Influence of changing deep ocean circulation on the Phanerozoic oxygen isotopic record

Journal Article · Tue May 01 00:00:00 EDT 1990 · Geochimica et Cosmochimica Acta; (USA)

DOI:https://doi.org/10.1016/0016-7037(90)90175-K· OSTI ID:6206771

Railsback, L B ^[1]

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1. Univ. of Georgia, Athens (USA)

Isotopic segregation in seawater caused by changing ocean circulation may in part explain the enigmatic oxygen isotopic record of Phanerozoic marine carbonates. Paleoceanographic evidence suggests that circulation of warm saline deep waters has occurred during at least two periods of warm global climate; those saline deep waters should have preferentially stored {sup 18}O in the deep oceans. Corresponding depletion of {sup 18}O in surface waters would have resulted in lower {delta}{sup 18}O of marine carbonates deposited on continental shelves. Modeling of paleoceanographic isotopic data suggests that this storage effect is similar in magnitude (but opposite in sign) to that of modern enrichment of {sup 18}O in the oceans by glacial storage. Modeling of carbonate compositions through time that takes into account such storage effects (as predicted by changing global climate) suggests that large changes in the mean oceanic isotopic composition, but neither extreme temperatures nor sudden changes in mean ocean compositions are needed to explain the isotopic record.

• OSTI ID: 6206771
• Journal Information: Geochimica et Cosmochimica Acta; (USA), Journal Name: Geochimica et Cosmochimica Acta; (USA) Vol. 54:5; ISSN GCACA; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
CARBONATE ROCKS
CHEMISTRY
CLIMATE MODELS
DEPOSITION
EVEN-EVEN NUCLEI
GEOCHEMISTRY
GEOLOGIC AGES
GEOLOGIC HISTORY
GEOLOGIC MODELS
ISOTOPE RATIO
ISOTOPES
LIGHT NUCLEI
MATHEMATICAL MODELS
NUCLEI
OCEANIC CIRCULATION
OXYGEN 18
OXYGEN ISOTOPES
PALEOCLIMATOLOGY
PALEONTOLOGY
PRECAMBRIAN ERA
ROCKS
SEDIMENTARY ROCKS
STABLE ISOTOPES