isotopylog.HeatingExperiment.change_ref_frame

HeatingExperiment.change_ref_frame(new_ref_frame, Ghosh_to_CDES_slope=1.0381, Ghosh_to_CDES_int=0.0266, aff=0.092)

Changes the HeatingExperiment reference frame and updates all clumped isotope data accordingly. Note, this is only possible for Ghosh and CDES reference frames, as I-CDES should always be used from now on and should never be converted into any “legacy” reference frames.

Parameters:new_ref_frame (string) –

The new reference frame to convert all data into. Options are:

'CDES25': Carbion Dioxide Equilibrium Scale acidified at 25 C.

'CDES90': Carbon Dioxide Equilibrium Scale acidified at 90 C.

'Ghosh': Heated Gas Line Reference Frame of Ghosh et al. (2006) acidified at 25 C.

Ghosh_to_CDES_slope : float

The slope to convert from Ghosh reference frame to CDES reference frame. Defaults to 1.038, the CalTech value taken from Table 4 of Dennis et al. (2011).

Ghosh_to_CDES_int : float

The intercept to convert from Ghosh reference frame to CDES reference frame. Defaults to 0.0266, the value taken from Table 4 of Dennis et al. (2011).

aff : float

The acid fractionation factor to use when converting 25 C and 90 C acidification. That is, 90 C acidified samples will be lower than 25 C acidified samples by an amount equal to aff. Defaults to 0.092, the value used for the CDES scale by Henkes et al. (2014).

Notes

These conversion factors are taken from the literature and might not apply to data generated in other labs or using alternative methods. Users should therefore only change reference frames when confident in the transfer function values, and should use lab-specific values where appropriate.

Examples

Converting from CDES90 to CDES25 increases all data by aff:

he.change_ref_frame('CDES25', aff = 0.092)

Converting old data from Ghosh to CDES90:

he.change_ref_frame('CDES90',
        Ghosh_to_CDES_slope = 1.0381,
        Ghosh_to_CDES_int = 0.0266,
        aff = 0.092)

References

[1] Ghosh et al. (2006) Geochim. Cosmochim. Ac., 70, 1439–1456.

[2] Dennis et al. (2011) Geochim. Cosmochim. Ac., 75, 7117–7131.