Falling rain picks up atmospheric carbon dioxide, forming carbonic acid. On passing through the soil, more carbon dioxide, from plant roots and decaying vegetable matter, becomes dissolved in the water, along with complex organic acids called humic acids. This slightly acidic water dissolves the limestone rock (calcium carbonate), forming cavities and tubes, which can enlarge and join up to make interconnected chambers known as caves.
The calcium carbonate solution slowly descends through the porous saturated rock and emerges into open cave. The calcium carbonate solution dries and deposits the dissolved calcium carbonate. This is known as precipitation. The product of precipitation is the myriad of cave decorations including Dripstones, Flowstone, Pore Deposits and Pool Deposits.
At the listed coordinates you are looking into Gouldens Waterhole. You can see the features of the waterhole from the car park. You can also visit the jetty at water level. At the viewing locations you can see a dramatic show of solution tubes and precipitated calcium carbonate.
Please observe the condition of the north wall of the water hole and answer the following questions. Send your answers to the cache owner for review.
- Immediately underneath the ground level is an extensive layer of solution tubes. Estimate the largest diameter of the tubes? Are any of the tubes vertical?
- Nearer to the water lever is a layer of coarse precipitate. Estimate the thickness of the precipitated layer? Are there any solution tubes in the precipitated layer?