age_ICP: Absolute FT ages

In tobiste/laftr: Calculates the ages from LA-ICP-MS based fission track dating

Absolute FT ages

Description

Calculation of the ages from LA-ICP-MS using zeta calibration

Usage

age_ICP(x, spotsize = 40, zeta, ...)

Arguments

x	data.frame containing counts of spontaneous tracks, U concentrations, and the uncertainties of U concentrations
spotsize	the laser ablation spot size (diameter in micrometer)
zeta	two-element vector with the zeta-factor and its standard error.
...	additional arguments

Details

The fission track age using the zeta calibration approach (Hasebe et al. 2009) is given by

t = \frac{1}{\lambda} \ln \left(1+\frac{1}{2} \lambda \zeta_{icp} \frac{N)s}{A_s [ ^{238}U/^xX]} \right)

where \lambda is the 238U decay constant, \zeta_{icp} is the zeta calibration factor, N_s is the count of spontaneous fission tracks, A_s is the size of the ablated area, and [ ^{238}U/^xX] either stands for the ^{238}U-concentration (in ppm) or for the U/Ca (for apatite) or U/Si (for zircon) ratio measurement.

Value

list with the single grain ages and their analytical uncertainties, the pooled age, and the chisq statistics

References

Hasebe, N., Carter, A., Hurford, A.J., Arai, S., 2009. The effect of chemical etching on LA-ICP-MS analysis in determining uranium concentration for fission-track chronometry. Geol. Soc. Lond. Spec. Publ. 324 (1), 37–46. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1144/SP324.3")}

Vermeesch, Pieter, 2017. Statistics for LA-ICP-MS based fission track dating. Chem. Geol. 456, 19–27. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1016/j.chemgeo.2017.03.002")}

Examples

data("sample")
age_ICP(sample, spotsize = 40, zeta = c(0.1188, 0.0119))

tobiste/laftr documentation built on Feb. 10, 2025, 11:10 p.m.