Calibration of Foraminifera Carbonate Calcification Temperatures Derived from Clumped Isotope Analysis
Abstract
A robust assessment of past ocean temperatures is essential to the investigation of environmental change. A relatively new chemical technique for estimating past ocean temperatures is based on the clumped isotope composition of foraminifera. Carbonate clumped isotope thermometry relies on the temperature dependence of the abundance of 13C-18O bonds formed during the calcification of carbonates. The goal of this study is to develop a clumped isotope calibration for foraminifera on new instrumentation based at UCLA by comparing isotope ratios with oxygen isotope-estimates of calcification temperatures and modern ocean water temperatures. We measured foraminifera from 3 different sample sets through a gas-source isotope ratio mass spectrometer. The sample sets are comprised of 10 species of modern planktonic foraminifera which were extracted from oceanic drill core-top sediments collected from 19 sites around the world. Calcification temperatures at these sites range from 2.96 °C to 30.1 °C. A linear regression was performed on the combined datasets to show the relationship between foraminifera Δ47 measurements and the independently determined calcification temperatures. Future work will also provide an assessment of the potential effects of carbonate dissolution at depth on Δ47 measurements in order to further refine the calibration of the foraminifera clumped isotope thermometer. The results of this calibration can be used in reconstructing past temperatures and patterns in carbon cycling, which can then be used for current climate model research.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMPP51F1198F
- Keywords:
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- 0419 Biomineralization;
- BIOGEOSCIENCESDE: 0473 Paleoclimatology and paleoceanography;
- BIOGEOSCIENCESDE: 4924 Geochemical tracers;
- PALEOCEANOGRAPHYDE: 4994 Instruments and techniques;
- PALEOCEANOGRAPHY