Luminescence (version 0.6.1)

calc_MaxDose: Apply the maximum age model to a given De distribution

Description

Function to fit the maximum age model to De data. This is a wrapper function that calls calc_MinDose() and applies a similiar approach as described in Olley et al. (2006).

Usage

calc_MaxDose(data, sigmab, log = TRUE, par = 3, bootstrap = FALSE, init.values, plot = TRUE, ...)

Arguments

data

RLum.Results or data.frame (required): for data.frame: two columns with De (data[,1]) and De error (values[,2])

sigmab

numeric (required): spread in De values given as a fraction (e.g. 0.2). This value represents the expected overdispersion in the data should the sample be well-bleached (Cunningham & Walling 2012, p. 100).

log

logical (with default): fit the (un-)logged three parameter minimum dose model to De data

par

numeric (with default): apply the 3- or 4-parametric minimum age model (par=3 or par=4).

bootstrap

logical (with default): apply the recycled bootstrap approach of Cunningham & Wallinga (2012).

init.values

numeric (with default): starting values for gamma, sigma, p0 and mu. Custom values need to be provided in a vector of length three in the form of c(gamma, sigma, p0).

plot

logical (with default): plot output (TRUE/FALSE)

...

further arguments for bootstrapping (bs.M, bs.N, bs.h, sigmab.sd). See details for their usage.

Value

Please see calc_MinDose.

Function version

0.3 (2015-11-29 17:27:48)

Details

Data transformation To estimate the maximum dose population and its standard error, the three parameter minimum age model of Galbraith et al. (1999) is adapted. The measured De values are transformed as follows: 1. convert De values to natural logs 2. multiply the logged data to creat a mirror image of the De distribution 3. shift De values along x-axis by the smallest x-value found to obtain only positive values 4. combine in quadrature the measurement error associated with each De value with a relative error specified by sigmab 5. apply the MAM to these data When all calculations are done the results are then converted as follows 1. subtract the x-offset 2. multiply the natural logs by -1 3. take the exponent to obtain the maximum dose estimate in Gy Further documentation Please see calc_MinDose.

References

Arnold, L.J., Roberts, R.G., Galbraith, R.F. & DeLong, S.B., 2009. A revised burial dose estimation procedure for optical dating of young and modern-age sediments. Quaternary Geochronology 4, 306-325. Galbraith, R.F. & Laslett, G.M., 1993. Statistical models for mixed fission track ages. Nuclear Tracks Radiation Measurements 4, 459-470. Galbraith, R.F., Roberts, R.G., Laslett, G.M., Yoshida, H. & Olley, J.M., 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, R.F., 2005. Statistics for Fission Track Analysis, Chapman & Hall/CRC, Boca Raton. Galbraith, R.F. & Roberts, R.G., 2012. Statistical aspects of equivalent dose and error calculation and display in OSL dating: An overview and some recommendations. Quaternary Geochronology 11, 1-27. Olley, J.M., Roberts, R.G., Yoshida, H., Bowler, J.M., 2006. Single-grain optical dating of grave-infill associated with human burials at Lake Mungo, Australia. Quaternary Science Reviews 25, 2469-2474. Further reading Arnold, L.J. & Roberts, R.G., 2009. Stochastic modelling of multi-grain equivalent dose (De) distributions: Implications for OSL dating of sediment mixtures. Quaternary Geochronology 4, 204-230. Bailey, R.M. & Arnold, L.J., 2006. Statistical modelling of single grain quartz De distributions and an assessment of procedures for estimating burial dose. Quaternary Science Reviews 25, 2475-2502. Cunningham, A.C. & Wallinga, J., 2012. Realizing the potential of fluvial archives using robust OSL chronologies. Quaternary Geochronology 12, 98-106. Rodnight, H., Duller, G.A.T., Wintle, A.G. & Tooth, S., 2006. Assessing the reproducibility and accuracy of optical dating of fluvial deposits. Quaternary Geochronology 1, 109-120. Rodnight, H., 2008. How many equivalent dose values are needed to obtain a reproducible distribution?. Ancient TL 26, 3-10.

See Also

calc_CentralDose, calc_CommonDose, calc_FiniteMixture, calc_FuchsLang2001, calc_MinDose

Examples

## load example data
data(ExampleData.DeValues, envir = environment())

# apply the maximum dose model
calc_MaxDose(ExampleData.DeValues$CA1, sigmab = 0.2, par = 3)