Spinels to characterize Solar System source regions and constrain variations in the flux of extraterrestrial materials delivered to Earth
Every year, large amounts (40,000 metric tons) of extraterrestrial material arrive on the Earth, mostly as cosmic dust and micrometeorites, rarely as meteorites and exceptionally as crater- forming projectiles. Changes in the intensity and origin of this extraterrestrial flux is the source of much scientific debate. Unfortunately, most of the minerals present in extraterrestrial material weather away relatively quickly and do not survive geological timescales, limiting robust reconstructions of the extraterrestrial flux through time. Among the minerals present, the spinel group is most resistant to alteration, and consequently constitutes the best- preserved extraterrestrial phase. So far, the potential of spinel group minerals as tracers of the extraterrestrial flux and faithful recorders of the physical and chemical processes occurring in meteorite parent bodies, remains to be fully exploited. Recent advances in analytical techniques make it possible to now target these minute (10 μm) spinel crystals for in-depth mineralogical, geochemical and isotopic analyses. The primary aim of this project is to characterize crystallization conditions during atmospheric entry and/or in the parent body as well as meteoritic source materials. This knowledge will better constrain the origin of sedimentary relict spinels, providing a solid foundation to document possible changes in the extraterrestrial flux over extended geological timescales.
Micrometeorites from Antarctica, meteorites from Antarctica and Atacama desert, impact spherules from all over the world (US to Antarctica)
Spinel group minerals, extraterrestrial flux, micrometeorites, meteorites, impact spherules, ablation material