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a18_CO2acid_c() calculates the 18O/16O fractionation factor between CO2 produced from acid digestion and carbonate.


a18_CO2acid_c(temp, min)



Acid digestion temperature (°C).


Mineralogy. Options are "calcite", "aragonite", and "dolomite".


Returns the 18O/16O fractionation factor.


calcite (Kim et al. 2015):

$$\alpha^{18}_{CO2acid/calcite} = e^{(3.48 \times \frac{1}{T} - 0.00147)}$$

aragonite (Kim et al. 2007):

$$\alpha^{18}_{CO2acid/aragonite} = e^{(3.39 \times \frac{1}{T} - 0.00083)}$$

dolomite (Rosenbaum & Sheppard 1986):

$$\alpha^{18}_{CO2acid/dolomite} = e^{(665 \times \frac{1}{T^{2}} + 0.00423)}$$


Sharma, T., and Clayton, R. N. (1965). Measurement of ratios of total oxygen of carbonates. Geochimica et Cosmochimica Acta, 29(12), 1347-1353. doi:10.1016/0016-7037(65)90011-6

Rosenbaum, J. and Sheppard, S.M.F. (1986). An isotopic study of siderites, dolomites and ankerites at high temperatures. Geochimica et Cosmochimica Acta, 50, 1147-1150. doi:10.1016/0016-7037(86)90396-0

Kim, S.-T., Mucci, A., and Taylor, B. E. (2007). Phosphoric acid fractionation factors for calcite and aragonite between 25 and 75 °C: Revisited. Chemical Geology, 246(3-4), 135-146. doi:10.1016/j.chemgeo.2007.08.005

Kim, S.-T., Coplen, T. B., and Horita, J. (2015). Normalization of stable isotope data for carbonate minerals: Implementation of IUPAC guidelines. Geochimica et Cosmochimica Acta, 158, 276-289. doi:10.1016/j.gca.2015.02.011

See also

Other fractionation_factors: a13_CO2g_CO2aq(), a18_CO2aq_H2O(), a18_CO2g_H2O(), a18_CO3_H2O(), a18_H2O_OH(), a18_HCO3_H2O(), a18_c_H2O(), a_A_B()


a18_CO2acid_c(temp = 90, min = "calcite")
#> [1] 1.008146
a18_CO2acid_c(temp = 72, min = "aragonite")
#> [1] 1.009032