title: Environmental effects of an impact-generated dust cloud: implications for the cretaceous-tertiary extinctions.
abstract: 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.
authors.forename: J B
authors.initials: JB
authors.lastname: Pollack
authors.forename: O B
authors.initials: OB
authors.lastname: Toon
authors.forename: T P
authors.initials: TP
authors.lastname: Ackerman
authors.forename: C P
authors.initials: CP
authors.lastname: McKay
authors.forename: R P
authors.initials: RP
authors.lastname: Turco