Squeaking in the November 1 issue (vol. 384) of Geochimica et Cosmochimica Acta:
Beyersdorf-Kuis, U. Ott, U. Trieloff, M. Complex irradiation history of chondrules and matrix- A study of CR2 and some other meteorites p. 65 .09.012
Asteroids (and thus meteorites from them) form from smaller bits- dust particles, mineral grains, and blobs of rock (chondrules, amoeboids, etc.) Tracing the history of those precursor materials then tells us of the history of asteroids, and in turn the history during the early Solar System. Beyersdorf-Kuis trace the history of these small precursor grains via their irradiation. In the early Solar System (and afterwards), these bits were bombarded with cosmic rays and high-energy atoms (solar and stellar winds). Until, that is, the material accreted into macroscopic bodies. Once a piece of rock is deep enough inside an asteroid, it is shielded from further bombardment. We can then take samples from meteorites, and check them for cosmic ray tracks, implanted solar wind gas, etc. and deduce some burial for that grain. This paper examines the burial history of two notable CR-group meteorites, other meteorites of other groups, and an ungrouped meteorite, for comparison. What do they tell us of the early Solar System? This paper is also a continuation of an earlier paper, Beyersdorf-Kuis et al. 2015. Between the two papers, and between grains from any single meteorite, we can draw some conclusions. In particular, the research group sampled some of the Allende meteorite. That meteorite dropped tons (yes, tons) of rock on an unsuspecting Mexican town. With that much material, Allende is called ‘the most studied rock’ in history. Using this reference sample, I feel Beyersdorf-Kuis et al. have a thing to say.