Climatic implications from the sequential changes in diversity and biogeographic affinities for brachiopods and bivalves in the Permian of eastern Australia and New Zealand

Brachiopoda and Bivalvia of successive macro-invertebrate zones of eastern Australia and New Zealand are analysed to demonstrate a sequence of climatic change throughout the Permian Period, reflecting glacial episodes, separated by warmer intervals. Three such glacial intervals are indicated for the Early (Cisuralian) Permian (a long Asselian episode, a brief Artinskian episode and a substantial Kungurian interval), followed by a cold Roadian interval (Middle Permian–Guadalupian), and a very late Permian (Lopingian) episode. Markedly warmer intervals developed in the possibly late Asselian, Baigendzinian and much of the Lopingian. In addition, relatively long cool times allowed the flourishing and comparative diversification of eastern Australian faunas at several stages.