The Kangaroo Rock Hole is a gnamma hole on Beringbooding Rock. A granite outcrop in WA’s wheatbelt. Beringbooding Rock has the largest rock water catchment tank in Australia. It was built in 1937 and when it was built held two and a quarter million gallons of water. “Sustenance Labour” was used to build the tank at a cost of 10,000 pounds. Beringbooding has an amazing balancing boulder, the huge gnamma hole “Kangaroo Rock Hole” and some of the Kalamaia Tribes paintings of hands in a cave at the rear of the rock.
A gnamma is a hole in a granite outcrop which acts like a natural water tank, holding water that is replenished from stores in underground decomposed rock and run-off. These cavities can be bowl-or funnel-shaped and can vary in depth up to 3 metres. These natural cavities are commonly found in hard rock, particularly granite outcrops. Gnamma holes vary in shape and depth, and the small surface area of the hole helps to minimise evaporation. Many granite rocks in Western Australia’s wheatbelt contain gnammas, and these vary widely in depth and width.
Such water reservoirs would have been greatly valued by the original Aboriginal inhabitants of this region.
You can immediately log the find and if there are any problems I will contact you.
1.How wide across do you estimate the water in the rock hole at the time of your visit?
2. What processes would have contributed to the formation of this gnamma?