A Late Oligocene-Early Miocene cool climate flora in Tasmania

Abstract

The Late Oligocene-Early Miocene Monpeelyata deposit occurs at 920 m above sea level on the Tasmanian Central Plateau, and was probably at least 700 m a.s.l. at the time of deposition. The palynoflora is dominated by Nothofagidites emarcidus/heterus (43%) and Phyllocladidites mawsonii (45%), although neither is represented in the macroflora. The total palynoflora is interpreted as representing a moderately diverse riparian rainforest, including and possibly dominated by one or more Nothofagus-conifer associations. The macroflora is dominated by imbricate-leaved conifers and microphyllous angiosperms. It is hypothesised that the macroflora represents the litter from exposed forest edges, where the microclimate was more variable than under the forest canopy. This forest edge habitat at high altitudes may represent the environment in which the alpine/subalpine flora evolved. Contemporaneous floras from mainland Australia are compared with Monpeelyata.