A fascinating morning on yet another beach with Dianne Bennett. Di is a dinosaurologist and local treasure who leads tours to see the famous dinosaur tracks of the Broome sandstone. It’s not a boat tour, no champagne and lobster just a walk on the rocks, a wealth of knowledge, enthusiasm and all at a very reasonable price.
The Broome Sandstone dates to 130 million years ago give or take a few million. It slowly built up in layers. Sometimes conditions were suitable for preservation of footprints, sometimes not. Tracks are found at several levels. Di showed us two very different sets of tracks belonging to Sauropods and Theropods.
Dinosaurs come in two big flavours Ornithiscians and Saurischians. The Ornithiscian pelvis resembles that of birds, the Saurischian pelvis that of lizards. The general consensus is that birds are living dinosaurs descended not from the Ornithischia but from the lizard-hipped Saurischia. Each of these main divisions are further divided. The tracks we saw were from Sauropods and Theropods which are both Saurischians.
The Sauropods were long-necked, long-tailed, small headed herbivores. Not all Sauropods were immense, some were only 5 or 6 metres long but the largest animal to ever walk the earth was a Sauropod around 30 metres long and weighing something in the order of 70 tonnes..
I have no idea how accurate this depiction is except that the feet fit what we found to a tee. The back foot is bigger than the front foot and comes up close to it at every stride …
and here it is heading from right to left across what was a mud flat and it was way bigger than a modern elephant.
Once the search pattern was established Sauropod footprints were all around us. Theropod footprints are smaller and were not impressed so deeply in the mud. Di pointed out the first then they too became easier to find.
Theropods walked on their hind legs. Diets were varied, herbivory, insectivory and carnivory were all represented. T. rex was a carnivorous Theropod but never visited Broome. Here is a Herrerasaurus to represent the group.
Three toes facing forward, a hind claw that may not have reached the ground or make a big impression if it did …
The local aboriginal people have stories about Marala, the Emu-Man. This print is considerably bigger than an emu’s and your average emu doesn’t leave prints in solid rock. It’s easy to see why they were impressed.
Sadly the Broome sandstone doesn’t seem to have preserved any body parts. We have no dinosaur skeletons to put in the museum. But we can follow in the footsteps of immense creatures that preceded us by 130 million years and raise our gaze to the Reef Egrets, Kites and Gulls – living Theropods.
We made contact with Dianne Bennett through Broome Visitor Centre. You can also find her on Facebook or ring her on 0457 681 265.
bobmcgee 