Description Usage Arguments Details References See Also Examples
Plots ThU data on a ^{234}U/^{238}U^{230}Th/^{238}U evolution diagram, a ^{234}U/^{238}Uage 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.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23  evolution(
x,
xlim = NULL,
ylim = NULL,
alpha = 0.05,
transform = FALSE,
detritus = 0,
show.numbers = FALSE,
levels = NA,
clabel = "",
ellipse.fill = c("#00FF0080", "#FF000080"),
ellipse.stroke = "black",
line.col = "darksalmon",
isochron = FALSE,
model = 1,
exterr = TRUE,
sigdig = 2,
hide = NULL,
omit = NULL,
omit.fill = NA,
omit.stroke = "grey",
...
)

x 
an object of class 
xlim 
xaxis limits 
ylim 
yaxis limits 
alpha 
probability cutoff for the error ellipses and confidence intervals 
transform 
if 
detritus 
detrital ^{230}Th correction (only applicable
when

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. 
clabel 
label of the colour legend. 
ellipse.fill 
Fill colour for the error ellipses. This can either be a single colour or multiple colours to form a colour ramp. Examples: a single colour: multiple colours: a colour palette: a reversed palette: For empty ellipses, set 
ellipse.stroke 
the stroke colour for the error
ellipses. Follows the same formatting guidelines as

line.col 
colour of the age grid 
isochron 
fit a 3D isochron to the data? 
model 
if

exterr 
propagate the decay constant uncertainty in the isochron age? 
sigdig 
number of significant digits for the isochron age 
hide 
vector with indices of aliquots that should be removed from the plot. 
omit 
vector with indices of aliquots that should be plotted but omitted from the isochron age calculation. 
omit.fill 
fill colour that should be used for the omitted aliquots. 
omit.stroke 
stroke colour that should be used for the omitted aliquots. 
... 
optional arguments to the generic 
Similar to the concordia
diagram (for UPb data) and
the helioplot
diagram (for UThHe data), the
evolution diagram simultaneously displays the isotopic composition
and age of Useries data. For carbonate data (ThU formats 1 and
2), the ThU evolution diagram consists of a scatter plot that sets
out the ^{234}U/^{238}Uactivity ratios against the
^{230}Th/^{238}Uactivity ratios as error ellipses, and
displays the initial ^{234}U/^{238}Uactivity ratios
and ages as a set of intersecting lines. Alternatively, the
^{234}U/^{238}Uratios can also be set out against the
^{230}Th^{234}U^{238}Uages. In both types of
evolution diagrams, IsoplotR
provides the option to project
the raw measurements along the best fitting isochron line and
thereby remove the detrital ^{230}Thcomponent. This
procedure allows a visual assessment of the degree of homogeneity
within a dataset, as is quantified by the MSWD.
Neither the Useries evolution diagram, nor the
^{234}U/^{238}U vs. age plot is applicable to igneous
datasets (ThU formats 3 and 4), in which ^{234}U and
^{238}U are in secular equilibrium. For such datasets,
IsoplotR
produces an Osmondstyle regression plot that is
decorated with a fanning set of isochron
lines.
Ludwig, K.R. and Titterington, D.M., 1994. Calculation of ^{230}Th/U isochrons, ages, and errors. Geochimica et Cosmochimica Acta, 58(22), pp.50315042.
Ludwig, K.R., 2003. Mathematicalstatistical treatment of data and errors for ^{230}Th/U geochronology. Reviews in Mineralogy and Geochemistry, 52(1), pp.631656.
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