|
The creation of Girraween's numerous rounded boulders begins underground, when the acidic groundwater seeps into the joints within the buried granite sheets and along minute fractures between - and even within - the mineral crystals that make up the rock itself. At the edges and corners of the blocks, the acidic water has more surface area to attack, thus the weathering is more pronounced and the blocks slowly become rounded in shape. The clay and sand in the joints and smaller cracks are washed away, as are the other surrounding materials, eventually exposing the rounded boulders to the sun and sky.
|
This granite sheet is well into the process of breaking up into boulders.
|
|
|
The remnant boulders of this sheet have weathered more. The boulders are more rounded in shape and there are large spaces between them.
|
|
|
Only a few stray rounded boulders are evidence of an ancient sheet that once covered this area.
|
|
|
There are rounded boulders everywhere in Girraween. Some are large, others are small, and there is an amazing variety of shapes.
Next...
Balancing Rocks.
|
