Those are very low levels of gold considering the SEM used doesn't detect oxygen, one of the principal components of silicate rocks.
And as I said in the previous post the beam size is about 2 microns. The field of view in those images varies. You can't see the scale on all the images but in general the field of view is between 20 and 60 microns in width. A very fine gold grain in a regular gold deposits can be as small as 10 microns. If you focussed a 2 micron beam into a 10 micron gold grain you should expect to get a spectral response for gold close to 100% as the gold grain would be more or less pure gold. Take for example the third bottom image in your set. The image has a field of view of about 20 micron. If that light coloured area in bottom right half of the image was a gold grain the spectrum should show a very strong gold response closer to 100% not 5.2%. Remember also this SEM does not detect oxygen so the 5.2% weight of gold in this image is likely to be over represented. A good micro-probe should be able to map out a complete gold grain. Larger gold grains should be able to also be seen under visible light. We have been through all this before. ie the resolution of microscopes that use visible light. I'd like to see a report from an independent mineralogist who has looked at all these samples in thin section under visible light, forget about SEMs. That would be a first step in understanding how the gold is emplaced. Apparently this sort of report is too elusive. Esh
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