Oceanic Carbon Isotope Constraints on Oxygen and Carbon Dioxide in the Cenozoic Atmosphere

  1. E.T. Sundquist and
  2. W.S. Broecker
  1. N. J. Shackleton

Published Online: 18 MAR 2013

DOI: 10.1029/GM032p0412

The Carbon Cycle and Atmospheric CO: Natural Variations Archean to Present

The Carbon Cycle and Atmospheric CO: Natural Variations Archean to Present

How to Cite

Shackleton, N. J. (1985) Oceanic Carbon Isotope Constraints on Oxygen and Carbon Dioxide in the Cenozoic Atmosphere, in The Carbon Cycle and Atmospheric CO: Natural Variations Archean to Present (eds E.T. Sundquist and W.S. Broecker), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM032p0412

Author Information

  1. Lamont-Doherty Geological Observatory, Palisades, N.Y. 10964

Publication History

  1. Published Online: 18 MAR 2013
  2. Published Print: 1 JAN 1985

ISBN Information

Print ISBN: 9780875900605

Online ISBN: 9781118664322

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Keywords:

  • Carbon cycle (Biogeochemistry)—Congresses;
  • Atmospheric carbon dioxide—Congresses;
  • Geological time—Congresses;
  • Paleothermometry—Congresses;
  • Geology, Stratigraphic—Congresses

Summary

The carbon isotope record of carbonate sediments deposited on the ocean floor during the past 108 years may be intepreted in terms of changes in the global organic carbon reservoir, which has dimished by about 1019 moles over the past few tens of millions of years, drawing down the atmospheric oxygen content from 0.25 atmospheres to its present value of 0.2 atmospheres.

The history of 13C gradients within the ocean, recorded in the 13C content of foraminiferal tests, constrains the upper limit of possible excursions in the total dissolved CO2 in the ocean, which was not appreciably higher in the early Cenozoic and Mesozoic than it is today, providing a useful constraint on the predictions of the Berner et al. (1983) model, and hence on the implication that that the cause of warm earth climate during the late Mesozoic and early Cenozoic was a high atmospheric CO2 concentration.