Atomic-scale age resolution of planetary events

作者：White L F^*; Darling J R; Moser D E; Reinhard D A; Prosa T J; Bullen D; Olson D; Larson D J; Lawrence D; Martin I

来源：Nature Communications, 2017, 8(1): 15597.

DOI：10.1038/ncomms15597

Resolving the timing of crustal processes and meteorite impact events is central to understanding the formation, evolution and habitability of planetary bodies. However, identifying multi-stage events from complex planetary materials is highly challenging at the length scales of current isotopic techniques. Here we show that accurate U-Pb isotopic analysis of nanoscale domains of baddeleyite can be achieved by atom probe tomography. Within individual crystals of highly shocked baddeleyite from the Sudbury impact structure, three discrete nanostructural domains have been isolated yielding average Pb-206/U-238 ages of 2,436 +/- 94Ma (protolith crystallization) from homogenous-Fe domains, 1,852 +/- 45Ma (impact) from clustered-Fe domains and 1,412 +/- 56Ma (tectonic metamorphism) from planar and subgrain boundary structures. Baddeleyite is a common phase in terrestrial, Martian, Lunar and asteroidal materials, meaning this atomic-scale approach holds great potential in establishing a more accurate chronology of the formation and evolution of planetary crusts.

• 出版日期2017-5-26