Distal Impact Ejecta Layers: Recognition, Confirmation, Dating, and Determining Source Craters

Abstract

Discovery of a possible distal impact ejecta layer may begin in the field with recognition of a relatively thin (<1 m) lithologic layer that seems out of place or with the discovery of spherules in a well-defined layer, or in the laboratory with the discovery of a geochemical anomaly (e.g., high Ir) that suggests the presence of a meteoritic component.