Subcalcic, Fe-Rich Amphiboles in Meta-Dolerites, Glenrock Station, NSW, Australia

R. Offler
Department of Geology, University of Newcastle, NSW, Australia 2308

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 high aFe2+ and aFe3+ in the fluid phase produced during the breakdown of clinopyroxene, hornblende, magnetite, and ilmenite. The high aFe2+ led to Fe led to Fe2- occupying the B site, resulting in the formation of subcalcic amphiboles. Variation in aFe2+, aFe3+, aMg, aSi, aAl, and aCa, in different domains resulted in the crystallization of chemically inhomogeneous amphiboles.

Mineralogical Magazine; March 1984 v. 48; no. 346; p. 47-52; DOI: 10.1180/minmag.1984.048.346.07
© 1984, The Mineralogical Society
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