classes: Geochronological data classes

Description

S3 classes to store geochronological data generated by read.data or diseq.

Usage

is.UPb(x)
is.PbPb(x)
is.ThPb(x)
is.ArAr(x)
is.KCa(x)
is.PD(x)
is.RbSr(x)
is.SmNd(x)
is.LuHf(x)
is.ReOs(x)
is.ThU(x)
is.UThHe(x)
is.fissiontracks(x)
is.detritals(x)
is.other(x)
is.diseq(x)
as.UPb(x, format = 3, ierr = 1, d = diseq())
as.PbPb(x, format = 1, ierr = 1)
as.ArAr(x, format = 3, ierr = 1)
as.ThPb(x, format = 1, ierr = 1)
as.KCa(x, format = 1, ierr = 1, sister = 44)
as.RbSr(x, format = 1, ierr = 1)
as.ReOs(x, format = 1, ierr = 1)
as.SmNd(x, format = 1, ierr = 1)
as.LuHf(x, format = 1, ierr = 1)
as.ThU(
  x,
  format = 1,
  ierr = 1,
  U8Th2 = 0,
  Th02i = c(0, 0),
  Th02U48 = c(0, 0, 1e+06, 0, 0, 0, 0, 0, 0)
)
as.UThHe(x, ierr = 1)
as.fissiontracks(x, format = 1, ierr = 1)
as.detritals(x)
as.other(x, format = NULL, ierr = 1)

Value

is.X(x) returns a logical value.

as.X(x) returns an object of class X.

Arguments

x: a data object returned by read.data or diseq.
format: data format. See read.data for details.
ierr: input error. See read.data for details.
d: an object of class diseq.
sister: the non-radiogenic (`sister') isotope of Ca that is to be used for K-Ca isochrons.
U8Th2: \(^{238}\)U/\(^{232}\)Th activity-ratio of the whole rock. Used to estimate the initial \(^{230}\)Th/\(^{238}\)U disequilibrium (for Th-U formats 3 and 4).
Th02i: 2-element vector with the assumed initial \(^{230}\)Th/\(^{232}\)Th-ratio of the detritus (for Th-U formats 1 and 2) and its standard error.
Th02U48: 9-element vector with the measured composition of the detritus, containing X=0/8, sX, Y=2/8, sY, Z=4/8, sZ, rXY, rXZ, rYZ.

Details

IsoplotR uses the following S3 classes to store geochronological data: UPb, PbPb, ThPb, KCa, UThHe, fissiontracks, detritals and PD, where the latter is the parent class of the simple parent-daughter chronometers RbSr, SmNd, LuHf and ReOs. All these classes have overloaded versions of the generic length() function and `[` subsetting method.

Additional functions for each class include as.X(x), which converts the data table x to an object of class X; and is.X(x), which checks if x has class X.

UPb: a list containing:

x

a matrix containing the isotopic measurements

format

a number between 1 and 8

d

an object of class diseq, i.e. the output of the diseq function
ArAr: a list containing

x

a matrix containing the isotopic measurements

J

a two-element vector with the J-factor and its uncertainty

format

a number between 1 and 3
ThU: a list containing

x

a matrix containing the isotopic measurements

format

a number between 1 and 4

Th02

a two element vector with the assumed initial \(^{230}\)Th/\(^{232}\)Th-ratio of Th-bearing detritus. Only aplicable to formats 1 and 2.

Th02U48

9-element vector with the measured composition of Th-bearing detritus

U8Th2

the measured \(^{238}\)U/\(^{232}\)Th activity ratio of the whole rock. Only applicable to formats 3 and 4
PbPb, ThPb, KCa, PD, RbSr, SmNd, LuHf, or ReOs: a list containing

x

a matrix containing the isotopic measurements

format

a number between 1 and 3
UThHe: a matrix of He, U, Th (and Sm) measurements
fissiontracks: a list containing

format

a number between 1 and 3

x

a matrix of spontaneous and induced fission track counts (only included if format=1)

rhoD

the track density of the dosimeter glass, extracted from the input data (only included if format=1)

zeta

the zeta calibration constant extracted from the input data (only included if format<3)

Ns

a list containing the spontaneous fission track counts (only included if format>1)

U

a list of lists containing the U-concentration or U/Ca-ratio measurements for each of the analysed grains (only included if format>1)

sU

a list of lists containing the standard errors of the U-concentration or U/Ca-ratio measurements for each of the analysed grains (only include if format>1)

spotSize

the laser ablation spot size (only included if format>1)
detritals: a list of named vectors, one for each detrital sample.
diseq: is a class that contains the output of the diseq function, which stores initial disequilibrium data for U--Pb geochronology.

Examples

Run this code

attach(examples)
ns <- length(UPb)
concordia(UPb[-ns,])
if (is.PD(RbSr)) print('RbSr has class PD')