The densities of New Zealand rocks

Abstract

Abstract The densities of 800 rock samples representing the major sedimentary, metamorphic, and igneous formations in New Zealand are summarised and tabulated. The youngest Pleistocene rocks have a wet density of l‐88g/cm 3 , and this increases down through the Tertiary column to 2‐55g/cm3 in the Cretaceous. Jurassic‐Permian greywackes have a wet density of 2‐65g/cm 3 and the oldest sediments a wet density of 2‐68 g/cm 3 . Metamorphosed rocks have higher densities. The greatest anomaly in the igneous rock densities is the very low value (2‐18g/cm 3 ) for the rhyolites of the Rotorua thermal area.