Geologically the Whitsundays are all drowned mountains that were once connected to the mainland. Melting ice in the Ice Age created a network of 74 islands.
About eighteen thousand years ago the earth entered a new orbital cycle that caused the northern latitude land masses to increase in heat from the sun. The ice began to melt which over the next twelve thousand years the sea rose some one hundred meters, isolating two mountain ridges from the Queensland central coast and flooding of the current natural Harbours around the Australian coast. During this time The Great Barrier Reefs corals grew on top of the ancient remains of earlier reefs.
Today if all global ice melted the sea level would rise by some eighty five meters. In recent times the sea level has been rising about one millimetre a year and this rate is accelerating due to the green house effect caused by unnatural gasses in the atmosphere.
The Great Barrier Reef is about 500,000 years old, but it has not been present in its current form for all of that time. Reefs have grown and receded on Australia’s continental shelf, depending on sea level changes. The present reef structure is only about 6,000 to 8,000 years old, and is growing on top of the underlying structure of old reefs formed during periods of higher sea levels. The Great Barrier Reef is not a single continuous reef along Australia’s continental shelf. Rather, it is composed of around 2,900 individual reefs of many shapes and sizes, and includes some continental (or rocky) islands surrounded by reefs.
The Great Barrier Reef comes quite close to the mainland, within a few kilometres, in the northern Great Barrier Reef, and is hundreds of kilometres offshore in the southern parts including the Swains Reefs.
A fringing reefs have formed adjacent to the mainland. Most reefs of the Great Barrier Reef have formed on the continental shelf rather than in the deep ocean like atolls, and are generally known as shelf reefs. Fringing reefs form adjacent to the mainland or high islands.
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Whitsundays Drowned Mountains |
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Whitsunday Islands |
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Hill Inlet lookout |
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Stunning island views |
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