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climatic effect of impacts on the oceanImpact-generated spherule layers provide information pertinent to the environmental consequences of very large impacts on Earth. The spherules are condensed from high velocity impact ejecta ballistically distributed worldwide. These ejecta comprise material from both the impacting body and the target. Much of this material was vaporized or atomized (in the sense of small droplets of fluid, although doubtless some of the vapor species were atomic) in the impact event, cooled and condensed, and then was re-melted or partially evaporated again on re-entry into the atmosphere far from the crater. The energy deposited in the atmosphere by the re-entering ejecta heat the stratosphere where the particles stop to the temperature of hot lava, and thermal radiation from the superheated stratosphere heats the lower atmosphere, any land surfaces, and the evaporate the surface of the ocean; how hot the atmosphere gets and how much water gets evaporated depends on the scale of the impact. The molten or solid raindrops and hailstones eventually fell out of the atmosphere and onto land or into the ocean over the course of hours and days to pile up as spherule beds, and later the finer dust falls out over months and years.
Document ID
Document Type
Conference Paper
Zahnle, K. J.
(NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
October 24, 2018
Publication Date
August 26, 2018
Subject Category
Lunar and Planetary Science and Exploration
Report/Patent Number
Meeting Information
Comperativr Climatology of terrestrial Planets III: From Stars to Surface(Houston, TX)
Distribution Limits
Work of the US Gov. Public Use Permitted.

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