Composition and Orientation of Clinopyroxene Lamellae in Bushveld-Type Orthopyroxene from the Greenhills Ultramafic Complex, Bluff Peninsula, Southland, New Zealand

D. J. Mossman1
Geology Department, University of Otago, Dunedin, New Zealand
1Present address: Dept. of Geological Sciences, University of Saskatchewan, Saskatoon.

Summary: Identification of clinopyroxene lamellae in Bushveld-type orthopyroxene from the Greenhills Ultramafic Complex has been made on the basis of partial analysis by electron microprobe as well as by unit cell determination by prolonged exposure to X-rays of single crystals of orthopyroxene. Lamellae averaging Ca42Mg47Fe11 in composition with an approximate unit cell a 9·79, b 8·90, c 5·29 Å, β 106° 14′, occur in orthopyroxene Ca2Mg67Fe31 with unit cell a 18·28, b 8·85, c 5·20 Å. The Greenhills lamellae are of orientation identical to those described by Hess (1960), which share c and b axes with host orthopyroxene.

Mineralogical Magazine; June 1971 v. 38; no. 294; p. 160-164; DOI: 10.1180/minmag.1971.038.294.04
© 1971, The Mineralogical Society
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