Dear Pavel,
if your bulk has e.g.
FE(10) and O(10), all Fe is Fe(II). (all Fe as FeO)
So if you need, for example, a model with 10 % of the Fe as Fe(III), you
just add O(0.5) as extra oxygen.
in THERIN the bulk definition would be:
FE(10)O(10)O(0.5)
meaning that 9 Fe are present as FeO and 1 Fe is present as FeO1.5
you do not need to write the oxygen separately, but I recommend doing
so. It helps you to remember what kind of redox state you are using.
An additional example: The THERIN input below defines the bulk rock
composition of a schist sample from the Zermatt area in the Alps:
SI(48.32)AL(26.33)FE(8.68)MG(4.66)CA(4.01)NA(3.19)K(3.71)O(156.935)H(50)O(25)O(0.217)*KB860
Zermatt 5% Fe as Fe(III)
Fe total is 8.68 thus 8.68 oxygen of the O(156.935) are contributed be
the Fe.
if 10 % of the Fe is Fe(III) then 0.434 extra oxygen is added to the bulk
if 5 % of the Fe is Fe(III), as above, 0.217 extra oxygen is needed.
H(50)O(25) in the THERIN bulk above ensures H2O saturation.
hope this is useful for you
Regards
Kurt Bucher
University of Freiburg
On 2/19/16 5:28 PM, Pavel Pitra wrote:
> Dear all,
>
> strongly rooted in the Thermocalc world, I started trying to play a
> little bit with Theriak-Domino. Although I read the manual and the
> various internet resources, I couldn't figure out how to specify a
> proportion of ferric iron (or Fe2O3) in the bulk rock composition.
> I would be grateful for a hint!
>
> Thanks a lot in advance!
>
> Cheers,
>
> Pavel
>
--
Kurt Bucher (Prof. Dr.)
Institute of Mineralogy and Geochemistry
University of Freiburg
Albertstrasse 23b D-79104 Freiburg Germany
Phone 49-761-203-6431 (direct) 6396 (general office) 6407 (FAX)
http://www.minpetro.uni-freiburg.de
[log in to unmask]
|