Time-resolved XAS to study laser shock-induced transformation from siderite to magnetite

Siderite (FeCO3) is a common carbonate mineral in iron-bearing sedimentary settings and soils. It is present on Earth in a large variety of environments, which can be targets of impacts, and it has also been identified in meteorites. Two previous studies on natural siderite have demonstrated the shock-induced decomposition of siderite into iron oxides and carbon-bearing species that could explain the origin of magnetite in the Martian meteorite ALH84001 as due to a shock event. Both studies have been performed on recovered samples and give no clues on the timing and mechanisms of this transformation (e.g. peak shock or adiabatic release). In this proposal, we aim at in-situ observation of such transformation by time-resolved X-ray Absorption Spectroscopy during laser shock compression by exploiting the capability of the new High-Power Laser Facility (HPLF) at the ESRF.