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D48() calculates the equilibrium carbonate D48 value for a given temperature.


D48(temp, eq)



Carbonate growth temperature (°C).


Equation used for the calculation.

  • "Fiebig21": the CDES90 calibration of Fiebig et al. (2021).

  • "Swart21": the CDES90 "PBLM1" calibration in Swart et al. (2021).


Returns the carbonate equilibrium D48 value expressed on the CDES90 scale (‰).



$$\Delta_{48, CDES90} = 1.028 \times (6.002 \times \frac{1}{T} - 1.299 \times \frac{10^{4}}{T^{2}} + 8.996 \times \frac{10^{6}}{T^{3}} - 7.423 \times \frac{10^{8}}{T^{4}}) + 0.1245$$


$$\Delta_{48, CDES90} = 0.0142 \times \frac{10^{6}}{T^{2}} + 0.088$$


Bajnai, D., Guo, W., Spötl, C., Coplen, T. B., Methner, K., Löffler, N., et al. (2020). Dual clumped isotope thermometry resolves kinetic biases in carbonate formation temperatures. Nature Communications, 11, 4005. doi:10.1038/s41467-020-17501-0

Fiebig, J., Daëron, M., Bernecker, M., Guo, W., Schneider, G., Boch, R., et al. (2021). Calibration of the dual clumped isotope thermometer for carbonates. Geochimica et Cosmochimica Acta. doi:10.1016/j.gca.2021.07.012

Swart, P. K., Lu, C., Moore, E., Smith, M., Murray, S. T., & Staudigel, P. T. (2021). A calibration equation between D48 values of carbonate and temperature. Rapid Communications in Mass Spectrometry, 35(17), e9147. doi:10.1002/rcm.9147

See also

Other equilibrium_carbonate: D47(), d17O_c(), d18O_c()


D48(temp = 33.7, eq = "Fiebig21") # Returns 0.237
#> [1] 0.2367946
D48(temp = 33.7, eq = "Swart21") # Returns 0.239
#> [1] 0.2388121