The Riversleigh Excavation
The Riversleigh excavation site provides views of life in Australia at chronologically different periods. These different periods are what lead Australia to its unique environment and habitats of today. This modern appearance developed in the Eocene time. The initial conditions of the early Paleocene and Eocene periods the land masses where experiencing tropical weather conditions. Lush vibrant rainforest developed in these conditions. Comparisons between leaves characteristics can be viewed at Maslin bay here leafs from the Eocene period are similar to modern notophyll forests. However, Eocene leaves still retained a distinctive quality because of Nothofagus and conifers.
The continents of Australia and South America were still coupled by way of Antarctica. Through this positioning it was possible for rainforests to extend between the continents. Routes were established due to the connections; however, there were sporadic breaks in the route. The breaks were cause by archipelagos and etc. Finally the eastern part was closed when Australia separated somewhere between 45 and 38 million years ago.
However, the continents of Australia and Antarctica separating brought previously isolated types of forests that included numerous types of trees, including Nothofagus. The fact that it was commonly associated with South America accounts for some similarities with forests of today in Tasmania. Discoveries of various fossilized animals also suggest the once connection of the continents.
Since the separation of Australia it has been heading in a northern direction. This northern movement is about 11 cm each year. Thus, around 25 million years ago the continent was actually ten degrees further south. The southerly positioning suggests that Australia was infested with rainforest. The Riversleigh's findings show that Australia's northern region once had a rich rainforest. Deposits found at the Simposn desert suggest central Australia had a closed forest. Yet, potentially less diverse than forest jacketing the northern regions.
Modern Rainforest offer a complex history of the Australasian regions rainforest. The 'palaeoaustral' rainforest have taken refuge in northeastern QLD and the mountains...