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Exploring Australia

Traveling Through the Land When the first Australians arrived in northern Australia, they found a land with a hot, wet climate similar to that in Southeast Asia. Gradually, groups of people began to travel south to cooler areas. It took about 10,000 years for Aborigines to explore and settle the whole of Australia. Fifty thousand years ago, Australia was 20 percent larger than it is now. It was joined to the islands of Papua New Guinea in the north and Tasmania in the south. The land became smaller as the sea level rose (because the ice caps melted, see page 10) and covered more of the coastline. Some scientists think that the sea has risen 500 feet (150 m) in the last 50,000 years. But the land of ancient Australia was not that different from modern-day Australia. There were low mountains in the east, deserts in the center, marsupial animals and eucalyptus or gum trees.

T asmania separated from the Australian mainland 12,000 years ago. Papua New Guinea separated from Australia 8,000 years ago.

Radiocarbon Dating Archaeologists use radiocarbon dating in their research into the ancient history of Australia. This is a technique which measures the level of radioactive carbon that is present in all natural things (such as shell, bone or wood). Because radioactive carbon breaks down and rots at a constant rate, it is possible to tell how old materials are by measuring how much they have decayed. Radio- carbon dating can be done on burnt materials like the shells found at Aboriginal campsites. A n archaeologist at work in Australia's outback. He is digging up fossils which will be radiocarbon dated in a laboratory.

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