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Science 21 January 1983:
Vol. 219. no. 4582, pp. 287 - 289
DOI: 10.1126/science.219.4582.287
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Articles

Environmental Effects of an Impact-Generated Dust Cloud: Implications for the Cretaceous-Tertiary Extinctions

JAMES B. POLLACK 1, OWEN B. TOON 1, THOMAS P. ACKERMAN 1, CHRISTOPHER P. McKAY 1, and RICHARD P. TURCO 2

1 Space Science Division, NASA Ames Research Center, Moffett Field, California 94035
2 R & D Associates, Marina del Ray, California 90291

A model of the evolution and radiative effects of a debris cloud from a hypothesized impact event at the Cretaceous-Tertiary boundary suggests that the cloud could have reduced the amount of light at the earth's surface below that required for photosynthesis for several months and, for a somewhat shorter interval, even below that needed for many animals to see. For 6 months to 1 year, the surface would cool; the oceans would cool only a few degrees Celsius at most, but the continents might cool a maximum of 40 Kelvin. Extinctions in the ocean may have been caused primarily by the temporary cessation of photosynthesis, but those on land may have been primarily induced by a combination of lowered temperatures and reduced light.

Submitted on June 21, 1982
Revised on September 28, 1982


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
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The greenhouse and antigreenhouse effects on Titan.
C. McKay, J. Pollack, and R Courtin (1991)
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Impact Theory of Mass Extinctions and the Invertebrate Fossil Record.
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Science 223, 1135-1141
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Nuclear Winter: Global Consequences of Multple Nuclear Explosions.
R. P. Turco, R. P. Turco, O. B. Toon, T. P. Ackerman, J. B. Pollack, and C. Sagan (1983)
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