A MULTI-PLATFORM APPROACH TO ORE MINERALOGY: ADVANCES AND FUTURE PROSPECTS

摘要

In the last decade, the rapid technological advancement of micro- and nanoimaging and microanalysis techniques has transformed the field of ore mineralogy. The improved spatial resolution and limit of detection of these techniques has allowed the physical and chemical signature of the minerals to be determined that would otherwise have been impossible in the not too distant past. The technological advancement of these techniques has met with a concurrent change to the way we approach analytical mineralogy. Increases in the sensitivity of analytical instruments now allows critical petrogenetic trace chemical data to be obtained from minerals that were otherwise impossible to analyse quantitatively with microbeam techniques. In situ nanoscale imaging and analytical characterisation is becoming an increasingly important field for understanding how the chemical signatures we measure at the micrometre-scale are distributed at the atomic level within the mineral. A complementary and crucial aspect of these imaging and analytical techniques has been the development of new geochronometers such as the U-Pb hematite geochronometer, allowing for important temporal information to be assigned to observable chemical changes. As a result, there is an increasing recognition that a holistic approach, encompassing both ore minerals and gangue, and across all spatial scales, is necessary. In the context of the ore deposit that hosts them, the chemical and structural characterisation of mineral assemblages can give important insights on fundamental questions of solid-state chemistry and ore-forming processes. It follows that broad regional- or deposit-scale genetic models can be tested and validated via observation and analysis of minerals down to the smallest scale, thus enabling improved exploration models. Increased volumes of data generated at different scales of observation on the same samples will in turn generate additional fundamental questions and catalyse further technological advancements. Fields likely to be the focus of future advancement include the atomic-scale distribution of metals within ore minerals, and the roles played by nanoparticles in that distribution. This includes observation of lattice-scale structural changes to minerals as they incorporate these metals as a response to changing physiochemical conditions.