My comment, in agreement with other previous comments, is that "resorption" implies "textural modification" -in this case, size or form of the
garnet grains- which is not always evident.
For me, "resorption" can be also established by "microprobe profile" across several garnet grains (porphyroblasts or not) in the same thin
section which show "reverse zoning" around the grains with a variable shortening of the "normal zoning".
It is also important to not forget that "resorption" -a concept different of "retrogression"- is possible during prograde or retrograde metamorphism.
In the same context, an other important aspect to consider, is the "refractory character" of the garnet in the context of "solid state reaction".
For example, with the "textural evidence" and "microprobe profile" see the following papers of what I was a co-author :
P.de Bethune et al,. 1968, Bull.Suisse, Min.Petr., 48, 437-454.
P.de Bethune and al., 1975, Contrib.mineral.Petrol., 50, 197-204
J.Desmons et al., 1977, Mém.Inst.Géol.Univ.Louvain, t.29, 327-347.
D.Laduron et al., 1981, Mém.Inst.Géol.Univ.Louvain, t.31, 335-347.
With best wishes.
Dominique
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