age2ratio: Predict isotopic ratios from ages

In IsoplotR: Statistical Toolbox for Radiometric Geochronology

Predict isotopic ratios from ages

Description

Groups a set of functions that take one (or more) ages (and their uncertainties) as input and produces the U–Pb, Th–Pb, Pb–Pb, Ar–Ar, K–Ca, Rb–Sr, Sm–Nd, Lu–Hf, Re–Os, concordia or Stacey-Kramers ratios as output.

Usage

age2ratio(
  tt,
  st = 0,
  ratio = "Pb206U238",
  exterr = FALSE,
  d = diseq(),
  J,
  sJ = 0,
  bratio = 0.895
)

Arguments

tt	a scalar or (except when ratio = 'Wetherill', 'Tera-Wasserburg' or 'U-Th-Pb') vector of ages.
st	a scalar or (except when ratio = 'Wetherill', 'Tera-Wasserburg' or 'U-Th-Pb') vector with the standard error(s) of tt. Not used when ratio = 'Stacey-Kramers'.
ratio	one of 'Pb206U238', 'Pb207U235', 'U238Pb206', 'Pb207Pb206', 'Pb208Th232', 'Wetherill', 'Tera-Wasserburg', 'U-Th-Pb', 'Ar40Ar39', 'Ca40K40', 'Hf176Lu176', 'Sr87Rb87', 'Os187Re187', 'Nd143Sm147' or 'Stacey-Kramers'.
exterr	logical. If TRUE, propagates decay constant uncertainties into st. Not used when ratio = 'Stacey-Kramers'.
d	an object of class diseq.
J	the J-factor of the Ar–Ar system (only used if ratio is 'Ar40Ar39').
sJ	the standard error of J (only used if ratio is 'Ar40Ar39').
bratio	branching ratio of ^40K

Value

If ratio is 'Pb207U235', 'U238Pb206', 'Pb207Pb206', 'Pb208Th232', 'Ar40Ar39', 'Ca40K40', 'Hf176Lu176', 'Sr87Rb87', 'Os187Re187' or 'Nd143Sm147': either a two-element vector or a two-column matrix with the predicted isotopic ratio(s) and its/their standard error(s).

If ratio is 'Wetherill', 'Tera-Wasserburg' or 'U-Th-Pb': a two-element list containing

x: the concordia ratios

cov: the covariance matrix of the concordia ratios

If ratio is 'Stacey-Kramers': a three-column matrix with predicted ^{206}Pb/^{204}Pb, ^{207}Pb/^{204}Pb and ^{208}Pb/^{204}Pb ratios.

Examples

ratios <- c('Pb206U238','Pb207U235','U238Pb206','Pb207Pb206',
            'Pb208Th232','Wetherill','Tera-Wasserburg','U-Th-Pb',
            'Ar40Ar39','Ca40K40','Hf176Lu176','Sr87Rb87',
            'Os187Re187','Nd143Sm147','Stacey-Kramers')
for (ratio in ratios){
     r <- age2ratio(tt=1000,st=10,ratio=ratio,J=1,sJ=0.1)
     print(r)
}

IsoplotR documentation built on Oct. 19, 2024, 5:07 p.m.