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Science 4 January 1991:
Vol. 251. no. 4989, pp. 67 - 70
DOI: 10.1126/science.251.4989.67
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Articles

Observational Evidence for a Possible New Diffusion Path

BRADLEY R. HACKER 1 and JOHN M. CHRISTIE 1

1 Department of Earth and Space Sciences, University of California, Los Angeles, CA 90024

Transmission electron microscopy of experimentally deformed amphibolite suggests that submicroscopic intracrystalline tubes formed around linear defects may be a previously unrecognized kind of diffusion pathway. Deformed and compositionally altered plagioclase and amphibole crystals include moderate densities of linear defects that morphologically resemble unit dislocations but display unusual contrast. During prolonged electron irradiation, the core regions of the defects expand to well-defined tubes that are sim20 nanometers in diameter. Both observations suggest that the regions about the defect cores are glassy and were filled with silicate-water fluid during the experiments. Intracrystalline transport along these tubes would likely be several orders of magnitude faster than traditionally conceived processes of solid-state volume diffusion, grain-boundary solvent transfer, and ordinary pipe diffusion along dislocation cores.

Submitted on June 12, 1990
Accepted on October 3, 1990


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Rates and Mechanisms of Isotopic Exchange.
D. R. Cole, D. R. Cole, and S. Chakraborty (2001)
Reviews in Mineralogy and Geochemistry 43, 83-223
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