dluskora1: dluskora1:A simulator of diffusion-limited REE uptake by...

Description Usage Arguments Note Author(s) References Examples

View source: R/dluskora1.R

Description

"dluskora1" is a useful function to simulate diffusion-limited REE uptake by a growing eclogite garnet. It returns plots of theoretical REE profiles of a given garnet and its growth time according to various parameters which you can set, such as REE diffusion coefficients around the garnet, its temperature path and the garnet's growth process.

Usage

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dluskora1(fac1, Q, syR, c_ave, D_0, R, T_1, T_2, K_d, Mr, Mt, fg, ft, garsize)

Arguments

fac1

This is a "diffusion length" and equal to D_0/A [cm]. A is the garnet growth coefficient (r = A t^(fg)). The meanings of D_0 and fg are shown below.

Q

Activation energy of REE diffusion around the garnet [J/mol]

syR

The size of the system concluding only a big garnet [cm]

c_ave

The initial concentration of REE on the system [ppm]

D_0

A pre-exponential factor of REE diffusion around the garnet [cm^2/year]

R

The universal gas constant [m^2 kg s^(-2) K^(-1) mol^(-1)]

T_1, T_2

This function can simulate a situation where the temperature around the system increased and you can set the initial and final temperature. T_1 is the initial temperature [degree Celsius] and T_2 is the final temperature [degree Celsius].

K_d

partition coefficient > 1 (REE concentration of garnet over REE concentration of the matrix)

Mr, Mt

They are the numbers of spatial(radial) and time meshes respectively.

fg

This is an exponent of the garnet's growth law. If you set fg as 1, the garnet will grow with the linear growth rate law: r = A t.

ft

This is an exponent of the temperature-increase law. If you set ft as 1, the temperature will increase with the linier increase rate law: T = B t.

garsize

The final size of the garnet [cm]

Note

>K_d and A do not depend on temperature in this function. Temperature increase affects only the REE diffusion coefficient around the garnet.

>Diffusion in the garnet is ignored.

>This program is based on a Crank-Nicholson scheme. If you set too large Mt, the result would not be appropriate.

>This function returns "mass_gain_percent" with the REE profile plot. Please check whether its absolute value is very small(~e-4). Your result is not appropriate when the value is too big.

Author(s)

Ryo Fukushima

References

Crank (1975) The mathematics of diffusion. Oxford University Press, p414.

Skora et al. (2006) Diffusion-limited REE uptake by eclogite garnets and its consequences for Lu-Hf and Sm-Nd geochronology. Contrib. Mineral Petrol., 152:703-720.

Examples

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dluskora1(fac1=(1.78 *10^(21)), Q=300000, syR=0.60, c_ave=30,
D_0=(4 * 10^(13)), R=8.3, T_1=450, T_2=600, K_d=15, Mr=100,
Mt=45, fg=1, ft=2, garsize=0.27)

Ryo-fkushima/dluskora documentation built on Nov. 13, 2019, 9:02 p.m.