Retrograde carbo-fracturing and resulting textures from Fe-skarn ores, Ocna de Fier-Dognecea, SW Romania

Textures resulting from retrograde overprinting are examined in Fe zone of the Ocna de Fier-Dognecea orefield, Romania. Refractory minerals preserve evidence for the following sequence of events. (1) Erratic decarbonation causes carbo-fracturing and a dramatic drop in fO₂, marking the shift to a retrograde fluid regime. (2) Piercing and shock impacting upon prograde assemblages. (3) Brecciation and deformation assisted by fluid pressure. (4) Annealing and recrystallization, accompanied by sealing and healing.