rice (version 0.3.0)

contaminate: Simulate the impact of contamination on a radiocarbon age

Description

Given a certain radiocarbon age, calculate the observed impact of contamination with a ratio of material with a different 14C content (for example, 1

Usage

contaminate(y, sdev = NULL, fraction, F14C, F14C.er = 0, decimals = 5)

Value

The observed radiocarbon age and error

Arguments

y

the true radiocarbon age

sdev

the error of the true radiocarbon age

fraction

Relative amount of contamination. Must be between 0 and 1

F14C

the F14C of the contamination. Set at 1 for carbon of modern radiocarbon age, at 0 for 14C-free carbon, or anywhere inbetween.

F14C.er

error of the contamination. Defaults to 0.

decimals

Rounding of the output. Since details matter here, the default is to provide 5 decimals.

Author

Maarten Blaauw

Examples

contaminate(5000, 20, .01, 1) # 1% contamination with modern carbon
# Impacts of different amounts of contamination with modern carbon:
real.14C <- seq(0, 50e3, length=200)
contam <- seq(0, .1, length=101) # 0 to 10% contamination
contam.col <- rainbow(length(contam))
plot(0, type="n", xlim=c(0, 55e3), 
  xlab="real", ylim=range(real.14C), ylab="observed")
for(i in 1:length(contam))
  lines(real.14C, contaminate(real.14C, c(), contam[i], 1, decimals=5), col=contam.col[i])
contam.legend <- seq(0, .1, length=6)
contam.col <- rainbow(length(contam.legend))
text(52e3, contaminate(50e3, c(), contam.legend, 1), labels=contam.legend, col=contam.col, cex=.7)