You can mount detrital mica separates on a glass slide by putting canadabalsum keeping the glass plate on a hot plate at low temperature to make canadabalsum become hard. When the grains are fixed  remove the plate from hot plate and cool.Then it can be polished for feeding it  in  microprobe.

Thank you both for your answers. Kenneth, I am simply looking at whether there are distinct populations based on the variation of the chemistry of the detrital micas as an extra parameter to better constrain their potential source (aside from just their ages). I have never tried to mount micas so I do not know if they would need polishing like one would do on a standard thin section that one would want to analyse with an EPMA. If a few come off then, as you say, it is not an issue. Brijraj, I already have the EpoThin so it would make sense to make use of it.

The attached images No 1-3 show a polished thin section of a biotite-muscovite gneiss, in which the mica flakes are oriented more or less perpendicular to the ground surface. Here the quality of the surface is largely free from scratches. Image 4 shows the mica flakes more or less parallel to the polished surface. Here you can see numerous cracks, holes and scratches which damage the surface.

With the following steps, you can (avoid cracks, holes and scatches) create a dispersed mica sample that meets the requirements of the electron microprobe analysis.

1) An acrylglass ring of 20 mm diameter, about 2 mm thickness and 5 to 10 mm height is ground plane-parallel (fig 5).

2) One of the ground surfaces is covered with a double-sided adhesive tape, the inner surface is to be removed.

3) A commercially available aluminum foil is fixed twice on a flat surface.

4) The one side covered with the tape will now be firmly pressed onto the aluminum foil.

5) The interior of the ring will be filled to just below the rim with resin.

6) A mixture of quartz grains and mica grains, which have about the same diameter now carefully scattered onto the resin surface.

7) The quartz and mica will sink down onto the aluminum foil surface due to the higher weight. Possible air bubbles must be removed carefully with a fine brush.

8) After curing, the aluminum foil can be drawn off and the mount can be sanded and polished.

The embedded quartz grains prevent flattening and stacking of the mica flakes.

Try it! It works!

Best regards,

Guenter Grundmann

One can choose a longer or shorter process. One suggested by  colleague Mr. Gunter is a bit longer process and perhaps needs a little experience to remove air bubbles etc.One can choose shorter method as we have been doing without much problem.

@Guenter

Thanks for sharing this methodology and the very useful pictures with us. I see several advantages in your approach, a.o. the fact that you probably obtain a very neat and flat surface after pealing of the Al foil. 

However, unfortunately you still have to (slightly) polish the sample to 'reveal' the grains. For optical/chemical analysis, this could be necessary, but for XRD it would be ideal if this would not have to be the case (even if just to avoid strain). 

As you see, I also made the connection to XRD and random orientation of the grains. Here however you would potentially have a density separation during the 'sedimentation' of the grains, skewing the amounts of Qz/mica (or another spike used instead of Qz). 

So, although you did get me thinking, for XRD it still makes more sense to me to use a glue spray to create droplets, and sprinkle the grains onto that substrate. 

But then again, you were not talking about prepping samples for the XRD, so already my excuses for side-tracking this discussion...

Guenter, thank you very much for that comprehensive contribution. I will definitely look into that method. Kenneth, you make an excellent point, XRD analysis could be a good way to differentiate between different populations of detrital micas. I might try all of the above and see which suites best. And Kris, your deviation is warranted given that XRD could be a useful in terms of discriminating between detrital mica populations. I will add another answer describing which method ended up working best for me. Thank you all.