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Comments on the BLAG model - The carbonate-silicate geochemical cycle and its effect on atmospheric carbon dioxide over the past 100 million yearsA self-consistent method of determining initial conditions for the model presented by Berner, Lasaga, and Garrels (1983) (henceforth, the BLAG model) is derived, based on the assumption that the CO2 geochemical cycle was in steady state at t = -100 m.y. (million years). This initialization procedure leads to a dissolved magnesium concentration higher than that calculated by Berner, Lasaga, and Garrels and to a low ratio of dissolved calcium to bicarbonate prior to 60 m.y. ago. The latter prediction conflicts with the geologic record of evaporite deposits, which requires that this ratio remain greater than 0.5. The contradiction is probably caused by oversimplifications in the BLAG model, such as the neglect of the cycles of organic carbon and sulfur.
Document ID
19850045852
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Kasting, J. F.
(NASA Ames Research Center Space Science Div., Moffett Field, CA, United States)
Date Acquired
August 12, 2013
Publication Date
December 1, 1984
Publication Information
Publication: American Journal of Science
Volume: 284
ISSN: 0002-9599
Subject Category
Space Biology
Accession Number
85A28003
Distribution Limits
Public
Copyright
Other

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