clumped isotopes, stable isotopes, calibration, standardization
Digital Object Identifier (DOI)
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.
Was this content written or created while at USF?
Citation / Publisher Attribution
Geochemistry, Geophysics, Geosystems, v. 20, issue 7, p. 3495-3519
©2019. American Geophysical Union. All Rights Reserved.
Scholar Commons 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.; 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.; and Winkelstern, I. Z., "Effects of Improved 17O Correction on Interlaboratory Agreement in Clumped Isotope Calibrations, Estimates of Mineral-Specific Offsets, and Temperature Dependence of Acid Digestion Fractionation" (2019). Marine Science Faculty Publications. 2425.
Supporting Information S1
ggge21932-sup-0002-supporting information table_s2_d47tevalues.xlsx (105 kB)
ggge21932-sup-0003-supporting information text_s4_rcode_functions.pdf (55 kB)
ggge21932-sup-0004-data set s1_allstudies_allsmpstd_replicates.txt (2434 kB)
Data Set S1
ggge21932-sup-0005-data set s2_allstudies_smpmeans.txt (73 kB)
Data Set S2