Australia: The Land Where Time Began

A biography of the Australian continent 

The Carpentaria Plain was exposed by the dropping sea level during the glacial phases of the Pleistocene ice age, with increases in the land area around northeastern Queensland and Great Australian Bight. Pollen cores from the Gulf of Carpentaria (Chivas et al., 2001; Torgersen et al., 1988) indicate that it was probably very open woodland of Callitris, Casuarina and Myrtaceae on the higher and better drained ground, swamps in the low-lying areas near the low points and grassland in between the 2 other vegetation types. It is assumed there were probably at least some eucalypts among the other tree types in the woodland. In the centre of the plain was Lake Carpentaria which received rivers from southern New Guinea across the plain.

Pollen in the marine sediment core from Lombok Ridge indicate the western side of the Carpentaria Plain had large mangrove stands along its coast and mainly a grassy eucalyptus woodland. In this part of the present seafloor are a number of small enclosed catchments that may have formed freshwater lakes at time of low sea level (Yokohama et al., 2001).

At the time of the LGM the Aru Islands, about 150 km south of New Guinea, were on the western edge of the plain, part of a dissected limestone plateau. A human occupation site, that has been dated to 27,000 BP to 12,000 BP, has been found in Lembadu Cave (O'Connor et al., 2002). It is believed the occupants came from northern Australia rather than southern New Guinea (Golson, 2001). The animals hunted by the people occupying the cave, agile wallabies, red-legged pademelons, northern brown bandicoots and long nosed Echymipera kaluba ( a spiny bandicoot now found only in New Guinea). They are all species living on high-rainfall savannas and rainforest edges.

Sources & Further reading

• Maey E. White, The Greening of Gondwana, the 400 Million Year story of Australian Plants, Reed, 1994
• Chris Johnson, Australia's Mammal Extinctions, a 50,000 year history, Cambridge University Press, 2006