Pyrope, Augite, and Hornblende From Kakanui, New Zealand

Abstract

Pyrope, augite, and hornblende occur as xenocrysts in a volcanic breccia of Whaingaroan (Lower Oligocene) age at Kakanui. The pyrope has the composition Py. Abo.o Gr,o.· Afb., Spo.,; n = 1'741; D = 3'72; a = 1l 536A. The augite is an aluminous variety with tschermakitic affinities; a = 1'686, {3 = 1'691, Y = 1'713; optically positive, 2V = 55°; D = 3'33. The hornblende is a hastingsite; a = 1'676, {3 = 1 687, Y = 1 695; optically negative, 2V = 80°; D = 3' 22. The occurrence and associations of these minerals suggest that they originated in the upper mantle. © 1966 Taylor & Francis Group, LLC. All rights reserved.