Australia: The Land Where Time Began

A biography of the Australian continent 

Evidence from Lake George                                                                                                    

A core drilled into the sediments of Lake George found pollen and charcoal that were dated to more than 100 000 years ago. In the top 8.6 m, covering 350,000 years, the longest continuous record of  fire and vegetation history in Australia. The core was drilled 72 m deep, the base of which was estimated to be from between 7 and 4.2 Ma. The sediment depth was estimated to be 134 m below the depth reached by the core, putting the estimated time for the formation of Lake George at about 20 Ma.

Pollen analysis (palynology) established the sort of plants in the vegetation growing in the environment around Lake George. In Zone F of the sediment there is a large increase in the amount of charcoal. It was suggested that the most likely explanation for this increase in charcoal is that it resulted from the arrival of humans in the area, with their fire-stick culture, for driving animals from cover and also as a method of encouraging fresh growth to support the populations of the animals they hunted, attracting their prey species to the area. The increase of fire led to the reduction of the number of fire intolerant species and the increase in the number of fire-tolerant species, and the first expansion of the area covered by the fire-tolerant Eucalyptus-dominated vegetation that has persisted to the present (Flood, 2004).

Gurdip Singh, who drilled the core, dated the sediment of zone F to 120,000 years ago, but Richard Wright has disputed this date, placing it closer to about 60,000 years ago. This would also fit with dates from Kakadu.

In 1980 a number of small amorphous quartz flakes were found in a gully. The site would have been the lake shore during the Ice Age. They were found in aeolian sand subsequently dated to 26,000-22,000 BP. In 1983 more were found in a perched sand dune on top of Butmaroo Hill near the highest former eastern shore of the lake.

In the 1.5 m deep sand deposit they found stratified stone artefacts. In the upper 12-20 cm was a micro-blade industry dated to about 4000 years ago. Based on 6 radiocarbon dates it is believed the base of the deposit dates to at least 10,000 years ago. The sand was on a large deposit of quartz and heavily metamorphosed volcanic rocks which was resting on bedrock. In this deposit there was a quartz core with negative flake scars - scars left  when flakes had been removed by humans. Several large, heavily weathered artefacts of metamorphosed volcanics have been found on the lake floor and in the tailings from sand mining operations. These artefacts include large flakes with rough lateral retouch, flaked cobbles, and dome-shaped 'horsehoof' cores - or core tools. It is believed these date from the terminal Pleistocene or possibly earlier.

Sources & Further reading

  1. Flood, Josephine, 2004, Archaeology of the Dreamtime, JB Publications.
Author: M. H. Monroe
Last updated: 30/09/2011

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