TY - JOUR
T1 - Effect of grain growth on cation exchange between dunite and fluid
T2 - Implications for chemical homogenization in the upper mantle
AU - Ohuchi, Tomohiro
AU - Nakamura, Michihiko
AU - Michibayashi, Katsuyoshi
N1 - Funding Information:
Acknowledgments T.O. carried out the experiments and interpretation of the results. M.N. contributed to the theoretical calculations and discussion, and K.M. contributed to the EBSD analysis. We thank R. Dohmen and T. Hiraga for their critical reviews. This work was financially supported by the JSPS Postdoctoral Fellowship for Research Abroad awarded to T.O., a Grant-in-Aid for scientific research to M.N., the Global COE program of Ehime University, and the 21st century COE and the Global COE programs of Tohoku University.
PY - 2010
Y1 - 2010
N2 - The effect of grain growth on the cation exchange between synthesized forsterite aggregates (i. e., dunite) and nickel-rich aqueous fluid was evaluated experimentally at 1. 2 GPa and 1,200°C. The grain boundary (GB) migration caused nickel enrichment in the area swept by the GBs in a fashion similar to that reported for stable isotope exchange in the quartz aggregates. The progress of the grain growth resulted in an increase in the average nickel concentration in the dunites of up to ~80 times that was calculated for a system having stationary GBs. The overall diffusivity of the nickel along the wet GBs and interconnected fluid networks was found to be 6.5 × 10-19-6.7 × 10-18 m3/s, which is 4-5 orders of magnitude higher than the grain boundary diffusivity in the dry dunite. These results show that the grain growth rate is a fundamental factor in the evaluation of the time scale of chemical homogenization in the upper mantle.
AB - The effect of grain growth on the cation exchange between synthesized forsterite aggregates (i. e., dunite) and nickel-rich aqueous fluid was evaluated experimentally at 1. 2 GPa and 1,200°C. The grain boundary (GB) migration caused nickel enrichment in the area swept by the GBs in a fashion similar to that reported for stable isotope exchange in the quartz aggregates. The progress of the grain growth resulted in an increase in the average nickel concentration in the dunites of up to ~80 times that was calculated for a system having stationary GBs. The overall diffusivity of the nickel along the wet GBs and interconnected fluid networks was found to be 6.5 × 10-19-6.7 × 10-18 m3/s, which is 4-5 orders of magnitude higher than the grain boundary diffusivity in the dry dunite. These results show that the grain growth rate is a fundamental factor in the evaluation of the time scale of chemical homogenization in the upper mantle.
KW - Forsterite
KW - Grain boundary diffusion
KW - Grain boundary migration
KW - Grain growth
KW - Nickel
UR - http://www.scopus.com/inward/record.url?scp=77955171221&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77955171221&partnerID=8YFLogxK
U2 - 10.1007/s00410-009-0481-7
DO - 10.1007/s00410-009-0481-7
M3 - Article
AN - SCOPUS:77955171221
VL - 160
SP - 339
EP - 357
JO - Contributions of Mineralogy and Petrology
JF - Contributions of Mineralogy and Petrology
SN - 0010-7999
IS - 3
ER -