Minerals such as apatite and zircon can incorporate and retain trace amounts of uranium and thorium. The spontaneous fission of uranium leads to energetic nuclear fragments, which induce narrow cylindrical trails of damage in the material just a few nm in diameter and several micrometers in length, so called ‘fission tracks’. Fission tracks are used for dating (geochronology) and constraining the thermal history (thermochronology) of geological samples with a commercial interest for oil exploration and to infer rates of tectonic uplift. The current dating technology utilizes chemical etching, which preferentially attacks the radiation-damaged volume in the undamaged bulk, to enlarge the nm-sized latent tracks such that they can be observed by optical microscopy. The currently lacking detailed understanding of the primary track damage and its dependence on relevant geological parameters can provide key information for geo- and thermochronology and interpretation of etched track distributions. We have demonstrated that synchrotron small angle x-ray scattering is well suited to study the primary track damage (for example see B. Afra et al. Phys Rev B (2011) 064116).
The project will study fission track formation and stability in a natural and synthetic apatites and zircon under a variety of geologically relevant conditions such as high pressure and temperature. Characterisation will be performed using synchrotron based small angle x-ray scattering (SAXS), transmission electron microscopy, x-ray diffraction and Rutherford backscattering spectroscopy. The emphasis will be on synchrotron SAXS at the Australian Synchrotron which enables in situ studies in high pressure and temperature environments.