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A calibration equation between Δ 48 values of carbonate and temperature
Author(s) -
Swart Peter K.,
Lu Chaojin,
Moore Evan W.,
Smith Megan E.,
Murray Sean T.,
Staudigel Philip T.
Publication year - 2021
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.9147
Subject(s) - isotopologue , chemistry , carbonate , calibration , dissolution , carbonate minerals , carbon dioxide , analytical chemistry (journal) , mineralogy , impurity , thermodynamics , environmental chemistry , statistics , physics , mathematics , organic chemistry , molecule
Rationale Information on the temperature of formation or alteration of carbonate minerals can be obtained by measuring the abundance of the isotopologues 47 and 48 (Δ 47 and Δ 48 values) of CO 2 released during acid dissolution. The combination of these two proxies can potentially provide a greater insight into the temperature of formation, particularly if the carbonate minerals form by non‐equilibrium processes. Methods We have precipitated calcium carbonates at seven temperatures between 5 and 65°C and measured their δ 48 values using a Thermo‐253 plus isotope ratio mass spectrometer. The values were transformed to Δ 48 values in the conventional manner and then converted to the carbon dioxide equilibrium scale. Results Using the Δ 48 values, we have established an empirical calibration between temperature and Δ 48 values: Δ 48 = 0.0142 ± 0.0012 × 10 6 / T 2 + 0.088± 0.014R 2 = 0.96 .Conclusions The calibration line produced allows the determination of the temperature of natural carbonates using the Δ 48 values and agrees with the measurements of the Δ 47 and Δ 48 values of some carbonates assumed to have formed under equilibrium conditions.