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Updated: Sep 12, 2025
07:57
Sampling and Pretreatment of Tooth Enamel Carbonate for Stable Carbon and Oxygen Isotope Analysis
Published on: August 15, 2018
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Mesozoic atmospheric CO2 concentrations reconstructed from dinosaur tooth enamel
Dingsu Feng1,2, Thomas Tütken3, Eva Maria Griebeler4
1Abteilung Geochemie & Isotopengeologie, Geowissenschaftliches Zentrum, Georg-August-Universität, Göttingen D-37077, Germany.
Summary
Fossil dinosaur teeth reveal past atmospheric carbon dioxide (CO2) levels and global plant growth. Triple oxygen isotope analysis of tooth enamel provides insights into Earth's ancient atmosphere and productivity.
Area of Science:
- Paleoclimatology
- Geochemistry
- Paleontology
Background:
- Air-breathing vertebrates incorporate atmospheric oxygen (O2) into body water.
- The triple oxygen isotope anomaly (Δ'17Oair) in O2 is linked to atmospheric carbon dioxide (pCO2) and gross primary production (GPP).
- Fossil tooth enamel preserves the isotopic signature of body water, offering a record of past environmental conditions.
Purpose of the Study:
- To demonstrate the potential of reconstructing past atmospheric pCO2 and GPP using triple oxygen isotope analysis of fossil dinosaur tooth enamel.
- To establish tooth enamel as a proxy for paleo-atmospheric greenhouse gas concentrations and global primary productivity.
Main Methods:
- Analysis of the triple oxygen isotope composition (Δ'17O) in unaltered fossil dinosaur tooth enamel samples.
- Utilizing the relationship between Δ'17O in body water and atmospheric O2, and its correlation with pCO2 and GPP.
- Comparing reconstructed pCO2 and GPP values with existing proxy data for the Mesozoic era.
Main Results:
- Estimated mean Late Jurassic pCO2 at 1,200 ± 150 ppmv and Late Cretaceous pCO2 at 750 ± 200 ppmv.
- Reconstructed GPP ratios (GPPt/GPP0) of 1.20 ± 0.17 for the Late Jurassic and 2.24 ± 0.96 for the Late Cretaceous, indicating 20-120% higher GPP than today.
- Reconstructed values show good agreement with other paleo-pCO2 proxy data.
Conclusions:
- Triple oxygen isotope analysis of fossil teeth provides a viable method for reconstructing past atmospheric pCO2.
- Tooth enamel Δ'17O can serve as a proxy for estimating Mesozoic GPP, suggesting significantly higher global primary productivity.
- This isotopic approach offers valuable insights into Earth's ancient atmospheric composition and biosphere function.
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