摘要
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.