AUTOMATIC ROUTINE TO MODEL 39-Ar DATA

by Oscar M. Lovera

NEWS: 6/17/96 Small bugs corrected. 'Rounded errors cause one of the parametes to become infinity.'

The autoarr.f (PC version autoarr.for)routine was develop to automatically model the 39-Ar laboratory data. The program starts by calculating the activation energy (E), and log(Do/ro^2), parameters which are common to all domains in the distribution. To calculate these parameters, a weighted least square fitting is applied to a few first heating steps. After that, an iterative variational process is started with a random initial guess of the distribution parameters. It is done for a certain numbers of initial guesses and also for diverse total number of domains. Finally the program selects the parameters which produce the minimum "chi-square", of the fraction 39-Ar function and calculate the Arrhenius and log(r/ro) plots for these parameters.

Here you will find instruccion for running the programs, samples of the used input and output files, and a description of the subroutines, a flux diagram (postcript) of the program and some hints for running it. Check on Examples to see results of the programs on MH-10 K-feldspar.

The diffusion and distribution parameters obtained using autoarr.f can be used as input of the agesme.f or the autoage.f program to estimate a Thermal History.


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