Oligocene: 40-24 mya (may 23, 40000000 BC – apr 1, 24000000 BC)

Description:

Climate: First glaciers on Antarctica. Cooler and drier- more seasonal.
Continental movement: Drake Passage opens. Circum-polar current forms.
Australia: Australia colliding with New Guinea
Tasmania: Carried north on Australian plate about 65° south
Vegetation history: 45mya Australia departs with its cargo of Gondwanan plants and begins to evolve in isolation for next 30 million years. 25mya Acacia and Eucalyptus pollen first recognized in Australia. Temperate rainforest widespread.