The power of water does weird and wonderful things to the southern coast of Tasmania. Strong winds from the southwest create pounding waves that attack the rockface and erode the coastline. In addition to the Tesselated Pavement, three other sites on the Tasman Peninsula illustrate the remarkable power of water: The Blowhole, Tasman Arch, and Devils Kitchen.
Before looking at The Blowhole, here’s a primer on how water forms caves. Imagine the sea as it crashes against the base of cliffs. The waves carry sand and rock debris, which act like a big horizontal piece of sandpaper, cutting a notch into the vertical rockface until a crack or joint is reached. Compressed water and air wedge in the crack, forcing the rock apart. Continued erosion makes a cave longer and wider.
The Blowhole was a sea cave and tunnel until the roof at the back of the tunnel collapsed. The result was a broad arch with a blowhole behind it.
Before looking at The Blowhole, here’s a primer on how water forms caves. Imagine the sea as it crashes against the base of cliffs. The waves carry sand and rock debris, which act like a big horizontal piece of sandpaper, cutting a notch into the vertical rockface until a crack or joint is reached. Compressed water and air wedge in the crack, forcing the rock apart. Continued erosion makes a cave longer and wider.
The Blowhole was a sea cave and tunnel until the roof at the back of the tunnel collapsed. The result was a broad arch with a blowhole behind it.
It may not look like much at low tide in the photo above; The Blowhole is far more impressive on a stormy day.
The second formation, Tasman Arch, was once a large sea cave like The Blowhole. Wave action over thousands of years made the cave wider and longer until most of the roof collapsed.
The second formation, Tasman Arch, was once a large sea cave like The Blowhole. Wave action over thousands of years made the cave wider and longer until most of the roof collapsed.
Eventually, the water will cause the rest of the arch to collapse as well so that it looks more like the next formation.
Devils Kitchen was likely a sea cave and then a tunnel. The waves over many thousands of years have eroded the rock, causing the roof to completely collapse. The water follows its inexorable path, cracking joints to create new caves in the rockface.
Devils Kitchen was likely a sea cave and then a tunnel. The waves over many thousands of years have eroded the rock, causing the roof to completely collapse. The water follows its inexorable path, cracking joints to create new caves in the rockface.
These three formations are remarkable examples of what the power of water can do.
“Water is patient, Adelaide. Water just waits. Wears down the cliff tops, the mountains. The whole of the world. Water always wins.”
- From “The Waters of Mars,” Doctor Who
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