Three-dimensional and microstructural fingerprinting of gold nanoparticles at fluid-mineral interfaces

Haoyang Zhou, Richard Wirth, Sarah A. Gleeson, Anja Schreiber, Sathish Mayanna - GFZ German Research Centre for Geosciences / Institute of Geological Sciences, Freie Universit├Ąt Berlin

Recent studies have identified gold nanoparticles in ores in a range of deposit types, but little is known about their formation processes. In this contribution, gold-bearing magnetite from the well-documented, world-class Beiya Au deposit, China, was investigated in terms of microstructure and crystallography at the nanoscale. We present the first three-dimensional (3D) focused ion beam/scanning electron microscopy (FIB/SEM) tomography of the distribution of gold nanoparticles in nanopores in the low-Si magnetite.

How Amira-Avizo Software is used

The 3D reconstruction was conducted with the software Avizo 7.0, but only the middle 600 SEM images were loaded to maximize the overlapping areas. Because of the low contrast of some nanopores to the background, the reconstructed results display locally high noise for nanopores. Except for this, the rendered nanopores basically match their distribution in the 2D SEM images.