Hello,
although in metamorphism the products of a reaction consuming a
mineral are mostly solids, it is not true that they always remain
next to the reactant, form a corona and are readily identifiable.
Sometimes also a corona may be present, but formed only by one of the
products.
In any case, personally I find it convenient to speak about
"resorption of garnet" rather than about "a process where garnet is
consumed while reacting with A+B+... to produce C+D+...".
I think it is a good idea to keep using the word resorption even in
metamorphism when describing the "consumption / corrosion" of a
mineral whatever are the products...
Cheers, Pavel
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> From an igneous perspective, I would say that resorbtion (or
>resorption) actually means corrosion of an earlier-formed crystal
>(whatever its origin) by the surrounding matrix (magma in the igneous
>context), without precipitation of a reaction rim (corona in
>metaspeak) of new minerals. If this happens in metamorphic rocks then
>use of the term resorbtion would be cognate with the igneous use. If
>not (reaction products always or nearly always in evidence, forming a
>corona or kelyphite?), I would suggest that the term might best be
>reserved for the magmatic cases and only used in mm petrology in the
>rare? cases where resorbtion (rather than reaction to solid products)
>has actually occurred. That's my ignorant position.
>Cheers,
>JC
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