Accession Number : AD0771169

Title :   Determination of the Effect of Pressure on the Molar Volumes of Ferromagnesian Olivine by X-Ray Diffraction.

Descriptive Note : Final rept. 30 Apr 70-31 May 73,


Personal Author(s) : Ahrens,Thomas J.

Report Date : 27 OCT 1973

Pagination or Media Count : 10

Abstract : The range of research problems pursued under this program has delat largely with the consitution and chemical equilibrium in the rocks of the upper mantle and lower crust of the earth. Specifically studied was the effect of high shock pressure on rhodonite, MnSiO3, a mineral which is a close structural analog of the pyroxene of the upper mantle. The diffusion rate of cations in mantle minerals (olivine and garnet) were examined to attempt to relate this phenomenon to the rates of phase changes in the rocks of the lower crust and mantle. Using thermochemical data the author has derived the distribution of Fe(++) and Mg(++) between coexisting phases as a function of temperature and depth. These results have led to new conclusions as to the total iron content and temperatures in the upper mantle. (Modified author abstract)

Descriptors :   *Minerals, *Earth mantle, Pressure, Silicates, Diffusion, Ions, Iron, Magnesium, Manganese, Loads(Forces), Shock, Earth crust, Phase transformations, X ray diffraction

Subject Categories : Geology, Geochemistry and Mineralogy

Distribution Statement : APPROVED FOR PUBLIC RELEASE