Bones of the Earth

by Mary Mageau

Granite boulders form an archIn Queensland’s Granite Belt all the bones of the earth are laid bare. Rock is everywhere — scattered in piles of rounded boulders, exposed in great slabs throughout ridges, creeks and forests, or appearing on bare domed mountains, soaring above the low lands and valleys. Here in the midst of an overpowering granite landscape the question begs to be asked, ‘Where did all this rock come from?’

Originally Stanthorpe granite was a molten mass of magma, thrust into the older surrounding rocks some 240 million years ago, during the early Triassic period. Deep below the surface it began to cool, allowing its minerals to solidify and grow into large crystals, still evident in the rocks today. Since then the slow process of erosion has exposed the granite to aeons of ongoing weather events.Weathered granite boulders

In the fresh rock surfaces, four mineral constituents can be plainly seen. Clear grains of quartz sparkle in the sun light, while pink and white feldspar crystals and black flakes of mica are sprinkled through the rocks like salt and pepper seasoning. As erosion slowly removes the great weight of rock above the land’s surface, stresses are released. These allow the granite to crack along fractures, particularly those located along major sheet joints, parallel to the surface. This action isolates large sheets of rock of varying thicknesses. As weathering and decomposition proceeds, this process eventually sculptures the sheets into rounded boulders or ‘tors.’

Tors: Rounded Granite boulders

Near Pozieres lies a tumble of these massive tors known as Donnelly’s Castle. Granite Boulders form a castlePiled helter-skelter into outlooks, caves and twisting corridors, this natural fortress sheltered Captain Thunderbolt, his outlaw gang and their horses for many years. The escaped convict freely roamed the New England Tablelands in the 1860s, evading capture through his prowess as a horseman and his intimate knowledge of the terrain. As we explore the rocky outcrop, we imagine him hiding in the caves or fleeing through a maze of passages.

The pristine beauty of this place with its stark shapes and forms will always remain a popular Australian destination. Here a visitor can marvel at the variety of nature’s distinct handiwork by experiencing the power and size of these magnificent bones of the earth.
Hiker stands by huge round boulder

Click Here to visit Mary Mageau’s blog: Nature as Art and Inspiration

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