ichnite – Georneys

An incredible collection of dinosaur trackways on display at the Queensland Museum in Brisbane. Part of the display (toward the front of the picture) is real rock and part is a replica (toward the back).

This week I’m sharing a few pictures of an incredible display at the Queensland Museum of a dinosaur stampede – the only known record of a dinosaur stampede. The display shows an area in Queensland, Australia, where there are thousands of dinosaur footprints (more than 3,000) of more than 130 different dinosaurs, all in an area about the size of a tennis court! Recently, there has been some debate about whether or not the footprints actually represent a stampede, but regardless there is a very high density of dinosaur footprints at the site.

The dinosaur footprints – or trackways – were discovered in the 1970s in western Queensland near the town of Winton. Today, you can visit the trackways at a place called Dinosaur Stampede National Monument. In the museum in Brisbane, there is a small section of the actual trackways that was brought to the museum in the 1970s. The rest of the display is a replica.

I hope that I have a chance to visit the monument in person at some point – until then, the museum display is pretty neat to see!

A closer view of the real section of rock.

An informational sign about the trackways display. Click to enlarge.

Fossil dinosaur footprint, Wyoming, Fall 2005.

def. Ichnite:
A fossilized footprint.

An ichnite is a type of trace fossil, which is a fossil that preserves evidence of biological activity but which is not part of an organism’s body. Examples of trace fossils are footprints (ichnites), burrows, and root cavities. Coprolites and other fossilized bodily excretions are also often considered trace fossils.

Footprints are everywhere. Just today, I went for a walk along a Cape Cod beach and there were footprints all over the beach. Footprints are rarely preserved as fossils, but when they are preserved the resulting ichnites can be spectacular. What kid- or grown-up- doesn’t find dinosaur footprints fascinating? Dinosaur (and other) ichnites are also very important for learning about how ancient animals moved.

Footprints on a Cape Cod beach, December 2010.

More footprints on a Cape Cod beach, December 2010.

During my undergraduate field camp, we did an exercise where we had to figure out how quickly various dinosaurs moved based on fossilized footprint trails. Using the size of the footprint and the distance between the footprints, you can estimate approximate dinosaur speeds. In field camp we did this for various tracks in Wyoming and Utah. Then, we ran as fast as we could and calculated our own speeds to see if any of us could outrun certain carnivorous dinosaurs. In most cases, we were slower than dinosaurs and would be a likely lunch for any dinosaurs brought back to life Jurassic Park style. Below are a few pictures I took during my undergraduate field camp of some dinosaur ichnites.The footprint fossils are a little difficult to make out from a distance, so we marked them with brightly-colored poker chips.

Fossilized dinosaur footprints, Wyoming, Fall 2005.

I have to say, though, that my favorite type of ichnite is the preserved footprints of ancient man, such as the famous Laetoli footprints in Tanzania. The Laetoli footprints (see pictures below) are 3.6 million years old and were made when Austrolopithecus afarensis walked through volcanic ash. Notice that there are actually two sets of footprints- one smaller, one larger- of two Austrolopithecus afarensis walking side-by-side, perhaps a mother and child or a man and a woman. These footprints show that very early man walked in a very similar way to modern man… even 3.6 million years ago!