IsoplotR (version 0.17)

evolution: Th-U evolution diagram

Description

Plots Th-U data on a \(^{234}\)U/\(^{238}\)U-\(^{230}\)Th/\(^{238}\)U evolution diagram, a \(^{234}\)U/\(^{238}\)U-age diagram, or (if \(^{234}\)U/\(^{238}\)U is assumed to be in secular equilibrium), a \(^{230}\)Th/\(^{232}\)Th-\(^{238}\)U/\(^{232}\)Th diagram, calculates isochron ages.

Usage

evolution(x, xlim = NA, ylim = NA, alpha = 0.05, transform = FALSE,
  detrital = FALSE, show.numbers = FALSE, levels = NA,
  ellipse.col = c("#00FF0080", "#FF000080"), line.col = "darksalmon",
  isochron = FALSE, exterr = TRUE, sigdig = 2, ...)

Arguments

x

an object of class ThU

xlim

x-axis limits

ylim

y-axis limits

alpha

confidence cutoff for the error ellipses

transform

if TRUE, plots \(^{234}\)U/\(^{238}\)U vs. Th-U age.

detrital

apply a detrital Th correction by projecting the compositions along an isochron?

show.numbers

label the error ellipses with the grain numbers?

levels

a vector with additional values to be displayed as different background colours within the error ellipses.

ellipse.col

a vector of two background colours for the error ellipses. If levels=NA, then only the first colour will be used. If levels is a vector of numbers, then ellipse.col is used to construct a colour ramp.

line.col

colour of the age grid

isochron

fit a 3D isochron to the data?

exterr

propagate the decay constant uncertainty in the isochron age?

sigdig

number of significant digits for the isochron age

...

optional arguments to the generic plot function

References

Ludwig, K.R. and Titterington, D.M., 1994. Calculation of \(^{230}\)Th/U isochrons, ages, and errors. Geochimica et Cosmochimica Acta, 58(22), pp.5031-5042.

Ludwig, K.R., 2003. Mathematical-statistical treatment of data and errors for 230 Th/U geochronology. Reviews in Mineralogy and Geochemistry, 52(1), pp.631-656.

Examples

# NOT RUN {
data(examples)
evolution(examples$ThU)
# }