X-ray nanoCT characterisation of petrologically diverse micrometeorites.

Micrometeorites (MMs) are 4.5 billion years old dust size particles (<300 micrometers) derived from the comet-forming region. When they enter Earth’s atmosphere, MMs experience various degrees of heating that change their original texture and composition. Some remain intact while others are fully molten. Unmolten, pristine MMs provide a unique opportunity to directly study the most primitive material in the Solar System. However, distinguishing between pristine and molten MMs using standard petrological techniques partially consumes the material, which prevents further investigation to extract meaningful isotopic data. Thus, we propose to use X-ray nanotomography (nanoCT) on beamline ID16B to non-destructively obtain 3D petrological and textural characterization of a set of 15 MMs, enabling us, for the first time, to determine and compare their nucleosynthetic isotope composition with that of planets and asteroids to test Solar System formation models.