A series of prehistoric dinosaur footprints have been discovered in a quarry in Dorset.
The footprints are those of a group of giant Sauropods from the early Cretaceous period, which once roamed close to the village of Worth Matravers above Swanage on the Isle of Purbeck (Dorset).
These giant dinosaurs walked in shallow water in a tidal lagoon and moved as a group, leaving a series of parallel trackways.
The tracks were “giant saucer-shaped depressions just a few millimetres deep,” according to Bournemouth University geologist Professor Matthew Bennett, a fossil footprint expert called in to examine the tracks found recently at Lewis Quarries.
The footprints were made between 139 and 145 million years ago and are infilled by lime rich muds. The footprints were revealed when the quarry surface was lowered to extract valuable Purbeck Stone, used in building work and housing.
David Moodie from Lewis Quarries said, “It became apparent that we had come across something of historical interest, so working closely with the National Trust and Professor Matthew Bennett of Bournemouth University, we were able to move forward in the best way without stopping progress in the quarry itself.”
National Trust Lead Ranger Jonathan Kershaw said, “The group of dinosaurs that made these tracks may be the same ones whose footprints can still be seen in situ just nearby at Keates Quarry just off the Priest’s Way bridleway.
“It’s exciting to think that giant sauropods once roamed where today there are dry stone walls, skylarks and nesting seabirds.”
Using a process of photogrammetry and special freeware developed at Bournemouth University called DigTrace, Professor Bennett carefully documented the tracks in 3D.
DigTrace was developed with government funding and help from the Home Office and National Crime Agency and is a great example of the pioneering research being done at BU.
“This technology is now being used by the police to help track criminals via their footprints, but we can also use it to record and preserve rare footprints like these,” said Professor Bennett.
“The beauty of capturing the tracks in 3D is that they can be analysed digitally and even printed in the future, no need to hold up the quarrying for long."
In conjunction with the National Trust, Lewis Quarries and Professor Bennett, a conservation plan was drawn up and the tracks that could be removed were lifted carefully and will be put on display in the near future. The ones that could not be preserved were captured in 3D before they were removed and this data will be made available to the public once processed.
The tracked surface is also exposed in nearby Keates Quarry where the National Trust maintains a small conservation area of similar tracks. The general public can see similar tracks there; nothing is preserved now at Lewis Quarries.
“What is remarkable,” says Professor Bennett “is that the tracks at both adjacent quarries were probably made by the same animals moving along the coast.
"The dip of the beds, folded when the European Alps were pushed up, means that the tracks are closer to the ground in Keates Quarry and can be preserved but are much deeper at Lewis Quarries where in situ preservation is not possible.”