Note to readers: This post appeared as a column in the Armidale Express on Wednesday 15 April 2009. I am repeating the columns here with a lag because the Express columns are not on line. You can see all the columns by clicking here.
My last column covered the likely first period of Aboriginal occupation of New England from around 40,000 years ago. This period ended with dramatic climate change affecting every aspect of life.
From perhaps 25,000 years ago Sahul, the name given to the continent that then included Tasmania, the Australia mainland and New Guinea, became very dry, both intensely hot and intensely cold. This climatic regime peaked during what is called the Last Glacial Maximum, 21,000 to 15,000 years ago.
The sea retreated to perhaps 120 metres below current levels. It became colder, 2-4 degrees C below current levels. On land, mean monthly temperatures probably fell by 6-10 degrees C. Extensive inland dune building suggests that the climate became much windier.
New England’s coastal strip grew as the sea retreated. The sclerophyll woodland and deciduous forests would have progressively colonised the new land, with the coastal dunes and associated wetlands following the shifting coast east. While colder and drier, there was sufficient food and water to maintain populations.
The Tablelands were very different. There average temperatures fell by perhaps 8 degrees C. A region of cold steppe and scattered sub-alpine woodland began in New England, sweeping down through the southern Snowy Mountains into Tasmania.
In the southern Snowy Mountains, the fall in temperature was sufficient to allow glaciers to form despite the lower precipitation.
In New England, the higher portions of the Tablelands in the centre and south where average heights are around 1,300 metres must have been very cold, dry and windswept. Along New England’s Snowy Mountains where the highest peak (Round Mountain) is almost 1,600 metres, there were probably blizzards and semi-permanent snow despite the much lower precipitation.
It seems likely that any previous human occupation of the Tablelands would have come to an end, although people may still have visited the lower areas.
To the west, the slopes and plains experienced cold arid conditions probably similar to modern Patagonia. The lower slopes were probably grassland with spring herbs and scattered patches of woodland and forests. Further west, the often dry streams crossed arid plains. Human occupation would have retreated to places with secure water supplies.
These changes took millennia and would not have been noticeable to individual generations. However, the long term effects on the human population were almost certainly severe.
While we can surmise this, the absence of archaeological evidence makes it hard to define the precise effects.
We know that there was Aboriginal occupation of the coastal strip, given that the Wallen Wallen site in South East Queensland shows continuous occupation from 20,000 years ago, a date in the earlier part the Late Glacial Maximum. Other coastal sites that might have given us clues are now deep under water.
It is reasonable to assume that any occupation on at least the majority of the Tablelands ceased. But what happened further west?
With diminished rainfall but also lower temperatures, it seems likely that there were areas on the Western Slopes and Plains that would have continued to provide sufficient water and food to maintain life. Why, then, is there still no archaeological record?
Assuming that the area was populated, the pattern of sites would have reflected then on-ground conditions. Many of the sites would have been camping sites, not easily identifiable beyond lithic scatter. Other sites would have reflected the past location of permanent water.
My feeling is that we need to chart what the landscape was like then to identify possible sites. However, it may be that the landscape has changed so much that we will never know.
As the long cold spell of the Last Glacial Maximum came to an end, New England entered a new period of dramatic geographic and climatic change. But that’s again a matter for another column.
Note on Sources: The material in this and the previous column is largely drawn from John Mulvaney & Johan Kamminga, Prehistory of Australia, Allen & Unwin, Crows Nest, 1999.