A new garnet-bearing mineral breccia from North Otago, New Zealand

Abstract

Recent road works have exposed a new outcrop of garnet-bearing breccia at Alma, North Otago. The rocks and minerals within the breccia are similar to those present in the classic mineral breccia at Kakanui. The mineral breccia is a mantle-sourced diatreme with associated marine reworked volcaniclastics. Mantle xenoliths include lherzolite and garnet pyroxenites occurring with megacrysts of garnet, clinopyroxene, kaersutite, and feldspar. However, detailed mineral chemistry and volcanic clast petrography suggest that the Alma deposit could be derived from a separate source. © 2002 Taylor & Francis Group, LLC.