Subsilicic Magnesian Potassium-Hastingsite from the Prince Olav Coast, East Antarctica

Kazuyuki Shiraishi, Takanobu Oba, Morihisa Suzuki and Ken’ichi Ishikawa
National Institute of Polar Research, Kaga, Itabashi-ku, Tokyo 173, Japan
Department of Geosciences, Joetsu University of Education, Joetsu 943, Japan
Department of Geology, Faculty of School Education, Hiroshima University, Hiroshima 734, Japan
Department of Earth Sciences, College of General Education, Tohoku University, Kawauchi, Sendai 980, Japan

Abstract: Two subsilicic magnesian potassium-hastingsites (4.55 and 4.34 wt.% K2O) and one magnesian potassium-hastingsite occur in calc-silicate pods in well-layered gneisses from the transitional amphibolite- and granulite-facies terrain of a Cambrian metamorphic complex, East Antarctica. Subsilicic magnesian potassium-hastingsite is the most K-rich Ca-amphibole yet reported: (K0.85Na0.11Ca0.02)0.98(Ca1.98Mn0.02)2.00(Mn0.01Mg1.92Fe1.202+Fe1.113+Ti0.13Al0.64)5.0−(Si5.64Al2.36)8O22.48(OH,F,Cl)1.52.

Keywords: subsilicic magnesian potassium-hastingsite • amphibole • East Antarctica

Mineralogical Magazine; December 1994 v. 58; no. 393; p. 621-627; DOI: 10.1180/minmag.1994.058.393.11
© 1994, The Mineralogical Society
Mineralogical Society (www.minersoc.org)