numOSL (version 1.6)

RadialPlotter: Estimating parameters of Rex Galbraith's statistical age model (by a Maximum Likelihood Estimation method) and drawing a radial plot

Description

Depending on the specified number of components, this function performs statistical age models analysis reviewed in Galbraith and Roberts (2012) dynamically. Age models that can be performed include: central age model (CAM), minimum age model (MAM), and finite mixture age model (FMM).

Usage

RadialPlotter(EDdata, ncomp = 0, addsigma = 0, 
              maxcomp = 6, algorithm = c("port","lbfgsb"),
              plot = TRUE, pcolor = "blue", psize = 1.5, 
              kratio = 0.3, zscale = NULL)

Arguments

EDdata

matrix(required): two columns, equivalent dose values and their standard errors

ncomp

numeric(with default): the number of components, -1=MAM3, -2=MAM4, 0 means fitting FMM automatically, 1=CAM, and >=1 means fitting FMM with a given number

addsigma

numeric(with default): an additional uncertainty

maxcomp

numeric(with default): the allowed maximum number of components (up to 9) when applying FMM

algorithm

character(with default): an algorithm used for optimizing MAM, default algorithm="port"

plot

logical(with default): draw a radial plot or not

pcolor

character(with default): the color of a data point, input colors() to see more available colors

psize

numeric(with default): the size of a data point

kratio

numeric(with default): an option used for modifying the shape of zscale

zscale

numeric(optional): an option used for modifying the z-scale of a radial plot. Example: zscale=seq(min(EDdata),max(EDdata),by=3L)

Value

• Return a list of S3 class "RadialPlotter" that contains following elements:
• pars
  the resulting parameters and standard errors
• bic
  the Bayesian Information Criterion value
• maxlik
  the maximum logged likelihood value

Details

Both CAM and FMM are fitted using the Maximum Likelihood Estimation method outlined by Galbraith (1988), while MAM can be estimated using either the "L-BFGS-B" algorithm (R function optim in package stats) or the "port" algorithm (R function nlminb in package stats).

References

Galbraith RF, 1988. Graphical Display of Estimates Having Differing Standard Errors. Technometrics, 30: 271-281.

Galbraith RF, 1990. The radial plot: Graphical assessment of spread in ages. International Journal of Radiation Applications and Instrumentation. Part D. Nuclear Tracks and Radiation Measurements, 17: 207-214.

Galbraith RF, Green P, 1990. Estimating the component ages in a finite mixture. International Journal of Radiation Applications and Instrumentation. Part D. Nuclear Tracks and Radiation Measurements, 17: 197-206.

Galbraith RF, Laslett GM, 1993. Statistical models for mixed fission track ages. Nuclear Tracks And Radiation Measurements, 21: 459-470.

Galbraith RF, 1994. Some Applications of Radial Plots. Journal of the American Statistical Association, 89: 1232-1242.

Galbraith RF, Roberts RG, Laslett GM, Yoshida H, Olley JM, 1999. Optical dating of single grains of quartz from Jinmium rock shelter, northern Australia. Part I: experimental design and statistical models. Archaeometry, 41: 339-364.

Galbraith RF, 2005. Statistics for Fission Track Analysis, Chapman & Hall/CRC, Boca Raton.

Galbraith RF, 2010. On plotting OSL equivalent doses. Ancient TL, 28: 1-10.

Galbraith RF, Roberts RG, 2012. Statistical aspects of equivalent dose and error calculation and display in OSL dating: An overview and some recommendations. Quaternary Geochronology, 11: 1-27.

Further reading

Duller GAT, 2008. Single-grain optical dating of Quaternary sediments: why aliquot size matters in luminescence dating. Boreas, 37: 589-612.

Kreutzer S, Schmidt C, Fuchs MC, Dietze M, Fischer M, Fuchs M, 2012. Introducing an R package for luminescence dating analysis. Ancient TL, 30: 1-8. Available at http://CRAN.R-project.org/package=Luminescence.

Rodnight H, 2008. How many equivalent dose values are needed to obtain a reproducible distribution? Ancient TL, 26: 3-10.

Rodnight H, Duller GAT, Wintle AG, Tooth S, 2006. Assessing the reproducibility and accuracy of optical dating of fluvial deposits. Quaternary Geochronology, 1: 109-120.

Schmidt S, Tsukamoto S, Salomon E, Frechen M, Hetzel R, 2012. Optical dating of alluvial deposits at the orogenic front of the andean precordillera (Mendoza, Argentina). Geochronometria, 39: 62-75.

Vermeesch P, 2009. RadialPlotter: a Java application for fission track, luminescence and other radial plots. Radiation Measurements, 44: 409-410. Available at http://www.ucl.ac.uk/~ucfbpve/radialplotter/.

See Also

dbED; mcMAM; mcFMM

Examples

# Loading equivalent dose data.
  data(EDdata)
# Finding the appropriate number of components in FMM.
  RadialPlotter(EDdata$al3,zscale=seq(24,93,7))
# Fitting a 3-parameter minimum age model. 
  RadialPlotter(EDdata$gl11,ncomp=-1,zscale=seq(20,37,3))