Published online by Cambridge University Press: 05 July 2018
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 high a Fe2+ and a Fe3+ in the fluid phase produced during the breakdown of clinopyroxene, hornblende, magnetite, and ilmenite. The high a Fe2+ led to Fe led to Fe2- occupying the B site, resulting in the formation of subcalcic amphiboles. Variation in a Fe2+ , a Fe3+ , a Mg, a Si, a Al, and a Ca, in different domains resulted in the crystallization of chemically inhomogeneous amphiboles.