Petrography, mineralogy, and chemistry of Pureora andesite volcano, North Island, New Zealand

Abstract

Pureora andesite volcano is sited at the junction of the Taupo Volcanic Zone with a line of andesite volcanoes extending from Ohakune to Waiheke Island. The lavas are porphyritic, with plagioclase, augite, and hypersthene the dominant phenocrysts. Chemically all samples may be classified as low-silica andesites, and both major and trace element contents are consistent with their derivation by crystal accumulation of pyroxene from a labradorite or labradorite-pyroxene andesite magma.