphere and the sea were restricted in element composition (see Chapter 1). 

The Piton de la Fournaise volcano (Indian Ocean) erupts basalts with chemical compositions that change with time. The rare-earth elements have been measured on eight dated historic lavas (Table 3.9 and Figure 3.7, Albarede and Tamagnan, 1988), and chondrite-normalized (Ce/Yb)N ratios over the time interval 1948-1985 are given in Table 3.9. Calculate an annual interpolation of these results. 

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