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Geochemical Evidence for a Comet Shower in the Late Eocene

Farley, K. A. and Montanari, A. and Shoemaker, E. M. and Shoemaker, C. S. (1998) Geochemical Evidence for a Comet Shower in the Late Eocene. Science, 280 (5367). pp. 1250-1253. ISSN 0036-8075. doi:10.1126/science.280.5367.1250.

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Analyses of pelagic limestones indicate that the flux of extraterrestrial helium-3 to Earth was increased for a 2.5-million year (My) period in the late Eocene. The enhancement began ∼1 My before and ended ∼1.5 My after the major impact events that produced the large Popigai and Chesapeake Bay craters ∼36 million years ago. The correlation between increased concentrations of helium-3, a tracer of fine-grained interplanetary dust, and large impacts indicates that the abundance of Earth-crossing objects and dustiness in the inner solar system were simultaneously but only briefly enhanced. These observations provide evidence for a comet shower triggered by an impulsive perturbation of the Oort cloud.

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Farley, K. A.0000-0002-7846-7546
Additional Information:© 1998 American Association for the Advancement of Science. Received 13 January 1998; accepted 27 March 1998. We thank P. Weissman for a constructive and thoughtful review and D. Patterson and K. Robinson for assistance with sample preparation. Supported by NASA and by the David and Lucille Packard Foundation through a fellowship award to K.A.F.
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David and Lucille Packard FoundationUNSPECIFIED
Issue or Number:5367
Record Number:CaltechAUTHORS:20121205-085724991
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:35810
Deposited By: Tony Diaz
Deposited On:05 Dec 2012 19:17
Last Modified:09 Nov 2021 23:17

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