The Devil’s Marbles are a collection of red, rounded granite boulders scattered across a wide, shallow valley in the middle of the Australian outback. As if by magic these giant rocks are balanced on top of each other and rise above the desert.
The “marbles” have a deep spiritual meaning for the Aboriginal culture and are originally called Karlu Karlu or Karlwekarlwe which means “round boulders“. Many ancient legends are told about the formation of these rocks but what is the geological story behind them?
It all started with cooling of molten rock which led to the formation of a huge granite block that lies beneath a layer of sandstone. Over time vertical and horizontal fractures began to form and split the granite into many rectangular blocks. Tectonic forces caused the whole area to rise closer to the surface where the blocks became exposed to water and wind. Under the influence of erosion the “marbles” started to receive their round shape. In addition, the extreme temperature differences between day and night in the desert caused the rocks to expand and contract constantly which results in thin layers coming off the boulders (exfoliation) or can even split a rock in half.
Some parts of the reserve still hint at the original rectangular shapes whereas others are totally rounded and precariously balanced on top of one another. They range from a few centimeters up to six meters and offer a variety of habitats for flora and fauna.
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