Effects of Improved 17O Correction on Interlaboratory Agreement in Clumped Isotope Calibrations, Estimates of Mineral‐Specific Offsets, and Temperature Dependence of Acid Digestion Fractionation
Petersen, S. V.; Defliese, W. F.; Saenger, C.; Daëron, M.; Huntington, K. W.; John, C. M.; Kelson, J. R.; Bernasconi, S. M.; Colman, A. S.; Kluge, T.; Olack, G. A.; Schauer, A. J.; Bajnai, D.; Bonifacie, M.; Breitenbach, S. F. M.; Fiebig, J.; Fernandez, A. B.; Henkes, G. A.; Hodell, D.; Katz, A.; Kele, S.; Lohmann, K. C.; Passey, B. H.; Peral, M. Y.; Petrizzo, D. A.; Rosenheim, B. E.; Tripati, A.; Venturelli, R.; Young, E. D.; Winkelstern, I. Z.
2019-07
View/ Open
Citation
Petersen, S. V.; Defliese, W. F.; Saenger, C.; Daëron, M. ; Huntington, K. W.; John, C. M.; Kelson, J. R.; Bernasconi, S. M.; Colman, A. S.; Kluge, T.; Olack, G. A.; Schauer, A. J.; Bajnai, D.; Bonifacie, M.; Breitenbach, S. F. M.; Fiebig, J.; Fernandez, A. B.; Henkes, G. A.; Hodell, D.; Katz, A.; Kele, S.; Lohmann, K. C.; Passey, B. H.; Peral, M. Y.; Petrizzo, D. A.; Rosenheim, B. E.; Tripati, A.; Venturelli, R.; Young, E. D.; Winkelstern, I. Z. (2019). "Effects of Improved 17O Correction on Interlaboratory Agreement in Clumped Isotope Calibrations, Estimates of Mineral‐Specific Offsets, and Temperature Dependence of Acid Digestion Fractionation." Geochemistry, Geophysics, Geosystems 20(7): 3495-3519.
Abstract
The clumped isotopic composition of carbonate‐derived CO2 (denoted Δ47) is a function of carbonate formation temperature and in natural samples can act as a recorder of paleoclimate, burial, or diagenetic conditions. The absolute abundance of heavy isotopes in the universal standards VPDB and VSMOW (defined by four parameters: R13VPDB, R17VSMOW, R18VSMOW, and λ) impact calculated Δ47 values. Here, we investigate whether use of updated and more accurate values for these parameters can remove observed interlaboratory differences in the measured T‐Δ47 relationship. Using the updated parameters, we reprocess 14 published calibration data sets measured in 11 different laboratories, representing many mineralogies, bulk compositions, sample types, reaction temperatures, and sample preparation and analysis methods. Exploiting this large composite data set (n = 1,253 sample replicates), we investigate the possibility for a “universal” clumped isotope calibration. We find that applying updated parameters improves the T‐Δ47 relationship (reduces residuals) within most labs and improves overall agreement but does not eliminate all interlaboratory differences. We reaffirm earlier findings that different mineralogies do not require different calibration equations and that cleaning procedures, method of pressure baseline correction, and mass spectrometer type do not affect interlaboratory agreement. We also present new estimates of the temperature dependence of the acid digestion fractionation for Δ47 (Δ*25‐X), based on combining reprocessed data from four studies, and new theoretical equilibrium values to be used in calculation of the empirical transfer function. Overall, we have ruled out a number of possible causes of interlaboratory disagreement in the T‐Δ47 relationship, but many more remain to be investigated.Plain Language SummaryMeasured stable and clumped isotope values are fundamentally tied to established compositions of international standard materials. When these standard compositions are updated, it impacts previously published isotope measurements such as those used to define the clumped isotope calibration relationship (the foundation for use of this isotopic proxy as a paleothermometer, recorder of burial history or past diagenetic conditions). Here we reprocess 14 published clumped isotope calibration studies using updated international standard compositions and identical data processing procedures to see if these changes would eliminate previously observed interlaboratory discrepancies in clumped isotope calibration relationships. We find that this update tightens the clumped isotope calibration relationship within most laboratories and improves overall agreement between laboratories but does not eliminate all interlaboratory differences. We also propose “best practices” for data processing and dissemination going forward. This study makes progress toward resolving discrepancies in clumped isotope calibration relationships between laboratories by eliminating a number of possible causes and moves the clumped isotope community closer toward our ultimate goal of applying this powerful new proxy routinely to exciting science questions.Key PointsUpdates to 17O correction parameters and international standard compositions affect clumped isotopic compositionsReprocessing published calibration data using new parameters and consistent methodology slightly improves interlaboratory agreementThere is no evidence (within error) for mineral‐specific offsets in calibration equation or temperature dependence of acid digestion fractionationPublisher
International Atomic Energy Agency Wiley Periodicals, Inc.
ISSN
1525-2027 1525-2027
Other DOIs
Types
Article
Metadata
Show full item recordCollections
Remediation of Harmful Language
The University of Michigan Library aims to describe library materials in a way that respects the people and communities who create, use, and are represented in our collections. Report harmful or offensive language in catalog records, finding aids, or elsewhere in our collections anonymously through our metadata feedback form. More information at Remediation of Harmful Language.
Accessibility
If you are unable to use this file in its current format, please select the Contact Us link and we can modify it to make it more accessible to you.