A Short Duration of the Cretaceous-Tertiary Boundary Event: Evidence from Extraterrestrial Helium-3
S. Mukhopadhyay,1*
K. A. Farley,1
A. Montanari2
Analyses of marine carbonates through the interval 63.9 to 65.4 million years ago indicate a near-constant flux of extraterrestrial helium-3, a tracer of the accretion rate of interplanetary dust to
Earth. This observation indicates that the bolide associated with the
Cretaceous-Tertiary (K-T) extinction event was not accompanied by enhanced solar system dustiness and so could not have been a member
of a comet shower. The use of helium-3 as a constant-flux proxy of
sedimentation rate implies deposition of the K-T boundary clay in
(10 ± 2) × 103 years, precluding the
possibility of a long hiatus at the boundary and requiring extremely
rapid faunal turnover.
1 Division of Geological and Planetary
Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
2 Osservatorio Geologico di Coldigioco, 62020 Frontale di Apiro, Italy.
*
To whom correspondence should be addressed. E-mail:
sujoy{at}gps.caltech.edu
