Widespread glasses generated by cometary fireballs during the late Pleistocene in the Atacama Desert, Chile

Abstract

Schultz et al. (2021) interpreted the unusual silicate surface glasses found in the northeastern part of the Atacama Desert as products of a comet airburst that occurred about12 k.y. ago. This interpretation contradicts our conclusions (Roperch et al., 2017). On the basis of abundant field and laboratory evidence, our work suggested that the glasses were formed during intense fires in soils with thick silica-rich plant litter. Here we point out several features that question the interpretation of Schultz et al.; namely, (1) the mode of emplacement of the glasses, (2) the chronology of heating events, (3) the identification of putative bolide composition in glass-hosted mineral inclusions, and (4) the mineralogical evidence for ultrahigh temperatures.