Carbon dioxide in the atmosphere: Evidence from cenozoic and mesozoic paleosols

Journal Article · Mon Apr 01 04:00:00 EST 1991 · American Journal of Science; (United States)

DOI:https://doi.org/10.2475/ajs.291.4.377· OSTI ID:5895659

Cerling, T E ^[1]

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1. Univ. of Utah, Salt Lake City (United States)

A diffusion-reaction model for the isotopic composition of soil CO{sub 2} and soil carbonate is evaluated. It shows which variables are important under different conditions and shows that under certain circumstances the carbon isotopic composition of soil carbonate can be used to estimate P(CO{sub 2}) of the atmosphere from late Paleozoic to the present. The isotopic composition of soil carbonate produced under uniform conditions is essentially constant below about 20 cm in most soils. Today, the isotopic composition of soil organic matter, which is mostly determined by the fraction of C{sub 4} biomass present, is the most important factor in determining the carbon isotopic composition of soil carbonate. However, prior to the advent of C{sub 4} plants making up a significant fraction of the biomass, probably in the Tertiary, the concentration of CO{sub 2} in the atmosphere can be estimated because of mixing of atmospheric CO{sub 2} with CO{sub 2} produced in the soil. The diffusion-reaction model also suggests that before the advent of higher land plants most soil carbonate should have {delta}{sup 13}C values between {minus}6.5 and {minus}8.5 permil suggesting that P(CO{sub 2}) was significantly higher than today, probably on the order of 1,500 to 3,000 ppmV.

• OSTI ID: 5895659
• Journal Information: American Journal of Science; (United States), Journal Name: American Journal of Science; (United States) Vol. 291:4; ISSN 0002-9599; ISSN AJSCA
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540120* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
ATMOSPHERIC CHEMISTRY
BIOMASS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBONATES
CHALCOGENIDES
CHEMISTRY
CLIMATIC CHANGE
ENERGY SOURCES
GREENHOUSE EFFECT
MATHEMATICAL MODELS
OXIDES
OXYGEN COMPOUNDS
PALEOCLIMATOLOGY
PALEONTOLOGY
PARTIAL PRESSURE
RENEWABLE ENERGY SOURCES