dluskora2: dluskora2:A simulator of diffusion-limited REE uptake by...

Description Usage Arguments Note Author(s) References Examples

View source: R/dluskora2.R

Description

"dluskora2" resembles dluskora1 but this can be more useful if you'd like to simulate REE profile with complicated growth of garnets. You can set radius-time path as a combination of four points and three straight lines.

Usage

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dluskora2(fac1, Q, syR, c_ave, D_0, R, T_1, T_2, K_d, Mr, Mt, ft, garsize, Tm_1, Tm_2, gmratio)

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.

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]

Tm_1, Tm_2

This function can simulate the REE profile with a bending radius-time path. Tm_1 and Tm_2 mean the bending points' temperature. Garnet growth stops when temperature is in the range between Tm_1 and Tm_2. They of course should be bigger than T_1 and smaller than T_2.

gmratio

"gmratio" is the ratio of the Tm_1 garnet radius divided by "garsize".

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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dluskora2(fac1=(10^(20)), Q=300000, syR=0.20, c_ave=30,
D_0=(10^(13)), R=8.3, T_1=450, T_2=600, K_d=15, Mr=100,
Mt=74, ft=1, garsize=0.1, Tm_1=500, Tm_2=550, gmratio=0.5)

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