Glaucophane grains in retrogressed metabasalt

Glaucophane grains in retrogressed metabasalt

by Samuele Papeschi, University of Pisa, Pisa, Italy

The metabasalt at the Rio Marina lighthouse outcrop (Island of Elba) contains relics of glaucophane, lawsonite, and omphacitic clinopyroxene that grew under blueschist-facies conditions. These rocks represent some of the highest pressure products of early continental underplating in the Northern Apennines.

The image shows some zoned blue glaucophane grain (with tiny actinolite rims) surrounded by chlorite, actinolite (greens), epidote (tiny high-relief grains), and clinopyroxene relics (large brown porphyroclasts).

Field of view is approximately 1.5 mm
Polarized light - parallel polars

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