Dear all,
I am doing clay analysis with XRD and I find peak 14 A; 10 A and 7 A.
The 14 A is interpreted as Chlorite because no change in Glycol and Heating 400 but increase intensity in Heating 550.
The 7 A is interpreted as Kaolinite as no change in Glycol and Heating 400 but destroyed in Heating 550.
I am confused with peak 10,18 A, no d spacing change in Glycol, H400 or H550 but the intensity increase in H400 and slightly collapse in H550. The peak is unsymmetrical in Air Dried and when Glycol it become more symmetric and the 14 A more broad but not much.
I interpret it as Illite-Vermiculite because I think that the unsymmetrical peak of 10A collapse when heating at 400 and more collapse/no change at heating 550. This I refer to Clay Mineral Identification Flow Diagram by USGS.
I don't interpret broad 14 A peak as montmorillonite because there is no 17-18 A peak when it Glycolled.
Is it correct? Or this 10 A peak is just Illite?
Here I also attached the picture so that it can help you better understanding.
Thank you very much and have a good day!
The peak near 10 Angstroms showinng the various changes in shape and intensity with the different treatments looks like it should be attributed to a mixture of illite plus some other(s) expandable minerals (which move about with the different treatments). The peak near 10 ansytroms in the glycoled traces probably gives you the best estimate of how much illite is in your sample, since the other expandable minerals move away form this position when glycolated, and you can see that the 10 ang peak is smallest in this trace reaktive to the others. That said, the term illite allows for small amounts of interstratification with other layer types, so if these are expandable (e.g.) smectite or vermiculite, the illite peak itself wil also show some movement. Hope this helps, your best bet it to try to learn how different clays behave with treatments such as glycolation and heating by modelling the XRD paterns, there are several programs available like NEWMOD, or PyXRD the latter is free.
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