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

In Ryo-fkushima/dluskora: Simulator of diffusion-limited REE uptake by eclogite garnets

Description

"dluskora2" (beta version) is another version of the program given by Skora et al. (2006). This resembles dluskora1 but can be more useful if you would like to simulate REE profiles with complicated garnet growths; you can set a radius-time path as a combination of three straight segments.

Usage

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 parameter equals D_0/A [cm]. A is the garnet growth coefficient (r = A t^(fg)). The meanings of D_0 and fg are shown below. This corresponds to the parameter "u" in Fukushima et al. (2021).
Q	The activation energy of REE diffusion around the garnet [J/mol]
syR	The radius of the system of which the garnet is located at the center [cm]
c_ave	The initial concentration of REE in the system [ppm]
D_0	The pre-exponential factor of the REE diffusion coefficient 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 temperatures. T_1 is the initial temperature [degree Celsius] and T_2 is the final temperature [degree Celsius].
K_d	The partition coefficient > 1 (REE concentration of garnet over REE concentration of the matrix)
Mr, Mt	The numbers of spatial(radial) and time meshes, respectively
ft	The 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 radius 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 temperatures at the bending points. 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	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 (Crank 1975).

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

Fukushima R, Tsujimori T, Aoki S, Aoki K (2021) Trace-element zoning patterns in porphyroblastic garnets in low-T eclogites: Parameter optimization of the diffusion-limited REE-uptake model. Isl Arc 30:e12394

Skora S, Baumgartner LP, Mahlen NJ, Johnson CM, Pilet S, Hellebrand E (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

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 April 24, 2021, 4:36 a.m.