Catalogue of crustal xenoliths from the St Heliers Volcanoes, Auckland Volcanic Field, New Zealand

Abstract

We describe a collection of xenoliths ejected by phreatomagmatic eruptions and preserved in tuff from Glovers Park and Taylors Hill volcanoes in St Heliers. These rocks are different from mantle-derived xenoliths and semi-assimilated crustal quartzose xenoliths within the monogenetic Auckland Volcanic Field in that they are a diverse suite of crustal rock fragments dominated by mafic schistose and non-schistose rocks ranging from a few mm up to 70 cm in diameter. The 310 specimens lodged at Auckland University are a useful resource for further research about the nature of the crust below the Auckland Volcanic Field and the eruption mechanisms for these two volcanoes.