Saturday, June 19, 2010

In the footsteps of dinosaurs

I had read that when the tide is very low, it is possible to find dinosaur footprints below the cliffs at Gantheaume Point near Broome.

A full moon made us check the tide tables. The lowest tide would be the next morning at around 8:30, so we decided to get up early to make our way along the exposed rocks below the cliffs.

IMG_8824The tide was still going out when we drove our “chubby camper” onto the beach at 6:15, so I brewed up some coffee and we watched a steady stream of vehicles drive out onto the hard sand to fish, put in boats and enjoy the cool morning.

We seemed to be the only ones interested in leaving the sand, and before long were exploring the eroded sandstone tidal pools on the way out to the point. By carefully lifting rocks in the pools, we found crabs, shellfish, and even two small octopus.

IMG_8826The cliffs at the point are made up of thick layers of coloured sandstone, and it was tempting to pack out some of the smooth stones. When we saw a number of people up on the cliff behind a barrier, we thought we must be close, so ventured out onto the flat rocks just exposed under the gentle swells.

I stepped out onto the outermost slab and looked down. There, beside my foot was the unmistakeable impression of a three-toed footprint! As we looked more closely, several other footprints became obvious. Within moments, several other people joined us, having clambered down the broken rocks after seeing our excitement.

Fossilized dinosaur footprints. One is at Eric's right toe; another in the upper left.

According to the information panels on top of the cliff, the tracks we’d seen were from a theropod dinosaur, a 2 metre high and perhaps 10 metre long creature designated Megalosauropus broomensis. During the Early Cretaceous period, about 115 million years ago, the dinosaur had walked through mud, leaving these prints behind. The tracks were subsequently covered by sand or softer mud, and gradually formed into rock. The softer layer was eroded, leaving the tracks under my feet.