On a recent trip to Tasmania, on Eaglehawk Neck, at the northern end of Pirate’s Bay Beach, I couldn’t believe my eyes. Looking down, it was as if some ambitious giant had decided to lay a walkway of rectangular tiles between the beach and the water. This phenomenon is called the Tessellated Pavement. Although this extremely rare geological formation appears to be manmade, it’s in fact created by erosion.
The erosion causes what are called “pans” and “loaves.” The pans occur on the shore, where high tides leave salt behind on the rockface. The rock at low tides dries out for longer before being immersed again. Salt crystals develop, which erode the rock surface more quickly than the joints, resulting in concave depressions.
In contrast, the rock surface closest to the water is wet much of the time. Salt crystals don’t have an opportunity to develop. Erosion results from the sand carried in the water, which tends to flow through channels in the rock. The edges of the rock erode faster than the surface. The results are formations that look like loaves of rising bread.
The depressions in the rockface create tidal pools, a haven for many kinds of sea life, and birds are attracted to the plentiful pickings.
This type of geological wonder is found in only a few places in the world, so I feel fortunate to have seen it.
Rose Ciccarelli is an American writer and editor living in Canberra, Australia.