Geoscience Reference
In-Depth Information
one, a sauropod had made a “narrow gauge” diagonal-walking trackway, and one
where its rear feet stepped directly on top of its front footprints. In other places,
though, tracks were paired and closely spaced, either offset or overlapping. These
were front- and rear-foot impressions, with the offset ones reflecting an understep
(slow walking) pace. We could even see some of the sauropod tracks in vertical
sections of the coastal outcrops. The normally near-horizontal layering of the sand-
stones had been distorted and contorted, showing where massive dinosaur feet had
deeply compressed soft sandy layers about 130 million years before we were there.
Sprinkled between the sauropod-made pits on the marine platform were three-toed
theropod tracks. These seemed minute in comparison to the sauropod footprints,
but were still 30 to 40 cm (12-16 in) long, indicating theropods with hip heights of
about 1.4 to 1.6 m (4.6-5.2 ft)—big enough to stare us in our faces had they come
back to life just then.
It was May 2009, and Ruth and I were on vacation in Broome, Western Aus-
tralia. We had just finished a week of field work in Victoria, and to celebrate we
were fulfilling one of the items on our Australian checklist, which was to visit
Broome. Although it's a long way from anywhere else, friends told us that it was a
lovely place to visit, with a gorgeous beach, art galleries, cultural tours, and some
quirky, unconventional touristy attractions such as an open-air theater and camel
rides on the aforementioned beach. What about the dinosaur tracks? Well, okay, as
a card-carrying ichno-nerd, I have to admit these factored into our decision, espe-
cially once I learned the dinosaur tracks at Broome were only a few kilometers out-
side town and publicly accessible at low tide.
Ifirstheardaboutthesetracksatascientificmeeting,thefirstInternationalPa-
laeontological Congress, which was held in Sydney in 2002. At this meeting, Tony
Thulborn—introduced previously as one of the original paleontologists to study the
LarkQuarrytracksite—gaveatalksimplytitled“GiantTracksintheBroomeSand-
stone (Lower Cretaceous) of Western Australia.” The audience of 25 to 30 pale-
ontologists attending his presentation was in for a treat. Along with some of the
