Hi Rietveld users,
Note: The question below relates specifically to some parameters in
the s/w I am using (Siroquant for Windows) but I hope others using
different s/w to refine similar materials may have some helpful
suggestions as well.
QUESTION 1:
I am using Siroquant for Windows (v1.0) to attempt some quant runs on
some natural granite samples that contain some highly oriented phases
(biotite and chlorite). When I try to refine on orientation, the
refinement blows up and gives an error something like "orientation
parameter, phase 2 too small. Reset to higher value ..." I dutifully
reset to 0.9 and try again. Same result.
Do any of you know of a way to constrain the refinement so that the
orientation parameter doesn't get too small (maybe stops at minimum)?
Tried setting a low value for damping factor but doesn't seem to make a
difference. The samples have been micronized and hand packed as
loosely as possible so I don't think I can improve the orientation
problem through sample prep.
QUESTION 2:
Also, are there any of you who have experience in refinemnets of phase
mixtures which contain feldspars or other minerals that are part of
solid solution series? Just determining the correct set of cell
parameters to use seems to be one of the biggest hurdles.
*Any* help you can offer would be *greatly* appreciated. I'm staring
at a deadline for an internal report this Thursday.
Thanks a bunch.
Stu
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/ \._ _|_ _.._ o _ Stu Miller - Mineralogist
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Geoscience Laboratories
Ministry of Northern Development & Mines
933 Ramsey Lake Road, Sudbury, Ontario, CANADA P3E 6B5
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