ES2 Metamorphic Rocks - Metamorphic Microstructures #19
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Reaction rim #2
The grain at the centre of the field of view is omphacite (sodic clinopyroxene)
enveloped by a rim of spongy greenish amphibole as a result of the overprinting of the eclogite by
amphibolite-facies metamorphism in the later stages of the Caledonian orogeny. Notice that the
phengitic white mica at lower left also has a narrow brown reaction rim composed of biotite and
feldspar.
Plane-polarised light and crossed polars. Field of view is 2.5 mm across.
Partly retrogressed eclogite, Kolset, Nordfjord, W Norway. Sample DWC-12.
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