Shedding light on ore deposits: A review of synchrotron X-ray radiation use in ore geology research

Geology researchers commonly confront critical research questions that require microscopic and sub-microscopic level observations (e.g., distribution of chemical elements of economic interest, nature of mineralising fluid) in order to explain the macroscale phenomena related to the characterisation of and controls on ore mineralisation. The emergence and technological evolution of fourth generation synchrotron radiation light sources render these facilities as important, but still largely under-utilised tools for advancing the frontiers of ore related research. To this end, the present contribution seeks to critically review and highlight the power and affordances of synchrotron X-ray techniques specifically to the fields of fundamental- and applied ore geology. The review introduces a range of commonly applied synchrotron X-ray techniques, before comprehensively highlighting past applications of synchrotron X-rays to a range of commodities and ore deposits types. A synthesis of this information highlights the historical importance of synchrotron X-ray techniques towards (1) understanding ore textures and chemical relationships at high (μm) spatial resolutions; (2) understanding coordination chemistry of metals in aqueous fluids at geologically relevant P-T conditions; (3) in situ evaluation of the chemistry and speciation of fluid inclusions; (4) evaluating the coordination environment of deleterious and economic trace metal substitutions in major mineral structures; and (5) understanding the biogeochemical behaviour and transformations of metals in the low temperature (supergene) mineralising environment. These applications as well as recommendations for future work are described in the hope that a greater diversity of ore geology researchers will incorporate synchrotron X-ray tools into their existing suite of analytical and experimental techniques.