140-million-year-old dinosaur tracks discovered in Western Cape a 'historic moment'

Helm and his colleagues have documented more than 370 vertebrate tracksites along South Africa’s southern coast, but these newly uncovered dinosaur footprints are particularly remarkable for their age and the unique geological context in which they were found.

Helm and his team say in the article...

Ichnology is the study of tracks and traces and, since 2008, the Cape South Coast Ichnology Project has documented more than 370 vertebrate track sites on South Africa’s southern coast.

These sites are from the Pleistocene Epoch, which stretched from approximately 2.6 million years ago to 11,700 years ago, much more recent than the Mesozoic.

Helm says the team knew this coastline contained Mesozoic sedimentary rocks, some of which include non-marine sediments that could potentially preserve dinosaur tracks.

They are familiar with dinosaur tracks from research in Canada, so they decided to investigate the possibility of tracks in South Africa’s Western Cape.

Helm says the team found some dinosaur tracks – and, once the team knew what to look for, it was evident that the tracks were not rare.

In a new paper published in the journal Ichnos, we describe our findings in detail, presenting evidence of tracks of sauropods (enormous plant-eating dinosaurs) and possibly ornithopods (another group of large herbivorous dinosaurs).

The tracks were found in a rugged, remote, breathtakingly spectacular coastal setting.

They were made by dinosaurs in a variety of estuarine settings.

Some were walking on sandy, inter-tidal channel bars. Others walked on the bottom of tidal channels, their feet sinking down into soft mud forming the bed of the channel.

Other vague “squishy” structures were formed by dinosaurs wading or even wallowing in the muddy fill of abandoned channels.

These tracks are around 140 million years old, from the very beginning of the Cretaceous period when the African and South American tectonic plates were starting to pull apart.

Southern Africa has an extensive record of Mesozoic vertebrate fossils, but that record ends around 180 million years ago in the Early Jurassic with the eruption of voluminous lava flows.

All the southern African dinosaur tracks known until now are from the Triassic and Jurassic periods, so they pre-date these eruptions.

That means, these tracks are not only the first from the Western Cape – they appear to be the youngest – that is, the most recent by 42 million years – thus far reported from southern Africa.