Mg self-diffusion in pyrope garnet

Other| June 01, 1995 Mg self-diffusion in pyrope garnet Craig S. Schwandt; Craig S. Schwandt Sandia National Laboratories, Geochemistry Department, Albuquerque, NM, United States Search for other works by this author on: GSW Google Scholar Randall T. Cygan; Randall T. Cygan Search for other works by this author on: GSW Google Scholar Henry R. Westrich Henry R. Westrich Search for other works by this author on: GSW Google Scholar American Mineralogist (1995) 80 (5-6): 483–490. https://doi.org/10.2138/am-1995-5-609 Article history first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Craig S. Schwandt, Randall T. Cygan, Henry R. Westrich; Mg self-diffusion in pyrope garnet. American Mineralogist 1995;; 80 (5-6): 483–490. doi: https://doi.org/10.2138/am-1995-5-609 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyAmerican Mineralogist Search Advanced Search Abstract Mg self-diffusion coefficients were experimentally determined for natural pyrope-almandine garnet in a 1 atm CO-CO2 gas-mixing furnace at temperatures of 800–1000 °C. Diffusion couples consist of polished garnet crystals covered with a thin film of enriched stable-isotope oxide produced by high-vacuum thermal evaporation of 25MgO. Experiments conducted at quartz + fayalite + magnetite fO2 provide 25Mg diffusion coefficients as a function of temperature. The short diffusion penetration profiles (<2000 Å) in the garnet were analyzed by secondary ion mass spectrometry and ion microprobe using a depth profiling technique. The resulting self-diffusion coefficients are lower than the low-temperature data of other experimental studies. The activation energy and preexponential term derived from the experimental diffusion coefficients obtained at 800, 900, and 1000 °C are given by Ea = 294 ± 51 kJ/mol and log D0 = −8.0 ± 2.3 m2/s. The activation energy is similar to that obtained from other cation diffusion studies of garnet at low temperature. Additional experiments conducted at 1000 °C to determine 25Mg diffusion as a function of fO2 and composition are inconclusive. However, comparison of the results of the present study with previous data indicates that fO2 and mineral composition are important factors for the diffusion of cations in garnet. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.