Plots cogenetic Ar-Ar, Pb-Pb, Rb-Sr, Sm-Nd, Re-Os, Lu-Hf, U-Th-He or Th-U
data as X-Y scatterplots, fits an isochron curve through them using
the york function, and computes the corresponding isochron
age, including decay constant uncertainties.
isochron(x, ...)# S3 method for default
isochron(x, xlim = NA, ylim = NA, alpha = 0.05,
sigdig = 2, show.numbers = FALSE, levels = NA,
ellipse.col = c("#00FF0080", "#FF000080"), line.col = "red", lwd = 2,
title = TRUE, model = 1, ...)
# S3 method for ArAr
isochron(x, xlim = NA, ylim = NA, alpha = 0.05,
sigdig = 2, show.numbers = FALSE, levels = NA,
ellipse.col = c("#00FF0080", "#FF000080"), inverse = TRUE,
line.col = "red", lwd = 2, plot = TRUE, exterr = TRUE, model = 1,
...)
# S3 method for PbPb
isochron(x, xlim = NA, ylim = NA, alpha = 0.05,
sigdig = 2, show.numbers = FALSE, levels = NA,
ellipse.col = c("#00FF0080", "#FF000080"), inverse = TRUE,
line.col = "red", lwd = 2, plot = TRUE, exterr = TRUE, model = 1,
...)
# S3 method for RbSr
isochron(x, xlim = NA, ylim = NA, alpha = 0.05,
sigdig = 2, show.numbers = FALSE, levels = NA,
ellipse.col = c("#00FF0080", "#FF000080"), line.col = "red", lwd = 2,
plot = TRUE, exterr = TRUE, model = 1, ...)
# S3 method for ReOs
isochron(x, xlim = NA, ylim = NA, alpha = 0.05,
sigdig = 2, show.numbers = FALSE, levels = NA,
ellipse.col = c("#00FF0080", "#FF000080"), line.col = "red", lwd = 2,
plot = TRUE, exterr = TRUE, model = 1, ...)
# S3 method for SmNd
isochron(x, xlim = NA, ylim = NA, alpha = 0.05,
sigdig = 2, show.numbers = FALSE, levels = NA,
ellipse.col = c("#00FF0080", "#FF000080"), line.col = "red", lwd = 2,
plot = TRUE, exterr = TRUE, model = 1, ...)
# S3 method for LuHf
isochron(x, xlim = NA, ylim = NA, alpha = 0.05,
sigdig = 2, show.numbers = FALSE, levels = NA,
ellipse.col = c("#00FF0080", "#FF000080"), line.col = "red", lwd = 2,
plot = TRUE, exterr = TRUE, model = 1, ...)
# S3 method for ThU
isochron(x, type = 2, xlim = NA, ylim = NA, alpha = 0.05,
sigdig = 2, show.numbers = FALSE, levels = NA,
ellipse.col = c("#00FF0080", "#FF000080"), line.col = "red", lwd = 2,
plot = TRUE, exterr = TRUE, model = 1, ...)
# S3 method for UThHe
isochron(x, xlim = NA, ylim = NA, alpha = 0.05,
sigdig = 2, show.numbers = FALSE, line.col = "red", lwd = 2,
plot = TRUE, model = 1, ...)
EITHER a matrix with the following five columns:
the x-variable
the standard error of X
the y-variable
the standard error of Y
the correlation coefficient of X and Y
OR
an object of class ArAr, PbPb, ReOs,
RbSr, SmNd, LuHf, UThHe or ThU.
optional arguments to be passed on to the
generic plot function if model=2
2-element vector with the plot limits of the x-axis
2-element vector with the plot limits of the y-axis
confidence cutoff for the error ellipses
the number of significant digits of the numerical values reported in the title of the graphical output
logical flag (TRUE to show grain numbers)
a vector with additional values to be displayed as different background colours within the error ellipses.
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.
colour of the isochron line
line width
add a title to the plot?
construct the isochron using either:
Error weighted least squares regression
Ordinary least squares regression
if TRUE and x has class ArAr,
plots \(^{36}\)Ar/\(^{40}\)Ar
vs. \(^{39}\)Ar/\(^{40}\)Ar.
if TRUE and x has class PbPb, plots
\(^{207}\)Pb/\(^{206}\)Pb vs. \(^{204}\)Pb/\(^{206}\)Pb.
if FALSE, suppresses the graphical output
propagate external sources of uncertainty (J, decay constant)?
following the classification of Ludwig and Titterington (1994), one of either:
`Rosholt type-II' isochron, setting out \(^{230}\)Th/\(^{232}\)Th vs. \(^{238}\)U/\(^{232}\)Th
`Osmond type-II' isochron, setting out \(^{230}\)Th/\(^{238}\)U vs. \(^{232}\)Th/\(^{238}\)U
`Rosholt type-II' isochron, setting out \(^{234}\)U/\(^{232}\)Th vs. \(^{238}\)U/\(^{232}\)Th
`Osmond type-II' isochron, setting out \(^{234}\)U/\(^{238}\)U vs. \(^{232}\)Th/\(^{238}\)U
if x has class PbPb, ArAr,
RbSr, SmNd, ReOs or LuHf,
ThU, or UThHe, returns a list with the following
items:
the intercept of the straight line fit and its standard error.
the slope of the fit and its standard error.
the covariance of the slope and intercept
the mean square of the residuals (a.k.a `reduced Chi-square') statistic
the p-value of a Chi-square test for linearity
the atmospheric \(^{40}\)Ar/\(^{36}\)Ar or initial \(^{207}\)Pb/\(^{204}\)Pb, \(^{187}\)Os/\(^{188}\)Os, \(^{87}\)Sr/\(^{86}\)Sr, \(^{143}\)Nd/\(^{144}\)Nd or \(^{176}\)Hf/\(^{177}\)Hf ratio and its standard error.
the \(^{207}\)Pb/\(^{206}\)Pb, \(^{40}\)Ar/\(^{39}\)Ar, \(^{187}\)Os/\(^{187}\)Re, \(^{87}\)Sr/\(^{86}\)Sr, \(^{143}\)Nd/\(^{144}\)Nd or \(^{176}\)Hf/\(^{177}\)Hf age and its standard error.
if plot=FALSE, and x has class ThU:
if type=1 or type=3: the best fitting
\(^{230}\)Th/\(^{232}\)Th intercept,
\(^{230}\)Th/\(^{238}\)U slope, \(^{234}\)U/\(^{232}\)Th
intercept and \(^{234}\)U/\(^{238}\)U slope, OR, if
type=2 or type=4: the best fitting
\(^{234}\)U/\(^{238}\)U intercept,
\(^{230}\)Th/\(^{232}\)Th slope, \(^{234}\)U/\(^{238}\)U
intercept and \(^{234}\)U/\(^{232}\)Th slope.
the covariance matrix of par.
if type=1: the \(^{230}\)Th/\(^{232}\)Th
intercept; if type=2: the \(^{230}\)Th/\(^{238}\)U
intercept; if type=3: the \(^{234}\)Th/\(^{232}\)Th
intercept; if type=4: the \(^{234}\)Th/\(^{238}\)U
intercept.
if type=1: the \(^{230}\)Th/\(^{238}\)U slope;
if type=2: the \(^{230}\)Th/\(^{232}\)Th slope; if
type=3: the \(^{234}\)U/\(^{238}\)U slope; if
type=4: the \(^{234}\)U/\(^{232}\)Th slope.
the covariance between a and b.
the mean square of the residuals (a.k.a `reduced Chi-square') statistic.
the p-value of a Chi-square test for linearity.
the initial \(^{234}\)U/\(^{238}\)U-ratio and its standard error.
the Th-U isochron age and its standard error.
# NOT RUN {
data(examples)
isochron(examples$ArAr)
# }
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