Abstract
Sub-greenschist facies metamorphism has produced unusual subcalcic, Fe-rich actinolitic amphiboles in meta-dolerites from the Glenrock Station area, NSW. They show edenite, riebeckite, ferri-tschermakite and Ti-tschermakite coupled substitutions. Their high Fe content is attributed to highaFe2+andaFe3+in the fluid phase produced during the breakdown of clinopyroxene, hornblende, magnetite, and ilmenite. The highaFe2+led to Fe led to Fe2-occupying theBsite, resulting in the formation of subcalcic amphiboles. Variation inaFe2+,aFe3+,aMg,aSi,aAl, andaCa, in different domains resulted in the crystallization of chemically inhomogeneous amphiboles.