Australia

The Land

For millions of years, Australia was part of the super-continent of Pangea. As the continent broke apart and began drifting on the surface of the planet, Australia was part of the southern segment of Gondwana. Since severing its last connections with Antarctica and the island of Tasmania in the mid-Cenozoic (about 35 million years ago), Australia has been drifting toward southeast Asia at the rate of about 2 inches per year. Geologically speaking,Australia's life span as a free-standing continent will be relatively brief.

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Source: © iStockphoto/Kim Meagher.

Australia has been free of volcanoes, earthquakes, and other mountain-building forces longer than any other continent. Wind and rain have been eroding the surface for about 100 million years, making Australia's dominant feature its flatness. The extreme state of erosion in Western Australia has exposed some of the Earth's oldest rocks, dating back 4.3 billion years.

Unique Geologic Features

Uluru, the world's largest single rock, is the most visited landmark in central Australia. Uluru is an Aboriginal word meaning “great pebble.” It is the largest of a group of about 30 similar dome-shaped rocks rising from the desert floor. These rocks are the remains of a buried mountain range and are collectively known as the Olgas. The Aboriginal name of the Olga Rocks is Kata Tjuta, which means “many heads.” Uluru's size and color attract visitors from around the world. As the sun travels across the sky, the rock changes from brilliant red to a deep blue color. The Olgas are sacred to the Aborigines. Rock art found in caves on Uluru is thousands of years old. Sacred areas of the rock are off limits to all visitors, and one must ask permission before climbing marked trails. Kata Tjuta lies within Uluru National Park, which the government returned to its Aboriginal owners, the Anangu people, in1985. Uluru was formerly called “Ayers Rock,” after Sir Henry Ayers, a former leader of South Australia, but the Aboriginal people prefer the original names for these sites be used.

The Great Barrier Reef is a 1,200-mile long coral reef running along the Queensland coast of northeast Australia. Coral is created from masses of small marine animals called polyps. As polyps die, they leave their skeletons behind, which form the mass of the reef. New polyps grow on the old, creating a rainbow of colors. The Great Barrier Reef is the largest structure created by living organisms in the world. Parts of it are millions of years old. The reef is home to hundreds of species of fish, mollusks, and other marine life.

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