Shock metamorphism in plagioclase

Our life on Earth, how it started and what can affect it, is still debated. On the planetary scale, formation and the evolution of the Solar System is also not completely understood, but we know that impact events played an important role in all the stages of the history of the Solar System. Differentiated bodies, such as our Earth, have developed a crust, which is strongly affected by impact events. In very large events, global implication might affect life. A clear example is the Chicxulub impact event that happened in Mexico 65 million years ago, at the end of the Cretaceous, creating a structure about 200 km in diameter and possibly causing a mass extinction, where a large part of the living species on Earth at that time disappeared. The solidified crust of planetary bodies mostly consists of plagioclase. Plagioclase can be therefore considered an analogue of the whole crust. Impact events generate shock waves that induce permanent modifications in the matter. We propose to investigate impact-induced effects in plagioclase, in order to understand which implications these catastrophic events can have in the formation and evolution of the crust of planetary bodies, in particular the conditions for melting of plagioclase and the chemical and physical processes activated in the shocked plagioclase. As little is known about plagioclase response to the shock metamorphism, our study will fill the gap in knowledge, specially focussing on the control of the chemical composition and crystal lattice on the development of specific shock features. Natural samples, from impact structures on Earth and from shocked meteorites, which are a proxy for the crust of other differentiated bodies, together with experimentally produced samples, under controlled shock pressure, will be analysed, with a combination of traditional and new petrologic- mineralogical approach. Plagioclase has a relatively complex structure and only recently developed analytical techniques enable the investigation and quantification of shock effects in this mineral. Therefore, both traditional instruments, such as optical and electron microscope and microprobe, and instruments that are less commonly applied to this type of studies, such as cathodoluminescence and Raman spectroscopy, as well as numerical approach for quantifying shock effects will be used. This project will require the expertise and the facilities of different departments of the Center for Earth Sciences of the University of Vienna, in collaboration with the Natural History Museum of Vienna. Finally, a scientific team, highly specialised in shock metamorphism, will be permanently established in Vienna, combining mineralogy, petrology, geochemistry, and physics, and the PI will gain the necessary experience for applying for the "Habilitation".

No additional funding sources recorded.