# a18_c_H2O: 18O/16O fractionation factor between carbonate and water In isogeochem: Tools for Carbonate Isotope Geochemistry

## Description

a18_c_H2O() calculates the 18O/16O fractionation factor between carbonate and water.

## Usage

 1 a18_c_H2O(temp, min, eq) 

## Arguments

 temp Carbonate growth temperature (°C). min Mineralogy. Options are "calcite", "aragonite", apatite, siderite, and "dolomite". eq Equation used for the calculations. See details.

## Details

Options for eq if min = "calcite":

"ONeil69": O'Neil et al. (1969), modified by Friedman and O'Neil (1977):

α^{18}_{calcite/water} = e^{(2.78 \times \frac{1000}{T^{2}} - 0.00289)}

"KO97-orig": Kim and O'Neil (1997):

α^{18}_{calcite/water} = e^{(18.03 \times \frac{1}{T} - 0.03242)}

NOTE: The "KO97-orig" equation should only be applied to data that considers a CO2(acid)/calcite AFF as in Kim & O'Neil (1997), i.e., 10.44 at 25 °C.

"KO97": Kim and O'Neil (1997), reprocessed here to match the IUPAC-recommended AFF as in Kim et al. (2007, 2015):

α^{18}_{calcite/water} = e^{(18.04 \times \frac{1}{T} - 0.03218)}

"Coplen07": Coplen (2007):

α^{18}_{calcite/water} = e^{(17.4 \times \frac{1}{T} - 0.0286)}

"Tremaine11": Tremaine et al. (2011):

α^{18}_{calcite/water} = e^{(16.1 \times \frac{1}{T} - 0.0246)}

"Watkins13": Watkins et al. (2013):

α^{18}_{calcite/water} = e^{(17.747 \times \frac{1}{T} - 0.029777)}

"Daeron19": Daëron et al. (2019):

α^{18}_{calcite/water} = e^{(17.57 \times \frac{1}{T} - 0.02913)}

Options for eq if min = "aragonite":

"GK86": Grossman and Ku (1986), modified by Dettman et al. (1999):

α^{18}_{aragonite/water} = e^{(2.559 \times \frac{1000}{T^{2}} + 0.000715)}

"Kim07": Kim et al. (2007):

α^{18}_{aragonite/water} = e^{(17.88 \times \frac{1}{T} - 0.03114)}

Options for eq if min = "apatite". Apatite refers to apatite-bound carbonate.

"Lecuyer10": Lécuyer et al. (2010):

α^{18}_{apatite/water} = e^{(25.19 \times \frac{1}{T} - 0.05647)}

Options for eq if min = "siderite":

"vanDijk18": van Dijk et al. (2018):

α^{18}_{siderite/water} = e^{(19.67 \times \frac{1}{T} - 0.03627)}

Options for eq if min = "dolomite":

"Vasconcelos05": Vasconcelos et al. (2005):

α^{18}_{dolomite/water} = e^{(2.73 \times \frac{1000}{T^{2}} + 0.00026)}

## Value

Returns the 18O/16O fractionation factor.

## References

O'Neil, J. R., Clayton, R. N., & Mayeda, T. K. (1969). Oxygen isotope fractionation in divalent metal carbonates. The Journal of Chemical Physics, 51(12), 5547-5558. doi: 10.1063/1.1671982

Grossman, E. L., & Ku, T. L. (1986). Oxygen and carbon isotope fractionation in biogenic aragonite: Temperature effects. Chemical Geology, 59(1), 59-74. doi: 10.1016/0009-2541(86)90044-6

Kim, S.-T., & O'Neil, J. R. (1997). Equilibrium and nonequilibrium oxygen isotope effects in synthetic carbonates. Geochimica et Cosmochimica Acta, 61(16), 3461-3475. doi: 10.1016/S0016-7037(97)00169-5

Dettman, D. L., Reische, A. K., & Lohmann, K. C. (1999). Controls on the stable isotope composition of seasonal growth bands in aragonitic fresh-water bivalves (unionidae). Geochimica et Cosmochimica Acta, 63(7-8), 1049-1057. doi: 10.1016/s0016-7037(99)00020-4

Vasconcelos, C., McKenzie, J. A., Warthmann, R., & Bernasconi, S. M. (2005). Calibration of the d18O paleothermometer for dolomite precipitated in microbial cultures and natural environments. Geology, 33(4), 317-320. doi: 10.1130/g20992.1

Kim, S.-T., Mucci, A., & 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

Coplen, T. B. (2007). Calibration of the calcite–water oxygen-isotope geothermometer at Devils Hole, Nevada, a natural laboratory. Geochimica et Cosmochimica Acta, 71(16), 3948-3957. doi: 10.1016/j.gca.2007.05.028

Lécuyer, C., Balter, V., Martineau, F., Fourel, F., Bernard, A., Amiot, R., et al. (2010). Oxygen isotope fractionation between apatite-bound carbonate and water determined from controlled experiments with synthetic apatites precipitated at 10–37°C. Geochimica et Cosmochimica Acta, 74(7), 2072-2081. doi: 10.1016/j.gca.2009.12.024

Tremaine, D. M., Froelich, P. N., & Wang, Y. (2011). Speleothem calcite farmed in situ: Modern calibration of d18O and d13C paleoclimate proxies in a continuously-monitored natural cave system. Geochimica et Cosmochimica Acta, 75(17), 4929-4950. doi: 10.1016/j.gca.2011.06.005

Watkins, J. M., Nielsen, L. C., Ryerson, F. J., & DePaolo, D. J. (2013). The influence of kinetics on the oxygen isotope composition of calcium carbonate. Earth and Planetary Science Letters, 375, 349-360. doi: 10.1016/j.epsl.2013.05.054

van Dijk, J., Fernandez, A., Müller, I. A., Lever, M., & Bernasconi, S. M. (2018). Oxygen isotope fractionation in the siderite-water system between 8.5 and 62 °C. Geochimica et Cosmochimica Acta, 220, 535-551. doi: 10.1016/j.gca.2017.10.009

Daëron, M., Drysdale, R. N., Peral, M., Huyghe, D., Blamart, D., Coplen, T. B., et al. (2019). Most Earth-surface calcites precipitate out of isotopic equilibrium. Nature Communications, 10, 429. doi: 10.1038/s41467-019-08336-5

Other fractionation_factors: a13_CO2g_CO2aq(), a18_CO2acid_c(), a18_CO2aq_H2O(), a18_CO2g_H2O(), a18_CO3_H2O(), a18_H2O_OH(), a18_HCO3_H2O(), a_A_B()
 1 2 a18_c_H2O(temp = 25, min = "calcite", eq = "Coplen07") a18_c_H2O(temp = 25, min = "aragonite", "GK86")