I have done this thin section from red rhyolite (in hand specimen), is it altered spherulitic rhyolite?
I think it is altered, but I will convey your message a specialist Professor Jabrane raouf and I will give you more...
The texture indicates the spherulitic stage of devitrified glass, common in rhyolites.
Dear Nasser: I agree with Alexandrina's answer, but it is an altered rhyolite tuff, I think it is a tuff because the lower-right part looks like a fragment of glassy obsidian which has developed quite clear spherules. The rest of the rock looks fragmented, it has angular shaped feldspar, plagioclase and quartz crystals in a glassy matriz, also devitrified and forming some spherules locally. How old is this rock, I assume due to its alteration that could be at least Miocene or even older? Vitreous and crystalline rhyolites here in Venezuela, of Jurassic age (200 Ma), have gone more than forming spherules, the matrix has developed a full fedged granophyric texture!
With regards, Sebastian.
Yes, Sebastian is right. It looks like granophyric texture. Could be a welded tuff. These stages of devitrification develop in coherent glass.
Agree with Sebastián Grande and Alexandrina Fulop that it is likely a rhyolitic tuff that may be deformed as well.
Thank you dear all for kind and scientific answers,
I'm sorry for taking so long to write back. I've not been able to access the RG.
Seems reasonable, what that Alexandrina and Sebastián were saying. It should be noted that the sample have been taken from a hydrothermal alliterated area related gold epithermal deposit from Eocene period. Most cavities are filled with quartz.
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