Séminaire Denis FOUGEROUSEA nanogeoscience approach to global Earth processes

Séminaire par Denis Fougerouse, Chercheur à l'Université de Curtin (Perth, Australie)

The study of nanometre compositional variations in minerals have the potential to yield fundamental insights into a range of geological and planetary processes associated with nucleation and mineral growth and the subsequent modification of mineral compositions by processes such as diffusion, deformation and recrystallization. However, the measurement of low abundance trace elements and isotopic compositions at the nanometre scale can only be achieved by atom probe tomography. Atom probe tomography is based on the controlled field-evaporation of atoms from a needle-shaped specimen (50-100 nm diameter at the apex) and produces 3-dimensionnal data at sub-nanometre resolution. The chemical information is given by time-of-flight spectrometry with comparable sensitivity across all elements of the periodic table.

The application of atom probe tomography to the geosciences has surged in recent years with published studies on a broad range of minerals including zircon, monazite, rutile, titanite, baddeleyite, plagioclase, calcite, pyrite, arsenopyrite, diamond and barite. In this presentation, we will highlight recent developments in the nanoscale geochemical and isotopic characterisation by atom probe tomography and highlight the exciting range of potential applications from both terrestrial and extra-terrestrial samples. A particular emphasis will be given on the development of nanogeochronology.