Devils Marbles Conservation Reserve - NT

The Devils Marbles are a collection of gigantic rounded granite boulders, many of which are precariously balanced on top of one another. Scattered heaps of these 'marbles' occur across a wide, shallow valley.
The original granite masses from which the 'marbles' were fashioned had three main sets of joint planes at right angles to one another, breaking each mass into rectangular blocks three by seven metres square. Erosion along the joints and the flaking away of thin slabs from the surface over millions of years, has gradually rounded the corners to the extent that most blocks are now egg-shaped or spherical.
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