Transport and coarsening of gold nanoparticles in an orogenic deposit by dissolution-reprecipitation and Ostwald ripening

The formation of gold deposits, particularly high-grade zones, has been a long-standing question. This paper investigates the role of gold nanoparticles in the formation of the Kenty orogenic gold deposit in Ontario, Canada. Using focused ion beam technology and transmission electron microscopy, the authors provide evidence of gold nanoparticles trapped in iron oxides and rutile, and non-oriented attachment of gold nanoparticles to bulk gold, suggesting coarsening via Ostwald ripening. This process, involving secondary dissolution-reprecipitation, offers a mechanism for explaining the formation of high-grade ore zones in orogenic deposits.

E. C. G. Hastie, M. Schindler, D. J. Kontak, B. Lafrance