The properties of natural materials are functions of complex deterministic sequences of interlinked physical and chemical processes that have operated over enormous scales of time and space.  Microanalysis, including X-ray mCT imaging, records snapshots, at the micron scale, of stages in such complex evolutionary histories. Iron ore, Australia’s largest export, is a prime example and in this talk I shall provide a framework for interpreting these snapshots in terms of the evolution of early microbial life more than 3 billion years ago and its control on atmosphere and ocean chemistry, large scale mountain building and more recent cycles of climate change. Natural gas and dinosaurs will appear along the way.

Here is a simple example of one such snapshot where the bright mineral is hematite (Fe2O3) and the grey is goethite (a mineral of variable composition but nominally ‘FeO(OH)’ but the sample is quite magnetic.