Description Usage Arguments Details Value Note Author(s) References See Also Examples

This function calculates the ages, confidence intervals and standard deviations from triplets (U,Th,Ph), obtained by electron microprobe, given together with corresponding errors.

1 2 | ```
calculateAges(measures, nloops = 1000, level = 0.05, verbose = TRUE,
seed = NULL)
``` |

`measures` |
a data.frame object with one electron microprobe measurement
by row and with columns U, corresponding error for U, Th, corresponding error
for Th, Pb, corresponding error for Pb, all expressed in ppm. See an example
with |

`nloops` |
the number of Monte Carlo (MC) simulations used to estimate the
confidence intervals for the ages. Default is |

`level` |
the level of significance of the confidence intervals for the
ages. Default is |

`verbose` |
logical; activates the verbose mode. Default is |

`seed` |
if supplied, initialize the random seed. Default is |

the ages are calculated by solving the Equation (1) of Montel *et al.*
(1996). The equation is solved by the Broyden method implemented in the
`nleqslv`

function.

The standard deviations and the confidence intervals are calculated using a MC
approach: randomized observations of the triplets are generated from normal
distributions with standard deviations equal to
*error/2* where 'error' denotes the error in the
measurement of Th, U or Pb, passed in measures. Standard deviations
are estimated by the empirical standard deviations and confidence intervals by
quantiles for probabilities *level/2*
and *1-level/2*, respectively.

an object of class `ages`

.

You should use at least 1000 MC simulations otherwise the estimated confidence intervals and standard deviations will not be reliable. Such simulations can take a few seconds/minutes for fifty or so triplets and corresponding errors.

Jean-Marc Montel [email protected]

Nathalie Villa-Vialaneix [email protected]

Montel J.M., Foret S., Veschambre M., Nicollet C., Provost A. (1996) Electron
microprobe dating of monazite. *Chemical Geology*, **131**, 37–53.

1 2 3 4 | ```
## Load the data
data(srilanka)
## Calculate the ages
calculateAges(srilanka, nloops=10)
``` |

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