Impact ejecta at the Paleocene-Eocene boundary
Morgan F. Schaller, Megan K. Fung, James D. Wright, Miriam E. Katz, Dennis V. Kent
Science 14 Oct 2016:
Vol. 354, Issue 6309, pp. 225-229
DOI: 10.1126/science.aaf5466
“Extraterrestrial impacts have left a substantial imprint on the climate and evolutionary history of Earth. A rapid carbon cycle perturbation and global warming event about 56 million years ago at the Paleocene-Eocene (P-E) boundary (the Paleocene-Eocene Thermal Maximum) was accompanied by rapid expansions of mammals and terrestrial plants and extinctions of deep-sea benthic organisms. Here, we report the discovery of silicate glass spherules in a discrete stratigraphic layer from three marine P-E boundary sections on the Atlantic margin. Distinct characteristics identify the spherules as microtektites and microkrystites, indicating that an extraterrestrial impact occurred during the carbon isotope excursion at the P-E boundary.”