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Paleotemperatures from deep-sea corals; overcoming "vital effects"

Jodie E. Smith, Henry P. Schwarcz, Michael J. Risk, Ted A. McConnaughey and Natalia Keller
Paleotemperatures from deep-sea corals; overcoming "vital effects"
Palaios (February 2000) 15 (1): 25-32

Abstract

Thirty-five azooxanthellate (non-photosynthetic) corals belonging to 18 species were collected at sites ranging from the Norwegian Sea to the Antarctic and of depths ranging from 10 to 5220 m. All specimens showed distinct, well-defined linear correlations between carbonate oxygen and carbon isotopic composition, with slopes ranging from 0.23 to 0.67 (mean 0.45+ or -0.9) and linear correlation r (super 2) values that averaged 0.89. These pronounced isotopic disequilibria have, to date, rendered azooxanthellate corals unsuitable for use in paleothermometry. Most, but not all, of the heaviest skeletal delta (super 18) O values reached or approached equilibrium. If the isotopically-heavy ends of the delta (super 18) O vs delta (super 13) C regression lines reliably approximated isotopic equilibrium with seawater, these values could be used to estimate the temperature of the water in which the coral grew. The delta (super 13) C values of the heavy ends of each line, however, were always depleted compared to carbon isotopic equilibrium with ambient bicarbonate by varying amounts. Despite the disequilibria, a reliable method for obtaining paleotemperature data was obtained. It was found that, if a delta (super 18) O vs delta (super 13) C regression line from an individual coral could be generated, the delta (super 18) O (sub arag) value corresponding to delta (super 13) C (sub arag) = delta (super 13) C (sub water) and corrected for delta (super 18) O (sub water) was a linear function of temperature: delta (super 18) O = -0.25 T( degrees C)+4.97.


ISSN: 0883-1351
Serial Title: Palaios
Serial Volume: 15
Serial Issue: 1
Title: Paleotemperatures from deep-sea corals; overcoming "vital effects"
Affiliation: McMaster University, School of Geography and Geology, Hamilton, ON, Canada
Pages: 25-32
Published: 200002
Text Language: English
Publisher: Society of Economic Paleontologists and Mineralogists, Tulsa, OK, United States
References: 27
Accession Number: 2000-051374
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 2 tables
S60°00'00" - N75°00'00", W80°00'00" - E20°00'00"
N30°10'00" - N46°40'00", W05°30'00" - E42°00'00"
Secondary Affiliation: Columbia University, Biosphere 2, USA, United StatesInstitute of Oceanology, RUS, Russian Federation
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2018, American Geosciences Institute.
Update Code: 200017
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