High-pressure alteration of eclogites from the Austroalpine basement north of Merano-Meran (Eastern Alps)

During high-P alteration in this area, clinopyroxene and phengitic mica belonging to an eclogitic mineral assemblage were altered to symplectites due to the reactions: 1) clinopyroxene I + K (super +) + H (sub 2) O = clinopyroxene II + plagioclase + amphibole + Na (super +) + Ca (super 2+) , and 2) phengite + quartz + Na (super +) + Ca (super 2+) = biotite + plagioclase K (super +) + H (sub 2) O. The P conditions prevailing during reaction (1) were evaluated by the jadeite content of clinopyroxene II as 9 kbar.