Meteorites condensation sequence

The process of condensation of minerals in the early solar nebula has long been invoked to explain the chemistry and mineralogy of primitive chondritic meteorites (e.g. Cameron 1963). Their observed bulk compositions show volatile-element depletions that are clearly smooth functions of calculated condensation temperature in a gas of solar composition (Davis 2006). Despite this success in explaining the bulk composition of chondrites, the diverse mineralogy of these bodies is not reproduced well in the condensation sequence calculations. To date, there is no incontrovertible evidence for direct condensation of rocky meteoritic material in the... 

Petaev M. I. and Wood J. A. (1998a) The CWPl model of nebular condensation effects of pressure on the condensation sequence. Meteorit. Planet. Sci. 33, A122. 

Condensation calculations in which the thermodynamic equilibrium condensate mineral assemblage is calculated as a function of temperature in a gas of fixed pressure and composition (usually solar) provide an extremely useful framework for interpreting bulk compositions of CAIs, chondrules, meteorites, and planets. Calculations of this sort date back to Urey (1952). Lord (1965) and Larimer (1967) calculated gas-solid equilibria for solar system composition, but did not correct the gas for removal of condensed material. The first detailed high-temperature condensation sequence was defined by Grossman (1972). The results of a calculation of Yoneda and... 

While there certainly must have been complications, such as radial mixing of material and non-equilibrium condensation and grain destruction, the equilibrium condensation sequence is generally consistent with the observed properties of the planets and meteorites. 

The analysis of the statistical or preferred orientation of the crystallites in solid polycrystaUine materials is commonly referred to as texture analysis. Again, the diffraction technique allows the definition of the relationship between a microscopic property, i.e. the orientation of the crystallites defined as coherent diffraction domains, and the macroscopic physical properties of the crystal aggregate. Texture studies are of course crucial in the characterization of oriented synthetic materials such as cold-rolled metals or oxide thin films, but they are also of great relevance in the study of the formation processes of mineral assemblages. As an example, the texture features of olivine or pyroxene minerals in meteoritic chondrules yield information on the early condensation sequence... 

The evolution of meteorites prior to their arrival on the Earth can be subdivided into a sequence of events that started with nucleosynthesis of atoms in stars followed by condensation of solid particles in the solar nebula and the accretion of the particles into the meteorite parent-bodies (Faure and Mensing 2007). These parent bodies were heated by the decay of unstable atoms which caused them to differentiate under the influence of their own gravitational fields into a metallic core, a silicate mantle, and a crust that was covered by a layer... 

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