Hi Bernardo,

I have seen anisotropic garnet many times in lawsonite eclogite-facies "blueschists". This is also common in bizarre metasomatic products with Fe-Ca-Mn garnet, but I guess you refer to "standard" rock types.

I have seen these garnets in both weakly and highly deformed rocks. One example from lawsonite eclogite-facies metagabbro (Corsica) is described in Vitale Brovarone & Herwartz, 2013 (LITHOS), where we also dated the garnet by Lu-Hf. In that case it was likely a slight hydrogarnet component in a Fe2+>>Ca>Mn garnet. This is quite common in Corsica.

I generally see this kind of anisotropy quite well with condensed transmitted light; In most cases it has sector zoning.

Best,

Alberto

2016-12-16 21:33 GMT+04:00 Bernardo Cesare <[log in to unmask]>:

Dear all,
we have found a highly deformed blueschist showing optically
anisotropic garnet, not yet probed but presumably a Fe-Mg(-Mn) solution.
A first, quick search for similar occurrences didn't bring results so
I'd greatly appreciate your feedback, and to receive references of
studies that might help us in the interpretation of this behaviour.

Thank you very much in advance!
Regards,
Bernardo

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Bernardo Cesare
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