rampedpyrox.RpoIsotopes.from_csv

classmethod RpoIsotopes.from_csv(file, model, ratedata, blk_corr=False, blk_d13C=(-29.0, 0.1), blk_flux=(0.375, 0.0583), blk_Fm=(0.555, 0.042), bulk_d13C_true=None, DE=0.0018, mass_err=0.01)[source]

Class method to directly import RPO fraction data from a .csv file and create an RpoIsotopes class instance.

Parameters:
  • blk_corr (Boolean) – Tells the method whether or not to blank-correct isotope data. If True, blank-corrects according to inputted blank composition values. If bulk_d13C_true is not None, further corrects d13C values to ensure isotope mass balance (see Hemingway et al., Radiocarbon 2017 for details).
  • blk_d13C (tuple) – Tuple of the blank d13C composition (VPDB), in the form (mean, stdev.) to be used of blk_corr = True. Defaults to the NOSAMS RPO blank as calculated by Hemingway et al., Radiocarbon 2017.
  • blk_flux (tuple) – Tuple of the blank flux (ng/s), in the form (mean, stdev.) to be used of blk_corr = True. Defaults to the NOSAMS RPO blank as calculated by Hemingway et al., Radiocarbon 2017.
  • blk_Fm (tuple) – Tuple of the blank Fm value, in the form (mean, stdev.) to be used of blk_corr = True. Defaults to the NOSAMS RPO blank as calculated by Hemingway et al., Radiocarbon 2017.
  • bulk_d13C_true (None or array) – True measured d13C value (VPDB) for bulk material as measured independently (e.g. on a EA-IRMS). If not None, this value is used to mass-balance-correct d13C values as described in Hemingway et al., Radiocarbon 2017. If not none, must be inputted in the form [mean, stdev.]
  • DE (scalar) – Value for the difference in E between 12C- and 13C-containing atoms, in kJ. Defaults to 0.0018 (the best-fit value calculated in Hemingway et al., Radiocarbon, 2017).
  • file (str or pd.DataFrame) – File containing RPO isotope data, either as a string pointing to a .csv file or as a pd.DataFrame instance.
  • mass_err (float) – Relative uncertainty in mass measurements, typically as a sum of manometric uncertainty in pressure measurements and uncertainty in vacuum line volumes. Defaults to 0.01 (i.e. 1% relative uncertainty).
  • model (rp.Model) – rp.Model instance containing the A matrix to use for inversion.
  • ratedata (rp.RateData) – rp.Ratedata instance containing the reactive continuum data.

Notes

For bookkeeping purposes, the first 2 rows must be fractions “-1” and “0”, where the timestamp for fraction “-1” is the first point in the all_data file used to create the rp.RpoThermogram instance, and the timestamp for fraction “0” is the t0 for the first fraction.

If mass, d13C, and Fm data exist, column names must be the following:

‘ug_frac’ and ‘ug_frac_std’

‘d13C’ and ‘d13C_std’

‘Fm’ and ‘Fm_std’

See also

RpoThermogram.from_csv()
Classmethod for creating rp.RpoThermogram instance directly from a .csv file.

References

[1] J.D. Hemingway et al. (2017) Assessing the blank carbon
contribution, isotope mass balance, and kinetic isotope fractionation of the ramped pyrolysis/oxidation instrument at NOSAMS. Radiocarbon, 59, 179-193.