Carbon, Fe and Ni-bearing grains are analyzed in two different ways in this study. One is their typical elemental abundances compared in crustal and meteoritic rocks. The other way is considered to be relicts on limestone rocks at the samples of the Cretaceous-Tertiary (KT) and Permian-Triassic (PT) geological boundary in European and Chinese countries, respectively. The latter material evidences are obtained by an in-situ observation with the Field- Emission analytical scanning electron microscopy (FE-ASEM) shown as various spherules and grains probably formed during rapid-impact reaction.

P/T boundary, K/T boundary, Carbon, Iron and Nickel spherules, FE-ASEM