Photogrammetry: Two dinosaur footprints from The Isle of Wight

The Isle of Wight, which lies off the south coast of England, has long been a good spot to find dinosaur footprints and other traces of ancient life. The rocks of the Wessex and Vectis Formations, part of the Lower Cretaceous of the Wealden of southern England, contain numerous examples of trace fossils of many kinds, from dinosaur footprints and invertebrate traces to palaeoenvironmental indicators such as ripples and mud cracks.

At least two distinct palaeoenvironments are represented in these formations. The Wessex Formation is interpreted as representing a braided river system complete with crevasse splay sandstones, ephemeral ponds and lakeside margins, all containing trace fossils (Naish and Martill, 2001). The deposits of the Vectis Formation were laid down in a coastal lagoonal environment and contain facies interpreted as mudflats and storm coquinas, both of which also preserve traces of ancient life (Radley and Barker, 2000).

On my last visit to the island I took the opportunity of recording some of these footprints using photogrammetry, and here are a couple of the meshes I was able to create. These are both from the trackway at Hanover Point, and are well-known; perhaps too well known as one print has been removed with a rock saw, and a second was in the process of being removed when the it finally dawned on the not-so-smart thieves that the rock was way too unstable to make the operation worthwhile, but not before one footprint was lost forever.

Figure 1: 3D mesh of tridactyl footprint from the Wessex Formation
of the Isle of Wight, UK.

Figure 1 shows the footprint that was in the process of being removed. This is the best preserved of the remaining prints. It's a tridactyl pes print, and has a distinct claw-mark on the leftmost digit.

Figure 2: 3D mesh of a second footprint from the same trackway as the footnoting illustrated
in figure 1.

The second print is much less well-defined and demonstrates how much variation is possible in footprint morphology within a single trackway.  The left most digit has one clearly defined node, the rest of the print indistinct; this might indicate the substrate might have variable texture and/or consistency, or the footprint was subject to alteration after being made. The line running throughout the print is a natural fault.

This trackway is well worth seeking out if you're visiting the island, although you'll need a low tide and some time to find them out on the rocks. Professionally guided tours are available from Dinosaur Isle. Please note it is illegal to remove or attempt to remove any footprint found on the south-east coast of the Island.

References:

Martill, D. and Naish, D (Eds). 2001. Dinosaurs of the Isle of Wight, 319pp. The Palaeontological Association, London.

Radley, J. and Barker, M. Paleoenvironmental significance of storm conquinas in a Lower Cretaceous lagoonal succession (Vectis Formation, Isle of Wight, England). 2000. Geological Magazine, 137. pp193-205. Cambridge University Press.