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Shock-induced devolatilization of calcium sulfate and implications for K-T extinctionsThe devolatilization of calcium sulfate, which is present in the target rock of the Chicxulub, Mexico impact structure, and dispersal in the stratosphere of the resultant sulfuric acid aerosol have been suggested as a possible mechanism for the Cretaceous-Tertiary extinctions. We measured the amount of SO2 produced from two shock-induced devolatilization reactions of calcium sulfate up to 42 GPa in the laboratory. We found both to proceed to a much lower extent than calculated by equilibrium thermodynamic calculations. Reaction products are found to be approx. 10(exp -2) times those calculated for equilibrium. Upon modeling the quantity of sulfur oxides degassed into the atmosphere from shock devolatilization of CaSO4 in the Chicxulub lithographic section, the resulting 9 x 10(exp 16) to 6 x 10(exp 17) g (in sulfur mass) is lower by a factor of 10-100 than previous upper limit estimates, the related environmental stress arising from the resultant global cooling and fallout of acid rain is insufficient to explain the widespread K-T extinctions.
Document ID
19950046266
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Chen, Guangqing
(California Inst. of Tech., Pasadena, CA United States)
Tyburczy, James A.
(California Inst. of Tech., Pasadena, CA United States)
Ahrens, Thomas J.
(California Inst. of Tech., Pasadena, CA United States)
Date Acquired
August 16, 2013
Publication Date
December 1, 1994
Publication Information
Publication: Earth and Planetary Science Letters
Volume: 128
Issue: 3-4
ISSN: 0012-821X
Subject Category
Geophysics
Accession Number
95A77865
Distribution Limits
Public
Copyright
Other

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