classes: Geochronological data classes

In IsoplotR: Statistical Toolbox for Radiometric Geochronology

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)

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)

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.
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.

Value

is.X(x) returns a logical value.

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

See Also

read.data diseq

Examples

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

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