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Published July 8, 1982 | public
Journal Article

Impact mechanics of the Cretaceous-Tertiary extinction bolide

Abstract

On Earth impact of ~ 10 km diameter, asteroidal or cometary objects the vaporized, melted and (< 1 mm) solid ejecta transfer ~40–50% of their energy to the atmosphere, giving rise to a short possibly lethal (to large animals) heating pulse. Some 1–20 projectile masses of early, high-speed and highly shocked (diameter, <1 µm) extraterrestrial-rich ejecta is lofted to altitudes of 10 km where it can be globally distributed. It is proposed that this material represents the global Cretaceous–Tertiary boundary layer. When in the upper atmosphere it may have caused decreases in solar tropospheric insolation and resulting major extinctions in biota.

Additional Information

© 1982 Macmillan Journals Ltd Received 14 September 1981; accepted 7 May 1982. This research was supported under NASA grant NSG 7129. We thank Michael Lainhart and Lynne Adler for computation assistance, L. Alvarez, C. Emiliani and S. Gerstl for preprints, E. M. Shoemaker and D. L. Orphal for reviews, and D. Stevenson, M. Allen, A. P. Ingersoll, Y. Yung, J.E. Hansen and Jonathon Lunine for helpful suggestions. Contribution no. 3675, Division of Geological and Planetary Sciences, California Institute of Technology.

Additional details

Created:
August 19, 2023
Modified:
October 18, 2023