Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (7) Citing Articles via Google Scholar Google Scholar Articles by Zhao, Z.-F. Articles by zheng, Y.-F. Search for Related Content GeoRef GeoRef Citation

Diffusion compensation for argon, hydrogen, lead, and strontium in minerals: Empirical relationships to crystal chemistry

CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Science, University of Science and Technology of China, Hefei 230026, China

Correspondence: ^* E-mail: yfzheng{at}ustc.edu.cn

Inspection of available experimental data reveals log-linear compensation effects between activation energies and pre-exponential factors for Ar, H, Pb, and Sr diffusion in a wide array of minerals. As a result, diffusion of Ar, H, Pb, and Sr converges to the same rates, respectively, at isokinetic temperatures in these minerals. Ionic porosity, Z, defined as the fraction of the unit-cell volume in a mineral not occupied by ions, is a measure of atomic packing density in silicate, carbonate, and phosphate minerals. Experimental diffusion parameters exhibit first-order correlations with ionic porosity, which proxies for mean metal-oxygen bond length/strength in minerals. An empirical kinetics-porosity model systematizes Ar, H, Pb, and Sr diffusion in minerals for which experimental diffusion data exist. For Ar and H diffusion, linear correlations are documented between activation energy and total ionic porosity. Combination of these correlations with diffusional compensation effects, which are also documented, yields empirical relationships among elemental diffusivity, total ionic porosity, and temperature. Linear correlations are also observed between experimental diffusion coefficients for Pb and Sr at given temperatures and calculated ionic porosities. For most minerals, the empirical predictions are remarkably consistent with experimental data, which strengthens the link between crystal chemistry and diffusion kinetics.

Key Words: Diffusion kinetics • compensation effect • ionic porosity • crystal chemistry • geochronology • geothermometry • geospeedometry

This article has been cited by other articles:

				P. S. Dahl and K. A. Foland Concentric slow cooling of a low-P-high-T terrane: Evidence from 1600-1300 Ma mica dates in the 1780-1700 Ma Black Hills Orogen, South Dakota, U.S.A. American Mineralogist, August 1, 2008; 93(8-9): 1215 - 1229. [Abstract] [Full Text] [PDF]