Lauraceae from rainforest surrounding an early Miocene maar lake, Otago, southern New Zealand

Abstract

Examination of over 700 fossil leaves from an early Miocene finely laminated lacustrine diatomite at Foulden Maar, near Middlemarch, Otago, New Zealand, provides evidence that a diverse subtropical Lauraceae-dominated evergreen forest once surrounded this small maar lake. Twenty-three million years ago, four leaf taxa with apparent affinities to Beilschmiedia, five with apparent affinities to Cryptocarya and one with apparent affinities to Litsea comprised 44% of the leaves preserved in a lacustrine rainforest growing on basalt- or schist-derived substrates, contributing leaves, flowers and fruits to the fossil deposit. Angiosperm and conifer pollen and macrofossils from numerous families present in the diatomite indicate a diverse rainforest flora (more or less equivalent to a modern simple notophyll vine forest from eastern Australia) growing under an apparently seasonally dry, mesothermal palaeoclimate on relatively nutrient-rich soils.